There exists a need for cleaner source of energy to meet the growing energy demand in an environmentally sustainable way and hydrogen and fuel cells are expected to play a significant role to give the solution. Clean energy is needed to address the change in climate, air pollution, energy independence and energy demand. The increased amounts of carbon dioxide and other greenhouse gasses from burning fossil increase the global average temperature since 1850. This climate patterns alters the weather events like rainfall, sea levels, ocean acidification levels, Arctic glaciers, extreme weather events, animal habitats, etc., Hence, many research groups worldwide are working towards reductions in CO2 emissions by re-examining our sources of energy. In addition, emissions from industry and motor vehicles release smog, ozone, particles, nitrogen oxides and sulphur oxides into our environment, which severely affects human health as well as the ecosystems. The other major reason for clean energy is energy independence and the technology to meet the supply demand chain. As the global population rises, and more and more people live energy-intensive lifestyles, there is a need to innovate new ways to meet this growing demand.These realities are driving the development of new technologies and ideas. Future energy systems will be cleaner, more efficient, and more reliable. Hydrogen and fuel cell systems can help meet the challenges ahead.
Hydrogen is the simplest element that consists of only one proton and one electron. It does not occur naturally as a gas, and always remains combined with other elements. Water, is a combination of hydrogen and oxygen (H2O). Hydrogen is also found in many organic compounds like hydrocarbons such as gasoline, natural gas, methanol, and propane. Hydrogen can be obtained from hydrocarbons by a reforming process and from water by electrolysis. Hydrogen is high in energy, yet an engine that burns pure hydrogen produces almost no pollution. Unlike conventional technologies, fuel is not ‘burned’ but is combined in a chemical process. Fuel cell technology dates back to the 1800s, can be used to make electricity to power vehicles, homes, and businesses. And if you use a renewable energy source as the main source of hydrogen, a fuel cell can be considered a renewable energy source. Fuel cell works like a battery except that the chemical fuel is stored external to the device unlike batteries.
A fuel cell consists of two electrodes sandwiched around an electrolyte. Oxygen passes over one electrode and hydrogen over the other, generating electricity, water, and heat. Hydrogen fuel is fed into the ‘anode’ of the fuel cell. Oxygen/air enters the fuel cell through the cathode. With the help of a catalyst, the hydrogen atom splits into a proton and an electron, and the proton passes through the electrolyte. The electrons create a separate current that can be utilized before they return to the cathode, to be reunited with the hydrogen and oxygen in a molecule of water. A fuel cell system that includes a ‘fuel reformer’ can obtain hydrogen from any hydrocarbon fuel – from natural gas, methanol, and even gasoline. Other possible fuels include propane, hydrogen, anaerobic digester gas from wastewater treatment facilities, and landfill gas. Fuel cells are being designed for use in stationary electric power plants to provide reliable, clean, high quality electricity for distributed power generation. These small systems can provide primary or backup power to commercial and industrial customers such as hotels, hospitals, manufacturing facilities, and retail shopping centers. Eventually, smaller fuel cells will be sold for use in homes, most of which will connect to natural gas supplies. For industries that require high quality uninterruptable power, such as the computer technology industry, fuels cells can provide power without disruptions or voltage distortions. In addition to electricity, customers can take advantage of the heat from the fuel cell and use it for hot water, space heating and cooling, and industrial processes. Fuel cells are classified according to the type of electrolytes and operating temperature.
They can power any device ranging from a few microwatts to megawatts, operate from room temperature to 100oC. The major challenges are in the hydrogen infrastructure, cost, durability etc., which prevents the market potential of fuel cells.
The application of fuel cells are divided into three broad categories viz., Portable fuel cells, including Auxiliary Power Units (APU), Stationary power fuel cells for a fixed location, Transport fuel cells for either primary propulsion or range-extending capability for vehicles. The power typically range from a few watts to 20kW for portable like campervans, boats, portable soldier power, personal electronics, battery chargers etc., 0.5kW to 500 kW for stationary like large stationary combined heat and power, small stationary micro CHP, UPS etc., and 1kW to 100 kW for transport applications like forklifts, electric vehicles. The type of fuel cells also can be varied depending on the application. For example, portable and transportation sector makes use of fuel cells like PEMFC and DMFC, while stationary applications use all the four types of fuel cells. The major players of fuel cell in the prime market are Fuel Cell Energy for Molten Carbonate Fuel Cells (MCFC), 300 kW, Bloom Energy for Solid Oxide Fuel Cells (SOFC), 200 kW, ClearEdge Power for Phosphoric Acid Fuel Cells (PAFC), 400 kW and Ballard for Proton Exchange Membrane Fuel Cells (PEMFC), 1MW using the ClearGen units at the headquarters of Toyota USA. One of the aspects of fuel cell technology that appealed to telecoms customers was the replacement of widely used fuels such as diesel, which is prone to theft. Ballard offers both hydrogen and methanol-fuelled backup power systems around 500 in numbers. During 2012, when Hurricane Sandy passed over the East Coast of the USA with devastating effect, fuel cell powered cell phone towers remained in operation for extended periods for customers in New York, New Jersey and Connecticut. Similarly, Altergy has more than 60 fuel cell systems installed in the disaster area and all were reported to function normally during and immediately after the storm. The more frequently fuel cells are seen to provide reliable power during similar events, the more interest there will be from around the world in utilising the technology.
Fuel cells for transportation sector includes Forklift trucks, other goods handling vehicles such as airport baggage trucks,Two- and three-wheeler vechicles such as scooters, Light duty vehicles (LDVs), such as cars and vans, Buses and trucks, Trains and trams, Ferries and smaller boats, Manned light aircraft, Unmanned Aerial Vehicles (UAVs) and Unmanned Undersea Vehicles (UUVs) etc. However, they have so far seen limited use but this is set to change as most major automakers have targeted 2018 for commercial sales of their fuel cell vehicles. Initial locations for this rollout will most likely concentrate around clusters of early hydrogen refuelling infrastructure in Japan, Germany and the USA, and will then spread outwards from these centres as the market is established. Toyota Mirai, Hyundai ix35 are the recent models that are on the road using PEMFC technology. Capable of traveling 300-400 miles on a tank of hydrogen and refueling in three-five minutes, Fuel cell based electric vehicles combine the emissions-free driving of an electric vehicle with the range and convenience of a traditional internal combustion engine. They are up to three times more efficient than conventional vehicles, and when natural gas is used as a source for hydrogen. Having no internal moving parts, fuel cells also are quiet and highly reliable.
The fuel cell bus sector is showing a slow growth, with more prototypes being unveiled. Successful deployments have taken place in Europe, Japan, Canada and the USA but the high capital cost is still a barrier to widespread adoption. However, it is hoped that soon fuel cell bus prices will be comparable to diesel-hybrid bus prices.
From the Indian context, Many research groups from ARCI, CGCRI, BHEL, IIT Mumbai, IITMadras, IIT Delhi, CECRI,VSSC, Anna university, VIT, etc., are working on various aspects of only two types of fuel cells viz., polymer electrolyte membrane fuel cells and solid oxide fuel cells. Most of the groups are at the science level while ARCI and CGCRI are working at the system level. ARCI has got a dedicated team to develop PEMFC modules from a few watts to higher capacity level. They have just initiated to demonstrate their products at the sites where hydrogen is available.
Two recent reports, the Yale Environmental Performance Index ranked India 174th out of 178 countries on air pollution and India’s growing telecom sector, the second largest in the world with more than 500,000 cellular towers, contributes more than 2% to India’s total greenhouse gas emissions. Currently, the majority of remote or rural telecom sites use diesel generators, which can be extremely noisy, dirty and difficult to maintain. More recently, scientists at the Indian Institute of Tropical Meteorology reported that the Indian telecom sector could utilise up to 7.5 billion liters of diesel per year to power these mobile towers.
Intelligent Energy has deployed about 100 megawatts of fuel cells for telco tower backup power in India with customers including Microqual and ATL, and has about 400 megawatts under contract.The unit was reported to improve site power availability while reducing fuel use by 18% in a six month period.
Ballard Power Systems with RelianceJioInfocomm Limited (RJIL) will install their 100 ElectraGen-ME fuel cell backup power systems in its wireless telecom network in India.
Tata motors in collaboration with ISRO has demonstrated a FC bus with Ballard stack and 12 buses with Ballard vfuel cell systems are in the pipeline for demonstration, once when hydrogen infrastructure is ready.
Conclusion
A hydrogen-powered car could be ten times costlier than a car with an internal combustion engine. Researchers are developing new diagnostic techniques to help optimise cost and lifetime of fuel cell systems.
The ability to support new catalysts and supports, membranes which reduce the cost, improve the performance and increase the stability of catalysts systems is important. When it comes to commercialisation, cost and hydrogen infrastructure are the major key elements.
Sources: www.hydrogen.energy.gov; www.hyafc.org; www.fuelcelltoday.org
