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Showing posts with label Electricity generation. Show all posts
Showing posts with label Electricity generation. Show all posts

Friday, November 14, 2014

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.

Friday, August 31, 2012

Indian black out and aftermath


The largest power outage that affected 650 million people in India recently was a major news around the world. Power outage is common in many countries including industrialized countries during the times of natural disasters such as cyclones, typhoons and flooding. But the power outage that happened in India was purely man-made. It was not just an accident but a culmination of series of failures as the result of many years of negligence, incompetency and wrong policies. Supplying an uninterrupted power for a democratic country like India with 1.2 billion people with 5-8% annual economic growth, mostly run by Governments of various political parties in various states is by no means an easy task. While one can understand the complexities of the problems involved in power generation and distribution, there are certain fundamental rules that can be followed to avoid such recurrence. The supply and demand gap for power in India is increasing at an accelerated rate due to economic growth but the power generation and distribution capacity do not match this growth. Most of the power infrastructures in India are owned by Governments who control the power generation, distribution, operation and maintenance, financing power projects, supplying power generation equipments, supplying consumables, supplying fuel, transportation of fuel and revenue collection. The entire system is based on the policy of ‘socialistic democracy’, after the independence from the British, though economic liberalization and globalization is relatively a new phenomenon in India. Since every department of power infrastructure is controlled by Government, there is a lack of accountability and competition. Many private companies and foreign companies do not participate in tendering process because it is a futile exercise. Some smart multinational companies set up their manufacturing facilities in India, often in collaboration with Governments in order to get an entry into one of the largest market in the world. Indigenous Coal is the dominant fuel widely used for power generation though the quality of coal is very low, with ash content as high as 30%.The calorific value of such coal hardly exceeds 3000 kcal/kg, which means more quantity of coal is required than any other fuel to generate same amount of power. Such coal generates not only low power but also generates huge amount of ‘fly ash’ (the ash content is the coal comes out as fly ash) causing pollution and waste disposal problems. Large piles of fly ash and age old cooling towers with a large pool of stagnant water are common sights in many power plants in India. Such low cost coal does not make any economic sense when considering the amount of fly ash disposal cost and environmental damages. Thanks to research institutions that have developed methods to utilize fly ash in production of Portland cement. The indigenous low grade coal is the fuel of choice by Indian power industries, though many plants have started importing coal recently from Indonesia and South Africa. Indigenous low grade coal and cooling water from rivers and underground sources are two major pollutants in India. Water is allocated for power plants at the cost of agriculture. There is a shortage of drinking water in many cities as well as irrigation water for agriculture. Since most of the power infrastructures are owned by Governments there is a tendency to adopt populace policies such as power subsidies, free water and power for farmers, low power tariffs etc, making such projects economically unviable in the long run. Most of the State Electricity boards in India are running at a loss and such accumulated losses amount to staggering figures. The Central electricity authority regulates the power tariff. They calculate the cost of power generation based on specific fuel and fix the power tariff that companies can charge their consumers even before the plant is set up. Most of such tariffs are based on their past experience using indigenous low grade coal and transport cost which are often impractical. Such low power tariffs are not remunerative for private companies and many foreign companies do not invest in large capital intensive power projects in India for the same reason. The best option for the Governments to solve energy problems in India will be to open to foreign investments and allow latest technologies in power generation and distribution. It is up to the investing companies to decide the right type of fuel, right type of equipments, source and procurement, power technology to be adopted and finally the tariff. India has come a long way since independence and Governments should focus on Governing rather than managing and controlling infrastructure projects. The latest scam widely debated in Indian media is 'Coal scam’. It is time India moves away from fossil fuel and allow foreign investments and technologies in renewable energy projects freely without any interference. India needs large investments in building power and water infrastructures and it will be possible to attract foreign investment only by infusing confidence in investing companies. It is not just the size of the market that is to be attractive for investors but they also need a conducive, fair and friendly environment for such investment.

Thursday, August 9, 2012

Irreversibility leads to unsustainability


People in the chemical field will understand the concept of ‘irreversibility’. Certain chemical reactions can go only in one direction and but not in the reverse direction. But some reactions can go on either direction and we can manipulate such reactions to our advantages. This concept has been successfully used in designing many chemical reactions in the past and many innovative industrial and consumer products emerged out of it. But such irreversible reactions also have irreversible consequences because it can irreversibly damage the environment we live in. There is no way such damage can be reversed. That is why a new branch of science called ‘Green Chemistry’ is now emerging to address some of the damages caused by irreversible chemical reactions. It also helps to substitute many synthetic products with natural products. In the past many food colors were made out of coal tar known as coal tar dyes. These dyes are used even now in many commercial products. Most of such applications were merely based on commercial attractiveness rather than health issues. Many such products have deleterious health effects and few of them are carcinogenic. We learnt from past mistakes and moved on to new products with less health hazards. But the commercial world has grown into a power lobby who can even determine the fate of a country by influencing political leaders. Today our commercial and financial world has grown so powerful that they can even decides who can be the next president of a country rather than people and policies. They can even manipulate people’s opinion with powerful advertisements and propaganda tactics by flexing their financial muscles. Combustion of fossil fuel is one such example of ‘irreversibility’ because once we combust coal, oil or gas, it will be decomposed into oxides of Carbon, oxide of Nitrogen and also oxides of Sulfur and Phosphorous depending upon the source of fossil fuel and purification methods used. These greenhouse gases once emitted into the atmosphere we cannot recover them back. Coal once combusted it is no longer a coal. This critical fact is going to determine our future world for generations to come. Can we bring back billions of tons of Carbon we already emitted into the atmosphere from the time of our industrial revolution? Politicians will pretend not to answer these question and financial and industries lobby will evade these question by highlighting the ‘advancement made by industrial revolutions’. People need electricity and they have neither time nor resources to find an alternative on their own. It is open and free for all. People can be skeptical about these issues because it is ‘inconvenient for them’ to change But can we sustain such a situation? Irreversibility does not confine only to chemical reactions but also applies for the environment and sustainability because all are intricately interconnected.Minig industries have scared the earth, power plants polluted the air with greenhouse emission and chemical industries polluted water and these damages are irreversible. When minerals become metals, buried coal becomes power and water becomes toxic effluent then we leave behind an earth that will be uninhabitable for our future generations and all the living species in the world. Is it sustainable and can we call it progress and prosperity? Once we lose
pristine Nature by our irreversible actions then that is a perfect recipe for a disaster and no science or technology can save human species from extinction. One need not be scientist to understand these simple facts of life. Each traditional land owners such as Aborigines of Australia or Indians of America and shamans of Indonesia have traditionally known and passed on their knowledge for generations. They too are slowly becoming extinct species in our scientific world because of our irreversible actions. Renewability is the key to sustainability because renewability does not cause irreversible damage to Nature.

Monday, August 6, 2012

Base load power generation with Solar thermal


All existing power generation technologies including nuclear power plants uses heat generation as a starting point. The heat is used to generate steam which acts as a motive force to run an alternator to produces electricity. We combust fossil fuels such as coal oil and gas to generate above heat which also emits greenhouse gases such as oxides of Carbon and Nitrogen. As I have disused in my previous article, we did not develop a technology to generate heat without combusting a fossil fuel earlier. This was due to cheap and easy availability of fossil fuel. The potential danger of emitting greenhouse gases into the atmosphere was not realized until recently when scientists pointed out the consequences of carbon build up in the atmosphere. The growth of population and industries around the world pushed the demand for fossil fuels over a period of time which enhanced the Carbon build up in the atmosphere. But now Concentrated Solar Power (CSP) systems have been developed to capture the heat of the sun more efficiently and the potential temperature of solar thermal can reach up to 550C. This dramatic improvement is the efficiency of solar thermal has opened up new avenues of power generation as well as other applications. “CSP is being widely commercialized and the CSP market has seen about 740 MW of generating capacity added between 2007 and the end of 2010. More than half of this (about 478 MW) was installed during 2010, bringing the global total to 1095 MW. Spain added 400 MW in 2010, taking the global lead with a total of 632 MW, while the US ended the year with 509 MW after adding 78 MW, including two fossil–CSP hybrid plants”. (Ref: Wikipedia) “CSP growth is expected to continue at a fast pace. As of April 2011, another 946 MW of capacity was under construction in Spain with total new capacity of 1,789 MW expected to be in operation by the end of 2013. A further 1.5 GW of parabolic-trough and power-tower plants were under construction in the US, and contracts signed for at least another 6.2 GW. Interest is also notable in North Africa and the Middle East, as well as India and China. The global market has been dominated by parabolic-trough plants, which account for 90 percent of CSP plants. As of 9 September 2009, the cost of building a CSP station was typically about US$2.50 to $4 per watt while the fuel (the sun's radiation) is free. Thus a 250 MW CSP station would have cost $600–1000 million to build. That works out to $0.12 to $0.18/kwt. New CSP stations may be economically competitive with fossil fuels. Nathaniel Bullard,” a solar analyst at Bloomberg “New Energy Finance, has calculated that the cost of electricity at the Ivanpah Solar Power Facility, a project under construction in Southern California, will be lower than that from photovoltaic power and about the same as that from natural gas However, in November 2011, Google announced that they would not invest further in CSP projects due to the rapid price decline of photovoltaics. Google spent $168 million on Bright Source IRENA has published on June 2012 a series of studies titled: "Renewable Energy Cost Analysis". The CSP study shows the cost of both building and operation of CSP plants. Costs are expected to decrease, but there are insufficient installations to clearly establish the learning curve. As of March 2012, there was 1.9 GW of CSP installed, with 1.8 GW of that being parabolic trough” Ref: Wikiedia. One Canadian company has demonstrated to generate Hydrogen from water using a catalytic thermolysis using sun’s high temepertaure.The same company has also demonstrated generating base load power using conventional steam turbine by CSP using parabolic troughs. They store sun’s thermal energy using a proprietary thermic fluid and use them during night times to generate continuous power. The company offers to set up CSP plants of various capacities from 15Mw up to 500Mw.

Wednesday, August 1, 2012

Global warming and man-made greenhouse gas.


There is a raging debate going on around the world especially in US about the global warming and its causes, among scientists and the public alike. When IPCC released its findings on the connection between greenhouse gas emission and the global warming and its disastrous consequences, there was an overwhelming disbelief and skepticism in many people. In fact many scientists are skeptical even now about these findings and many of them published their own theories and models to prove their skepticism with elaborate ‘scientific explanations’. I am not going into details whether greenhouse gas emission induced by human beings causes the globe to warm or not, but certainly we have emitted billions of tons of Carbon in the form of Carbon dioxide into the atmosphere since industrial revolution. Bulk of these emissions is from power plants fueled by Coal, oil and gas. Why power plants emit so much Carbon into the atmosphere and why Governments around the world allow it in the first place? When the emission of Oxide of Nitrogen and Sulfur are restricted by EPA why they did not restrict Oxides of carbon? The reason is very simple. They did not have a technology to generate heat without combustion and they did not have a technology to generate power without heat. It was the dawn of industrial revolution and steam engines were introduced using coal as a fuel. The discovery of steam engines was so great and nobody was disturbed by the black smoke it emitted. They knew very well that the efficiency of a steam engine was low as shown by Carnot cycle, yet steam engine was a new discovery and Governments were willing to condone Carbon emission. Governments were happy with steam engine because it could transport millions of people and goods in bulk across the country and Carbon emission was not at all an issue. Moreover carbon emission did not cause any problem like emission of oxides of Sulfur because it was odorless, colorless and it was emitted above the ground level away from human sight. However the effect of Carbon is insidious. Similarly, power generation technology was developed by converting thermal energy into electrical energy with a maximum efficiency of 33%.This means only 33% of the thermal energy released by combustion of coal is converted into electricity. When the resulting electricity is transmitted across thousands of kilometers by high tension grids, further 5-10% power is lost in the transmission. When the high tension power is stepped down through sub stations to lower voltage such as 100/200/400V further 5% power is lost. The net power received by a consumer is only 28% of the heat value of the fuel in the form of electricity. The balance 67% of heat along with Greenhouse gases from the combustion of coal is simply vented out into the atmosphere. It is the most inefficient method to generate power. Any environmental pollution is the direct result of inefficiency of the technology. Governments and EPAs around the world ignore this fact.Thanks to President Obama who finally introduced the pollution control bill for power plants after 212 years of industrial revolution. Still this bill did not go far enough to control Carbon emission in its current form. Instead of arguing whether globe is warming due to emission of Carbon by human beings or not, Scientists should focus on improving the science and technology of power generation. For example, the electrical efficiency of a Fuel cell is more than 55% compared to conventional power generation at 33% and emits reduced or no carbon. Recent research by MIT shows that such conversion of heat into electricity can be achieved up to 90% compared to current levels of 35%.Had we developed such a technology earlier, probably we will not be discussing about GHG and global warming now. MIT research group is now focusing on developing new Thermophotovoltaics and according to their press release: “Thermal to electric energy conversion with thermophotovoltaics relies on radiation emitted by a hot body, which limits the power per unit area to that of a blackbody. Micro gap thermophotovoltaics take advantage of evanescent waves to obtain higher throughput, with the power per unit area limited by the internal blackbody, which is n2 higher. We propose that even higher power per unit area can be achieved by taking advantage of thermal fluctuations in the near-surface electric fields. For this, we require a converter that couples to dipoles on the hot side, transferring excitation to promote carriers on the cold side which can be used to drive an electrical load. We analyze the simplest implementation of the scheme, in which excitation transfer occurs between matched quantum dots. Next, we examine thermal to electric conversion with a glossy dielectric (aluminum oxide) hot-side surface layer. We show that the throughput power per unit active area can exceed the n2 blackbody limit with this kind of converter. With the use of small quantum dots, the scheme becomes very efficient theoretically, but will require advances in technology to fabricate.” Ref:J.Appl.Phys. 106,094315c(2009); http://dx.doi.org/10.1063/1.3257402 “Quantum-coupled single-electron thermal to electric conversion scheme”. Power generation and distribution using renewable energy sources and using Hydrogen as an alternative fuel is now emerging. Distributed energy systems may replace centralized power plants in the future due to frequent grid failures as we have seen recently in India. Most of the ‘black outs’ are caused by grid failures due to cyclones, tornadoes and other weather related issues, and localized distribution system with combined heat and power offers a better alternative. For those who are skeptical about global warming caused by man-made greenhouse gases the question still remains, “What happened to billions of tons of Caron dioxide emitted into the atmosphere by power plants and transportation since industrial revolution?”.

Sunday, July 8, 2012

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.

Wednesday, July 4, 2012

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!

Thursday, June 28, 2012

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.

Tuesday, June 19, 2012

Lithium batteries and Electric cars


All forms of renewable energy sources are intermittent by nature and therefore storage becomes essential. Energy is used mainly for power generation and transportation and the growth of these two industries are closely linked with development of energy storage technologies and devices. Electrical energy is conventionally stored using storage batteries. Batteries are electrochemical devices in which electrical energy is stored in the form of chemical energy, which is then converted into electrical energy at the time of usage. Batteries are key components in cars such as Hybrid electric vehicles, Plug-in Hybrid electrical vehicles and Electrical vehicles - all store energy for vehicle propulsion. Hybrid vehicle rely on internal combustion engine as the primary source of energy and use a battery to store excess energy generated during vehicle braking or produced by engine. The stored energy provides power to an electric motor that provides acceleration or provides limited power to the propulsion. Plug-in hybrid incorporates higher capacity battery than Hybrid eclectic vehicles, which are charged externally and used as a primary source of power for longer duration and at higher speed than it is required for Hybrid electric vehicles. In Electric cars, battery is the sole power source. All electric vehicles require rechargeable batteries with capacity to quickly store and discharge electric energy over multiple cycles. There are wide range of batteries and chemistries available in the market. The most common NiMH (Nickel Metal Hydride) used Cathode materials called AB5; A is typically a rare earth material containing lanthanum, cerium, neodymium and praseodymium; while B is a combination of nickel, cobalt, manganese and/or aluminum. Current generation Hybrid vehicles use several Kg of rare earth materials. Lithium ion battery offers better energy density, cold weather performance, abuse tolerance and discharge rates compared to NiMH batteries. With increasing usage of electrical vehicles the demand for lithium ion batteries and Lithium is likely to go up substantially in the coming years. It is estimated that a battery capable of providing 100miles range will contain 3.4 to 12.7 Kgs of Lithium depending upon the lithium-ion chemistry and the battery range. Lithium -ion batteries are also used in renewable energy industries such as solar and wind but Lead-acid batteries are now used widely due to lower cost. The lithium for Cathode and electrolyte is produced from Lithium Carbonate which is now produced using naturally occurring brines by solar evaporation with subsequent chemical precipitation. The naturally occurring brine such as in Atacama in Chile is now the main source of commercial Lithium. The brine is a mixture of various chlorides including Lithium chloride, which is allowed to evaporate by solar heat over a period of 18-20 months. The concentrated lithium chloride is then transferred to a production unit where it is chemically reacted with Sodium carbonate to precipitate Lithium Carbonate. Chile is the largest producers of Lithium carbonate. Though Lithium ion batteries are likely to dominate electric vehicle markets in the future, the supply of Lithium remains limited. Alternative sources of Lithium are natural ores such as Spodumene.Many companies around the world, including couple of companies in Australia are in the process of extracting Lithium from such ores. Manufacturers produce battery cells from anode, cathode and electrolyte materials. All lithium-ion batteries use some form of lithium in the cathode and electrolyte materials, while anodes are generally graphite based and contain no lithium. These cells are connected in series inside a battery housing to form a complete battery pack. Despite lithium’s importance for batteries, it represents a relatively small fraction of the cost of both the battery cell and the final battery cost. “Various programs seek to recover and recycle lithium-ion batteries. These include prominently placed recycling drop-off locations in retail establishments for consumer electronics batteries, as well as recent efforts to promote recycling of EV and PHEV batteries as these vehicles enter the market in larger numbers (Hamilton 2009). Current recycling programs focus more on preventing improper disposal of hazardous battery materials and recovering battery materials that are more valuable than lithium. However, if lithium recovery becomes more cost effective, recycling programs and design features provide a mechanism to enable larger scale lithium recycling. Another potential application for lithium batteries that have reached the end of their useful life for vehicle applications is in stationery applications such as grid storage. The supply chain for many types of batteries involves multiple, geographically distributed steps and it overlaps with the production supply chains of other potential critical materials, such as cobalt, which are also used in battery production. Lithium titanate batteries use a lithium titanium oxide anode and have been mentioned as a potential candidate for automotive use (Gains 2010), despite being limited by a low cell voltage compared to other lithium-ion battery chemistries.” (Ref: Centre for Transportation, Argonne National Laboratory) Usage of power for extraction of Lithium from naturally occurring brines is lower compared to extraction from mineral sources because bulk of the heat for evaporation of brine is supplied by solar heat. However Lithium ion batteries can serve only as a storage medium and the real power has to be generated either by burning fossil fuel or from using renewable energy sources. Governments around the world should make usage of renewable power mandatory for users of Electrical vehicles. Otherwise introduction of Lithium ion battery without such regulation will only enhance carbon emission from fossil fuels.

Saturday, June 2, 2012

Global warming - a race against time


Governments and industries seek comfort from the fact that Global Warming is not directly linked with greenhouse gas emissions and there is no concrete scientific proof yet linking these two, and think they can carry on the business as usual. Few scientists in the scientific communities also have backed such sentiments. Alternative technologies such as renewable energy technologies are expensive and cannot compete with fossil fuel based power plants in near terms. Advanced renewable technologies require rare earth materials such as Lanthanum, cerium, praseodymium, neodymium, cobalt and lithium that are used in electric vehicle batteries; Neodymium, praseodymium and dysprosium that are used in magnets for electric vehicles and wind turbines. Lanthanum, cerium, europium, terbium and yttrium that are used in Phosphors for energy-efficient lighting; Indium, gallium and tellurium that are used in solar cells. The supply of these materials are limited or confined to few countries such as China. These new material also require additional energy to mine, process and extract such rare earth materials using only fossil fuel generated power. Transport vehicles such as Hybrid or Electrical cars require substantial amount of rare earth material such as Lithium for Battery production. The cost of Lithium batteries according to Centre for Transportation, Argonne National Laboratory is: High energy 35 kwh battery costs $706/kwh or $ 24,723. High Power battery 100 10A-h cell costs $2,486. The cost and maintenance of such vehicles are expensive compared to gasoline cars. The looming financial crisis, unemployment and political instability in many parts of the world have overshadowed the problem of greenhouse house and global warming. Governments in power are trying to postpone the issue of global warming as long as possible because they are unpopular among their public, who are increasingly wary of high energy cost and their household budgets. Industrialized countries such as US, China, India and Australia have projected their production and utilization of their coal, oil and gas usage in the future, which are steadily on the rise. Australia’s mining and resources industries are booming with increasing production of Coal, Coal seam Methane gas, LNG, Iron ore, Copper, Nickel and Gold. Increasing demand by growing economies such as India and China have propelled the production of coal and LNG and other minerals in Australia. The booming mining and shipping industries of Australia have prompted UNESCO to warn Australia about the impending danger of ‘Great Barrier reef’ being destroyed by its busy shipping activities. The Great Barrier Reef is the world's largest coral reef ecosystem. The only living organic collective visible from space, it is considered one of the seven natural wonders of the world, and is a World Heritage listed area. It boosts the Queensland’s image of sun, swimming and tropical islands, and around 2 million people visit the reef every year, generating more than $2 billion in direct tourism revenue in the area. The mining boom brings revenue but it also brings natural disasters and destruction of its natural wonders. The net effect will be destruction of Nature and displacement of people at the cost of mining revenue. But how long such a boom will last, and if the economies of China and India starts slowing down then, what happens to all the investments and the damage caused? The above developments paint a grim picture on global warming. The world has witnessed natural disasters causing huge human and financial losses. The natural disasters have costed an economic loss of nearly 13 to 30 billion dollars in the past two years in Australia alone. Yet, people and Governments want a ‘concrete proof’ that man made greenhouse gases cause global warming and trigger natural disasters. Well, we can carry on such conversation indefinitely till we reach a point of no return. “Wisdom comes from experience; but experience comes from foolishness”.

Tuesday, May 15, 2012

Concentrated solar power - a game changer


We acknowledge that solar energy is a potential renewable energy source of the future. The total energy requirement of the world is projected in the next 40 years to be 30 TW (terra watts) and only solar energy has a potential to meet the above demand. However, harnessing sun’s energy to its fullest potential is still a long way to go. Concentrated solar power (CSP) offers a greater hope to fill this gap. The main reason is the cost advantage of CSP compared to PV solar and energy storage technologies and their costs. The cost of PV solar has steadily decreased in the past few years. Though the cost of solar cell has come down to $0.75 per watt, the overall cost of the PV system is still around $ 3.00 per watt. This is due to the cost of encapsulation; interconnect wiring, mounting of panels, inverters and battery bank. The overall cost of the system will not come down drastically beyond a point. This makes PV solar still more expensive compared to conventional power generation using fossil fuels. People can understand the value of renewable energy and impending dangers of global warming due to greenhouse gases, but the ultimate cost of energy will determine the future of energy sources. In PV solar the sun’s light energy is directly converted into Electricity, but storing such energy using batteries have certain limitations. PV solar is suitable for small scale operations but it may not be cost effective for large scale base load power generation. The best option will be to harness the suns thermal energy and store them and use them to generate power using the conventional and established methods such as steam or gas turbines. Once we generate thermal energy of required capacity then we have number of technologies to harness them into useful forms. As we mentioned earlier, the thermal energy can trigger a chemical reaction such as formation of Ammonia by reaction between Hydrogen and Nitrogen under pressure, which will release a large amount of thermal energy by exothermic reaction. Such heat can be used to generate steam to run a stem turbine to generate power. The resulting ammonia can be split with concentrated solar power (CSP) into Hydrogen and Nitrogen and the above process can be repeated. The same system can also be used to split commercial Ammonia into Hydrogen and Nitrogen. The resulting Hydrogen can be separated and stored under pressure. This Hydrogen can be used to fuel Fuel cell cars such as Honda FXC or to generate small scale power for homes and offices. By using CSP, there is potential of cost savings as much as 70% compared to PV solar system for the same capacity power generation on a larger scale. Focusing sun’s energy using large diameter parabolic troughs and concentrators, one can generate high temperatures. Dishes can typically vary in size and configuration from a small diameter of perhaps 1 meter to much larger structures of a dozen or more meters in diameter. Point focus dish concentrators are mounted on tracking systems that track the sun in two axes, directly pointing at the sun, and the receiver is attached to the dish at the focal point so that as the dish moves, the receiver moves with it. These point focus systems can generate high temperatures exceeding 800ºC and even 1,800ºC. The temperature required to run a steam turbine does not exceed 290C and it is quite possible to store thermal energy using mixture of molten salts with high Eutectic points and use them to generate steam. Such large scale energy storage using lead-acid batteries and power generation using PV solar may not be economical. But it will be economical and technically feasible to harness solar thermal energy using CSP for large scale base load power generation. It is estimated that the cost of such CSP will compete with traditional power generation using coal or oil in the near future.CSP has potential to generate cost effective clean power as well as a fuel for transportation.

Tuesday, March 13, 2012

Coal-water-slurry- a new source of Hydrogen?

Dirty coal is still a popular choice for power generation around the world, irrespective of the status of the country, whether industrially advanced or backward. The abundant availability and cheap cost, makes coal more attractive from investor’s point of view; they care less for the environment, while Governments turn a blind eye to all the emissions and pollutions. It is a question of survival for millions of people who work in coal mines and industries. It is one of the toughest challenges many Governments are facing. Take for example India; about 65% of power generation still comes from coal. The import of coal increases year after year and there is no immediate solution in sight. Indian coal is a low grade coal with very high ash content. Each coal-fired power plant generates huge amount of fly ash and they stockpile them; supposed to be used in the production of Portland cement. It is a big business. China and Indonesia too uses coal as a major fuel for power generation. But they have come out with an innovative and pragmatic method of using coal. They use coal-water-slurry (CWS), a finely pulverized high grade coal (calorific value 5100-6100Kcal/kg) in water. They use some chemical additives that make the slurry a homogeneous fluid, similar to a Hydrocarbon such as Heavy fuel oil (HFO).The advantage with CWS is it can be easily pumped and injected into a furnace or boiler using ceramic nozzles, obviously to avoid erosion due the abrasive nature of coal, just like firing diesel or heavy oil. According to the literature, 1.8 -2.2 tons of CWS is equivalent to 1 ton of Heavy fuel oil (HFO) and it costs the same. It cost only US$ 62 million to retrofit an existing coal fired power plant with CWS system and the yearly savings are estimated at US$ 41 mil per year, an attractive rerun on investment. The beautiful aspect of this method is it generates Hydrogen rich Syngas according to the following chemical reaction. 2C + O2+2 H2O -------- 2H2+2 CO2, when the mixture is subject to gasification instead of mere combustion. The combustion efficiency is about 96-99% and the boiler efficiency of more than 90%. It generates less Sulfur dioxide and Nitrogen oxide emissions and good for the environment compared to conventional coal- fired power plants. It is a good technology that needs the attention of Governments especially India, China and Indonesisa.Even coal rich countries like US, Australia should focus on this technology apart from their persuasion such as carbon sequestration. In fact, this will open up new avenues for India and China to switch over to Hydrogen economy, without making substantial investments. The coal-water-slurry fluid has a property similar to a Hydrocarbon as shown below. Density 65-70% ,Viscosity 1000Cp, Size d< 50 microns, Ash content <7, Sulfur<0.5%. It is easier to handle a liquid than solid coal. Pulverised coal is pneumatically conveyed and fired in rotary cement kilns for so many years. There is nothing new about it. Similarly coal water slurry can be a game changer for the power industry if it is combined with Gasification and combined cycle. It will lead into Hydrogen based power generation industries using Fuel cell such as Molten Carbonate Fuel cell (MCFC). I believe there is a clear opportunity for the Governments and private industries to seriously look into CWS technology which I believe, is a ‘precursor’ for Hydrogen economy of the future.