By Wilson da Silva
SYDNEY – At a, laboratory in suburban Melbourne, Australian scientists have built tiny models of ceramic fuel cells which convert natural gas directly into electricity without using, steam'or turbines.
The chemical reaction yields 30 percent more electricity than the best conventional gas-fired plants, and could power everything from a water pump to a city centre, say the scientists who are developing it and the consortium formed to commercialise it.
“If you’re lucky, average gas power stations have 40 percent, efficiency,” said Dr Mike Murray, chief of the Commonwealth Scientific and Industrial Research Organisation’s (CSIRO) materials science division in Australia.
Existing gas-fired power stations heat water into steam, which drives turbines that generate electricity. The new zirconia fuel cells utilise the mineral sand zircon mixed with other exotic substances to bypass this process, converting gas directly into power.
“Zirconia fuel cells can yield 60 percent,” said, Murray. “The. process also generates about 1,000 degrees Celsius (1,830 degrees Farenheit) of heat. If this heat is used to drive a turbines the conventinal way, total system could yield efficiencies of 80 percent, scientists say.
The process is also “greener” than conventional gas-fired plants, producing only half of the carbon dioxide emissions. It also amjts much smaller quantities of nitrogen oxides, which are smog creators, and sulphur dioxide, which causes acid rain. Poitential applications are widespread, proponents say, and a consortium formed to ommercialise it expects to have large prototypes operating within seven years.
Partners in the venture are Australia’s largest company, resources and steel giant The Broken Hill Pty Co. Ltd., the CSIRO, the state-owned New South Wales Electricity Commission utility and two state-owned research funding and analysis bodies.
Called Ceramic Fuel Cells Ltd., the venture plans to spend about A$30 million (US$24 million) developing the fuel cell technology over the next five years.
BHP’s Dr John Parrott said the cells, should they prove commercially feasible, could allow companies to power large industrial complexes more efficiently, site steelworks near iron ore bodies, power offshore oil rigs and propel seaborne tankers.
“Whenever we plan remote area operations, we always have to consider: Do we set up our own power facility or buy power from the existing grid?” Parrott said. In a modular form, the cells would power a remote operation more cheaply than using diesel generators or connecting the site to nearby electricity grids. As the operation grows, fuel cells can be stacked up to satisfy increased power needs.
“We have an interest in applying the technology to make our operations more efficient. But we might also become involved in manufacturing (the cells). We will have had the experience in developing it,” Parrott said.
Australia supplies 60 percent of the world’s zircon sands from which the cells are made. Zirconia is tougher and lighter than steel, performs well in extreme heat, and is used in high-wear applications like oil drilling and engine parts.
The first generation of fuel cells were used in spacecraft in-the 1960s, utilising phosphoric acid, but proved very innefficient. Mollen carbonate cells have also been studied. The third generation of fuel cells based on zirrconia, is generically known as solid-oxide fuel cells.
Researchers in Japan and the United States are working hard to develop solid- oxide cells based on different zirconia mixes.
But the Australian group believes its mixture, for which it has proprietary rights, when combined with other components under development, gives the team a technological edge. Because the cells operate at high temperatures, the ceramic components eventually degrade and have to be replaced, said Dr Sukhvinder Badwal, technical leader of the CSIRO team.
Cell stacks represent some 20 to 30 percent of the cost of a generating facility, and will have to last five years of continuous operation to be economically feasible, a target Badwal is confident the cells can exceed. CSIRO envisages small cell stacks powering shopping centres, hospitals, military bases and oil rigs, and could even be used aboard submarines, while, larger stacks could power cities.
“You can locate power generation closer to the customer,” said Paul Smith of the New South Wales utility.
“The beauty is you can stack it according to need. It’s early in the project, but we think it has a lot of potential,” he said.