Hydrogen set to clean up

Fuel cell technology isn't just for vehicles.

With several commercial installations and demonstration sites across the UK, fuel cells are increasingly taking a central role in turning hydrogen into a viable and sustainable source of energy.

Hydrogen fuel cells generate a current by passing hydrogen and oxygen over either side of a special membrane. This allows an exchange of protons through the membrane (hence 'proton exchange membrane', or PEM), and causes electrons to flow around the circuit. The hydrogen and oxygen combine to produce water, which, along with heat, is the only by-product of the fuel cell process.

Fuel cells have few moving parts and are comparatively efficient - they typically convert 50 per cent of the energy content of the hydrogen into electrical power. They are, for example, significantly more efficient than diesel generators.

Fuel cells are undisputedly 'clean' technology; whether you can consider them to be truly 'green' really depends on how you produce the fuel on which the fuel cell runs.

Industrial companies produce hydrogen in volume as a by-product of chemical processes. You can also produce it - at the site where it is consumed - by a process of reforming natural gas or anaerobic digester gas, a biogas produced from waste products.

However, a 'green' alternative for on-site production, which is attracting considerable interest and research, is to use renewable energy sources - wind or solar power - to produce hydrogen by electrolysis.

Power for today

Stationary and portable power applications don't always have the same physical constraints as transport uses. One of the main challenges in using hydrogen fuel cells for transport is the need to compress as much hydrogen fuel as possible into a smaller space, so that the car goes further between re-fuelling. 

The versatile nature of fuel cell technology means that many stationary and portable applications make commercial sense.

Fuel cells have applications for both prime (i.e. continuous) and backup power. The market is constantly changing as suppliers bring out new products and update existing product lines. 

Fuel cells can power entire buildings and campuses. For example, the Pool in the Park leisure centre in Woking, UK uses a 200kW fuel cell to produce electricity for the entire complex, and it uses the heat emitted as a by-product to warm the centre so that nothing is wasted.

One example of fuel cells operating on a smaller scale with prime power is road signs. In remote areas there may be limited access to electricity to illuminate the signs at night; furthermore, the cost of distributing mains power to the signs can be prohibitive. Fuel cells offer a cost-effective way of ensuring the power is always available.

Some systems require power for telemetry equipment in difficult-to-reach locations. For example, monitoring the flow of water in an aqueduct, or gas in a pipeline, will require electricity to operate the equipment to make and transmit the measurements to a remote monitoring facility. For such situations, fuel cells offer a practical and cost-effective alternative to mains grid power - and to alternative energy options. In some circumstances, such as heavily-wooded areas, a lack of sunlight and wind power precludes the use of solar panels and wind turbines.

Maintaining a stable, continuous power supply is critical in many sectors to ensure the effectiveness of ongoing operations to an organisation's IT and communications infrastructure. Losing the power - if only for a second - can have disastrous effects and usually results in financial losses to the business as a result of its inability to operate.

Smaller, lighter, cleaner

The most common approach organisations use to ensure a consistent backup power supply is with batteries and diesel generators. However, large battery banks take up a considerable amount of room, and problems can arise due to their added weight, which can necessitate reinforced flooring.

In many instances, generators are simply not a viable solution, either because outside space is limited (consider a high-rise office location) or air quality restrictions prevent them being installed. In these instances, fuel cells can provide an ideal alternative. Because there are no harmful emissions, planning permission is usually not an issue. Their small size and the fact that they run almost silently means they can be housed indoors - either inside or close to the computer room - thus reducing any space and location issues.

Unlike batteries, hydrogen fuel cells can provide unlimited standby runtime. This is achieved by continuing to supply hydrogen to the unit, either in the form of additional cylinders or from hydrogen compressed and stored on-site, possibly created from a renewable energy source.

Due to their modular design, additional fuel cell modules can be added to the overall system, increasing the amount of power it produces without needing to replace the whole system.

When sourced from renewable energy, hydrogen offers a greener alternative to fossil fuels and reduces an organisation's dependence on oil.

Organisations choosing to install a fuel cell into their infrastructure may incur higher initial costs as the technology is relatively new. As the take-up of fuel cells grows, production costs will fall.

Even today, for some applications, fuel cell costs compare very favourably with the alternatives. Also, because fuel cells have relatively few moving parts, ongoing maintenance costs are lower, which helps to reduce the overall lifetime cost.

Fuel cells are a viable alternative source of both prime and backup power for many non-transport applications, evidenced by the growing number of commercial and demonstration installations throughout the world.

Fuel cells and hydrogen energy offer an alternative source of power that is sustainable and reduces our dependence on oil and fossil fuel. They offer organisations a way to be cleaner, greener and more energy-efficient while ensuring the success and stability of their operations.

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