Fuel cells are electrochemical devices that convert hydrogen fuel directly into electricity and heat without any combustion. They can do this continuously as long as their is a constant source of fuel.
By the nature of its electrochemical reaction, a fuel cell can be more than twice as efficient as an internal combustion engine which is typically around 30% efficient in converting fuel into reusable energy.
A conventional engine such as the ones used in diesel generators burn fuel to create heat and in turn convert heat into mechanical energy and finally electricity. A fuel cell produces electricity, water and heat directly from hydrogen and oxygen, bypasses the inefficient mechanical processes.
Conventional Engine Conversion Process
FUEL+OXYGEN > COMBUSTION > HEAT+MECHANICAL ENERGY = ELECTRICITY
Fuel Cell Conversion Process
FUEL+OXYGEN > CHEMICAL REACTION = HEAT+WATER+ELECTRICITY
Cells are stacked to produce a fuel cell stack to the power output required. They can be used independently or integrated with other components to deliver operational power tailored to the application.
Hydrogen is one of the most abundant elements on our planet. It can be sourced in various ways;
- Using reformation which converts a gas or liquid fuel such as propane or LPG.
- From carbon-neutral sources of methane such as bio-mass or land-fill gas.
- Through electrolysis using renewable power such as wind or solar.
Type Of Fuel Cells
The most promising fuel cells are PEM or proton exchange membranes which have a manageable operating temperatures (40 – 100 deg. C) and are highly efficient (~60%). Also new developments in SO or solid oxide fuel cells are now making them equally promising.
Due to their high power densities, modular construction, low operating temperatures and solid polymer electrolyte they can be used in all sorts of ways where other sources of power would not be practical.
The electrolyte (a conductor and insulator) allows ions to travel between the cathode and anode to keep the power-generating process under-way, while at the same time keeping the reactive oxygen and hydrogen apart are poly-perfluorosulphonic acid.
You can you this link to read more about the types of fuel cells.
Benefits of Fuel Cell Technology
Conventional power technologies reach their maximum efficiency stage at a single operating point known as the power band. Fuel cells on the other hand can achieve high efficiency under partial loads and at full capacity, with rapid load following capability.
This makes them suited to both stationary and automotive power applications, as they are capable of rapid start-up and immediate response to changes in demand.
NO to Low Pollution
Fuel cells do not emit any polluting by-products. Even when operating on hydrocarbon fuels, pollutant levels are significantly lower and with few moving parts, fuel cells are a quiet source of power.
Due to their modular design fuel cells have the advantage of economies of scale, meaning a cell can be reused to make varying sizes of stacks and power outputs. This also keeps production costs low.
Their modular build gives them a high fault tolerance, so if by chance a fuel cell failed the rest of the system would continue to function, resulting in only a small loss of power when compared to conventional mechanical failures which can render the system inoperable.
Fuel cells can operate without grid power and can be used in remote or portable applications
Tailoring a fuel cell to any kind of hydrocarbon based fuel source from pure hydrogen to heavy stocks like diesel means a system can be adapted for any application or even multi fuel capability.
Enhance or Replace
Weight for weight, fuel cells can deliver 1000x times more energy than a lead-acid battery and 200x times more than the latest lithium ion technology and as the fuel source is external it can be replaced quickly making them ideal compliments or complete replacement to conventional batteries.
Advantages of PEM and SO Fuel Cells
PEM is the most widely adaptable technology of all fuel cells because of its special characteristics.
Because the cells are solid they are less sensitive to shock and vibration making them ideal for portable or motion applications.
High Power Density
Their power density make them ideal where compact space and weight demands are critical.
Low Fabrication Costs
Due to their low operating temperatures they can be built from lower cost materials making them ideal for mass market adoption.
Rapid Load Response
Power output can be varied in response to rapid and variable demands such as “on demand” throttling or heat and power applications.
Can exceed 90% overall efficiency when in combined heat and power (CHP) mode with an electrical efficiency of around 50%. Conventional electricity generation is around 35% efficient and combustion engines 20%.
PEM Fuel Cells Applications
Any power generation applications, such as:
- Replacing the internal combustion engine in vehicles like cars, motorbikes, buses, locomotives, forklifts, light aircraft and UAVs.
- On board auxiliary power units (APUs) for air, sea and land transportation.
- Decentralised power generation for industrial or domestic applications.
- Portable generation systems for domestic, industrial, military and maritime application.
- Small scale power packs for remote, unattended and military applications.
- General battery replacements or displacement.
Watch TV personality Robert Llewellyn explore the inner workings of Hydrogen Fuel Cell Technology with academics at Birmingham University.