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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 electrochemical 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”.Toyota mirai power supplyToyota mirai layout

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.

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 camp.

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

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 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 : BMW,Honda,Toyota and Tesla Roadster websites)


When Carbon emission is high and the globe is warming due to such emissions then the simple and immediate solution to address this issue is to convert Carbon into Hydrocarbon, and the simplest Hydrocarbon is Methane (CH4).By simply introducing Hydrogen atom into Carbon atom the entire fuel property changes. For example the heating value of coal is only 5000-6500 kcal/kg at the maximum while the heating value of Methane (natural gas) increases to 9500 kcal/m3 by the above conversion. It means the same power generated by coal can be generated by using almost half the quantity of natural gas. Converting Carbon into substituted natural gas (SNG) is one way of addressing climate change in a short span of time. By switching over the SNG from coal will cut the CO2 emission almost by 50%.

Global warming due to GHG emission has become a serious environmental issue in recent times and more and more investments are made on renewable energy projects such as solar and wind etc. In spite of the major thrust on renewable energy projects the main source of power is still generated around the world  using fossil fuel especially Coal  due to its abundance and low-cost. Moreover the investment already made on fossil fuel infrastructures are too big to be ignored and investment required to substitute coal-fired power plants by renewable energy are too large and gestation periods are too long to maintain the current electricity demand and to meet the future demands. The cost of renewable energy also is high and there is great resistance by consumers to switch over to renewable energy. Many Governments are reluctant to subsidize renewable energy due to their financial constraints. That is why countries like China which is growing at the rate of more than 8% pa are trying to decrease the ‘Carbon intensity’ rather than closing down the coal–fired power plants by setting up SNG (synthetic natural gas) plants by gasification of  coal . This will cut their Carbon emissions almost by 50% surpassing all other countries around the world in short span of time, thus meeting their emission targets agreed in “Kyoto protocol”. They can also meet the increasing electricity demand by using “syngas” generated by coal gasification plants, while reducing the Carbon pollution. They will also be able to produce Diesel and Gasoline from coal similar to the “SESOL” plant in South Africa which is already operating successfully for the past 50 years.

“Leveraging Natural Gas to Reduce Greenhouse Gas Emissions” – a summary report by Center for Energy and Climate Solutions (C2ES) have highlighted the following in their report.

“Recent technological advances have unleashed a boom in U.S. natural gas production, with expanded supplies and substantially lower prices projected well into the future. Because combusting natural gas yields fewer greenhouse gas emissions than coal or petroleum, the expanded use of natural gas offers significant opportunities to help address global climate change.

The substitution of gas for coal in the power sector, for example, has contributed to a recent decline in U.S. greenhouse gas emissions. Natural gas, however, is not carbon-free. Apart from the emissions released by its combustion, natural gas is composed primarily of methane (CH4), a potent greenhouse gas, and the direct release of methane during production, transmission, and distribution may offset some of the potential climate benefits of its expanded use across the economy.

This report explores the opportunities and challenges in leveraging the natural gas boom to achieve further reductions in U.S. greenhouse gas emissions. Examining the implications of expanded use in key sectors of the economy, it recommends policies and actions needed to maximize climate benefits of natural gas use in power generation, buildings, manufacturing, and transportation. More broadly, the report draws the following conclusions:

•The expanded use of natural gas—as a replacement for coal and petroleum—can help our  efforts to cut greenhouse gas emissions in the near to mid-term, even as the economy grows. In 2013, energy sector emissions are at the lowest levels since 1994, in part because of the substitution of natural gas for other fossil fuels, particularly coal. Total U.S. emissions are not expected to reach 2005 levels again until sometime after 2040.

• Substitution of natural gas for other fossil fuels cannot be the sole basis for long-term U.S. efforts to address climate change because natural gas is a fossil fuel and its combustion emits greenhouse gases. To avoid dangerous climate change, greater reductions will be necessary than natural gas alone can provide. Ensuring that low-carbon investment dramatically expands must be a priority. Zero-emission sources of energy, such as wind, nuclear and solar, are critical, as are the use of carbon capture-and-storage technologies at fossil fuel plants and continued improvements in energy efficiency.

• Along with substituting natural gas for other fossil fuels, direct releases of methane into the atmosphere must be minimized. It is important to better understand and more accurately measure the greenhouse gas emissions from natural gas production and use in order to achieve emissions reductions along the entire natural gas value chain.”

Countries like India should emulate the Chinese model and become self-sufficient in meeting their growing energy demand without relying completely on imported Petroleum products. Import of petroleum products is the single largest foreign exchange drain for India, restricting their economic growth to less than 5%. Countries that rely completely on coal-fired power plants can set up coal hydro-gasification and gasification plants to cut their Carbon emissions in the immediate future while setting up renewable energy projects as a long-term solution.

Transiting Carbon economy into Hydrogen economy is a bumpy road and it will not be  easy to achieve in a short span of time. The logical path for such transition will be to switch coal based power generation into gas based power generation for the following reasons.

The largest Carbon emissions are from power generation and transportation. Transportation industry is already going through a transition from fossil fuel to Hydrogen. More future cars will be based either on Fuel cell or Electric and in both cases the fuel is the critical issue. Battery technology also will be an issue for Electric cars. It is more practical to generate Hydrogen from natural gas and to set up Hydrogen fuel stations than generating Hydrogen from solar-powered water electrolysis. With improvement on Fuel cell technology it is more likely that PEM Fuel cell may be able to operate on Hydrogen derived from natural gas that is completely free from any Sulphur compounds. Even for Electric cars, natural gas will play an important role as a fuel for power generation and distribution in the near future as we transit from Carbon economy to  full-fledged Hydrogen economy.

Countries like India with highest economic growth will have to be pragmatic by setting up more SNG plants with indigenous coal than depending on imported LNG. India has only two LNG terminals now in operation but do not have gas transmission infrastructure. With increasing demand for natural gas from all over the world and lack of LNG receiving terminals, India will have to face a serious fuel and power shortage in the future. By installing more coal gasification and SNG plants with down-stream products like Diesel and petrol, India can overcome the fuel and power shortage. In fact India set up the first coal gasification and Ammonia and Urea plant in Neyveli (Neyveli Lignite Corporation) way back in Fifties after her independence and it is time to visit the past.

Renewable energy is certainly the long-term solution for energy demand but we have to consider the amount of GHG emission associated with production PV solar panels, wind turbines and batteries. There is no easy fix to cut GHG emission in short span of time but switching Carbon to hydrocarbon will certainly reduce the emissions scientists are advocating and water (steam) is the key to introduce such Hydrogen atom into the Carbon atom. That is why we always believe “Water and Energy are two sides of the same coin” and renewable Hydrogen will be the key to our future energy.

For more information on the above topic please refer to the following link:

Source: Harvard University

Link: Coal to Natural gas Fuel switching and Carbon dioxide (CO2) emission reduction.

Date: Apr 2011.

Author: Jackson Salovaara.

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