Bloom Energy Fuel Cell -- Worth Watching

Bloom Energy has been getting some good press lately. The company has produced a type of solid oxide fuel cell that includes an inexpensive electrolyte, thus avoiding expensive precious metals, corrosive acids, and molten materials. A bread-box sized module is said to be able to power a typical residence. Two questions remain: cost and reliability. Some big-name organizations are testing the product. Bloom claims the product will be affordable. Visit Bloom Energy at http://www.bloomenergy.com/products/solid-oxide-fuel-cell/. Stay tuned! Below, read a brief description of solid oxide fuel cells.

Solid Oxide Fuel Cells (from EERE Fuel Cell Technologies Program):

Solid oxide fuel cells (SOFCs) use a hard, non-porous ceramic compound as the electrolyte. Because the electrolyte is a solid, the cells do not have to be constructed in the plate-like configuration typical of other fuel cell types. SOFCs are expected to be around 50%–60% efficient at converting fuel to electricity. In applications designed to capture and utilize the system's waste heat (co-generation), overall fuel use efficiencies could top 80%–85%.

Solid oxide fuel cells operate at very high temperatures—around 1,000°C (1,830°F). High-temperature operation removes the need for precious-metal catalyst, thereby reducing cost. It also allows SOFCs to reform fuels internally, which enables the use of a variety of fuels and reduces the cost associated with adding a reformer to the system.

SOFCs are also the most sulfur-resistant fuel cell type; they can tolerate several orders of magnitude more of sulfur than other cell types. In addition, they are not poisoned by carbon monoxide (CO), which can even be used as fuel. This property allows SOFCs to use gases made from coal.

High-temperature operation has disadvantages. It results in a slow startup and requires significant thermal shielding to retain heat and protect personnel, which may be acceptable for utility applications but not for transportation and small portable applications. The high operating temperatures also place stringent durability requirements on materials. The development of low-cost materials with high durability at cell operating temperatures is the key technical challenge facing this technology.

Scientists are currently exploring the potential for developing lower-temperature SOFCs operating at or below 800°C that have fewer durability problems and cost less. Lower-temperature SOFCs produce less electrical power, however, and stack materials that will function in this lower temperature range have not been identified.