Fuel Cell Provides Cheap, Clean Energy
Researchers at the Lawrence Berkeley National Laboratory (LBNL) have developed a solid oxide fuel cell that they say can generate electricity as cheaply as the most efficient gas turbine.
Their innovation, which paves the way for pollution free power generators that serve neighborhoods and industrial sites, lies in replacing ceramic electrodes with stainless steel supported electrodes that are stronger, easier to manufacture, and cheaper. This latter advantage marks a turning point in the push to develop commercial fuel cells.
“We’re closer to breaking the cost barrier than ever before,” said Steve Visco, who developed the solid oxide fuel cell (SOFC) technology with fellow Materials Sciences Division researchers Craig Jacobson and Lutgard De Jonghe.
The cost barrier is $400 per kilowatt, a bar set by the Department of Energy’s Solid State Energy Conversion Alliance, a government, industry, and scientific group tasked with developing affordable fuel cell based power generators. The $400 target – about one-tenth the cost of today’s fuel cells – is equivalent to the most efficient gas turbines and diesel generators, and is based on the premise that a fuel cell’s success hinges on its competitiveness.
“Green is great for marketing, but people won’t buy an environmentally friendly product if it’s twice as expensive,” Visco said.
Fuel cells work by converting chemical energy to electrical energy, capitalizing on hydrogen and oxygen’s tendency to bond and form water. Unlike gas turbines, this process does not emit air pollutants such as nitrous oxide and sulfur dioxide.
Because fuel cells are more efficient than gas turbines, they emit far less carbon dioxide, a greenhouse gas.
Visco and colleagues’ foray into affordable fuel cell design began several years ago when they developed a way to lower a fuel cell’s operating temperature to 800 degrees Celsius without sacrificing efficiency. Until then, fuel cells worked best at 1,000 degrees Celsius, a high temperature that decreases the cell’s life span and precludes the use of metal components.
They fabricated thin ceramic electrodes that conduct ions at 800 degrees Celsius as well as thicker electrodes do at 1,000 degrees Celsius. Lowering the temperature also allowed them to use metal components, instead of ceramic, to connect several ceramic cells into a stack.
Their design did not hit the $400 per kilowatt target, but it allowed them to reduce the cell’s operating temperature without sacrificing performance.
Since then, they have developed a fuel cell that features 10 to 15 microns of a zirconia based electrolyte layered onto 10 to 20 microns of a nickel based electrode. These are supported by and bonded to about two millimeters of porous high strength commercial alloy.
“The low cost of a metal based SOFC’s raw materials, and its design flexibility, should allow a stack to be manufactured below the $130 fuel cell target,” Visco said.
To meet the $400 generator target, the Berkeley Lab fuel cell must now be developed into other stack designs, and paired with a low cost inverter and other supporting technology.
“Instead of building a large, fuel cell based power plant, which is expensive and therefore risky, it makes sense to start smaller,” Visco concluded. “The big question is not if fuel cells will enter the market, but when.”
Provided by the the Environmental News Service.