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Another Step Forward In Small Scale Electrical Generators
NicknamesAreStupid writes "Product Design & Development reports another breakthrough in small scale solid oxide fuel cells. This methane-fueled cell achieves about 50% efficiency at around 2kW, enough to power an average home. It does so by efficiently recycling its heat to perpetuate the process. Of course, this is not practical for most homes, which only have natural gas that contains nearly one fifth impurities. However, that could change if gas suppliers refined their product."
Could it be used on board an electric vehicle to provide power in lieu of a battery?
No. Even though solid oxide fuel cells work and are commercially available (in larger sizes), they have problems for automobile applications - to run efficiently, they operate close to 1000 degrees C, and they don't like being bounced around. Dealing with that kind of temperature in a car is a problem.
For mobile applications, PEM fuel cells are far more likely to be practical.
A classic problem with fuel cells is extreme intolerance to contaminants. Even trace amounts of contaminants tend to damage fuel cells. Hydrogen fuel cells need cleaner hydrogen than is normally available commercially. Research continues on making fuel cells more tolerant of contaminants, but it's hard. Fuel cells are surface chemistry systems. 40 years of research hasn't solved this problem.
Reverse osmosis water purification systems once had the same problem. Today they routinely take in raw seawater and pump out clear water. They just need a backflush cycle once in a while to flush the crud off the membranes. Fuel cells aren't there yet.
I have a 2.9Kw solar, so let me explain how this works.
My bet is that this device does not switch on and off real fast, nor does it modify it's out put much.
And for most systems, like the solar, that produce DC, you need an AC converter. The most efficient ones take the "heartbeat" of the grid to time themselves and makes sure you are not out of sync with the grid power.
That means while you are using .5 or 1Kw steady, you are pumping power out to the grid, running the meter backwards.
When it comes time for a peak surge, you draw from the grid to provide the peak.
So my solar that puts out 22 to 26KW a day during the peak months of May to September roughly half that energy goes back on the grid, I pull some back for peak usage, and pull the rest back at night.
The GRID is my battery, and it is better than free, I get 3.2c credit for producing at peak and pulling at night.
Never answer an anonymous letter. - Yogi Berra
Electricity can be more than 100 % efficient if you use a heat pump ( http://en.wikipedia.org/wiki/Heat_pump ).
You're forgetting that power plants have efficiencies of 30% or less. So add a heat pump with a typical COP of 3 and the overall cycle is no better than burning the gas directly. Now if the 50% efficiency figure quoted for this fuel cell is really just for the electricity generation side (i.e. does not take into account heat generation), then that may be more interesting. It would actually be a step up from standard power plants too so if it can be scaled up it should be.