Solid Oxide Fuel Cells

What are Solid Oxide Fuel Cells (SOFCs)? A fuel cell is a converter technology that produces electricity directly from the electrochemical oxidation of fuel without burning the fuel. A solid oxide fuel cell is so named because of the solid ceramic material at the centre of the device. How Do SOFCs Produce Electricity? Air enters the cathode side of the cell. At the cathode, oxygen in the air is converted (reduced) to oxide ions, which cross the ceramic interior to the anode. On the anode side, the fuel is electrochemically oxidized producing both heat and electrical energy.

If the fuel was composed only of hydrogen, water would be the only emission. If a fossil fuel is used, containing carbon as well as hydrogen, carbon dioxide is formed at, and expelled from, the anode in addition to water. The electrical energy (electrons) produced during the oxidation of the fuel flow through an external circuit, doing some useful work along the way, to the cathode where they are used to convert oxygen to oxide ions, thus completing the circuit.

Links:
Solid Oxide Fuel Cells
Ceramic Fuel Cells: A Century of Research (A. Petric, J. Can. Ceram. Soc., 68, 63-69 (1999).)

Benefits of SOFCs

As we move into a carbon-constrained future, any technology that maintains industrial growth and enhances the sustainable development of Canada’s economy, while simultaneously reducing the environmental footprint, is of very high strategic importance. Fuel cell technology, which involves the highly efficient and clean conversion of the chemical energy of fuels to electrical energy, fully meets this challenge. SOFCs, which operate at high temperatures (600-800oC) and can thus tolerate many of the fuel components that poison proton exchange membrane (hydrogen) fuel cells, hold a particularly pivotal position for the following key reasons:

• SOFCs co-generate electricity and useful high-temperature heat at efficiencies of >85%.
  
  • High efficiencies directly translate into reduced greenhouse gases. The generation of energy from fuel combustion in Canada can produce 187 million tonnes of greenhouse gases (CO2 equivalent) in a year.
    *If SOFC technology had generated this energy at only 60% efficiency, emissions would have been reduced by 78 million tonnes, or 41%.  * Based on 2008 data.
  • High efficiencies directly translate into reduced costs for heat and power, and extended lifetime of fossil fuel reserves. The efficiency of large-scale electricity generation by SOFC technology would result in worldwide savings in fossil fuel use over a 50 year period equivalent to 250,000 billion barrels of oil
    (Jan 1, 2007 estimate).
• SOFCs do not produce the sulfur/nitrogen oxides and particulates formed by burning fossil fuels. SOFC technology would enable cleaner cities and reduced health care costs.
• SOFCs use “Canada’s fuels cleanly”, as they can operate on natural gas, propane, and diesel. The fuel flexibility of SOFCS also allows operation on emerging fuels such as biofuels, coal syngas, and pure and impure hydrogen.
• The waste stream from SOFCs operating on hydrocarbon fuels contains primarily humidified carbon dioxide (CO2) and thus SOFCs can serve as an excellent CO2 capture technology, further reducing greenhouse gas emissions.
• SOFCs can integrate directly into existing fuel and electricity infrastructures.
• SOFCs can provide power from milliwatts to large scale megawatt power generation systems, providing unprecedented flexibility to meet Canada’s various user needs.
  • Secure and affordable stationary power systems in remote communities, such as Canada’s far north, where increasing accessibility will create a demand for power with much less environmental impact than conventional diesel generators.
  • Distributed power systems for larger urban centres, addressing public fears of health risks from high power transmission lines as well as efficiency losses due to long distance transmission of electricity.
    

A Canadian Fuel Cell Industry?

The Canadian Fuel Cell Commercialization Roadmap (Industry Canada 2008), recognizes that “significant benefits will accrue to countries that succeed in establishing a viable fuel cell industry as:

• The fuel cell industry is a high value-added sector driven by innovation.
• It will contribute to a strong technology driven economy in jurisdictions where it develops and supports an educated labour force with advanced skills.
• Fuel cell research and development and early products are generating new areas of knowledge and expertise for the industry and its suppliers, with possible technology spin-offs.
• Significant export market opportunities for fuel cells, fuel cell components, balance-of-plant, equipment required for fueling infrastructure, and IP are emerging.
• Strategic partnerships are being forged with companies that recognize the benefits and market potential of fuel cells in established industry sectors, such as automotive, oil and gas, utilities and electronics, as well as emerging sectors such as micro-technology.
• Such partnerships result in the development of new joint national and international ventures and alliances that create jobs and investment in the economy.
• Reduced reliance on central generation facilities for electricity and dependence on oil imports in import-dependent countries, thus increasing energy security.”