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.

Which car Hydrogen, Fuel cell or Electric that will win the race?

Automobile industry has come a long way since the time of Henry Ford. The internal combustion engine that drives the modern car is slowly but steadily evolving into an emission free engine. The carbon pollution has caused globe to warm and changed the climate and also caused respiratory illness for millions of people around the world for decades. The Carbon pollution was completely ignored in the past while other design features of the car have undergone massive changes. However, when the smog and deteriorating air quality of Delhi and Beijing was beamed around the world in our TV sets, people realized how vulnerable they are to carbon pollution. But how to eliminate the Carbon emission from our automobiles? 1.The simple answer is to substitute the fossil fuels we use every day such as Petrol and Diesel with Carbon free fuel such as Hydrogen. Hydrogen being a light gas it has to be compressed and liquefied so that it can occupy less space. However, it requires a special ‘cryogenic tank’ to store liquid Hydrogen at – 253 C. BMW has already produced a commercial vehicle and it is in the market. However, the Hydrogen dispensing stations are limited in numbers. It uses existing internal combustion engine suitably modified for Hydrogen fuel so that they can use existing infrastructure that produces their petrol engines. There is no carbon emission except for water vapour. However, Hydrogen should be generated using renewable energy sources such as solar or wind. Hydrogen generated by reformation of natural gas will still have a Carbon foot print. It can be classified as a Carbon free car depending upon how Hydrogen is generated. However, producing liquid hydrogen or filling in a cryogenic tank is not commercially feasible for individual household. Hydrogen supply will have to be a centralized filling station. BMW has recently focussing their attention towards Fuel cell car. While those early vehicles were fun to drive, they suffered from the inefficiencies of super-cooling the liquefied hydrogen, and the hydrogen vaporizing in storage. Around the turn of the century, BMW began to research the hydrogen-powered, fuel-cell electric vehicle as an alternative to the hydrogen-powered combustion engine. 2.The other alternative is to substitute fossil fuel with compressed Hydrogen that generates an electric power using Fuel cell that drives the motor and the car. Here both fossil fuel and internal combustion engine are substituted with Hydrogen fuel and Fuel cell. This is a marked deviation from a conventional car. Honda of Japan was the first to introduce a commercial car using a Fuel cell. It uses compressed Hydrogen at 70 Mpa pressure that supplies Hydrogen to PEM (proton exchange membrane) Fuel cell that generates power that drives the motor and the car. There is no emission except for water vapour. The car runs smoothly and silently because there is no mechanical engine or moving part. It is truly a Carbon free car if the Hydrogen is generated from a renewable energy source such as solar or wind. It is ideal for houses with roof top solar panels. However, one has to install a water purifier, an electrolyser, a compressor and a compressed tank for Hydrogen storage. If the Hydrogen is generated by steam reforming of Natural gas, then it will have a Carbon footprint and cannot be classified as carbon free car. Generation of Hydrogen using roof top solar panel, electrolysis and compression is possible by individual households but it involves still some risk due to the explosive nature of Hydrogen. A centralized Hydrogen dispensing is still a safer method. Toyota Mirai Fuel cell car is a new model introduced by Toyota motor Co of Japan. It too has certain additional features such as a power generator for a remote households or camps. 2.The third alternative is to eliminate fuel as well as the engine completely; instead supply power to the motor from a storage battery. Here there is no emission or noise because there is no engine or moving parts similar to Fuel cell car. However, the battery is heavy and occupies a large space and it requires frequent charging from an external power source. The power often comes from the main power grid which carries the power generated from a power station which invariably uses fossil fuel. Though there is no Carbon emission from the electric car it still has Carbon footprint. However, if the power is generated from a renewable energy source such as solar and wind then it can be classified as Carbon free car. It is ideal for houses with roof top solar panels. However, it should be connected to the power grid in parallel. Alternatively, it can be connected to a storage battery if there is no grid. The Lithium ion battery pack in Tesla Roadster weighs 990 pounds, stores 56 kWh of electric energy, and delivers up to 215 kW of electric power. Tesla battery packs have the highest energy density in the industry. To achieve this energy density, Tesla starts with thousands of best-in-class Lithium-ion cells and assembles them into a liquid-cooled battery pack, wrapped in a strong metal enclosure. The battery is optimized for performance, safety, longevity, and cost. The cells used in a Roadster employ an ideal chemistry for electric vehicles Nickel Metal Hydride (NiMH) batteries are commonly used in hybrid cars. However, a 56 kWh NiMH battery pack would weigh over twice as much as the Roadster battery. Instead, Tesla uses Li-ion battery cells which dramatically decrease the weight of the Roadster pack and improve acceleration, handling, and range.

With Lithium-ion chemistry, there is no need to drain the battery before recharging - there is no “memory effect”. Roadster owners simply "top-off" each night.However long term supply of Lithium is still an issue. Each of the above cars have their own advantages and disadvantages. However, Fuel cell cars have certain advantages over Electric cars in spite of the advancement in battery technology primarily due to the weight of the battery and frequency and time required to charge the battery. Fuel cell car has a capacity to store Hydrogen fuel as well as to generate power onsite and this advantage will go a long way to make fuel cell cars truly carbon free not only for transportation but also for stationery power generation in remote locations. A large scale deployment of renewable energy generation such as solar and wind around the world can deliver a Car that is truly carbon free. However fossil fuel power generation will continue for years to come as the new technologies are developed to generate power using fossil fuel without emitting Carbon emission such as Carbon recycling. The real winner of the car race will depend upon how a Carbon emission free power generation technology will emerge in the future. Whatever may the power technology Fuel cell will be here to stay and if a cheap alternative catalyst is developed for Fuel cell then the race will be well and truly on. (Ref : Honda, Toyota and Roadster websites)

Bioethanol fuel for Fuelcell cars

Bioethanol has successfully substituted Gasoline as a fuel for cars both in the form of blends with Gasoline or individually as an Anhydrous Ethanol. This successful demonstration by Brazil opens up new generation of cars called flex-fuel cars that allow usage of various blends of Ethanol and Gasoline.Bioethanol can also be used to generate Hydrogen onsite by steam reformation so that even Fuel cell cars such as Honda FCX can be felled by Bioethanol.This makes Bioethanol unique as an alternative fuel for transportation. It also facilitates onsite power generation using Fuel cell, replacing diesel engines. Substitution of Gasoline by Bioethanol has several advantages over other alternative fuels. The biggest advantage with Bioethanol is, it is renewable and it allows reduction of greenhouse gases from the atmosphere and it will be eligible for Carbon credit. It can be produced by both developing as well as developed countries using locally available agriculture produces such as cane sugar, corn, tapiaco, sorghum etc. Hydrogen generated from Bioethanol is also free from Sulfur compounds normally associated with natural gas, making it an ideal fuel for Fuel cell application in cars, as well as for power generation using SOFC (solid oxide Fuel cell) or PAFC (Phosphoric acid Fuel cell).The resulting high purity Hydrogen 99.99% can be used as fuel for all type of transportation including Fuel cell Buses, scooters and even boats. The stoichometric reaction of steam reformation in presence of catalyst can be represented by the following chemical reaction: C2H5OH + 3 H2O---------- 6H2 + 2 CO2 The Ethanol and water mixture is preheated and the vaporized mixture is fed into a catalytic reactor. The resulting Hydrogen is contaminated with carbon monoxide. This gas mixture is separated using membrane such as Palladium to get Hydrogen with less than 50ppm CO as contaminant. Such purity is acceptable by Fuel cell such as SOFC as well as PAFC.In future a small micro-reactor for on-board reformation may be possible making Fuel cell cars with onboard liquid fuel storage. Commercial reformers consumes about 0.88 lits of Bioethanol of 96% purity to generate 1 Nm3 of Hydrogen with 60% conversion. This translates to $ 5.90 per Kg of Hydrogen. Fuel cell cars offer a mileage of 240 from 1 kg Hydrogen costing only $5.90. For onsite power generation 1 kg Hydrogen generates as much as 15Kw electricity and 20Kw heat .Onsite Hydrogen generation with steam reformation also facilitates using SOFC and PAFC for high temperature power generation applications. They are ideal for CHP (combined heat and power) applications for 24x7 operations like hospitals, hotels and super markets. These fuel cells are silent in operation without any emissions except water vapor. Governments should encourage Bioethanol production and distribution for both transportation and power generation. There is a fear that Ethanol could be diverted for potable purposes illegally depriving Governments of potential reveneues.But this can be solved by denaturing Bioethanol and making it unsuitable for potable purposes. Denaturants such Pyridine has no effect on steam reformation and number of denaturants are available. Such policies will allow transition from fossil fuels to Hydrogen or Bioethanol.This is a simple and straight forward step any Government can take irrespective of the size or type of a nation. But it requires political will, determination and leadership. Developing countries need not wait for big greenhouse emitters such as US, China and India to make a decision on their Carbon emissions but start introducing Bioethanol as fuel locally.

How to power your home and fuel your car with Hydrogen?

There is a general opinion that Hydrogen is dangerous or explosive; people are often reminded of Hindenburg accident or Hydrogen bombs. Hydrogen is as safe as Gasoline or Butane gas. It should be handled with care like any combustible material. We have used Hydrogen in industries for so many decades and transported by pipelines across thousands of kilometers; the methods and procedures of handling Hydrogen is well established. It is a very light, colorless and odorless gas and it can easily escape into the atmosphere. Hydrogenation of vegetable oils for production of certain Margarines is one of the classical industrial examples of Hydrogen usage. When 100m3 Hydrogen is compressed to 10,000psi pressure, it is reduced to just 0.163 m3 by vlume.That is how the Hydrogen storage space is reduced in passenger cars. This volume of gas can give a mileage of 652 miles using Fuel cell power. The only emission is just pure water vapor! No noise, no smoke and it is entirely a new experience driving a Hydrogen Fuel cell car. Powering your home with Hydrogen or fuelling your Fuel cell car is not very difficult. It is expensive compared to grid power for two simple reasons. Grid power is generated by power generation companies somewhere else using coal, oil or gas and transmitted across to millions of people.Therefore investment on power generation is shared by millions of people through their monthly energy bills. When you use the grid power, you do not pay any large sum except, a small deposit of few hundred dollars towards connection fee, and you pay your bills based on your monthly electricity usage. But when you try to generate your own power using a solar panel or Fuel cell then you have to make an investment fully upfront. Of course your bank can help financing the system. However, when you calculate the energy cost over the life period of 25 years, you can clearly see the value of such investment. The grid power cost will only increase and never decrease while your generation cost will decrease as the time passes. The future energy cost is likely to increase substantially due to various factors. You can export surplus power to the grid and your payback time will be reduced as the energy cost increases. The first step in powering your home is to calculate your power requirements accurately in terms of watt.hrs.How many appliances you will be using and how many hours you will using each of these appliances per day. Suppose you estimate 15,000 watt.hrs/day or 15kwhrs/day of power, and then a small Fuel cell consuming 1 Kg/day of Hydrogen or 30 kgs/month of Hydrogen will be sufficient to meet your power demands. Similarly you can calculate the amount of Hydrogen you will be using as a fuel for your Fuel cell car. For example if you will be driving your Fuel cell car for 1000 miles per month, then your Hydrogen requirement will be about 14 kgs/month. Your Hydrogen requirement per month for both power and car together will be 44 kgs only. Your total power requirement to generate the above Hydrogen will be 2464 kwhrs/month costing less than $250 per month for both power and fuel. Of course, you need to calculate other fixed costs on the investment. You can export your solar power at a higher tariff to the Government and import your power requirement from the grid during off-peak season at a lower tariff and generate Hydrogen and store it. You can generate your power as and when you need, and you are in complete control of your situation, even if there is a blackout due to grid failure!

Water- Fuel of the future

Water constitutes 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 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 DC power source. Water of certain purity is a critical component 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 eliminate batteries and rectifiers 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 whenever 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 individual 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.