When it comes to generating electricity, fuel-cell technology has always been of interest to scientists and to engineers. One reason has been the fuel cell’s power-generation efficiency. There’s only one more efficient method of generating electricity, and it requires large quantities of water (Figure A).
In this video, Dr. Kristen Brosnan, Materials Scientist in the Ceramic Structures and Processing Laboratory at General Electric Global Research, explains how fuel cells are able to obtain such high efficiency. She says, “Most conventional power-generation methods convert a chemical energy into heat and mechanical work, then into electrical energy. Fuel cells offer the ability to convert chemical energy directly into electrical energy with a very low environmental impact.”
One type of fuel cell is of special interest
Fuel-cell technology shows great promise and is already powering portions of or entire data centers, as I reported in this TechRepublic article. The Solid Oxide Fuel Cell (SOFC) is of special interest to researchers.
SOFCs (Figure B) generate electricity by feeding hydrogen-rich fuel, heated to 1,500 degrees F, through channels in the anode. Hot air, also 1,500 degrees F, travels over the cathode. The electrolyte enables an electrochemical reaction between the hydrogen in the fuel and the oxygen in the air to generate electricity. The reaction also creates byproducts, including water, heat, and syngas (synthetic gas containing hydrogen).
However, the technology is expensive, forcing data-center managers to look at other power-generation methods in order to get a decent return on investment. The high cost of SOFC technology results from needing platinum and rare-earth elements to create the reaction.
A recent press release by GE Global Research created quite a stir by proclaiming their researchers figured out how to replace the platinum and rare-earth elements with stainless steel, which is more abundant and much cheaper (Figure C).
The GE scientists and engineers also met a critical design requirement: 40,000 hour life span. In order to get that kind of life, Brosnan used her expertise in ceramic coatings to adapt GE’s ceramic additive spray technology (originally developed to coat jet-engine parts) to protect the fuel-cell’s components.
How efficient is GE’s SOFC?
GE tested its fuel cell design, and it generates power at 65% efficiency, which is remarkable considering the efficiencies of the methods now producing most of the world’s electricity. The 65% is due in part to making use of one of the fuel cell’s byproducts — syngas, which has enough potential energy to power another GE power-producing technology called Jenbacher Engine.
In addition, the GE research team feels there is more efficiency to be gained (predictions max out at 95%) when a process to capture the waste heat is added to the fuel-cell assembly. As built, the GE fuel cell can generate between 1 and 10 megawatts of power.
Brosnan reminded all of us why this is important, “There needs to be a paradigm shift in how we all think about using energy. Fuel cells may not be the answer for everything, but it is one of the answers.”
If major enterprises like Apple and eBay already consider fuel cells a viable alternative to more typical power-generation methods, imagine what it will be like once GE’s fuel-cell technology becomes available.