Glamorgan University
Hydrogen and fuel cells
What is hydrogen energy?
Hydrogen is the lightest, simplest and most abundant of the chemical elements, making up about 90% of all matter. It is found in water and most organic compounds. In its gaseous form it is colourless, odourless, tasteless and non-toxic. Hydrogen can be burnt with oxygen producing heat or combined electrochemically in a fuel cell to produce electricity producing only water as exhaust. Hydrogen energy “covers all aspects of the use of hydrogen in energy systems, including transport, stationary energy and other applications” (E4tech, 2004).Why hydrogen and fuel cells?
Reasons for a move towards a ‘hydrogen economy’ include:- Increasing demand for energy;
- Concerns about security and continuity of supply;
- Global climate change;
- Poor air quality.
- The creation of new business and job opportunities.
Hydrogen has the potential to radically change the way in which energy is produced and used and could bring significant environmental and social benefits. In theory it could offer an alternative for all the final forms of energy we use today and provide all our energy services. Although considerable technological and cost barriers exist, efforts to develop the ‘hydrogen economy’ have become a priority for countries across the world including the UK, European Union, USA and Japan.
Hydrogen production
Approximately 500 billion cubic metres of hydrogen are produced worldwide mainly from natural gas or oil. Most hydrogen production (95%) in the UK is generated by steam methane reforming (SMR) of natural gas. SMR is the most economical large scale route to produce hydrogen at the present time. However, 10 tonnes of CO2 are released per tonne of hydrogen, unless coupled with carbon sequestration. Other production methods using fossil fuel feed stocks such as coal or oil includes partial oxidation, gasification and pyrolyis. These fossil fuel dependent routes are not sustainable but could be a transition step to the hydrogen economy.Vast quantities of hydrogen are also produced by the chemical industry as a by-product of processes such as production of chlorine. Hydrogen can also be generated via electrolysis of water. Electrolyser technology is widely used in industry e.g. in metal extraction and refining.
For hydrogen to be ‘clean’ (emission-free) it must be produced from renewable energy sources or nuclear power or, if based on fossil fuels, then the CO2 emitted must be captured and permanently stored (Carbon Capture and Sequestration).
Renewable production routes include:
- Electrolysis – using electricity from wind, wave, tidal, hydro, photovoltaics, etc.
- Photolysis - water
- Biophotolysis - (algae) water
- Pyrolysis/gasification - biomass (woody)
- Photo-fermentation - biomass (wet)
- Dark fermentation - biomass (wet)
Utilisation technologies
Today’s uses of hydrogen are based on industrial use, with artificial fertiliser and the petroleum industries being the heaviest users. However, hydrogen can be used in internal combustion engines, fuel cells and turbines.Fuel cells generate electricity directly via electrochemical reactions and have no moving parts. They are energy efficient, clean and can utilize a variety of fuels. Proton Exchange Membrane fuel cells use hydrogen directly and have the potential to provide an alternative to the internal combustion engine as well as to power stationary and portable applications. One of the early pioneers of hydrogen and fuel cell technology was a Welshman: Sir William Robert Grove, born in Mount Pleasant in Swansea in 1811.
Petrol engines have been converted to use hydrogen since the 1930’s and the adaptation required is relatively inexpensive. Hydrogen is similar to conventional fuel when used in a turbine or jet engine.
End use applications
Hydrogen has a potentially important role in all areas of transportation, electricity generation and mobile applications. Applications that are initially promising are in the areas of distributed generation, combined heat and power, and fleet vehicles. The main challenges will be achieving cost competitiveness and provision of safe, easy to use, affordable and ‘clean’ products and services to end users.Considerable effort across the world is now being focused on developing less carbon intensive, clean transport systems. Nearly all major car manufactures are currently developing prototype hydrogen cars e.g. Ford, Honda, Toyota and DaimlerChrysler. BMW has developed a fleet of combined hydrogen/petrol internal combustion engine cars that allow the driver to fill up on either hydrogen or petrol.
Stationary fuel cell systems can be used in large and small scale applications. They are quiet, excess heat can be used in heating and hot water production for surrounding buildings and there is no need to reinforce the national grid. Near term use is likely to be for provision of auxiliary power and distributed generation. Such technologies are ideal for remote and rural areas as hydrogen that is produced and stored locally can be used to power communities where grid connection is expensive, poor or needs replacing.
Fuel cells could be an important source of power for mobile electronic devices, offering several advantages over conventional batteries, such as increased operating times, reduced weight and ease of recharging. In recent years micro fuel cells have been developed for use in cell phones, laptops and video cameras.
Figure 1: Hydrogen and fuel cell end use applications
The future
The European Commission views hydrogen and fuel cells as strategic technologies to achieving a sustainable energy system and has put forward a challenging vision for implementing the hydrogen economy. A key priority is to exploit the benefits of hydrogen and fuel cell technologies for decentralised energy generation and transport applications. Countries around the world have developed hydrogen energy visions, including Iceland, which plans to move to a hydrogen economy by 2030 with up to 75% of their boat fleet converted. The US predicts mass market breakthrough starting in 2020, growing to full market development by 2040. Whilst, Japan has a set itself an ambitious target to get 5,000,000 hydrogen vehicles on the road by 2020.Hydrogen and Wales
Wales is potentially well placed to exploit the opportunities offered by hydrogen. It has a strategically placed existing hydrogen industry, is well endowed with renewable energy resources and has a number of national competences that could be of benefit in developing a hydrogen economy, such as expertise in agriculture, manufacturing, engineering and world leading research. The National Assembly for Wales is constitutionally committed to sustainable development and sees the development of renewable energy as a source of employment. Wales has the opportunity to take a leading role in the development of sustainably-produced hydrogen and be at the forefront of the technology export market.Further Information
Donna MarchSustainable Environment Research Centre
University of Glamorgan
Tel: +44 (0) 1443 483335
Email: Dmarch@glam.ac.uk
Web: http://www.serc-wales.org.uk/