Fuel cells are highly efficient, quiet, with zero emissions at the point of use and in many applications offer greater energy density by volume or weight than even the most advanced batteries. Fuel cells using hydrogen derived from renewable energy provide truly zero carbon power. As a result we are confident that fuel cells powered by hydrogen will have an important role in future energy systems, often in combination with other technologies such as solar PV or batteries.
Fuel Cells were first demonstrated by Sir William Grove in 1839 but the first workable fuel cell was not demonstrated until 1959. Early fuel cells powered the NASA Apollo missions and a wide number of uses have been developed since then.
Like a battery a fuel cell is an electrochemical device. Batteries and Fuel Cells generate their energy by converting chemical potential energy to electrical energy and with heat as a by-product. The electrochemical process is highly efficient.
A battery stores energy within it and once depleted the battery must be discarded or recharged using an external supply of electrical energy.
In contrast a fuel cell uses an external source of chemical energy, the fuel, can will run for as long as there is a fuel supply. Many, but not all, fuel cells types use hydrogen as a fuel.
In practice a fuel cell device is made up of many cells lined up in series into a fuel cell “stack”, with the number and size of the cells determining the voltage and power output. A stack will then be built into a fuel cell system with hydrogen supply, electronics and control integrated to make a working device for the desired use. This integration is where Arcola Energy has key expertise.
Advantages of Fuel Cells
Electrochemical processes have high theoretical efficiency and fuel cells are generally around 50% efficient, much better that internal combustion engines. The efficiency means that, even if the hydrogen is produced from fossil fuels, fuel cells offer CO2 reductions in most situations compared to conventional generators or engines.
Fuel cells running on hydrogen produce zero emissions at the point of use. No CO2, no NOx and no SOx, just water. Hydrogen can be generated from renewable sources, such as electrolysis from excess renewable generation so fuel cells can offer fully zero emissions solutions.
Fuel cells are very quiet with the only noise generally coming from cooling fans if they are needed. There are few moving parts so fuel cells have very good reliability and maintenance is more straightforward.
What can they be used for?
Fuel cells can generate electricity for a very wide range of uses, transport, buildings, portable devices, back-up systems and many more. Some fuel cell technologies are capable of generating power in MW-scale, others more suitable for lower power, from W to kW scales.
Fuel cells are very good at generating power at a consistent level, for long periods of time and with high reliability. They are less good at powering very dynamic loads and frequent stop-start scenarios. For this reason they are often combined in hybrid systems along with batteries or other technologies that are better at balancing out dynamic power needs.
At Arcola we believe the fuel cells have a key role in renewing energy systems, working in combination with other efficient and renewable energy technologies.
Most of the hydrogen on earth is bound up in molecular form in water or hydrocarbons. To be used as a fuel, energy needs to be used to generate the hydrogen from its source. Hydrogen can be extracted from water by electrolysis and from hydrocarbons like methane by a process called “reforming”, as well as a range of other chemical and biochemical processes. While these different routes to hydrogen have different costs and different impacts on CO2 emissions, in principle affordable, zero-carbon hydrogen production is entirely feasible.
Hydrogen is best thought of as an “energy carrier”, enabling energy to be generated in one place, stored and then moved to where it is needed. This energy storage capability is an important role for hydrogen in enabling much wider uptake of renewable electricity generation as electrolysers creating hydrogen can use excess renewable power when it is available, protecting the electricity grid. The hydrogen can then be used elsewhere in the energy system; in transport, in local power generation or by injecting it into the gas grid, in domestic heating.
New technologies for generating hydrogen efficiently and cheaply are emerging all the time and at Arcola Energy we are excited about the potential for combining these with real-world fuel cell applications