By Molly Spencer
郑洪 译 申雨平 校
The 21st century leading energy source may very well depend on the development of a technology that was first discovered in 1839. Indeed, many experts believe that the future of electricity generation will not come from further refinement of solar, wind, coal or nuclear energy, but from fuel cells. Among the various types of fuel cells, the ceramic or solid oxide fuel cell promises to achieve the greatest efficiency of conversion of fossil fuels such as gas and coal to electricity while producing only very low levels of pollutants. To this end, a consortium comprising five leading organisations has established Ceramic Fuels Ltd, initially to expand fuel cell research and development and secondly, to bring the technology to commercial application.
Ceramic fuel cells are electrochemical devices that directly convert fuels such as gasified coal or natural gas into electricity without the limitation of the Carnot cycle (an ideal thermodynamic cycle in which heat is taken onto a working fluid at a constant upper temperature and rejected at a constant lower temperature). In many respects, fuel cells work like batteries. As long as they are constantly supplied with fuel and oxidant, fuel cells can continuously produce power, removing the need for recharging.
Fuel cells offer several advantages over traditional thermal power plants. The major difference between these two power generators is that the chemical energy of the fuel cell is converted directly to electrical power without intermediate conversion first to heat. The efficiency of a coal-fired thermal plant is typically in the range of 30%-35%. In a combined cycle gas turbine system running on natural gas, the maximum efficiency is in the range 45%-50%. Many experts believe high temperature fuel cells could reach efficiencies of 80%-85%. Ceramic fuel cells thus offer a more efficient and less polluting alternative to current power generation technologies.By-products from fuel cells are high quality heat, carbon dioxide and steam. The temperature of the exhaust gases is well above 500℃, meaning that solid oxide fuel cells are very attractive for electricity and heat generation as, in addition to supplying electricity, the leftover amounts of heat created during the process could be used to produce heat for industries, provide hot water supplies or warm buildings.
Fuel cell technology is not new. In fact, the principles of fuel cell operation were first reported by British scientist Sir William Grove in 1839. His prototype used dilute sulphuric acid and operated at room temperature. Ceramic fuel cells developed much later, with the first one operating at 1000℃in 1937.Ceramic fuel cells offer many advantages over other energy systems:
·they have the potential to produce electricity efficiently from several fuel sources
·they can generate large amounts of electricity
·they are relatively quick to install
Fuel cell research and development is extremely competitive worldwide, with the USA, Japan and some European countries leading the charge to commercialise this promising technology. For instance, a Dutch-Belgian company has developed a fuel cell for a Volkswagen van and is also working on a larger unit to power a bus. Additionally, a German company is working on a fuel cell for the European space shuttle program and for submarines, while a Canadian company is evaluating a fuel cell to be used in small buses.
Recent reports point to promising large international markets for ceramic fuel cells. Prospects for fuel cells in South East Asian markets appear good. Several countries, including Indonesia, Thailand and The Philippines, are expected to demonstrate high rates of growth in demand for power, an encouraging situation for those countries quick enough to develop and commercialise fuel cell technology.
Energy is a vital component of a technology-based society, and the growing need for electricity generation by the most efficient method will ensure a promising future for ceramic fuel cell technology. The Ceramic Fuel Cells Ltd initiative represents a major collaborative venture between public and private sectors. It is envisaged that this venture will go a long way towards achieving a greater efficiency of energy use worldwide.