“The method adopted in Vedanta to impart the knowledge of Brahman is known as the method of superimposition (adhyaaropa) and subsequent negation (apavaada). In the Bhashya, Bhagavatpada says, “The transmigrating self is indeed Brahman. He who knows the self as Brahman which is beyond fear becomes Brahman. This is the purport of the whole Upanishad put in a nutshell. It is to bring out this purport that the ideas of creation, maintenance and dissolution of the universe, as well as the ideas of action, its factors and results were superimposed on the Self. Then, by the negation of the superimposed attributes the true nature of Brahman as free from all attributes has been brought out. This is the method of adhyaaropa and apavaada, superimposition and negation, which is adopted by Vedanta.” (Ref: What are Upanishads? : An over view by S.N. Sastri on Luthur.com)
The analogy that is often used to describe the process of superimposition and negation is that of ‘using a thorn to remove a thorn’. Finally, when the last thorn is removed, the thorn used to remove it is thrown away as well. Similarly, Carbon can be used to reduce carbon emission while power is generated!
Let us consider the issues of Carbon emission and global warming resulting in climate change in the above context. Recent conference in Climate change held in Paris is acclaimed to be a success to the planet earth collectively adopted by 195 countries both developed and developing. In a nutshell they all have agreed to reduce their carbon emissions to limit the global warming to less than 2C or even 1.5 between 2030 and 2050. Is it really practical to achieve the above target given the nature of reduction and the complexity of imposing such a reduction within the time frame? It is a big question mark.
The only practical method to reduce CO2 is by using Hydrogen CO2 + H2-à CO + H2O and then convert CO into a useful product such as Urea NH2CONH2 a fertilizer. Production of Urea requires additional Hydrogen which is again obtained by combustion of fossil fuel resulting in CO2 emission. Moreover, CO2 will eventually be released at the point of usage of urea later. While trying to reduce Carbon emission one will end up with more Carbon emission in the atmosphere.
The carbon emission from power plants can be substituted with renewable energy sources such as wind and solar at a very high cost but how the emissions from chemical plants such as urea or from automobile emissions, steel plants and cement plants be contained? We should also remember that silicon wafer to produce solar panels consume large amount of power which now comes invariably from fossil fuels. There is a long list of such plants emitting Carbon every day from all over the world.
But there is a possibility to reduce emissions substantially by converting CO2 emissions from power plants into a synthetic fuel which can then substitute fossil fuel to continue power generation. The CO2 resulting from combustion of synthetic fuel will be recycled in the same manner mentioned above thus completing a cycle. To convert CO2 into a synthetic fuel we will require Hydrogen either by renewable sources or non-renewable sources. The non-renewable sources for Hydrogen cannot be a long term solution but renewable Hydrogen is very expensive at this stage. Therefore, Hydrogen is the only source which will not only help reduce Carbon emissions but also help eliminate Carbon completely from planet earth. Renewable Hydrogen is the key to decarbonize the planet earth. However, it may be possible to decarbonize the planet temporarily by using Hydrogen derived from fossil fuel without emitting CO2! It is not just a theory but practical because the technology has already been tested! In this process the Carbon will remain in the loop where it will neither be buried nor emitted into the atmosphere but constantly recycled.
Nature has a wonderful way of capturing Carbon and recycling it through a process called ‘carbon cycle’ for millions of years. The greenhouse gases in the atmosphere were restricted within certain limits when it was left to Nature. But when human being started burning fossil fuels to generate power or to run cars, the GHG emission surpassed the limit beyond a point where global warming became an issue. The GHG level has increased to 392 ppm level for the first in our long history. Many Governments and companies are exploring various ways and means to reduce greenhouse emissions to avoid global warming. Some Governments are imposing taxes on carbon emission in order to reduce or discourage such emissions. Others are offering incentives to promote alternative energy sources such as wind and solar. Some companies are trying to capture Carbon emission for sequestration.
While we try to capture Carbon and store them underground, there are many potential commercial opportunities to recycle them. This means the Carbon emission is captured and converted into a commercial fuel such as Gasoline or Diesel or Methane so that future sources of fossil fuels are not burnt anymore. But this is possible only by using ‘Renewable Hydrogen’. Hydrogen is the key to reduce carbon emission by binding carbon molecules with Hydrogen molecule, similar to what Nature does.
When NASA plans to send a man to Mars they have to overcome certain basic issues. Mars has an atmosphere with 95% Carbon dioxide, 3% Nitrogen, 1.6% Argon and traces of oxygen, water and methane.Nasa is planning to use Carbon dioxide to generate Methane gas to be used as a fuel and also generate water by using the following reaction.
CO2 + 4H2—–CH4 + 2 H2O
2H2O——-2H2 + O2
The water is electrolyzed to split water into Hydrogen and Oxygen using solar power. The resulting Hydrogen is reacted with Carbon dioxide from Mars to generate Methane gas and water using a solid catalyst. This methanation reaction is exothermic and self sustaining. How this can be achieved practically in Mars in those conditions are not discussed here. But this is a classical example on how the Carbon emission can be tackled to our advantages, without increasing the emissions into the atmosphere. There are several methods available to convert Carbon emission in to valuable products including gasoline. The reaction of the methane with water vapor will result in Methanol.
2H2 + CO——– CH3OH
On Dehydration, 2CH3OH —– CH3COCH3 + H2O.Further dehydration with ZSM-5 Catalyst gives Gasoline 80% C5+ Hydrocarbon. Gas to liquid by Fischer-tropic reaction is a known process.
Carbon dioxide is also a potential refrigerant to substitute CFC refrigerants that causes Ozone depletion. Carbon recycling is a temporary solution to mitigate Greenhouse gas emission till Hydrogen becomes an affordable fuel of the future. It depends upon individual Governments and their policies to make Hydrogen affordable. Technologies are available and only a political will and leadership can make Hydrogen a reality.
We live in a carbon constrained world where carbon emission is considered as the biggest challenge of the twenty-first century. We unearthed fossil fuel which Nature buried for millions of years and burnt them for our advantage to generate power and to run our cars. Scientist pointed out that the unabated emission of greenhouse will cause the globe to warm with dire consequences. However this came as an ‘inconvenient truth’ to industries and Governments around the world. The economic consequences of stopping fossil fuels weighted more than the global warming. Governments were in a precarious situation and unable to take a concrete policy decision. Popular Governments were not willing to risk their power by taking ethical decisions and opted for popular decision to keep up their growth. Then the financial crisis became an issue, which has nothing to do with greenhouse emission or global warming. Yet, the economic and industrial growth stumbled in many developed countries and unemployment skyrocketed. Governments are caught in a situation where they need to take a balanced view between an ethical decision and economic decisison.The overwhelming evidence of global warming and their consequences are slowly felt by countries around the world by natural disasters of various sizes and intensities.
Some scientist suggested that there is nothing wrong using fossil fuels; we can continue with greenhouse emission without risking the economic growth by capturing the carbon emission and burying them underground. Carbon sequestration and clean coal technologies became popular and more funds were allocated to them than renewable energy development.Countires like India and China are not in a hurry to discontinue fossil fuels but continue to make massive investments on coal-fired power plants. They neither tried to capture carbon nor bury them, but continue to emit carbon claiming that it is their turn of economic growth and right to emit carbon emission. The chief of UN panel on climate change headed by an Indian has no sayin the matter.Politicians push scientists into the background when the truth is inconvenient to them.
How feasible in the carbon sequestration technology and what is the cost? Even if we can come up with a successful technology of capturing carbon and burying them underground, there will be a cost involved. This cost will invariably be passed on to the consumer which will eventually increase the cost of energy. Constraining carbon emission without incurring a cost can only be a dream. Capturing carbon emission is nothing new; Carbon dioxide is absorbed by solvents like MEA (Monoethanolamine) in many chemical industries. The absorbed carbon dioxide can be stripped free of solvent and the solvent can be recycled. This carbon dioxide can be treated with Ammonia to get Urea, a Fertilizer. But the source of Hydrogen can come only from renewable energy sources. That is why ‘Renewable Hydrogen ‘is the key to solve global warming problem. We can produce Urea from “captured Carbon” and ‘Renewable Hydrogen’ so that we can cut a real quantity of greenhouse emission. Carbon recycling is a sustainable solution than Carbon capturing and burying. Countries like India who depend upon import of Urea for their agriculture production should immediately make Carbon recycling into Urea production mandatory. It is a win situation for everybody in the world.
Synthesis of Ammonia is one of the remarkable achievements of Chemical engineering in forties .It is a precursor for Urea, the fertilizer that brought about ‘Green revolution’ in agriculture industry and helped to achieve record food production all over the world. It was a milestone in modern chemistry to synthesis a molecule containing I atom of Nitrogen and 3 atoms of Hydrogen, represented by NH3 called Ammonia. The HeberBosch process for the production of Ammonia is a well established mature, commercial technology.
The process uses a Hydrocarbon source such as Naphtha or Natural gas as the feed stock to generate a synthesis gas composed of Hydrogen and Carbondioxide.The gas mixture is separated into carbon dioxide and Hydrogen using PSA (pressure swing adsorption ) technology. The resulting Hydrogen is used to combine with Nitrogen to synthesize Ammonia.
The chemical reaction can be represented by the following equation.
N2 + 3H2 ———- 2 NH3
The above reaction takes place at a pressure of 100-200 bars and temperature of 300-500C in presence of catalysts. It is an exothermic (heat releasing) reaction and the catalyst bed is cooled and maintained at 400C to be efficient.But this process of Hydrogen generation using Hydrocarbon emits greenhouse gases. Alternatively, Hydrogen can be generated using different methods using renewable energy sources using water electrolysis. Such process may be used in the future for this application.
Nitrogen is derived from atmospheric air. The air we breathe has about 79% of Nitrogen and 21% Oxygen. But these two gases can be separated by liquefying the air by cryogenic process and distilling them into two fractions. Alternatively, they can separated using pressure swing adsorption or membrane separation process, utilizing their density differences. In either way, Nitrogen can be separated from atmospheric air. By combining the above Hydrogen and Nitrogen, it is possible to synthesis Ammonia on a commercial-scale.
The ammonia can be easily split into Hydrogen and Nitrogen by passing Ammonia through a bed of Nickel catalyst at 200-400C as and when required to generate on site Hydrogen. This Hydrogen can be used for power generation or to run our cars using PEM Fuelcell.As we have seen previously, we are now looking for various sources of Hydrogen, and Ammonia is one of the promising sources for couple of reasons. The process and technology of Ammonia production, transportation and usage is well documented and has been practiced for few decades. It does not emit greenhouse gases.Liquified Ammonia has been widely used in air-conditioning and refrigeration systems. Ammonia can be easily metered into any system directly from the cylinder.
It is easier to use Ammonia directly into a convention internal combustion engines in place of Gasoline and this technology has already been practiced in 1880. Ammonia is pungent and any leakage can be easily identified. The advantage of using Ammonia as a fuel in cars, it does not emit any smoke but only water vapour.It can be admixed with Gasoline or used as 100% anhydrous Ammonia. It also helps in reduction of NO2 emission, especially is diesel engines.
Ammonia has a great potential as a source of future fuel provided the sources of Hydrogen comes from water using renewable technologies or by photo electrolysis using direct sunlight.
The sun is bright and warm and your roof top solar panels and solar heaters are working hard to generate power and hot water. But the rate of power generated is too small to use immediately. The hot water is not hot enough for your shower. Your 200 watt rooftop solar panel generates only 0.12 kwhrs after 5 hours of hard work. It does not meet your expectations. You expect 200 watts solar panel to generate about 1000 watt.hrs (1kwhr) in 5 hours. It is not happening. You don’t think renewable energy can meet your electricity demand.
There is a strong wind in the island and the wind turbines are rotating faster than usual but there are hardly any people living there. Wind turbine generates good power when the wind velocity is above certain level. But the electricity generated by the wind has no immediate takers.
There is a good rain this year and the dams are overflowing and the Hydro is generating surplus power but not many people are living near the catchment area. The power has to be transmitted hundred of kilometers to the nearby town through a sub-station. When the dams are dry there is hardly any power generation and power supply is rationed to the town.
When there is a demand for power Mother Nature does not offer the resources for power generation. When Mother Nature offers the resource we do not need power. This anomalous situation is the single largest obstacle that is undermining the potential of renewable energy. Of course, the high initial cost and half-hearted approach by Governments to offer subsidies or grants for renewable energy are other factors that add to the anomaly.
The only option to get over this situation is to store the energy 24×7 when it is generated and use them when we need them. It requires good storage technology, automation and information technology that can communicate with Natures energy resources and harness them, store them and deploy them judiciously and intelligently to meet our demands.
Current battery technology cannot be a long-term sustainable solution; it is expensive, requires constant maintenance and replacement, which adds to the expensive initial investment on renewable systems. The best option is to generate Hydrogen on-site when sunshine’s or wind blows and store them under pressure that can be used as and when we need electricity using Fuel cell. It is easier to handle gas than stored electricity in batteries. Batteries are very heavy, has a limited life cycle and poses health hazard and not suitable for large-scale power storage and not sustainable in the long run.
An Electrolyzer can generate Hydrogen from water on site when a sun or wind energy available and they can work from 10% to 100% capacity depending upon the availability of renewable resources. The surplus power from Hydro can be converted into Hydrogen and stored. With so much advancement in information and communication technology, harnessing nature’s energy, storing them and deploying them in a timely manner is not major issue. Hydrogen can bridge the gap between Nature resource availability and human demand. This is what science is all about. We developed science by learning from Nature or duplicating Nature and Renewable energy is nothing different.
Renewable Hydrogen is the key that can offer us energy independence in the twenty-first century. Fossil fuel usage will still continue for some more time because the world has already invested massively on fossil fuel infrastructures. The stacks are too high for them to switch over to renewable over night. It is the Mother Nature who provided us coal, oil and gas all these years using her manufacturing process under the earth over millions of years. But we human beings exceeded her tolerance limit by emitting greenhouse emission by our rapid growth in population and industrialisation.We failed to discover an alternate fuel in time and continued with an age-old technology with all its inefficiencies. Inefficiencies breed pollution. We were keen to use the heat of combustion by burning a fossil fuel to generate electricity or drive our cars, but paid no attention to the gases released during such combustion. We learnt Thermodynamics and the relationship between heat and work, but failed to understand the consequences of gases of combustion and its impact on our environment.
There are two issues involved in burning a fossil fuel to generate electricity. The heat of combustion is an exothermic reaction and we get a certain amount of heat. Then we convert this heat energy into electrical energy and the overall efficiency of such conversion is about thirty-five percent. Only thirty-five percent of the heat input energy becomes electrical energy and the remaining sixty-five percent heat along with gases of combustion are released into atmosphere. Of course part of this heat is recovered in a commercial plant, but the bulk of heat is released into the atmosphere as greenhouse gases. We failed to understand the potential of Hydrogen even though we used Hydrocarbon for several decades. We even discovered Urea, the fertilizer that caused ‘green revolution’ in agriculture, using the same Hydrogen present in the Hydrocarbon feedstock. It is time for us to make best use of a fossil fuel to its most potential when we burn each kilogram of fuel. We should burn coal not just with air but also with steam so that we can generate Hydrogen rich gas that can run a gas turbine in a combined cycle or run our cars on roads. Such a conversion will lead to a substantial increase in energy efficiency as well as in greenhouse gas emission reduction. Governments in industrialized countries should make it a mandatory to convert all their power plants to syngas generation as described above. They should also discourage new plants using fossil fuels with punitive power tariffs and encourage renewable energy projects with higher tariffs. Governments can also impose similar tariffs for transportation depending upon the fuel used such as fossil fuel or Hydrogen.
Governments should encourage renewable energy projects such as solar and wind to generate Hydrogen from water as centralized power plants and distribute DC (direct current) by rural electrification. If the country side is electrified using this system then, agriculture, business and industries can thrive in rural areas. Direct current (DC) distribution net work can be installed in rural areas and encourage people to use energy-efficient appliances such as Direct current air-conditioners with energy star ratings and tariffs. Governments can bring about these changes by adopting a ‘carrot and stick ‘policy to encourage renewable and discourage fossil fuels.
Solar energy is the key from which all other forms of energy emanate such as wind, geothermal and ocean thermal energy conversion system. It is of paramount importance to increase the efficiency of renewable systems and improve energy efficiencies of appliances we use. It is simpler to use LED bulbs using a Direct current generated by Renewable Hydrogen. It is once again the Mother Nature that can come to the rescue of human beings through solar, wind and water to generate clean energy for the twenty-first century.
Energy generation and distribution is no longer a business or revenue issue but a moral and ethical issue for Governments. It is only people who can bring about such sweeping changes by electing the right Government who can care for the environment. The future generation will judge us only based on what kind of environment we leave them behind.
We have discussed about the formation of fossil fuel as part of carbon cycle. It takes several million years before the carbon from the plants and animals turn into fossil fuels due to chemical reactions under higher pressure and temperature. The fossil fuels include solid coal, liquid oil and gaseous Hydrocarbons such as crude oil and natural gas. The natural gas forms the top layer due to its lightness. Natural gas is also the result of anaerobic reaction by microorganism in the absence of air converting organic matter under the earth into a gas. The gas during exploration comes with great pressure to be transported across several kilometers. We are actually duplicating this process to generate Biogas from our food and agriculture wastes and other organic matters. The end product is a mixture of methane and carbon dioxide. During oil and gas exploration we get methane and carbon dioxide and other gases such as Hydrogen sulfide depending upon the location of the oil field. That is why Sulfur and other products such as Mercaptans are present in crude oil and natural gas. When these fossil fuels are burnt the gaseous combustion products contain sulfur dioxide and oxide of nitrogen along with oxides of carbon. Air is normally used for combustion which is a mixture of Nitrogen and oxygen in the ration of 71:21,therefore, the combustion products invariably consist of oxides of nitrogen.
We are so addicted to oil and we are even trying to convert natural gas into oil, similar to gasoline using GTL (gas to oil) process. However all these combustion processes can be reacted with steam to form synthesis gas, a precursor for liquid Hydrocarbon. It is quite obvious that water in the form of steam is a key part in future energy mixes because that is how one can introduce a Hydrogen molecule in the reaction process. Hydrogen in the form of water is the key. Even if we can successfully steam reform natural gas to get Hydrogen we still have problems deal thing with traces of sulfur and Mercaptans, potential poison for catalyst in PEM (Proton exchange membrane) Fuelcells.The idea is to generate Hydrogen using a carbonaceous source such as fossil fuel for simple reasons. It is abundantly available but it emits greenhouse gases; but when you introduce Hydrogen into the mix then there is a good possibility of reducing greenhouse emission, even though we still use fossil fuels. Secondly, we are cautious to handle pure Hydrogen due to its explosive nature and the best available option is to mix Hydrogen with combustion products of fossil fuels. The result is the formation of Syngas.
Syngas is an important intermediary that will lead us to the Hydrogen economy of the futue.The syngas can be generated by various methods as long as we have an organic source and water (steam) source. In fact all food and agriculture waste can be converted into syngas either using a biological process or by gasification process. Both will lead to formation of Methane or syngas.
Syngas is a mixture of hydrogen with carbon dioxide formed in the following sequences, starting with carbon ,air and steam.
2C + O2——– 2 CO
2CO + 2H2O———2H2 +2 CO2
The carbon source can be any organic source such as coal, coke, wood etc.As you can see in the reaction, the quantity of carbon source is equally important to generate Hydrogen. One can say that Syngas is a match maker between fossil economy of the past and Hydrogen economy of the future. It is a very important chemical reaction that will change the future energy scene in the world.
That is why many counties like US and Australia and in Europe who have much coal deposits are now trying to generate Hydrogen from coal. Once coal is converted into a gas such as syngas then they are one step closer to separate Hydrogen from syngas.Number of companies and research organizations around the world are trying to develop an efficient and economical method of generating Hydrogen from coal. They have to find suitable conditions to generate higher yield of Hydrogen from syngas and then find an efficient system to separate Hydrogen from carbon dioxide. As I have mentioned earlier, the purity of Hydrogen is important especially when we use coal as the basic material because it has number of impurities to be removed before converting into a syngas.
As we can see, all energy roads are now leading to Hydrogen as the final clean fuel of the future. When the demand for Hydrogen increase, the demand for water too will increase because it is the direct source of Hydrogen. Energy and water are two side of the same coin as I have mentioned earlier in the past.
This article provides an overview on Hydrogen cars and how we can generate renewable hydrogen to fuel these cars. There are two well-known brands of Hydrogen based cars already in the market, BMW7 and Honda FCX Clarity models.
BMW7 works on Hydrogen Internal Combustion engine fuelled by Liquid Hydrogen. It is a 6 Liters V12 engine with 191Kw capacity and 390 N of torque. It offers 100km from 50 Liters of Liquid Hydrogen with a density of about 70-80gms/lit and offers 100kms from Gasoline of 16.7 liters. It has a capacity of 170 liters for liquid Hydrogen storage at the rear end of the car. It can run both on Hydrogen as well as on Gasoline. Liquid hydrogen has a better power density but liquefaction is a cryogenic technology and consumes power for liquefaction. The storage tank also is of special construction because Liquid Hydrogen is stored at -253C.
Honda FCX Clarity car is fuel cell car fuelled by compressed Hydrogen gas. It offers 100kms for 3.5 lits of Hydrogen (at 5000 psi pressure with density at 30gms/lit.). It has Hydrogen storage of 3.92kgs kgs with a total mileage of 240miles. Increasing Hydrogen storage gas pressure up to 10000psi, the Hydrogen power density is considerably increased making it comparable with liquid Hydrogen. Moreover fuel cell car is silent while driving because there is no combustion engine.
BMW is able to use their existing conventional internal combustion engine with slight changes suitable for Hydrogen so that they can use their existing infrastructure. But Honda FCX uses proton exchange membrane Fuel cell. It is an electrochemical device that converts Hydrogen into electricity which runs the motor for transmission of power. It is similar to an electric car in which power is stored in batteries and used to drive the motor for transmission. The only difference is the power is generated in Fuel cell car as and when hydrogen is supplied whereas in Electric cars, power is drawn from stored energy from the battery.
We can inject pure Hydrogen along with Gasoline, CNG or LPG to assist the combustion to save fuel consumption up to 30% and to reduce harmful emissions. The conventional gasoline cars can be fitted with water electrolyzer to generate Hydrogen using the car battery. The electrolyzer currently sold in the market is quite different. They generate ‘water gases’ and not pure Hydrogen. They electrolyze water using pulsating DC current which essentially breaks down water into Hydrogen and oxygen molecules. The complete mixture of Hydrogen, Oxygen and undissociated water molecules are injected into fuel manifold of the car. The hydrogen will assist in the process of combustion to certain extend and help save the fuel consumption of gasoline.
Renewable Hydrogen is a potential source for fuelling automobiles. One can use solar panels and simple tap water to generate hydrogen gas and store them under high pressure in cylinders. We will be releasing an eBook in the near future to design a suitable Renewable Hydrogen system and install them at homes and businesses for power generation as well as to fuel two-stroke engines such as scooters and bikes. Initially the book will offer DIY kits to design and install power generation for homes and businesses up to 10Kw capacity electricity generation. We will be conducting trials on two-stroke engines using renewable Hydrogen to get approvals from proper transport authorities for safety and usage on Indian roads.
Hydrogen can be safely handled as long as we take appropriate safety measures as we normally do while handling petroleum products like gasoline or butane gas. It may look like a daunting task to fuel a car with Hydrogen gas but in reality, all necessary equipment and systems are commercially available including High pressure Carbon fiber tanks fully tested and approved.
Water makes up 71% of the planet earth and it is the most potential energy source of the future. Water is a product of combustion between Hydrogen and Oxygen, two most abundantly available elements and vital for life on earth. The bondage between Hydrogen and Oxygen is so strong that it requires a certain amount of energy to separate them. Separation of Hydrogen and Oxygen using the process of Electrolysis is a well-known technology. Separation of water by high temperature using Thermolysis has also been studied. In both the processes the separation of Hydrogen and Oxygen after decomposition is a key step because of the strong affinity between the two elements. Hydrogen has to be separated in a pure form without any trace of Oxygen. Currently most of Hydrogen is generated commercially by steam reforming natural gas because of its easy availability as piped gas in many developed countries. Moreover steam reforming is a well established commercial technology that has been used for decades in chemical process industries. The hydrogen resulting from steam reforming is acceptable for combusting in Hydrogen internal combustion engines but not pure enough for a Fuel cell car. Any trace of impurity from natural gas such as Sulfur or Mercaptans can potentially poison the catalyst used in fuel cell which is very expensive. Hydrogen with purity less than 99.99% is not recommended for Fuel cell applications.
Currently there are few issues to be addressed before Hydrogen becoming a commercial fuel. The energy required to separate Hydrogen from water by commercial electrolysis is about 6Kws (kilowatts) to generate 1 m3 (cubic meter) of Hydrogen. Two key factors for electrolysis are purity of water and direct current source. Water of certain purity is a critical part for Hydrogen generation. Deionized water with electrical conductivity less than 0.10 micro Siemens/cm is required. Normal drinking water conductivity is less than 100micro Siemens/cm. The potable water can be deionized with reverse osmosis system to get necessary quality. In fact both high purity water and direct current are not commercially available. A renewable energy sources such as solar or wind that generates direct current can be used for electrolysis. This will drop batteries and rectifier that we normally use in renewable energy systems. The generated Hydrogen can be stored in cylinders under high pressure. The stored hydrogen is the stored energy that can be used as and when required. We can use the stored Hydrogen to generate electricity to meet our power requirement whether it is a home or business or industry. The major advantage with this system is that we can generate power when we need and we don’t have to depend on the grid power. We can also export surplus power to the grid. In fact all DC appliances can be connected with DC power from Fuel cell and operated to improve the efficiency. Such a system is ideal for remote locations without any grid supply such as remote villages or islands.
The same stored Hydrogen can also be used as fuel for a car whether it is a combustion engine or a Fuel cell car. Hydrogen can be compressed and stored under high pressure. Alternatively, Hydrogen can be stored using metal hydrides in smaller volumes. Honda introduced the first fuel cell car in the market in 1999. Since then they have made considerable improvements. Honda FCX Clarity, sedan offers a mileage of 270 miles for a single cylinder of Hydrogen at 5000 psi pressure. They are introducing a latest model with Hydrogen pressure at 10,000 psi which will considerably improve the mileage further. Unlike Hybrid cars, Fuel cell cars run silently and experts who have test-driven the car are very much impressed with the performance. Similarly Ford introduced Hydrogen combustion engine 6.8 liters V-10 engine to power E-450 Hydrogen shuttle bus. Ford modified their Gasoline engine to suit Hydrogen fuel.
Substituting Gasoline with Hydrogen is no longer a theory but a commercial reality. More and more research is being undertaken to improve the performance. Currently the cost of Hydrogen cars and Hydrogen fuel is expensive, due to lack of infrastructures to manufacture such cars or to distribute Hydrogen. However these cars will soon replace gasoline cars. Similarly homes and business can generate their own electricity for their daily use using stored Hydrogen. Water will become the fuel of the future and Hydrogen will clean up the air that has been heavily polluted by fossil fuels for decades.
I use the word ‘renewable Hydrogen’ for the Hydrogen derived from water using renewable energy sources such as solar, wind, geothermal, wave energy, ocean thermal energy conversion systems and biological processes. Hydrogen is clearly the energy source of the future because it has got the highest energy content, compared to any other fossil fuels such a diesel, gasoline, or Butane. The energy content is more than three times that of natural gas, which is considered as the cleanest commercial fuel available in the market. The heating value of Hydrogen is 61,100Btu/lb compared to 23,879 Btu/lb of natural gas. Moreover, only Hydrogen can guarantee a complete reduction of Carbon dioxide from the atmosphere. The problem with renewable Hydrogen is the cost, at current situation. The DOE (department of energy, USA) has targeted a cost for Hydrogen production at $10to $15 per mmBtu, which is comparable with current Natural gas cost. Currently bulk of the Hydrogen is commercially produced by steam reforming natural gas. However; this process will emit carbon dioxide at the rate of 11,888gms per Kg of Hydrogen produced. Though the cost of Hydrogen by this route is cheaper, mitigation of carbon dioxide is clearly an environmental issue. However it is an important route during the transition process from fossil fuel to a full fledged Hydrogen economy of the future.
Natural gas is increasingly in demand and the price of natural gas keeps increasing as the supply demand gap widens. Large natural gas liquefaction plants are already in operation in many parts of the world and number of new plants are under implementation or under planning stages. Japan, South Korea, Taiwan are three largest importers of LNG (liquefied natural gas) from Australia in Pacific region. There are many coal seam methane gas facilities already in operation in Australia and many are under planning. Due to the disaster at Fukushima nuclear plant, Japan has stepped up its import of LNG. India and China, which have been traditionally using coal as a major fuel, have started importing LNG for their power plants. This has pushed the prices of LNG in the international market significantly. Though LNG is relatively a cleaner fuel, it is very expensive to build import terminals. Moreover countries like India and China do not have a good distribution network by peipelines.The economy of scale also favor only large capacity LNG plants and terminals. However it is not a sustainable solution in the long run considering the fact that supply of natural gas also keeps dwindling steadily. Despite all these obstacles, Governments around the world are looking only for short-term solutions like LNG, simply because it is an easy fix.
Biogas can be generated from organic waste and waste waters by anaerobic digestion. Many sewage treatment plants around the world have started generating biogas to generate power for captive use and to export the surplus power to the grid. Similarly municipalities are also implementing projects to convert ‘waste garbage’ to ‘energy’. However, the scale of operation favors only large capacity plants in larger cities. However these biogas plants will still emit carbon dioxide because biogas will be combusted using conventional engines, micro turbines and Fuelcells.This is once again a temporary solution only. We need to look beyond all these technologies to really cut the greenhouse emissions.
The only option is by Renewable Hydrogen and we need to take steps to make it a commercial reality. Biohydrogen is another potential technology. However the technology is still in a nascent stage but it is promising. Renewable Hydrogen using renewable energy sources are our best bet. Countries have already started investing in renewable energy infrastructures such as solar and wind. They can as well plan for renewable Hydrogen so that they can be certain about three things. One, they can generate and use uninterrupted power supply without importing oil or gas. Secondly they can be certain that greenhouse emissions can be reduced to pre-industrialization level. Thirdly they can be certain about the last cost of energy and its stability in the long run. These are three important factors every citizen of a country is looking for. It requires political will, determination and swift action on the part of each Government.