With regulatory and market focus moving to the use of renewable energy and alternative fuels, one technology contractors will soon be facing is fuel cells. Here’s what you should know.

1 What are fuel cells?

Fuel cell technologies provide an efficient and environmentally friendly way to generate heat and electricity. Their operation is similar to batteries – they convert the energy from a chemical reaction by combining a fuel such as hydrogen with oxygen, producing low voltage dc electricity and heat. They are seen as a combined heat and power (chp) solution for buildings. Systems are now available in capacities of 1-200 kWe, with more under development, and they are predicted to feature strongly in future electricity production.

The London Hydrogen Partnership (LHP) cites small fuel cells as 30-40% electrically efficient and over 80% efficient overall. Capital costs are high relative to traditional power generation, with manufacturers yet to set list prices as mass production of systems is not yet required. At an industry conference earlier in 2005, $3000/kWe was quoted as current capital cost; the CIBSE CHP Group estimates projected costs of around £750/kWe, with generating costs of 3-4 p/kWh if manufacturing costs are reduced. Annual maintenance costs are estimated to range from 1.5-5 p/kWh.

2 Market forces

Government and international legislation such as the Climate Change Levy is increasing the use of environmentally-friendly technologies through targets to reduce CO2 emissions.

Hydrogen is seen by many as key to a sustainable energy future and its use in fuel cells eliminates CO2 emissions from electricity production. The UK market has yet to take off, but others such as the USA, Germany, Japan and Iceland are working towards a hydrogen economy.

The worldwide installed capacity is relatively small to date due to the lack of commercially competitive products, but CIBSE estimates that the global value of fuel cell business could rise to £13 billion per year by 2025, with generating capacity reaching 15 GW by 2011.

The government recently announced £7 million of funding for demonstration projects over the next 3·5 years; the LHP expects guidance to be issued later this year on how this may be spent. The European Commission is also expected to confirm a 27 billion euro funding project.

3 Applications

Over 200 fuel cell systems have been installed worldwide, with applications including hospitals, hotels, offices and schools.

In the foreseeable future, they are most likely to be installed in large, prestigious developments and their use influenced by energy regulations such as the London Plan. This requires new developments to include energy efficient and renewable energy technology when feasible, with fuel cells listed as one of the options.

As well as individual buildings, fuel cells can be used in community schemes. The first UK installation was by Woking Borough Council. Here a 200 kWe fuel cell helps light Woking Park and supplies the heating and power to a nearby swimming pool, where it can also be used for summer cooling. The system has an estimated 11·8 year payback, partly due to high capital costs involved in shipping plant from USA. (see www.woking.gov. uk/environment/greeninitiatives).

Demonstration projects include the lighting of London’s Trafalgar Square Christmas tree in 2004 and buses around the capital.

4 Cell selection

Several types of fuel cell are available for use and/or under development. Contractors should be aware that some are more suited to building applications than others.

  • Alkaline fuel cells – this is one of the oldest types. It operates at low temperature and is susceptible to contamination so pure oxygen and hydrogen must be used. It is also expensive, so unlikely to become a large player in the commercial market.
  • Molton carbonate fuel cells – these are suited to large power generation and chp, with installations up to 2 MW demonstrated. They operate at around 600-700°C, so generate steam that can be used to produce more power.
  • Phosphoric acid fuel cells – this is the most developed technology and CIBSE estimates that to date around 400 systems are in commercial use worldwide. They can be used for small power generation, chp and distributed power. They are also being marketed for ups and premium power.
  • Proton exchange membrane
  • fuel cell – this type operates at relatively low temperatures of 60-80°C. They are suited to several applications including power generation for buildings.

    • Solid oxide fuel cells – these operate at temperatures of around 1000°C, enabling steam to be produced to run turbines for further electricity generation. They are deemed one of the most promising for large-scale power generation and chp applications.
    • Solid polymer fuel cells – these are suited to vehicle and stationary applications, such as buildings. They have been used in various commercial areas including chp and distributed power.
    Over 100 UK firms are involved in the creation of a global fuel cell industry, with input varying from r&d to systems integration and servicing.

    Manufacturers including Baxi, Johnson Matthey, Vaillant and Viessmann are currently developing products specifically for the UK market, with some offering training programmes specifically for installers.

    • Source

    Electrical and Mechanical Contractor