How desalination plants contribute to global warming and solutions to address them?

How desalination plants contribute to global warming and solutions to address them? I posted the following article in my blog www.clean-energy-water-tech.com in 2014. We are now addressing this problem by setting one the largest integrated membrane-based sea water desalination plants in India using renewable power without using oil and gas. Highly contaminated and concentrated effluent discharge from existing and operating desalination plants around the world have greatly contributed to global warming according to world’s leading research institutions in marine science and oceanography. https://www.clean-energy-water-tech.com/2014/02/desalination-plants-contribute-to.html The ocean’s circulation which acts as conveyor belt distributes the increasing salinity and temperature of the sea across the globe. Several companies are researching on solutions to address the above problem and to achieve a Zero Liquid Discharge (ZLD) concept. Concepts such as FO (forward osmosis), OARO (osmosis assisted RO), NF pre-treatment with EDR, recovery of minerals such as Potassium chloride, Magnesium chloride (a precursor for extraction of Magnesium metal), Lithium chloride, Bromine etc. Theoretically all these solutions are encouraging but when to come to practise there are several hurdles to get over. Currently the most popular SWRO process is to recover 40% fresh water from seawater and discharge the balance 60% with twice its salinity and contaminated chemical are discharged in the sea. Such practice is going on since sixties when RO membranes were introduced. SWRO is an energy intensive process along with thermal evaporation they contribute to a great amount of green house gases. Despite several improvements in energy conservation in membrane processes the emissions of GHG was never addressed till date. Meanwhile several large-scale desalination plants are planned and implemented to overcome severe shortage of fresh water especially in African countries and pacific island and many arid regions of the world. We in CEWT are introducing CAPZ (clean water at affordable price with zero discharge) desalination a proprietary technology that not only achieve the highest recovery of fresh water from sea water but also generates simultaneously a highly value added ultrapure saturated Sodium chloride brine that serves as feed stock for chloralkaline industries substituting ‘solar evaporated salt’ as a source of Sodium. The pure saturated Sodium chloride brine is the feedstock to produce Caustic soda using membrane electrolysis as well as to produce Soda ash using Solvay process. Modern chloralkaline plants are very large in scales of operation which requires large quantities of solar salts. Due to climate change and unseasonal monsoon rains that have severely affected the solar salt production world-wide leaving a large gap between demand and supply. It has sharply increased the price of solar salt in the international market. Bulk of the solar salt is also used in ‘de-icing’ road due to severe snow in the industrialised countries. CAPZ desalination can recover up to 72% fresh water as well as 4.70% saturated sodium chloride brine simultaneously. Directly from seawater. Our current proposed plant in India will produce about 10,000 Mt of saturated Sodium chloride brine per day or 3150 Mt/day of high-quality salt along with 80,000 m3/day of fresh water from a seawater intake of 182,000 m3/day achieving zero liquid discharge (ZLD). We can also retrofit OARO system in our process to further increase water and salt production making it the most effective and economical and environmentally desalination technology in the world!

New realities of decarbonizing fossil economy and the science of climate change

Global warming and climate change are the topics of the day and doomsday predictions are abounding. In a divided world of differing ideologies and dogmas, emotions play a major role and all conclusions are drawn out of such emotions. Emotional intelligence is the key and in-depth analysis will clear the clouds of doubts and disbeliefs and not just raw emotions.

 When quantum science emerged as a mainstream science substituting classical science the world changed dramatically often leading to spirituality or eastern philosophy of ancient India. When Albert Einstein said, “I hope the moon is still there when I am not looking at it”, it had huge implications and a few decades later quantum science confirmed that Einstein was wrong. In other words, it is the conscience that creates the reality. With  this is the reality of science  one may wonder whether “reality” has anything to do with “science” at all. Albert Einstein in his own words said, “As far as the laws of mathematics refer to reality, they are not certain; as far as they are certain they do not refer to reality”.

Let us examine about the science of global warming due to man-made GHG emissions resulting in climate change. Electricity was a new form of energy discovered in eighteenth century and it became part of human civilization ever since. But it was already existed in nature in the form of lightning, but we were unable to recognize it or reproduce it in the scale that can be useful to us. Then the question is whether electricity was discovered by human beings at all and if so, can we reproduce “lightning?” and use this electricity without emitting any carbon emission at all. The answer is no, at least for now due lack of technology to predict lightning, tapping it economically and storing it for distribution. Theoretically lightning alone can supply all the electricity world needs but practically it is almost impossible to utilize it for the above reasons. When electromagnetism and electricity were discovered they did not relate it to “lightning” but claimed as a separate discovery between the relationship between magnetic and electric charges which resulted in generating electricity. Then later we were able to explain “lightning” due to positive and negative charges between the cold clouds and rising hot air with water.

Science is nothing but explaining nature with theoretical concepts and physical demonstrations. That is why yoga sutra describes the world as a phenomenal world and it is an irreducible experimental substance. That is the peculiarity of science because it is the human conscience that creates this scientific reality. I too conclude that “as far as law of science of climate change refers to reality, they are not certain; as far as they are certain they do not refer to reality.” Similarly, science has nothing to do with economics and but we human beings made economics as a measure of one’s life and his or her success. This is the fundamental flaw in human thinking. One can conclude that all man-made theories and practices are fundamentally flawed which is evident from the world of turmoil we are witnessing and living in. We failed to ask emotionally intelligent questions by endless pursuit of happiness through money and materials in the name of science.

As I mentioned in my previous article we developed generating electricity from thermal source and we ended up digging fossil fuels at enormous cost and added further value by combustion with air generating huge amount of CO2.But we never estimated the cost of CO2 at that time and we never realized the future impact of such a CO2 emissions from fossil fuels till now. Even now we do not want to put a price for CO2 emissions and continue to emit by simply denying the fact that such unabated emissions will have consequences. We conveniently use science and economics when it suits us, otherwise we reject them outright when it does not suit us. All climate change denials come from the fear of economic collapse unconsciously.

Therefore, the first step in achieving zero carbon emission is to eliminate fossil fuels completely or impose penalty to discourage emissions if we accept global warming and climate change as the reality. Without taking this first step we cannot move forward. 

Now there is a new awakening that Hydrogen will substitute fossil fuels with zero emissions. This is again a mistake. Imaging all cars and power plants using hydrogen and fuel cell and emit (only) water vapour into the atmosphere. I am sure that will drastically change our climate in a very short span of time. The atmospheric moisture will dramatically increase trapping enormous amount of heat and precipitation. The consequences will be dire. Every kg of Hydrogen will require 9 kgs of water. Renewable Hydrogen is a precious commodity and it can be used only to decarbonize the fossil economy and cannot be used a fuel directly. Such an attempt will be a failure.

Alternatively, we can continue to use fossil fuel as usual but eliminate CO2 emission by simply recycling in the form of RNG (renewable natural gas) using renewable hydrogen. This may look as an expensive proposal at the first instance, but it will become a norm in the long run and we human beings have a capacity to adopt to this new reality.  It is now possible to capture CO2 economically and substantially while generating power using direct Carbon fuel cell with highest electrical efficiency. It can be easily recycled in the form of RNG. Why Governments don’t act?

In the absence of above alternative, we may have to face the consequences of climate change due to man-made emissions and simply be content with an American slogan, “In God we trust”.

References:

1.http://dx.doi.org/10.1016/j.jpowsour.2013.11.122

2. DCFC by Fuelcell energy and Exxon.

Carbon Recycling Technology

CRT Carbon Recycling Technology known as “Ramana Cycle” is a new patented concept and system that addresses current problems faced by energy industries with a single solution Current problems: 1.Renewable energy is only a fraction of total energy generated world-wide. Fossil fuel especially natural gas in the cleanest and most widely accepted fuel for base load power generation. However, it emits CO2 a greenhouse gas causing climate change. 2. Electric and Fuel cell cars can eliminate Carbon emission from our roads, but it will dramatically increase the electricity requirement which cannot be met by renewable energy sources alone. Eventually the electricity demand will have to be met by fossil fuels which will sharply increase CO2 emissions in a short span of time thus exacerbating global warming. 3.Grid connected renewable energy has many problems due to intermittent nature of renewable energy such as synchronicity, electronic interface with HT lines, metering etc. There is at least 22% loss while transmitting renewable energy into the grid creating dispatchability issues. Power is transmitted 24 x 7 on HT lines. Solution: CRT addresses all the above issue with a single solution as described below. CRT synthesizes a synthetic fuel CH4, a Hydrocarbon known as SNG (synthetic natural gas) using Carbon from CO2 emissions of gas based power plants and renewable Hydrogen generated from water using renewable energy sources such as Hydro/solar/wind /biomass/ geothermal etc. Once SNG is generated then it can substitute natural gas currently used in power generation. It means one can generate their own SNG and need not depend on oil and gas industries and use conventional gas turbine and generate base load power and transmit using existing transmission lines. This power can be used by electric as well by Fuel cars. There will be a net Zero Carbon emission.The same system can also supply Hydrogen to Fuel cell cars. CRT can be implemented using existing systems supplied by internationally known companies with proven technologies and systems. There are absolutely no commercial risks whatsoever. These systems can be deployed immediately, and they are commercial ready. Each plant is designed specifically based on the capacity, location and purpose.

Why climate change is irreversible and Science is helpless?

The "intuitive mind" is a sacred gift and the rational mind is a faithful servant.We have created a society that honors the servant and has forgotten the gift" - Albert Einstein. United Nation’s panel on climate change (IPCC) recently confirmed that climate change is real, it is man-made and it is irreversible and if nations do not act now then they will have to face catastrophic climate events in the future. They were categorical and unequivocal in their statements this time. They have come to this conclusion because science has not demonstrated how to capture carbon emission and sequester them under the earth using current technologies. Scientists neglected carbon emissions while generating power using fossil fuels for decades because they had no idea what would be the consequences of such emissions in the future. It is a clear example how a human mind has a limited capacity to conceive an idea “holistically” but has a capacity to satisfy human needs temporarily without knowing the unforeseeable consequences. When human beings interfere with Nature in the name of Science there are consequences to face and a price to pay because Nature is nothing but the manifestation of the highest intelligence. A real science can be no further than asserting this truth. Ignorance when combined with greed can be a deadly combination and the consequences will be costly and to be paid dearly by generations to come. Carbon emission and climate change is one such issue. Science has improved human life on earth in so many ways but at the same time they also have created many side effects which can be identified only after decades of their use. When they are identified it is often too late and causes irreversible damage to system or nature. Any irreversible change human beings cause in Nature will have its own consequences. Science has shown Carbon is the backbone of all organic matter on planet earth whether it is DNA of a human being or a glittering diamond from deep under the earth. The same Carbon reveals the age of a skeleton of a Dinosaur buried millions of years ago. Science is a powerful tool but it also has two sides, benign and malign. The power to discriminate between the good and bad is the fundamental pre-requisite of science. Carbon plays an indispensible role in the natural world due to its unique atomic structure and ease with which it can build molecules especially with hydrogen. That is why hydrocarbon is playing such an important role in human civilization and it is not easy to substitute it with another candidate without a long term research and development work. But we have a very short time to discover a substitute for hydrocarbon which can serve our current purposes. Few nuclear power plants around the world can satisfy the growing demand for the electricity without any carbon emission but their long term consequences are unknown. The result of a thermo-nuclear explosion over Hiroshima and Nagasaki are the grim reminder of such consequences. When earth converts organic matter into a fossil over a period of millions of years deep under the earth, it gives us a clue why Nature has buried them and not left them on the surface of the earth. But that did not deter human beings from digging them out and burning them to generate heat to meet their temporary energy needs without realizing the long term consequences of such actions. Many technologies have become obsolete over a period of time for various reasons but some of them lingered long enough to create long lasting consequences and there are many evidences in history to emphasize this truth. Power generation using fossil fuel is one such clear example of a technological bungle. It only confirms the inadequacy of human knowledge. It also reveals the temporary nature of such inventions stemming from temporary nature of human life. Science also has changed dramatically in the last few decades and it no longer serves the original purpose of unraveling and understanding the mysteries of Nature but caters and serves to the greed and dominance of selected rich and powerful people and the nations in the world. Science has become a tool to create material wealth and power rather than to understand nature and apply them into our lives in a compatible way and to enrich human life. These experiences have taught one important lesson. Any scientific discovery when applied in real life must be “holistic” and be compatible with Nature and should follow Natural laws. When science becomes a wealth creating tool then any knowledge born out of such science can only serve to create wealth often at the cost of Nature. That is why rich and powerful corporate and nations spend billions of dollars in such wealth creating discoveries rather than on discoveries that address human problems of the world that may not return their investment in time. The anomaly is more they invest on wealth creating science more damage they cause to earth and human life. Such discoveries serve only one purpose namely “the wealth creation “. Wealth and power has overtaken science and knowledge. Climate change has become a serious issue and it is absolutely clear that CO2 in the atmosphere has increased to the current level for the first time in millions of years and human beings have contributed greatly to this increase. Yet, nations around the world are unable to come to-gather and agree on how to reduce such emissions. The only way to solve this issue is to use Science as a tool which created this problem in the first place. When steam engine was invented it was considered as the dawn of industrial revolution: when electricity generation using electro-magnetism was invented it was hailed as a land mark in scientific development. When power was generated using fossil fuel to accelerate the industrial growth very little attention was paid to the carbon emission. When huge quantities of sea water was used to cool the cooling towers in fossil fuel powered or nuclear power plants very little attention was paid to the discharge of effluent in to the sea. When large desalination plants were set up to quench the thirst of oil rich countries very little attention was paid to the toxic discharge of effluent in to the sea. What was missing in all the above developments was the negligence of Nature by discharge of emissions or effluents into the Natural world. We have taken Nature for granted and treated her with great indignity and contempt. Few decades ago Scientists were able to make remarkable discoveries using only their mind as a tool and theorizing certain concepts. They were abstract in nature but were validated whenever applied in practice. There were no big investments by Governments or companies on scientific discoveries, no Intellectual property portfolios, no personal ownership, no disputes on infringement as to who owns and what. Today scientific inventions and intellectual properties are the biggest assets and monopolies of few corporate and nations. Several hundred billions are spent on patents, trademarks and copy rights to stamp their authorities and ownerships. But where such knowledge came from? Who pays for the consequences of ill -conceived scientific discoveries that prove disastrous in the long run? Who can sue them when such technologies are passed on to several generations without knowing their long term consequences? Science is now suggesting methods to address carbon emission using various renewable energy sources such as solar, wind, biomass etc. But these methods often use capital intensive equipments to use such energy even though Nature provides them free of cost. Such equipments also require large energy input to produce which again comes from fossil fuel maintaining the level of CO2 in the atmosphere. The investment on renewable energy has come down by nearly 70% according to latest news and many countries are gearing up to step up their fossil fuel production in the name of “energy security” simply because they have become “addicted “to old ways of living. In fact there is too much at stake for these countries and they are stubbornly sticking to old ideas. Science has become useless in addressing climate change because it is no longer about science but about nation’s security and maintaining material wealth of the citizens of a particular nation and the popularity of politicians among the ignorant masses and winning their elections and holding to their power. Sun is the only source of energy on the planet earth and all other forms of energy such as wind and biomass etc are only by-products of sun. Current power generating technologies heavily depends of conversion of thermal energy into electrical energy and the source of thermal energy is by fossil fuel or nuclear. Recently light energy from sun is converted directly into electrical energy using photovoltaics. They also use thermal energy of the sun using solar concentrators to generate power in conventional way using turbines. But high initial cost, lack of energy storage technologies and intermittent nature of renewable sources increases the cost of energy compared to conventional coal fired power and alternative energy has created an uncertainty in the power industry. Energy industry is now at the cross road and it has divided people into two categories; one group accepts science of global warming and climate change and advocate substituting fossil fuel with carbon free energy sources and another group express skepticism over climate science and support fossil fuel energy sources in order to continue and maintain the industrial growth and employment. If countries like US and Australia who have rich deposits of high grade coal and depend heavily on coal based power plants and industries then they have an option to increase the efficiency of coal utilization by way of emission reduction. For example they can reduce carbon emission substantially using gasification technologies. In fact, under certain special conditions it is possible to generate syngas from coal with highest Hydrogen content (even up to CO: H2 ratio of 20:80).This will increase not only the calorific value of syngas but also reduce carbon emission. Companies like GE, USA are developing special gas turbines for syngas with high hydrogen content. Alternatively conversion of coal into synthetic natural gas (SNG) can reduce the carbon emission without dispensing with coal completely. Renewable hydrogen is a potential long term substitute for fossil fuel both for power industry and transportation. But it requires special handling due to its high explosive nature and it is often easier to handle it with a mix of hydrocarbon such as Methane or Carbon monoxide. Fuel cell is an emerging technology that can use hydrogen for power generation as well as for transportation. However it requires expensive catalysts and they are currently confined to smaller applications in power industry. Fuel cell opens up a new way to generate electricity by simply stripping electrons from a hydrogen atom with Platinum and allowing the resulting proton exchange by special membranes in a cell converting chemical energy into an electrical energy. It is certainly a breakthrough in power generation but there is a long way to go before commercializing them on larger scale. It seems Carbon will continue to play an important role for years to come due to its unique nature in the natural world. But high carbon intensity fuel such as coal and current methods of direct combustion will have to be abandoned and substituted with SNG or Syn gas with high hydrogen content by gasifying coal. By this way hydrogen can be introduced into the current energy mix without substantial deviation from using coal while maintaining the carbon emission well within the limit. However a long term strategy will require complete substitution of fossil fuel with renewable hydrogen or with completely a new method of electricity generation such as Fuel cell without using a thermal energy. Electricity is nothing but a flow of electrons and techniques that are currently used in Fuel cell such as proton exchange membrane should be developed using low cost catalyst and materials on a much larger scale to substitute fossil fuel completely. It is clear that power generation technology should be delinked with using carbon source or combustion for that matter. Combustion of hydrogen electrochemically is an elegant solution but lot of research and development is required. But the stark reality is climate is already changing and the climate change is irreversible and we have to use science to adopt our lives to the changing climate in the future. We cannot capture the carbon and bury them under the earth as Nature does because Nature has not taught us how to do it in a short span of time. The impact of climate change can be minimized or averted depending upon how fast carbon emission is reduced using new technologies. Climate change is an important lesson from which the scientific community should learn how not to interfere with Nature without a complete understanding of it. Sun shine and clean air are not just for rich and powerful but to the entire humanity on the planet. Any scientific discovery should be “holistic” and compatible with Nature and easily accessible to all human beings. Solar and biomass are emerging as alternative technologies to tackle climate change but these simple and holistic solutions were in fact practiced for decades in rural India. Farmers in India feed their cattle with cellulosic fibers (polysaccharides) as a feed and use their waste in the form of “solar” dried cakes (cow dung cakes) as a fuel that has a calorific value of 2100kj (Wikipedia). They also use the waste to generate Methane by anaerobic digestion. These technologies are not new but the challenge is they should to be built on large commercial scales to meet the demand of the growing population in a holistic way. Industrialized countries are now trying to convert the same cellulose (polysaccharides) into industrial alcohol instead of converting corn starch. When plants grow by photosynthesis using sun, it generates starch, lignin, cellulose as well as fatty acids in oil seeds. It is important to understand that Nature provides them as food for human beings and animals and not as a raw material to generate fuel or energy and that is why “holistic solutions” are the key for the survival of science and technology as well as humanity in the future.

Solar thermal- a cool solution for a warming planet

It is a fact that solar energy is emerging as a key source of future energy as the climate change debate is raging all over the world. The solar radiation can meet world’s energy requirement completely in a benign way and offer a clear alternative to fossil fuels. However the solar technology is still in a growing state with new technologies and solutions emerging. Though PV solar is a proven technology the levelised cost from such plants is still much higher than fossil fuel powered plants. This is because the initial investment of a PV solar plant is much higher compared to fossil fuel based power plants. For example the cost of a gas based power plant can be set up at less than $1000/Kw while the cost of PV solar is still around $ 7000 and above. However solar thermal is emerging as an alternative to PV solar. The basic difference between these two technologies is PV solar converts light energy of the sun directly into electricity and stores in a battery for future usage; solar thermal plants use reflectors (collectors) to focus the solar light to heat a thermic fluid or molten salt to a high temperature. The high temperature thermic fluid or molten salt is used to generate steam to run a steam turbine using Rankine cycle or heat a compressed air to run a gas turbine using Brayton cycle to generate electricity. Solar towers using heliostat and mirrors are predicted to offer the lowest cost of solar energy in the near future as the cost of Heliostats are reduced and molten salts with highest eutectic points are developed. The high eutectic point molten salts are likely to transform a range of industries for high temperature applications. When solar thermal plants with molten salt storage can approach temperature of 800C, many fossil fuel applications can be substituted with solar energy. For example, it is expected by using solar thermal energy 24x7 in Sulfur-Iodine cycle, Hydrogen can be generated on a large commercial scale at a cost @2.90/Kg.Research and developments are focused to achieve the above and it may soon become a commercial reality in the near future. “The innovative aspect of CSP (concentrated solar power) is that it captures and concentrates the sun’s energy to provide the heat required to generate electricity, rather than using fossil fuels or nuclear reactions. Another attribute of CSP plants is that they can be equipped with a heat storage system in order to generate electricity even when the sky is cloudy or after sunset. This significantly increases the CSP capacity factor compared with solar photovoltaics and, more importantly, enables the production of dispatchable electricity, which can facilitate both grid integration and economic competitiveness. CSP technologies therefore benefit from advances in solar concentrator and thermal storage technologies, while other components of the CSP plants are based on rather mature technologies and cannot expect to see rapid cost reductions. CSP technologies are not currently widely deployed. A total of 354 MW of capacity was installed between 1985 and 1991 in California and has been operating commercially since then. After a hiatus in interest between 1990 and 2000, interest in CSP has been growing over the past ten years. A number of new plants have been brought on line since 2006 (Muller- Steinhagen, 2011) as a result of declining investment costs and LCOE, as well as new support policies. Spain is now the largest producer of CSP electricity and there are several very large CSP plants planned or under construction in the United States and North Africa. CSP plants can be broken down into two groups, based on whether the solar collectors concentrate the sun rays along a focal line or on a single focal point (with much higher concentration factors). Line-focusing systems include parabolic trough and linear Fresnel plants and have single-axis tracking systems. Point-focusing systems include solar dish systems and solar tower plants and include two-axis tracking systems to concentrate the power of the sun. Parabolic trough collector technology: The parabolic trough collectors (PTC) consist of solar collectors (mirrors), heat receivers and support structures. The parabolic-shaped mirrors are constructed by forming a sheet of reflective material into a parabolic shape that concentrates incoming sunlight onto a central receiver tube at the focal line of the collector. The arrays of mirrors can be 100 meters (m) long or more, with the curved aperture of 5 m to 6 m. A single-axis tracking mechanism is used to orient both solar collectors and heat receivers toward the sun (A.T. Kearney and ESTELA, 2010). PTC are usually aligned North-South and track the sun as it moves from East to West to maximize the collection of energy. The receiver comprises the absorber tube (usually metal) inside an evacuated glass envelope. The absorber tube is generally a coated stainless steel tube, with a spectrally selective coating that absorbs the solar (short wave) irradiation well, but emits very little infrared (long wave) radiation. This helps to reduce heat loss. Evacuated glass tubes are used because they help to reduce heat losses. A heat transfer fluid (HTF) is circulated through the absorber tubes to collect the solar energy and transfer it to the steam generator or to the heat storage system, if any. Most existing parabolic troughs use synthetic oils as the heat transfer fluid, which are stable up to 400°C. New plants under demonstration use molten salt at 540°C either for heat transfer and/or as the thermal storage medium. High temperature molten salt may considerably improve the thermal storage performance. At the end of 2010, around 1 220 MW of installed CSP capacity used the parabolic trough technology and accounted for virtually all of today’s installed CSP capacity. As a result, parabolic troughs are the CSP technology with the most commercial operating experience (Turchi, et al., 2010). Linear Fresnel collector technology: Linear Fresnel collectors (LFCs) are similar to parabolic trough collectors, but use a series of long flat, or slightly curved, mirrors placed at different angles to concentrate the sunlight on either side of a fixed receiver (located several meters above the primary mirror field). Each line of mirrors is equipped with a single-axis tracking system and is optimized individually to ensure that sunlight is always concentrated on the fixed receiver. The receiver consists of a long, selectively-coated absorber tube. Unlike parabolic trough collectors, the focal line of Fresnel collectors is distorted by astigmatism. This requires a mirror above the tube (a secondary reflector) to refocus the rays missing the tube, or several parallel tubes forming a multi-tube receiver that is wide enough to capture most of the focused sunlight without a secondary reflector. The main advantages of linear Fresnel CSP systems compared to parabolic trough systems are that: LFCs can use cheaper flat glass mirrors, which are a standard mass-produced commodity; LFCs require less steel and concrete, as the metal support structure is lighter. This also makes the assembly process easier. »»The wind loads on LFCs are smaller, resulting in better structural stability, reduced optical losses and less mirror-glass breakage; and. »»The mirror surface per receiver is higher in LFCs than in PTCs, which is important, given that the receiver is the most expensive component in both PTC and in LFCs. These advantages need to be balanced against the fact that the optical efficiency of LFC solar fields (referring to direct solar irradiation on the cumulated mirror aperture) is lower than that of PTC solar fields due to the geometric properties of LFCs. The problem is that the receiver is fixed and in the morning and afternoon cosine losses are high compared to PTC. Despite these drawbacks, the relative simplicity of the LFC system means that it may be cheaper to manufacture and install than PTC CSP plants. However, it remains to be seen if costs per kWh are lower. Additionally, given that LFCs are generally proposed to use direct steam generation, adding thermal energy storage is likely to be more expensive. Solar to Electricity technology: Solar tower technologies use a ground-based field of mirrors to focus direct solar irradiation onto a receiver mounted high on a central tower where the light is captured and converted into heat. The heat drives a thermo-dynamic cycle, in most cases a water-steam cycle, to generate electric power. The solar field consists of a large number of computer-controlled mirrors, called heliostats that track the sun individually in two axes. These mirrors reflect the sunlight onto the central receiver where a fluid is heated up. Solar towers can achieve higher temperatures than parabolic trough and linear Fresnel systems; because more sunlight can be concentrated on a single receiver and the heat losses at that point can be minimized. Current solar towers use water/steam, air or molten salt to transport the heat to the heat-exchanger/steam turbine system. Depending on the receiver design and the working fluid, the upper working temperatures can range from 250°C to perhaps as high 1 000°C for future plants, although temperatures of around 600°C will be the norm with current molten salt designs. The typical size of today’s solar power plants ranges from 10 MW to 50 MW (Emerging Energy Research, 2010). The solar field size required increases with annual electricity generation desired, which leads to a greater distance between the receiver and the outer mirrors of the solar field. This results in increasing optical losses due to atmospheric absorption, unavoidable angular mirror deviation due to imperfections in the mirrors and slight errors in mirror tracking. Solar towers can use synthetic oils or molten salt as the heat transfer fluid and the storage medium for the thermal energy storage. Synthetic oils limit the operating temperature to around 390°C, limiting the efficiency of the steam cycle. Molten salt raises the potential operating temperature to between 550 and 650°C, enough to allow higher efficiency supercritical steam cycles although the higher investment costs for these steam turbines may be a constraint. An alternative is direct steam generation (DSG), which eliminates the need and cost of heat transfer fluids, but this is at an early stage of development and storage concepts for use with DSG still need to be demonstrated and perfected. Solar towers have a number of potential advantages, which mean that they could soon become the preferred CSP technology. The main advantages are that: »»The higher temperatures can potentially allow greater efficiency of the steam cycle and reduce water consumption for cooling the condenser; »»The higher temperature also makes the use of thermal energy storage more attractive in order to achieve schedulable power generation; and »»Higher temperatures will also allow greater temperature differentials in the storage system, reducing costs or allowing greater storage for the same cost. The key advantage is the opportunity to use thermal energy storage to raise capacity factors and allow a flexible generation strategy to maximize the value of the electricity generated, as well as to achieve higher efficiency levels. Given this advantage and others, if costs can be reduced and operating experience gained, solar towers could potentially achieve significant market share in the future, despite PTC systems having dominated the market to date. Solar tower technology is still under demonstration, with 50 MW scale plant in operation, but could in the long-run provide cheaper electricity than trough and dish systems (CSP Today, 2008). However, the lack of commercial experience means that this is by no means certain and deploying solar towers today includes significant technical and financial risks. Sterling dish technology: The Stirling dish system consists of a parabolic dish shaped concentrator (like a satellite dish) that reflects direct solar irradiation onto a receiver at the focal point of the dish. The receiver may be a Stirling engine (dish/ engine systems) or a micro-turbine. Stirling dish systems require the sun to be tracked in two axes, but the high energy concentration onto a single point can yield very high temperatures. Stirling dish systems are yet to be deployed at any scale. Most research is currently focused on using a Stirling engine in combination with a generator unit, located at the focal point of the dish, to transform the thermal power to electricity. There are currently two types of Stirling engines: Kinematic and free piston. Kinematic engines work with hydrogen as a working fluid and have higher efficiencies than free piston engines. Free piston engines work with helium and do not produce friction during operation, which enables a reduction in required maintenance. The main advantages of Stirling dish CSP technologies are that: »»The location of the generator - typically, in the receiver of each dish - helps reduce heat losses and means that the individual dish-generating capacity is small, extremely modular (typical sizes range from 5 to 50 kW) and are suitable for distributed generation; »»Stirling dish technologies are capable of achieving the highest efficiency of all type of CSP systems »»Stirling dishes use dry cooling and do not need large cooling systems or cooling towers, allowing CSP to provide electricity in water-constrained regions; and »»Stirling dishes, given their small foot print and the fact they are self-contained, can be placed on slopes or uneven terrain, unlike PTC, LFC and solar towers. These advantages mean that Stirling dish technologies could meet an economically valuable niche in many regions, even though the levelised cost of electricity is likely to be higher than other CSP technologies. Apart from costs, another challenge is that dish systems cannot easily use storage. Stirling dish systems are still at the demonstration stage and the cost of mass-produced systems remains unclear. With their high degree of scalability and small size, stirling dish systems will be an alternative to solar photovoltaics in arid regions.” (Source : IRENA 2012)

Can Bio-gasification transform our world?

Carbon neutral biomass is becoming a potential alternative energy source for fossil fuels in our Carbon constrained economy. More and more waste –to-energy projects is implemented all over the world due to the availability of biomass on a larger scale; thanks to the increasing population and farming activities. New technological developments are taking place side by side to enhance the quality of Biogas for power generation. Distributed power generation using biogas is an ideal method for rural electrification especially, where grid power is unreliable or unavailable. Countries like India which is predominantly an agricultural country, requires steady power for irrigation as well as domestic power and fuel for her villages. Large quantity of biomass in the form of agriculture waste, animal wastes and domestic effluent from sewage treatment plants are readily available for generation of biogas. However, generation of biogas of specified quality is a critical factor in utilizing such large quantities of biomass. In fact, large quantity of biomass can be sensibly utilized for both power generations as well as for the production of value added chemicals, which are otherwise produced from fossil fuels, by simply integrating suitable technologies and methods depending upon the quantity and quality of biomass available at a specific location. Necessary technology is available to integrate biomass gasification plants with existing coal or oil based power plants as well as with chemical plants such as Methanol and Urea. By such integration, one can gradually change from fossil fuel economy to biofuel economy without incurring very large capital investments and infrastructural changes. For example, a coal or oil fired power plant can be easily integrated with a large scale biomass plant so that our dependency on coal or oil can be gradually eliminated. Generation of biogas using anaerobic digestion is a common method. But this method generates biogas with 60% Methane content only, and it has to be enriched to more than 95% Methane content and free from Sulfur compounds, so that it can substitute piped natural gas with high calorific value or LPG (liquefied petroleum gas). Several methods of biogas purification are available but chemical-free methods such as pressurized water absorption or cryogenic separation or hollow fiber membrane separation are preferred choices. The resulting purified biogas can be stored under pressure in tanks and supplied to each house through underground pipelines for heating and cooking. Small business and commercial establishments can generate their own power from this gas using spark-ignited reciprocating gas engines (lean burnt gas engines) or micro turbines or PAFCs (phosphoric acid fuel cells) and use the waste heat to air-condition their premises using absorption chillers. In tropical countries like India, such method of distributed power generation is absolutely necessary to eliminate blackouts and grid failures. By using this method, the rural population need not depend upon the state owned grid supplies but generate their own power and generate their own gas, and need not depend on the supply of rationed LPG cylinders for cooking. If the volume of Bio-methane gas is large enough, then it can also be liquefied into a liquified bio-methane gas (LBG) similar to LNG and LPG. The volume of bio-methane gas will be reduced by 600 times, on liquefaction. It can be distributed in small cryogenic cylinders and tanks just like a diesel fuel. The rural population can use this liquid bio-methane gas as a fuel for transportation like cars, trucks, buses, and farm equipments like tractors and even scooters and auto-rickshaws. Alternatively, large-scale biomass can be converted into syngas by gasification methods so that resulting biomass can be used as a fuel as well as raw materials to manufacture various chemicals. By gasification methods, the biomass can be converted into a syngas (a mixture of Hydrogen and Carbon monoxide) and free from sulfur and other contaminants. Syngas can be directly used for power generation using engines and gas turbines. Hydrogen rich syngas is a more value added product and serves not only as a fuel for power generation, but also for cooking, heating and cooling. A schematic flow diagram Fig 3, Fig4 and Fig 6 (Ref: Mitsubhisi Heavy Industries Review) shows how gasification of biomass to syngas can compete with existing fossil fuels for various applications such as for power generation, as a raw material for various chemical synthesis and as a fuel for cooking, heating and cooling and finally as a liquid fuel for transportation. Bio-gasification has a potential to transform our fossil fuel dependant world into Carbon-free world and to assist us to mitigate the global warming.

Hydrogen from seawater for Fuelcell

We have used Hydrocarbon as the source of fuel for our power generation and transportation since industrial revolution. It has resulted in increasing level of man-made Carbon into the atmosphere; and according to the scientists, the level of carbon has reached an unsustainable level and any further emission into the atmosphere will bring catastrophic consequences by way of climate change. We have already witnessed many natural disasters in a short of span of time. Though there is no direct link established between carbon level in the atmosphere and the global warming, there is certainly enough evidence towards increase in the frequency of natural disasters and increase in the global and ocean temeperatures.We have also seen that Hydrogen is a potential candidate as a source of future energy that can effectively substitute hydrocarbons such as Naphtha or Gasoline. However, hydrogen generation from water using electrolysis is energy intensive and the source of such energy can come only from a renewable source such as solar and wind. Another issue with electrolysis of water for Hydrogen generation is the quality of water used. The quality of water used for electrolysis is high, meeting ASTM Type I Deionized Water preferred, < 0.1 micro Siemen/cm (> 10 megOhm-cm). A unique desalination technology has been developed by an Australian company to generate onsite Hydrogen directly from seawater. In conventional seawater desalination technology using reverse osmosis process only 30-40% of fresh water is recovered as potable water with TDS less than 500 ppm as per WHO standard. The balance highly saline concentrate with TDS above 65,000 ppm is discharged back into the sea which is detrimental to the ocean’s marine life. More and more sweater desalination plants are set up all over the world to mitigate drinking water shortage. This conventional desalination is not only highly inefficient but also causes enormous damage to the marine environment. The technology developed by the above company will be able to recover almost 75% of fresh water from seawater and also able to convert the concentrate into Caustic soda lye with Hydrogen and Chlorine as by-products by electrolysis. The discharge into the sea is drastically reduced to less than 20% with no toxic chemicals. This technology has a potential to revolutionize the salt and caustic soda industries in the future. Caustic soda is a key raw material for a number of chemical industries including PVC.Conventionally, Caustic soda plants all over the world depends on solar salt for their production of Caustic soda.Hydrogne and Chlorine are by-products.Chlrine is used for the production of PVC (poly vinyl chloride) and Hydrogen is used as a fuel. In the newly developed technology, the seawater is not only purified from other contaminants such as Calcium, Magnesium and Sulfate ions present in the seawater but also concentrate the seawater almost to a saturation point so that it can be readily used to generate Hydrogen onsite. The process is very efficient and commercially attractive because it can recover four valuable products namely, drinking water, Caustic soda lye, Chlorine and Hydrogen. The generated Hydrogen can be used directly in a Fuel cell to generate power to run the electrolysis. This process is very ideal for Caustic soda plants that are currently located on seashore. This process can solve drinking water problems around the world because potable water becomes an industrial product. The concentrated seawater can also be converted in a salt by crystallization for food and pharmaceutical applications. There is a growing gap between supply and demand of salt production and most of the chemical industries are depending upon the salt from solar pans. Another potential advantage with this technology is to use wind power to desalinate the water. Both wind power and Hydrogen will form a clean energy mix. It is a win situation for both water industry and the environment as well as for the salt and chemical industries. In conventional salt production, thousands of hectares of land are used to produce few hundred tons of low quality salt with a year long production schedule. There is a mis- match between the demand for salt by large Caustic soda plants and supply from primitive methods of solar production by solar evaporation contaminating cultivable lands. The above case is an example of how clean energy technologies can change water, salt and chemical industries and also generate clean power economically, competing with centralized power plants fuelled with hydrocarbons. Innovative technologies can solve problems of water shortage, greenhouse gases, global warming, and environmental pollution not only economically but also environmental friendly manner. Industries involved in seawater desalination, salt production, chemical industries such as Caustic soda, Soda ash and PVC interested to learn more on this new technology can write directly to this blog address for further information.

Fuelcell power using Biogas

Fuel cell technology is emerging as a base-load power generation technology as well as back-up power for intermittent renewable energy such as solar and wind, substituting conventional storage batteries. However, Fuelcell requires a Fuel in the form of Hydrogen of high purity. The advantage of Fuel cell is, its high electrical efficiency compared to conventional fossil fuel power generation technology, using Carnot cycle. Fuel cell is an electro-chemical device similar to a battery and generates power using electro-chemical redox reaction silently with no gaseous emission, unlike engines and turbines with combustion, rotary movements and gaseous emissions. The fuel Hydrogen can be generated using a renewable energy sources such as solar and wind as described in my previous articles, “Solar Hydrogen for cleaner future” dated 4 July 2012, and “Renewable Hydrogen for remote power supply “dated 28 June 2012. Alternatively, Hydrogen can also be generated using biomass through Biogas. Biogas is an important source of renewable energy in the carbon constrained economy of today’s world. The biogas can be generated from waste water and agro-waste by anaerobic digestion using enzymes. Biomass such as wood waste can also be gasified to get syngas, a mixture of Hydrogen and Carbon dioxide. In anaerobic digestion, the main product will be methane gas accompanied by carbon dioxide and nitrogen while the main product in gasification will be Hydrogen, cabon monoxide and carbon dioxide and oxides of Nitrogen. Whatever may be the composition of the resulting gas mixture, our focus will be to separate methane or Hydrogen from the above mixture. In anaerobic digestion, the resulting Methane gas has to be steam reformed to get Hydrogen gas suitable for Fuel cell application. In gasification, the resulting Syngas has to be separated into pure Hydrogen and Carbon dioxide so that pure Hydrogen can be used as a fuel in Fuel cell applications. As I have outlined in many of my previous articles, Hydrogen was the only fuel we have been using all these years and we are still using it in the form of Hydrocarbons and it will continue to be the fuel in the future also. The only difference is future Hydrogen will be free from carbon. We have to address two issues to mitigate Carbon emission, and it can be done by 1.Elimination of Carbon from the fuel source. 2. Generation of Renewable and Carbon free clean energy directly from solar and wind. One option to eliminate Carbon from the fuel source is to use Biomass as the raw material to generate Hydrogen so that fresh Carbon will not be added into the atmosphere by emissions .The second option is to generate pure Hydrogen from water by electrolysis using renewable energy such as wind and solar. Environmentally friendly waste-to-energy projects are becoming popular all over the world. But currently most of these waste-to-energy projects generate either Biogas (Methane) by anaerobic digestion or Syngas (Hydrogen and Carbon dioxide) by gasification. Both these gases require further purification before they can be used as a fuel for power generation. The Methane content in the Biogas (about 60% methane and 40% Carbon dioxide with other impurities) needs to be enriched to 90% Methane and free from other impurities. The composition of a typical Biogas is shown in table1. The resulting purified methane gas will be reformed using steam reformation in presence of a catalyst to obtain syngas; finally Hydrogen should be separated from resulting syngas so that it can be used directly into the Fuelcell.The common Fuel cell used for this application is invariably Phosphoric acid fuel cell. PAFC uses 100% Phosphoric acid in Silicon carbide matrix as an electrolyte. PAFC is a self contained unit completely enclosed in a cabin consisting of a gas reformer, Fuellcell power generator, Power conditioning unit and other auxiliaries. The PAFC is of modular construction with capacities ranging from 100Kw up to 500Kw as a single unit. It can be installed outdoor in the open and it can be readily connected to a piped Biogas. It can also be connected to existing piped natural gas or LPG bullet as a stand-by fuel. Any waste-to energy project can be integrated with Fuel cell power generation with CHP application to get maximum economic and environmental benefits. Hydrogen derived from biomass will be an important source of fuel in the future of clean energy; and Fuel cell will become an alternative power generation technology for both stationary power generation and transportation such as Fuel cell car or Hybrid cars. PAFC is a compact, self-contained power generation unit that is used even for base load power. The electrical efficiency of PAFC is about 42% .It is suitable for CHP applications so that the total energy efficiency can reach up to 85%.It is ideal for supplying continuous power 24x7 and also to use waste heat for space heating or space air-conditioning with an absorption chiller in CHP applications. The ideal candidates for PAFC power generation using CHP will be hospitals, super markets, Data centers, Universities or any continuous process industry.PAFC is currently used as a backup power for large scale renewable energy project with an access to piped natural gas. A schematic flow diagram of a fuel cell power generation is shown in Fig 3 using biogas at Yamagata sewage treatment plant in Japan. Biomass based Fuecell power generation has a great potential all over the world irrespective of location and size of the country.

Fuelcell or battery for Renewable energy back-up?

Batteries have become indispensable for energy storage in renewable energy systems such as solar and wind. In fact the cost of battery bank, replacements, operation and maintenance will exceed the cost of PV solar panels for off grid applications during the life cycle of 20 years. However, batteries are continued to be used by electric power utilities for the benefits of peak shaving and load leveling. Battery energy storage facilities provide the dynamic benefits such as voltage and frequency regulation, load following, spinning reserve and power factor correction along with the ability to provide peak power. Fuel cell power generation is another attractive option for providing power for electric utilities and commercial buildings due its high efficiency and environmentally friendly nature. This type of power production is especially economical, where potential users are faced with high cost in electric power generation from coal or oil, or where environmental constraints are stringent, or where load constraints of transmission and distribution systems are so tight that their new installations are not possible. Both batteries and fuel cells have their own unique advantages to electric power systems. They also contain a great potential to back up severe PV power fluctuations under varying weather conditions. Photovoltaic power outputs vary depending mainly upon solar insolation and cell temperature. PV power generator may sometimes experience sharp fluctuations owing to intermittent weather conditions, which causes control problems such as load frequency control, generator voltage control and even system stability. Therefore there is a need for backup power facilities in the PV power generation. Fuel cells and batteries are able to respond very fast to load changes because their electricity is generated by chemical reactions. A 14.4kW lead acid battery running at 600A has maximum load gradient of 300 A/sec, a phosphoric-acid fuel cell system can match a demand that varies by more than half its rated output within 0.1 second. The dynamic response time of a 20kW solid-oxide fuel cell power plant is less than 4 second when a load increases from 1 to 100%, and it is less than 2 msec when a load decreases from 100 to 1%. Factory assembled units provides fuel cell and battery power plants with short lead-time from planning to installation. This modular production enables them to be added in varying increments of capacity, to match the power plant capacity to expected load growth. In contrast, the installation of a single large conventional power plant may produce excess capacity for several years, especially if the load growth rate is low. Due to their multiple parallel modular units and absence of combustion and electromechanical rotary devices, fuel cell and battery power plants are more reliable than any other forms of power generation. Fuel cells are expected to attain performance reliability near 85%. Consequently, a utility that installs a number of fuel cell or battery power plants is able to reduce its reserve margin capacity while maintaining a constant level of the system reliability. The electrochemical conversion processes of fuel cells and batteries are silent because they do not have any major rotating devices or combustion. Water requirement for their operation is very little while conventional power plants require massive amount of water for system cooling. Therefore, they can eliminate water quality problems created by the conventional plants’ thermal discharges. Air pollutant emission levels of fuel cells and batteries are none or very little. Emissions of SO2 and NOx in the fuel cell power plant are 0.003 lb/MWh and 0.0004 lb/MWh respectively. Those values are projected to be about 1,000 times smaller than those of fossil-fuel power plants since fuel cells do not rely on combustion process. These environmentally friendly characteristics make it possible for those power plants to be located close to load centers in urban and suburban area. It can also reduce energy losses and costs associated with transmission and distribution equipment. Their location near load centers may also reduce the likelihood of power outage. Electricity is produced in a storage battery by electro-chemical reactions. Similar chemical reactions take place in a fuel cell, but there is a difference between them with respect to fuel storage. In storage batteries chemical energy is stored in the positive/negative electrodes of the batteries. In fuel cells, however, the fuels are stored externally and need to be fed into the electrodes continuously when the fuel cells are operated to generate electricity. Power generation in fuel cells is not limited by the Carnot Cycle in the view that they directly convert available chemical free energy to electrical energy than going through combustion processes. Therefore fuel cell is a more efficient power conversion technology than the conventional steam-applying power generations. Fuel cell is a one-step process to generate electricity, the conventional power generator has several steps for electricity generation and each step incurs certain amount of energy loss. Fuel cell power systems have around 40-60% efficiencies depending on the type of electrolytes. For example, the efficiencies of phosphoric-acid fuel cells and molten-carbonate fuel cells are 40-45% and 50-60%, respectively. Furthermore, the fuel cell efficiency is usually independent of size; small power plants operate as efficiently as large ones. Battery power systems themselves have high energy efficiencies of nearly 80%, but their overall system efficiencies from fuel through the batteries to converted ac power are reduced to below 30%. This is due to energy losses taking place whenever one energy form is converted to another A battery with a rated capacity of 200Ah battery will provide less than 200 Ah. At less than 20A of discharge rates, the battery will provide more that 200 Ah. The capacity of a battery is specified by their time rate of discharge. As the battery discharges, its terminal voltage, the product of the load current and the battery internal resistance gradually decreases. There is also a reduction in battery capacity with increasing rate of discharge. At 1-hr discharge rate, the available capacity is only 55% of that obtained at 20-hr rate. This is because there is insufficient time for the stronger acid to replace the weak acid inside the battery as the discharge proceeds. For fuel cell power systems, they have equally high efficiency at both partial and full loads. The customer’s demand for electrical energy is not always constant. So for a power utility to keep adjustment to this changing demand, either large base-load power plants must sometimes operate at part load, or smaller peaking units must be used during periods of high demand. Either way, efficiency suffers or pollution increases. Fuel cell systems have a greater efficiency at full load and this high efficiency is retained as load diminishes, so inefficient peaking generators may not be needed. Fuel cells have an advantage over storage batteries in the respect of operational flexibility. Batteries need several hours for recharging after they are fully discharged. During discharge the batteries’ electrode materials are lost to the electrolyte, and the electrode materials can be recovered during the recharging process. Over time there is a net loss of such materials, which may be permanently lost when the battery goes through a deep discharge. The limited storage capacity of the batteries implies that it is impossible for them to run beyond several hours. Fuel cells do not undergo such material changes. The fuel stored outside the cells can quickly be replenished, so they do not run down as long as the fuel can be supplied. The fuel cells show higher energy density than the batteries when they operate for more than 2 hours. It means that fuel cell power systems with relatively small weight and volume can produce large energy outputs. That will provide the operators in central control centers for the flexibility needed for more efficient utilization of the capital-intensive fuel cell power plants. In addition, where hydrogen storage is feasible, renewable power sources can drive an electrolysis process to produce hydrogen gas during off-peak periods that will be used to operate the fuel cells during peak demands. The usage of storage batteries in an electric utility industry is expected to increase for the purposes of load leveling at peak loads, real-time frequency control, and stabilizing transmission lines. When integrated with photovoltaic systems, the batteries are required to suppress the PV power fluctuations due to the changes of solar intensity and cell temperature. The fact that the PV power outputs change sharply under cloudy weather conditions makes it hard to decide the capacity of the battery power plants since their discharging rates are not constant. For a lead-acid battery, the most applicable battery technology for photovoltaic applications to date, the depth of discharge should not exceed 80% because the deep discharge cycle reduces its effective lifetime. In order to prevent the deep discharge and to supplement varying the PV powers generated on cloudy weather days, the battery capacity must be large. Moreover, the large battery capacity is usually not fully utilized, but for only several days. Fuel cells integrated with photovoltaic systems can provide smoother operation. The fuel cell system is capable of responding quickly enough to level the combined power output of the hybrid PV-fuel cell system in case of severe changes in PV power output. Such a fast time response capability allows a utility to lower its need for on-line spinning reserve. The flexibility of longer daily operation also makes it possible for the fuel cells to perform more than the roles of gas-fired power plants. Gas turbines are not economical for a purpose of load following because their efficiencies become lower and operating costs get higher at less than full load conditions Fuel cell does not emit any emission except water vapor and there is absolutely no carbon emission. However, storage batteries themselves do not contain any environmental impacts even though the battery charging sources produce various emissions and solid wastes. When an Electrolyzer is used to generate Hydrogen onsite to fuel the Fuel cell, the cost of the system comes down due to considerable reduction in the capacity of the battery. The specific cost of energy and NPC is lower than fully backed battery system. During dismantling, battery power plants require significant amount of care for their disposal to prevent toxic materials from spreading around. All batteries that are commercially viable or under development for power system applications contain hazardous and toxic materials such as lead, cadmium, sodium, sulfur, bromine, etc. Since the batteries have no salvage value and must be treated as hazardous wastes, disposal of spent batteries is an issue. Recycling batteries is encouraged rather than placing them in a landfill. One method favoring recycling of spent batteries is regulation. Thermal treatment for the lead-acid and cadmium-containing batteries is needed to recover lead and cadmium. Sodium-sulfur and zinc bromine batteries are also required to be treated before disposal. Both batteries and fuel cells are able to respond very fast to system load changes because they produce electricity by chemical reactions inside them. Their fast load-response capability can nicely support the sharp PV power variations resulted from weather changes. However, there are subtle different attributes between batteries and fuel cells when they are applied to a PV power backup option. Power generation in fuel cell power plants is not limited by the Carnot Cycle, so they can achieve high power conversion efficiency. Even taking into account the losses due to activation over potential and ohmic losses, the fuel cells still have high efficiencies from 40% to 60%. For example, efficiencies of PAFCs and MCFCs are 40-45% and 50-60% respectively. Battery power plants, on the other hand, themselves have high energy efficiency of nearly 80%, but the overall system efficiency from raw fuel through the batteries to the converted ac power is reduced to about 30%. A battery’s terminal voltage gradually decreases as the battery discharges due to a proportional decrease of its current. A battery capacity reduces with increasing rate of discharge, so its full capacity cannot be utilized when it discharges at high rates. On the other hand, fuel cell power plants have equally high efficiency at both partial and full loads. This feature allows the fuel cells to be able to follow a changing demand without losing efficiency. The limited storage capacity of batteries indicates that it is impossible for them to run beyond several hours. The batteries when fully discharged need several hours to be recharged. For its use in PV power connections, it is as hard to estimate the exact capacity of the batteries. In order to prevent the batteries’ deep discharge and to supplement the varying PV powers on some cloudy weather days, the battery capacity should be large, but that large capacity is not fully utilized on shiny days. For fuel cells, they do not contain such an operational time restriction as long as the fuel can be supplied. Thus, the fuel cell power plants can provide operational flexibility with the operators in central control centers by utilizing them efficiently. As intermediate power generation sources, fuel cell power plants may replace coal-fired or nuclear units under forced outage or on maintenance. For the PV power backup the batteries’ discharge rate is irregular and their full capacity may usually not be consumed. So, it is difficult to design an optimal capacity of the battery systems for support of the PV power variations and to economically operate them. Instead of batteries fuel cell power plants exhibit diverse operational flexibility for either a PV power backup or a support of power system operation.

Energy,water and global warming

At the outset it may sound odd but in reality water and energy are two sides of the same coin and both industries have a great impact on global warming.We take for example, power generation industries. Two basic requirements for any power plant are fuel and water. It does not matter what kind of fuel is used whether it is a coal based power plant, liquid fuel based plant like Naphtha, and gas based plants using piped natural gas or LNG. We will consider only power generation involving conversion of thermal energy into electrical energy. Currently more than 80% of power generation in the world is based on thermal power including nuclear plants. All thermal power plants use steam as the prime motive force to drive the turbines, gas turbine is an exception but even, in gas based plants the secondary motive force is steam using waste heat recovery boilers, in combined cycle operations. The quality of water for conversion into steam is of high quality and purer than our drinking water. The second usage of water is for cooling purpose. The water consumption by power plants using once through cooling system is 1 lit/kwhr, and by closed circuit cooling tower, it is 1.7lit/kwhr. Only about 40% power plants in Europe for example use closed circuit cooling towers and the rest use only ‘once through’ cooling systems. The total power generated in 2010 by two largest users US and China, were 3792Twhrs and 3715 Twhrs respectively. The total world power production, in 2008 was 20,262 Twhrs, using following methods. Fossil fuel: Coal 41 %, Oil 5.50%, Gas 21%, Nuclear 13% and Hydro 16%.Renewable: PV solar 0.06%, PV thermal 0.004%, Wind 1.1%, Tide 0.003 %, Geothermal 0.3%, Biomass &others 1.30%. (1Twhrs is = 1,000,000,000 kwhrs)(Ref: Wikipedia). The above statistics gives us an idea on how much water is being used by power generating plants in the world. Availability of fresh water on planet earth, is only 2.5% (96. 5% oceans, 1.70% ground water, 1.7% glaciers and ice caps, and 0.001% in the air, as vapor and clouds).The world’s precious water source is used for power generation, while millions of people do not have water to drink. The cost of bottled drinking water is US$ 0.20 /lit, in countries like, India. This situation is simply unsustainable. The prime cause of this situation is lack of technology to produce clean power without using water. The power technology we use today is based on the principle of electromagnetism invented by Michael Faraday in the year 1839. That is why, renewable energy is becoming critically important at this juncture when the world is at the cross road. Many countries are now opting for seawater desalination to meet their water demand. Desalination again is an energy intensive process. For example, 3-4 kwhrs of power is used to desalinate 1 m3 of water. This power now comes from fossil fuel fired thermal power plants, which are often co-located with desalination plants, so that all the discharge from both the plants can be easily pumped into the sea. Since the world is running out of fresh water, we have to look for attentive source of water. In countries like India, the ground water is being exploited for agricultural purpose and power generation and the ground water is getting depleted. Depleting water resources is a threat to agriculture production especially when countries depend only on monsoon rains. Unabated emission of greenhouse from fossil fuel power plants and transportation causes globe to warm. Draught and water scarcity threatens food security. It is a vicious circle. Recent delay in onset of monsoon rains in India have caused grave concern for Government and the people of India. Shortage of power and water has compounded the problem for farmers and suicide rate among the farmers is increasing at alarming rate in India. “Globally, this seems to be one of the worst summers in recorded history. The global average temperature for May was the second hottest ever since 1880 - the year records were first compiled - US National Climatic Data Centre (NCDC) has said. Only 2010 witnessed a worse May. The NCDC said such a hot May was never recorded in the northern hemisphere. No scientist will pin it on human-induced climate change - it is scientifically untenable to do so - but many affirm that these extreme weather phenomena is along predicted lines of rise in global temperatures For India, the looming possibility of El Nino dulling the monsoon rains in July-August only means things could get worse. There is half a chance that the El Nino phenomenon will pick up intensity and hit the tail of the monsoon. Thirteen of the 20 times El Nino has been recorded, it has dimmed the intensity of the monsoon, causing widespread drought. Already, the northwest region of India has suffered a rainfall deficit worse than the rest of India. But the misery of rising heat is being felt worldwide with "normal weather" systems in disarray. If large areas of the western Himalayas in Uttarakhand have suffered raging forest fires, so has the US - more than 8 lakh hectares have been engulfed in flames. The March-May period for the US has been the hottest ever. Brazil is in the midst of its worst drought in five decades with more than 1,000 towns suffering. Heavy downpours and unheard of hail has hit China and flash floods have ravaged crops in Ethiopia. The Eurasian snow cover extent has been recorded at its smallest ever for the month of May since such records were maintained for the first time in 1967. The cover was 2.67 million sqkm below average in May,theUSNCDCsaid. The southern hemisphere, where winters prevail at the moment, too has been recording extremes like never before. The Australian winter has been exceptionally cold, with the fifth coolest winter minimum temperature in over half a century of record keeping. The Antarctic sea ice extent has gone above the 1979-2000 average. In contrast, the Arctic sea ice recorded a much smaller than average extent for the same period”. (Ref: The Economic Times). The global warming has caused many natural disasters such as recent bush fires in Colorado springs in US destroying more than 300,000 houses and heavy storms in Washington causing power black outs for days together in sweltering heat. No country is immune to global warming and sea level rising. How the consequences of global warming will manifest in different forms affecting human beings and other lives is yet to be seen in years to come. That is why distributed energy systems using Hydrogen as an alternative fuel is an important step towards sustainability. One can generate Hydrogen from water, using renewable energy source like solar or wind, and store them for future usage. The stored Hydrogen can be used to generate power, as and when required, at any remote location, even where there is no grid power. The water is regenerated during this process of power generation using Fuel cell which can be recycled. There is no large consumption of water and there is no greenhouse emission. It is a clean and sustainable solution. The same stored Hydrogen can also be used to fuel their cars in the near future!

Solar Hydrogen for a cleaner future

With recent announcement of the prestigious award to NREL (National renewable energy laboratory, USA) for developing SJ3 solar cells along with their industrial partner Solar Junction, there is a new hope and expectation that PV solar will become a major source of clean energy of the future.Togather with Hydrogen as an energy carrier, the PV solar hydrogen will certainly be a game changer. With increasing efficiency of solar panel from 17.24% up to 50%, and generating high pressure hydrogen using improved solid polymer electrolyzer, the sun and water will become the future source of clean energy replacing our decade long dependency on fossil fuel. There is also a distinct possibility of converting water into hydrogen by direct sunlight using photo-electrolysis as explained in my previous article, “Can we duplicate Nature’s photosynthesis for Hydrogen production?”’ dated April 2,2012. SJ3 solar cell uses tunable band gaps, lattice matched architecture with ultra-concentration tunnel junction to achieve the highest conversion efficiency of 43.5% with a possibility to reach an efficiency of 50%.This conversion efficiency is the percentage amount of solar energy converted directly into electrical energy. Such a high efficiency is due to the lens focusing the sunlight with 418 times intensity of the sun. There is no additional cost involved except the bottom Germanium layer of three junctions with Gallium and a dash of dilute nitride alloy. This small change boosts the bottom band-gap from 0.67 eV (electron volts) to 1.0 eV.The three layered SJ3 cell captures various frequencies of sunlight at various times and conditions achieving the best efficiency of converting photons to electrons. High pressure PEM Hydrogen generators producing 99.99% purity Hydrogen at elevated pressures are already under development. With carbon fiber storage tanks up to 10,000 psi pressure ratings, Fuel cell cars will become commercial reality overtaking Lithium battery powered electrical vehicles.PV solar Hydrogen will significantly alter the transportation and stationary power generation industries in the future simply because hydrogen has the highest heat value and it is absolutely clean. Age old centralized power plants using fossil fuels with highest carbon emission and water consumption has created serious environmental problems all over the world. Coastal power plants discharge huge amount of ‘once through’ cooling water into the sea at higher temperature and at higher salinity.Tranasport industries using fossil fuels emit high greenhouse gases due to age old, inefficient combustion engines causing global warming. Low humidity, high surface temperatures, dry conditions and lightning are perfect combination of conditions for bush fires similar to the one witnessed in Colorado mountain ranges. It is a right time to adopt distributed energy systems so that individual houses and business can generate their own power using PV solar and wind Hydrogen with no transmission grids and grid failures. It is time to replace fossil fuel with sun’s light and pure water so that we can hope for a cleaner future. We have all the necessary technologies and we need a will and concerted effort to make these changes.