Hydrogen Engine Center Sells 50kW Hydrogen-Fueled GenSet to Xcel Energy
05 July 2006
Hydrogen Engine Center (HEC) has sold a 50kW hydrogen-fueled generator set to Xcel Energy for use in a wind-to-hydrogen research, development and demonstration project. Researchers will analyze and compare hydrogen production directly from wind power versus using the electric grid. The hydrogen will be produced from electrolysis using an electrolyzer.
In May, Natural Resources Canada ordered a 250kW hydrogen-fueled genset from HEC for use in a wind/hydrogen project on Ramea Island off the southern coast of Newfoundland, Canada. Wind energy will generate electric power and hydrogen. Under slack wind conditions, the stored hydrogen will fuel the genset to produce electric power. (Earlier post.)
Wind-generated electricity is not constant. The conversion of excess electrical output from the wind generator to hydrogen allows for the storing of energy to be used at times of no wind and thus solves the time-of-use problem.—Ted Hollinger, president of Hydrogen Engine Center
The Xcel Energy application is part of a joint venture between the US Department of Energy’s National Renewable Energy Laboratory (NREL) and Xcel Energy. The generator will be shipped to NREL’s National Wind Technology Center in Boulder, Colorado. HEC is currently working with several other utility companies nationwide with similar interests in producing renewable power.
HEC’s basic product is a rebuilt Ford 4.98-liter six-cylinder engine that is hydrogen-ready and can also run—after minor adjustments—propane, methane, ethanol (and gasoline). (Earlier post.)
It's a start, but if new batteries prove to be more efficient/cost effective, then a wind turbine/battery combo is the way to go. There is a niche market for local fuel though, but you'll need vehicles/facilities with the ability to store/use hydrogen first.
Posted by: allen Z | 05 July 2006 at 10:10 AM
ok Engineers out there, why not just store excess as gravitational potential that can be later used to turn a generator (maybe even the same one on the windmill). Wouldn't a few tons of concrete on a pulley with gears be cheaper than huge banks of batteries or hydrogen tanks.
Posted by: Neil | 05 July 2006 at 10:39 AM
I looked into using a gravitational potential energy system as an alternative too lead acid batteries for an off-grid renewable electric system. I'm sure it would be possible but there really isn't very much energy there. If I remember right i worked out it would take 1/2 the capacity of a car battery to lift 1 tonne 10 meters into the air, assuming 100% efficiency. This idea is used all over the world in pumped hydroelectric storage, what makes it vialble is the huge volume of water thats moved between two heights.
Here's a good link with all the formula's http://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity
Posted by: NickF | 05 July 2006 at 03:46 PM
Thanks for the reply Nick, I can see that the weight involved would have to be hugh indeed. I assume that other mechanical energy storage device (flywheel etc..) would produce too much friction/heat to be efficient. I have heard of a large scale stationary chemical battery being used by industry almost as a capacitor.
Posted by: Neil | 05 July 2006 at 05:56 PM
Hi Neil, maybe you're thinking of flow batteries? IIRC, there are examples of 8MW units in Japan used for peak-shaving.
Posted by: JN2 | 06 July 2006 at 02:21 AM
Thats it thx.
Posted by: Neil | 06 July 2006 at 06:22 AM
The energy efficiency in conversion from electricity to hydrogen is 70-80%, let's say 75%. Then, the energy efficiency of hydrogen-ICE is 45% at most, then the efficiency of the generator powered by the hydrogen-ICE is ~90%. Multiply all together: .75 x .45 x .90 = .30, or only 30%. So, the hydrogen-ICE-genset route is only 30% efficient.
However, if you would use compressed air at 5000 psi (~300 bars) as energy storage medium, then assuming 90% efficiency for the air compressor that is directly connected to the wind turbine, and 90% efficiency for the air motor running off the compressed air, and 90% efficiency for the generator running off the air motor, then you will have: .9 x .9 x .9 = .73, or 73% efficiency, much better than the hydrogen route. Of course, you will need a high-capacity heat exchanger during the compression process to take away the heat that is released from adiabatic compression (to achieve quasi isothermal compression) and to obtain the heat from the ambien during the adiabatic expansion process by the airmotor (to achieve near isothermal expansion). If you have good insulation for your compressed air tanks and do not wish to store energy for long, then you do not need too good a heat exchanger, just enough cooling to prevent thermo-structural damage to your air tanks. The "aircar" (theaircar.com) is rather ridiculous in mobile application due to the large bulk of the compressed air tank and the need for large-size heat exchanger to realize near-isothermal expansion to maximize the car's range, but for a stationary energy storage medium where bulk and weight would be more tolerable, I think that this would be a very viable idea. Unlike battery storage medium, which has about comparable efficiency at ~70-80% with comparable bulk and weight, the steel air storage tanks are cheaper to make with less environmental impact and will last practically forever, while the battery will wear out after several hundred charging cycles or after only a few year's time.
I wonder what would be the reason why compressed air storage means not adapted to store excess wind turbine production? Or for storing excess electrical output from your home PV panels?
Posted by: Roger Pham | 07 July 2006 at 08:33 AM
I researched the efficiency of pumping water uphill and generating power downhill and the numbers came out to 70% efficiency nominally. That beats .8 x.5 = 40% efficienct for electrolysis and SOFCs. You eliminate more losses if the wind turbines run pumps. There is a lake in southern California that pumps water up from the desert side and generates power on the down side into LA. They get water and power at the same time.
Posted by: sjc | 14 July 2006 at 09:33 AM