Renewable Hydrogen, an emerging alternative to fossil fuel

Fossil fuels such as coal, oil and gas have helped transformed our power and transport industries for decades till now. But recent geo-political situations, depleting fossil sources and Carbon pollution, global warming and climate change have raised serious questions about the future of fossil fuels. However, countries who have massively invested in fossil fuel infrastructure and who have been heavily relying on supply of fossil fuels have started realizing an inescapable truth that they are running out of time to find an alternative to fossil fuels. Recently Hydrogen has been suggested as an alternative source of energy and many countries are gearing up to promote Hydrogen on a massive scale. The countries who have been traditionally using fossil fuels are now focussing on generating hydrogen from fossil fuels as an easier option. But the basic problem with this approach is they still depend on fossil fuels which means they still contribute to Carbon emission and climate change. They can conveniently dispute or deny the fact that man-made Carbon emissions cause global warming in order to score political points among the ‘gullible public’. Democracy is all about numbers and as along as these number stack up the political parties will take advantage of the system and try to push their agenda. But all these efforts are only short term and they still cannot escape the truth that man made Carbon emission is transforming our world for the worst and the future looks bleak. However, there is a silver lining in the dark clouds of global warming and climate change in the form of renewable Hydrogen. It is now possible to generate Hydrogen using renewable energy sources such as Hydro, solar, wind, geothermal and OTEC (ocean thermal energy conversion systems) that can used not only decarbonize our present economy and also has the capacity to transform future energy and to a cleaner and more sustainable environment. It is now possible to achieve a circular economy in energy sector which means the CO2 emission from existing and operating power plants using fossil fuels can be reversed using renewable Hydrogen so that one can continue to generate power but with Zero Carbon emission. This is a huge transformation. However, the usage of fossil fuels will continue in other industries such as petrochemicals, polymers and additives, and other synthetic materials. But one can take advantage of using renewable Hydrogen even in such industries using Green Chemistry initiatives so that they can become more sustainable. However Renewable Hydrogen is currently very expensive though it is generated from abundantly available natural resources such as sun, wind and water because PV solar panels are made from high purity silicon material again made from simple sand. We cannot afford to take natural resources lightly because they are precious commodities. With limited usage of renewable energy at current levels the cost of PV solar panels is still very expensive but likely to come down as we deploy more and more solar panels in the future. We should also be careful how we use renewable Hydrogen. Our first and foremost usage of renewable Hydrogen should be to decarbonize the fossil economy and achieve a circular economy. It means we must convert CO2 emissions into renewable natural gas (RNG) using renewable Hydrogen so that the Carbon can be recycled indefinitely with Zero Carbon emission while power plants using fossil fuels can continue to generate a base load power. By this way we will be able to address two issues namely meeting the rising energy demand at a cheaper price while eliminating global warming and climate change. All other use of renewable hydrogen such as Hydrogen vehicles for transportation using fuel cell etc will be secondary because they are not our priority. If we can generate a base load power (24 x7) using renewable Hydrogen with zero Carbon emission, then that should be our focus whether we believe it climate science or not. This will also help us conserve fossil fuels that may be rarely used to meet certain critical needs while substantially reducing the carbon emission. Renewable hydrogen will require massive deployment of renewable energy projects all over the world. One can generate renewable energy and use it directly for domestic or commercial use. But they are intermittent and require large scale energy storage. Moreover, all HT transmission lines are old and designed for transmitting base load power. Such an approach will not help decarbonizing fossil economy currently widely used. That is why renewable Hydrogen will have to play a key role in the future energy mix. Renewable hydrogen can be used as a fuel for transport industries using fuel cell and Japan is leading the way in this field. But such an application has along way to go and it requires massive investment and creation of infrastructure by way of filling stations. Countries like Japan do not have vast land area for solar industries, and they are likely to use cheap nuclear power and sea water to generate large scale hydrogen infrastructure. By this way they can supply power to both hydrogen as well as electric (battery) vehicles. Alternatively, they are looking to import liquified hydrogen (LH2) from countries like Australia who are ready to use cheap brown coal to generate Hydrogen by gasification despite CO2 emissions. Currently Australian government is very keen to encourage LH2 from cheap coal. They have already approved a pilot plant in the state of Victoria and only future can tell whether such a decision is prudent or not. Japanese companies may prefer to invest in Australia to generate and export clean liquid hydrogen leaving behind all emissions including CO2 in Australia. They may generate LH2 from natural gas and export it to Japan, but it may not be acceptable by Japanese companies because it has a potential to poison the Platinum catalyst used in their Fuel cell cars. In fact, Australia has an enormous potential to generate renewable hydrogen and then use it locally as well as to export. This will be more sustainable in the long run.

Battery versus Hydrogen

The technology towards zero Carbon emissions from transportation has gained importance due to increasing air pollution from automobiles. It is not just the Carbon emission but oxides of Nitrogen and Sulphur, but also water vapour (more potent Greenhouse gas) to gather with particulate matters that compounds the emission problems. Current automobiles based on Internal combustion is not only energy inefficient but generates noise and air pollution. Therefore, battery cars and Hydrogen cars are increasing in popularity and competing with each other. We can examine the merits and demerits of these two technology for a better understanding. Transportation uses mechanical energy derived from thermal energy generated by combustion of fossil fuels but battery cars as well as hydrogen cars convert an electrochemical energy into mechanical energy. As we know energy can neither be created not destroyed but can be converted from one form to another form. The word “energy storage” is a misnomer because electrical energy is generated at the point of usage from stored chemicals by way of redox reactions. In both cases, we generate electrical energy from batteries or from Hydrogen through Fuel cell and then convert it into mechanical energy. Both battery as well as Fuel cell convert chemical energy into electrical energy by electro-chemical reaction namely redox reactions. For a redox reaction, we need both reduction (reductant) and oxidation (oxidant) reactions to take place simultaneously to effect flow of electrons from corresponding ions which we call electricity. It is clear from the above we need two reactants namely reductant and oxidant. In batteries both the reactant and oxidant are stored in solid form or in a liquid form in ‘flow batteries’. The chemistry of the redox reaction will determine the speed, size and the life of the battery. This creates a constraint on the size, weight and life of the battery to achieve a specific mileage. It means battery has a limitation when comes to size, life and mileage to be achieved. Tesla is currently leading the way in batteries both for stationery as well as transport applications. For stationery applications the space, weight and life may not be a big constraint but the life is a constraint and therefore the cost. But in transport applications all the above three parameters are critical and therefore battery may not be a long-term solution. In Hydrogen Cars Hydrogen gas is stored in a compressed form at high pressure in a cylinder. There is no Oxygen storage but only air is used as the Oxidant. Fuel cell uses both Hydrogen and Oxygen to generate electrical energy at the point of usage to run the motor. Electricity is not stored. The main difference between battery and fuel cell is, battery carries both Oxidant as well as reductant on board in solid form which weighs and occupies space; Fuel cell carries only Hydrogen as the reductant in gaseous form and not Oxidant. Hydrogen is a light weight and only the storage tank in the form of composite material is the actual weight. Moreover, there is more room to store Hydrogen like a Hydrogen bus which carries cylinders at the roof top. If we use renewable energy source such as solar and wind then Hydrogen generation and dispensing will not be a serious constraint for Hydrogen generation and distribution in the future. The biggest disadvantage with Fuel cell is the cost due to expensive catalyst such as Platinum. Each technology has its own advantages and disadvantages but the fundamental facts of these technologies will give us a glimpse of the future potential. In battery technology storing the reactants in solid form is an issue. Air metal battery has a good potential yet a long way to go. Similarly, if Hydrogen can be generated at the point of usage without storing Hydrogen on board that will open a greater potential. There may a hybrid solution in the future that can integrates both battery and Hydrogen- Fuel cell technologies will be the way forward. Research is being carried out to design a rechargeable Fuel cell battery with enhanced performance and cyclability. Such technologies will also guarantee a clean renewable energy storage technologies for stationery applications in the future. Hydrogen can be derived from many abundant natural sources such as seawater as I have explained in my previous article “CAPZ desalination technology uses only sun, sea and wind”.

Many people argue that Hydrogen is not an energy source but an energy carrier. Hydrogen is certainly an energy source by itself but is to be derived from other primary sources such as water or natural gas because Hydrogen is not available in a free form. Generation of Hydrogen from its sources require an additional energy but when such an energy is provided by renewable sources such as sun, wind and sea then the cost becomes secondary in the long run. Therefore, battery may not be able to compete with hydrogen in the long run though it provides a temporary solution to pressing power problems in short term. Moreover, batteries rely on materials like Lithium whose availability is limited even though they are recyclable.

Clean power and water for remote island communities

Most of the renewable energy projects that are currently set up around the world are grid connected with feed-in power tariff arrangement. People can generate their own electricity by solar/wind to meet their demand and supply the surplus power to the grid at an agreed power rates. They can also draw power from the grid if there is any short fall in their production of renewable energy. It is two way traffic. There is an opportunity for people to generate revenue by sale of surplus power. It is an incentive for people to invest on renewable energy and that is why the investment on renewable energy has steadily increased over a period of time. But this is not the case with many developing and under developed countries. The situation is still worse in many islands where there is no centralized power generation at all or power distribution through grids. They depend on diesel generators. Even to transport diesel from mainland they have to use diesel operated boats. They have no drinking water even though they are surrounded by sea. I happened to visit a remote island in PNG few years ago and saw the plight of those people first hand. They live in absolute poverty and nobody cares to provide them a solution. Their voices are never heard and permanently drowned in the deafening roar of the sea. The problems of supplying clean power and water to these remote islands are not only political but also technical and commercial in nature. One has to use only commercially available systems and components which are basically meant for a single or three phase grid connected power supplies. Even though renewable energy sources basically generate only direct current (DC), one has to convert them into alternate current (AC) for easy distribution and to utilize appliances which are basically designed for AC operations. Isolated communities like islands can use direct current and also use DC operated appliances because they are commercially available and they are more efficient. Anyhow most of the house appliances need DC supply and AC/DC converters are commonly used for this purpose thus sacrificing efficiency in the process. They also need better storage solutions because they are not connected to the grid and they have to necessarily store power for several days. Some of these islands are connected with inefficient wind turbines backed by diesel generators. It is an absolute necessity to incorporate a long term storage capabilities in the system if one has to provide a continuous power and clean water. If the wind velocity is not sufficient (during off seasons) or if there is no sun (cloudy) for days together and if there is not sufficient storage capacity, then all the investment made on the project will be of no use. Any half baked solutions will not serve the real purpose. There are also commercial problems because a well designed system will cost more, which will eventually increase the power tariff. Unless the Government subsidizes the power sufficiently, people cannot afford to pay for their electricity or water. It requires a careful planning and community consultations to set up a ‘stand alone renewable energy projects in islands’. Governments in the pacific islands should act with great urgency because there is also a risk of inundation by sea level rising due to global warming. We are in the process of designing a solution to provide such islands with clean power, clean drinking water and even wireless connectivity for schools so that children can get education. It may sound ambitious but it is the first step one has to take into long journey of sustainability and self reliance by these isolated communities. There is a good possibility that such island may one day become completely independent and self sufficient with clean power and water. The same solution can be implemented in other countries too. Many countries have necessary infrastructure to generate and distribute power yet they suffer regular power cuts and black outs due to inefficiencies in their system. Our proposed solution can provide uninterrupted clean power and water because the system will have long duration centralized energy storage. We have made a detailed analysis of various alternatives available for the above purpose using Homer hybrid solution software. The solution proposes a PV solar with storage solutions using battery bank as well as Fuel cell back up. The solution also proposes long duration of storage ranging from few hours up to a fortnight .It is a standalone system with complete energy management and suitable for remote operations. The solution can also incorporate wind turbine in addition to PV solar depending upon the location and wind velocity profile. The model is to supply clean power and drinking water for 600 families with an average 3 people in a family. The system will supply power at the rate of 1.50kwhrs/day/person (1800 x1.5 = 2700kwhrs/day) and drinking water at the rate of 200 lits/day/person (1800 x 200 lit/person= 360,000 lits/day).The power for a desalination plant will be 1980 kwhrs/day. The system is designed for a total power generation capacity of 4680Khwhrs/day. The model is based on battery storage as well as based on Hydrogen storage with varying durations. Comparative analysis is shown in the figures. The first window is based on PV solar with 2 months Hydrogen autonomy. The third window is based on PV solar with battery 5 days and 17 hrs Hydrogen autonomy. The fourth and fifth window is based on PV solar with battery 17 hrs and Hydrogen 18 hrs storage autonomy with varying panel cost. The sixth window is based on PV solar with 172 hrs (one week) battery autonomy. The resulting analysis indicates that a centralized Hydrogen storage with Fuel cell back up offers the most economical solution even though the power tariff is higher than a system with battery storage. The investment for long duration battery storage is almost double that of Hydrogen based solution. The cost can further be reduced if and when the Electrolyzers as well as Fuel cells are manufactured on mass scale. The added advantage with this system is it can also provide Hydrogen fuel for Fuel cell cars and boats substituting diesel. One day it may become a reality that these isolated islands can become completely self- sufficient in terms of water, fuel and power with no greenhouse gas emissions. This solution can be replicated to all the islands all over the world. Note: The above system can also be installed in many developing countries in Africa which is an emerging market. An Africa-Australia Infrastructure Conference will be be held in Melbourne, Australia on 2-3 September 2013 and it will offer a platform for Australian companies to invest in Africa on infrastructural projects.

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)

Renewable Hydrogen for remote power supply

PV solar is expanding as a potential renewable energy source for individual houses, and the cost of solar panels are slowly coming down as the volume of production increases. However, the intermittent nature of solar energy is still an issue, especially for off grid and remote locations. Now solar energy is stored using lead acid batteries for such applications and inverters become part of the system. The capacity of the battery bank is designed to meet the electrical demand and to absorb the fluctuation of the energy generated by solar panels and it varies from location to location. This method stores the electrical energy generated by PV solar in the form of DC current and delivers it in the form of AC current. Though this method is the simplest one for remote locations, storing solar power in the form of Hydrogen is more economical and environmentally friendly in the long run. Solar energy can directly be used to generate Hydrogen using solid polymer electrolyzers and stored in cyclinders.The stored Hydrogen can then be used to fuel a stationary Fuel cell to generate power onsite. One can design a system by integrating various components in such a way; the Hydrogen generated by solar energy is used to generate power on site as and when required. By this method one can generate required power throughout the day 24x7 irrespective of the availability of sun. The system integration involves various components supplied by various manufacturers with various specifications and the success of a system depends on the careful design using data acquired over a period of time on a specific location. Many winds to Hydrogen projects also have been tested in locations around the world.NREL (National renewable energy laboratory, USA) has conducted number of tests by integrating various components such as PV solar and wind turbines with Electrolyzers (both PEM electroylzers and alkaline electrolyzers) and Hydrogen IC engines for remote power generation as well as for fuelling vehicles with Hydrogen. Though the cost of this system is still expensive, such integration offers enormous potential as a clean energy source for remote locations without any grid power. When one takes into account the fluctuating oil prices, cost of global warming, cost of power transmissions and losses during long distance power transmission from fossil fuel power plants, Renewable Hydrogen offers the best and sustainable alternative to fossil fuels. Such a system offers complete independence, energy security, reliability and fixed power tariff. System integration of renewable energy sources for Hydrogen production and onsite power generation using Fuel cell or Hydrogen engine is the key to a successful deployment of solar and wind energy for rural electrification and to remote islands. Such system will offer greater return on investment even to supply power to the grid based on power purchase agreements with Government and private companies. Renewable Hydrogen is the only viable solution for clean power of the future and sooner we embrace this integrated solution better for a cleaner future. Government and private companies investing on oil and gas explorations can focus their attention in developing renewable Hydrogen based solutions so that the cost of Hydrogen can become competitive to fossil fuel. Once the cost of Hydrogen reaches parity with cost of fossil fuel then, it will set the beginning of a green revolution in clean energy.

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.

Solar panel to generate Hydrogen

Photovoltaic solar energy is becoming popular as a source of clean energy and an alternative to fossil fuels to combat climate change. Though the initial cost is expensive people have started realizing the potential of PV solar as a real alternative to grid power, especially when they can export surplus power to the grid and earn some revenue. It is a source of income for potential investors as the energy cost keeps rising steadily. The cost of solar panels, batteries and inverters are slowly coming down as the systems get more popular and more competition is created in the market. However, during cloudy days or when the solar hours are less, the power generation by solar panels is considerably low. Moreover, the ‘power in tariff ‘ system is not available in many countries especially in developing countries. Therefore, energy storage becomes an issue. Lead acid batteries serve as storage devices for smaller applications but it becomes expensive for lager systems. Operation and maintenance, replacement and waste disposal are some of the issues with battery storage. Generating Hydrogen onsite using solar power and storing Hydrogen under pressure in a tank is the best method of storing solar energy. The stored Hydrogen can be used to generate power using a Fuel cell as and when we need power. However, the amount of energy required to convert water into Hydrogen using Alkaline Electrolyzer or Solid Polymer Electrolyzer is still high, averaging 5-7 kwhrs/m3.When you calculate the economics of Hydrogen storage versus battery storage using a computer modeling for a stand alone system, it is clear that Hydrogen storage is more economical and also guarantees an uninterrupted power supply using a Fuel cell. One US company has developed a Carbon doped Titanium oxide nanopowder visible light photo catalyst to generates Hydrogen using sun’s light energy. The company claims that it consumes only one third of the power consumed by PEM Electrolyzer or half of an Alkaline Electrolyzer.It can be easily installed at roof tops and it can generate Hydrogen even at one third of sunlight because it can effectively use short UV light and blue wave length of suns light because these energetic wavelengths penetrate cloud cover more effectively than the rest of sunlight. A 2mm modular solar panel can be installed on roof top or installed in multi-acre field installations. Even during the absence of sunlight the company claims it can use grid power to generate Hydrogen using its hybrid integral (MMO) Mixed metal oxide Titanium anode as efficiently as PEM Electrolyzer. While a PEM electrolyzer generates about 1.3kg Hydrogen from a power input of 100Kwhrs, this model can generate about 2.5kg Hydrogen using MMO + TiO2 anode and about 3.8kg using TiO2 alone. (Based on higher heating value of Hydrogen at 39.4 kwhrs/kg).The panel consuming 26.7kwhr power at 1.0Volt DC current at Anode can generate 1.25kg Hydrogen with Electrolysis electrical efficiency at 148%. This will make Hydrogen fuel a commercial reality because it will consume only 21.36 kwhrs of Dc power to generate 1 Kg Hydrogen. The generated Hydrogen can generate about 15 Kw power using a Fuel cell. This is an elegant solution to generate and store power using sun’s light than Photovoltaic power.

Why should you choose Photovoltaic Hydrogen over Photovoltaic battery?

Photovoltaic (PV) power is becoming popular worldwide as an alternative to grid power for various reasons. It gives an energy independence and freedom, it helps reduce greenhouse gas emission and combat global warming, it helps people taking advantage of various Government subsidies and incentives, and it also generates some revenue by selling surplus power back to the grid. At the end of the period you own the system and claim depreciation and some tax benefits. All these compelling factors may motivate people to opt for PV solar power. But you should also do some maths and make a cost benefit analysis to choose a right system for you. When there is a good sunshine day after day and throughout the year, PV solar is a good proposition and can be really rewarding. Unfortunately, that is not the reality. There may be many cloudy, rainy and fogging days in a year and your PV solar capacity may be overestimated or underestimated. You know the actual data only after one or two years of life experience. It is a long term financial and ethical decision one has to make and the decision should be absolutely right. You can make such a decision by carefully examining all the factors, not just by looking at the initial cost but looking at operating and maintenance costs during the life cycle and all the costs and benefits associated with them. Storage batteries are inevitable in PV solar systems, especially for grid independent systems. Even with grid connected PV solar system the design and installation of a correct battery bank, controllers and rectifiers are important issues. In this article we will discuss about grid independent system because many developing countries in Africa and Asia do not have 24x7 uninterrupted grid power supplies. Many people living in islands have to manage their own power by using diesel generators. This is the stark reality. Let us assume that you design a system assuming a daily average power consumption of 25,000 kwhrs/day, which is suitable even for a medium size family in US. We made an optimum design study between two systems; first containing PV solar,battery,controlle for grid independent power supply; and second system with PV solar, battery, water Electrolyzer,Hydrogen storage and PEMFuel cell and a rectifier for grid independent system, based on the same power consumption of 25,000kwhrs/day. You can clearly see the difference between the two systems by the following data. This financial analysis was made assuming there is no Government subsidies and incentives. Grid independent system with battery storage for 25,000kwhrs/day power: Total NPV (net present value):$ 342,926 Levelized cost of energy: $2.94/kwhrs Operating cost/yr: $22,764 Grid independent system with Hydrogen storage for 25,000kwhrs/day power: Total NPV (net present value): $ 169,325 Levelized energy cost: $ 1.452/kwhrs Operating cost/yr: 8,330 The number of batteries required in the first case is 17 numbers. In the second case, number of batteries required is only 2. Obviously, the levelized cost of power using PV Hydrogen (storage) is less than 50% of the power generated using PV battery (storage) for the same energy consumption of 25,000kwhrs/day. The operating cost is only one third for PV Hydrogen system compared to battery system. Batteries are indispensable in any renewable energy system but reducing their numbers to the lowest level is important, when the life of the system varies from 25 years to 40 years. The numbers and the cost of battery will make all the difference.

Why PV solar is still considered expensive?

Photovoltaic solar industry has started expanding in recent years in US and Europe and the rest of the world also started following. Still solar energy is considered expensive in many parts of the world for various reasons. In most of these countries, energy is predominantly managed by Governments with age old technologies and transmission systems. Coal is still the major fuel used for power generation and their distribution infrastructures are old and inefficient. Transmission losses, power pilferring, subsidized power tariffs and even free power for farmers, are some of the issues that compound the problems. Energy and water are considered more of social issues rather than business issues. For example in India, frequent power failures are common and sometimes people do not have power even up to 8 to 12 hours a day, especially in country sides. Standby diesel generators are integral part of an industry or business. The heavily subsidized power supply by Government from coal fired power plants is underrated. The average power tariff in India is still less than $0.07/kwhr.But the reality is they will be using diesel generated power for equal number of hours in a day and the cost of diesel power varies from $0.24 up to $0.36/kwhrs, almost in par with solar power. The average power cost will amount to $0.18 to $0.20 /kwhrs. Any slight increase in oil price will have a dramatic effect in energy cost in India and their balance of payment situation.Governments are in a precarious situation and they have to make a balancing act between subsidizing the energy cost and winning the elections. They often subsidize the power resulting in heavy revenue losses for Government run electricity boards. Most of the electricity boards in India are in red .People are used to low power tariffs for several decades and any increase in the tariff will make the Government unpopular. Greenhouse effect and global warming are secondary issues. With an average economic growth rate at 7% year after year, their energy requirements have gone up substantially. They may require several hundred thousands of MW power in the next 5 to 10 years. They have opened up energy sector to private only in recent years. Renewable energy industry is relatively new and there are very few large commercial scale solar and wind power plants in India. Majority of residents and businesses cannot afford high cost of PV solar installation. Even if they install, there is no ‘power- in tariff’ mechanism by Government where consumers can export surplus energy at a higher tariff to the grid. With current power failures lasting 8-12 hours/day, such mechanisms will have no value. The situation is the same in many Asian countries. The solar panel costs are high due to lack of local production of silicon wafers, batteries and inverters and most of them are still imported. State electricity boards do not have funds to buy power at higher tariffs. Import duties and taxes on imported components are still high making renewable industries uncompetitive against cheap coal fired, subsidized power cost of $0.07/kwhrs .India requires massive investment on renewable energy industries. But most of the power projects which are under planning stage or under implementation are based on either coal or oil or LNG.There is no sign that India will soon become a major player in renewable energy. In PV solar projects, the cost of storage batteries are higher than the solar panel during the life cycle of 25 years. If the life of a battery is 8 years then you will need 3 batteries during the life cycle. For example, if you use 100 watts solar panel with a life span of 20 years, the initial cost of solar panel may be $300 which will generate an average power of 140 watt.hrs /day. If you plan to store 5 days energy using a battery, you will enquire 5x 140= 700 watt.hrs battery, costing about $175.If you have to replace batteries 3 times during the life span of 20 years then the cost of battery is 3x175= $525.You have to add operation and maintenance cost, in addition to it. Therefore, your investment on batteries is 1.75 times more than solar panels. This cost will substantially add up to your energy cost. In most of the Asian countries where they cannot export surplus power to the grid, they have to rely only on batteries. This high cost of stored energy is not remunerative because they cannot export this surplus to the grid at a higher tariff. This situation is not likely to change at least in the short term.

Air-conditioning with direct solar

Air-conditioning is considered as a luxury, even in tropical countries where the day temperatures are well above 35C, and humidity high. The increasing electricity cost makes air-condisononing unaffordable to many people, though it is necessary for simple comfort. One of the main reasons why the cost of power is high and still keeps rising is, the way the power is generated and distributed. • The primary cost is the fuel cost and its ever increasing trend • The inefficiency of power generation and distribution • All house hold appliances are made to be compatible with AC power distribution. • Even solar generated power (DC direct current) is converted into AC (alternate current), in order to be compatible with AC grid. The above issues can be easily addressed by following the simple method, outlined below, so that air-conditioning becomes affordable to everyone. We are discussing about various renewable energy source options, particularly about solar energy for air-conditioning in this article. The centralized power plants operate in remote locations with an easy access to fuel source. They generate power from coal, oil or gas and then transmit power through a common grid to various consumers. During this transmission, there is a grid loss up to 10%.First it reaches a sub-station, where the high voltage power such as 11Kv/22kv/33Kv is stepped down to 220V/440V as the case, may be. During this process, there is a loss of power up to 5%. When this low voltage power reaches your home, you have to convert them into DC supply, using AC/ DC converter. For example, you need to use your laptop or PC, you need a converter. During this process, there is again a loss of power up to 5%. The efficiency of power generation by fossil fuels is only about 35%, and the balance 65% is emitted as waste heat in the form of greenhouse gases. The net power efficiency at the point of usage at our home will be only about 25-27%. Only 27% of the heat value of the fuel is converted and supplied, reaches you in the form of electricity. The rising cost of fuel and inefficiencies in generation and distribution, are the major factors for such high cost of power. Imagine, how many decades we have been using this power using the same technology, and paying our bills! One can easily justify why we should switch over to renewable energy source. It makes a great sense of economics and environmental protection! Since we have been using such power distribution systems for so many decades, all the house appliances are manufactured to be compatible, to the power supply. Unfounately, many of our electronic appliances can operate only on DC current. This has forced us to use many converters at our homes, of various specifications, for various uses. That is exactly why we are using a rectifier to convert the solar power, which is a DC current, into Ac current, so that we can use air-conditioners readily available at stores, which are AC power compatible. But this conversion results in power loss of at least 5%. It will be easier and economical to use directly, solar DC power into DC powered Air conditioners. The solar panel should be connected directly to a split air conditioning unit, through a charge controller and battery bank. The power supply to the unit will be 48VDC, connected to the outdoor unit. The compressor used in this air conditioner is DC operated, scroll compressor, which is more efficient and operates smoothly, and it can be connected directly to your solar panel, without using a rectifier. You can also use a small wind turbine to connect to this air-conditioning system. You can even use this system in your caravan, when you are not driving! As a matter of fact, all your house appliances from TV to Vacuum cleaners can be directly connected to your solar panel without any rectifiers.

Power your home with sun and water

Is it really possible, to power your home, with just sun and water? It sounds very simple and a perfect solution, for our energy hungry world. It is true, and it is possible, to generate your own electricity, for all your home needs, without depending upon the grid power. Even when, there is no sun for a week! Let us see how, this is possible. Photovoltaic (PV) solar, is getting popular, and many Governments in developed countries, subsidies the cost of solar panels, and also buy surplus power, at a higher tariff, than the grid power tariff.Goverments are doing this, to encourage more and more people, to opt for solar energy, a cleaner form of energy. Currently, solar panels are set up on roof tops, and the solar energy is used to power your appliances, and the surplus power, exported to the grid. At times of shortage, the power from the grid is drawn, to meet your home requirements. When you import power from the grid, the energy meter revolves in clock wise direction. When you export power to the grid, the energy meter, runs in anti-clockwise direction, indicating the export of surplus power to the grid. At the end of the month, you calculate the net power exported or imported, and accordingly collect the revenue from the Government based on fixed tariff, or pay to the Government based on their bill. But there is a catch! Power distribution companies distribute power, to consumers, at variable tariff, such as peak power and off peak power. The tariffs are high, during peak periods, and lower at off-peak periods. Solar system generates more power when the sun is bright, and generates less power during cloudy times. One should be able to generate solar power when the sun is bright, use it during the peak period. But grid tariff is at peak normally during the daytime, between 9 and 5. And lower at night time, between 6pm to 6am. Therefore, one should be able to generate power during bright sun shine, and use it during peak period. That means you should be able to generate your required power during the daytime, and use them in the night, because you don’t use much power, during daytime. How to overcome this anomalous situation, and still to meet your hundred percent power requirement at home? We can offer you a system that will generate power, while the sun shines. This power will generate Hydrogen gas, from pure water, and store it under pressure. Stored Hydrogen is your stored energy. It is like your overhead water tank. You can pump water and store it in the overhead tank, and use it, whenever you need it. But, your solar generated electricity cannot be stored in this way. You can store it, in a battery bank. But, these lead acid batteries are heavy, it requires regular maintenance, you cannot draw stored power from the battery more than 80% of its stored capacity, and finally, batteries have certain life span, usually 3-5 years, when it has to be substituted, with new batteries. If you calculate, the economics of solar system for its whole life cycle of say 10-15 years, including all battery replacements and maintenance cost, the initial investment will be high. In spite of all these expenses, one cannot guarantee with uninterrupted supply of power, to your home. But, you can store Hydrogen gas, any quantity, without any loss. You can generate your own electricity, using this stored Hydrogen, as and when, you require. You can still export your surplus power to the grid, and also meet all your power needs, even during peak periods! The overall cost of the system is higher, than solar grid connects system but it will offer you, an uninterrupted power, throughout the year. You will be eligible for carbon credit, and your system will earn you money, as you relax at home, with no worries about mounting power bills! The cost of energy keeps rising, as the oil prices go up. You may even be able to generate and store more Hydrogen, to fuel you car, like Honda FCX.Hydrogen solution is the solution of the future. We can design, engineer and install a system to meet your specific needs. Of course, we need to study your specific requirement, and suitability of your location.