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Showing posts with label .Hydrogen. Show all posts
Showing posts with label .Hydrogen. Show all posts

Thursday, April 27, 2017

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.

Wednesday, April 19, 2017

CAPZ desalination technology uses only Sun,Sea and WInd !


CAPZ (Clean water at affordable price with zero discharge) is a new desalination concept that separates seawater into fresh drinking water and industrial salt both simultaneously using only sun and wind power. Seawater is nothing but fresh water in abundance with valuable mineral salts dissolved in it. These minerals include Sodium, Potassium, Lithium and Magnesium and a host of other minerals in traces. It requires a holistic approach to separate them in their pure form along with fresh water for potable and industrial applications. CAPZ technology precisely attempts to do that so that the seawater intake can be put into huge economic usage while reducing or eliminating completely the discharge of highly saline effluent contaminated with chemicals back into the sea. With increasing demand for fresh water and depleting sources of fresh water due to natural and man-made causes , sea water has become an important source for fresh drinking water. Sea water is not only a source of fresh water but also a new source of clean Hydrogen an energy of the future. It requires only sun ,sea and wind to achieve this!

Monday, August 19, 2013

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.

Thursday, July 11, 2013

How to control Carbon emissions in coal-fired power plants?


“Over two-thirds of today’s proven reserves of fossil fuels need to still be in the ground in 2050 in order to prevent catastrophic levels of climate change” – a warning by scientists. There is a great deal of debate on climate change due to man-made Carbon emissions and how to control it without any further escalation. The first obvious option will be to completely stop the usage of fossil fuel with immediate effect. But it is practically not feasible unless there is an alternative Non-Carbon fuel readily available to substitute fossil fuels. The second option will be to capture carbon emission and bury them under ground by CCS (Carbon capture and sequestration) method. But this concept is still not proven commercially and there are still currently many uncertainties with this technology, the cost involved and environmental implications etc.The third option will be not to use fresh fossil fuel for combustion or capture and bury the Carbon emissions but convert the Carbon emissions into a synthetic hydrocarbon fuel such as synthetic natural gas (SNG) and recycle them. By this way the level of existing Carbon emission can be maintained at current levels without any further escalation. At least the Carbon emission levels can be reduced substantially and maintained at lower levels to mitigate climate changes. It is technically feasible to implement the third option but it has to be implemented with great urgency. One way of converting Carbon emission is to capture and purify them using conventional methods and then react with Hydrogen to produce synthetic natural gas (SNG) CO2 + 4 H2 ----------> CH4 + 2 H2O The same process will be used by NASA to eliminate carbon built-up in the flights by crew members during their long voyage into the space and also to survive in places like Mars where the atmosphere is predominantly carbon dioxide. But we need Hydrogen which is renewable so that the above process can be sustained in the future .Currently the cost of Hydrogen production using renewal energy sources are expensive due to high initial investment and the large energy consumption. We have now developed a new process to generate syngas using simple coal, which is predominantly Hydrogen to be used as a Carbon sink to convert Carbon emissions into synthetic natural gas (SNG). The same Hydrogen rich syngas can be directly used to generate power using gas turbine in a simple or combined cycle mode. The Carbon emission from the gas turbine can be converted into SNG (synthetic natural gas) using surplus Hydrogen-rich syngas. The SNG thus produced can be distributed for CHP (combined heat and power) applications so that the Carbon emission can be controlled or distributed. By implementing the above process one should be able to maintain Carbon at specific level in the atmosphere. Existing coal fired power plants can retrofit this technology so that they will be able to reduce their Carbon emissions substantially; they can also produce SNG as a by-product using their Carbon emissions and achieve zero Carbon emission at their site while generating revenue by sale of SNG. Coal is the cheapest and widely used fossil fuel for power generation all over the world. Therefore it will be a win situation for everyone to use coal and also to reduce Carbon emissions that can address the problems of climate change. Meanwhile research is going on to generate renewable Hydrogen cheaply directly from water using various technologies. But we believe we are still far away from achieving this goal and we require immediate solution to address our climate change problems. Recently BASF made a press release :www.basf.com/group/pressrelease/P-13-351‎ claiming a break-through technology to generate Hydrogen from natural gas without any CO2 emissions.