My thoughts on fuel cells oscillate. Now I'm down on them.
Last year, the NY Times Magazine published a promising story on the future of fuel-cell powered homes. Now (10 Nov. 2008) they find that the company that was featured has yet to install a single new system. Too expensive.
Also Materials Technology (December 2008) points out that large-scale application of fuel cells depends on the availability of Pt catalysts, which material is in limited supply. Efforts to find a substitute are still in early development.
Thursday, December 18, 2008
Tuesday, December 9, 2008
Cost of Conservation
The Ohio Environmental Council has come up with an estimate of the cost of conserving electricity. They argue that energy saved is freed for use elsewhere. In essence, conservation creates energy.
To understand their thinking, consider a 25 W CFL bulb replacing a 100 W incandescent bulb. If the CFL burns for 8000 hrs, it saves 75*8000/1000 kW = 600 kWh. If the CFL bulb costs $6, it frees up (‘creates’) 600 kWh. So the cost of conservation is $6/600 or 1 cent/kWh.
OEC actually estimates the average cost to be somewhat higher if they average all energy-saving equipment, about 2.25 cents/kWh. I like to think that a saving is a saving and that people will save enough that the freed-up energy never needs to be generated.
To understand their thinking, consider a 25 W CFL bulb replacing a 100 W incandescent bulb. If the CFL burns for 8000 hrs, it saves 75*8000/1000 kW = 600 kWh. If the CFL bulb costs $6, it frees up (‘creates’) 600 kWh. So the cost of conservation is $6/600 or 1 cent/kWh.
OEC actually estimates the average cost to be somewhat higher if they average all energy-saving equipment, about 2.25 cents/kWh. I like to think that a saving is a saving and that people will save enough that the freed-up energy never needs to be generated.
Friday, November 28, 2008
Fuel-Cell 'Gas' Stations
Any discussion of fuel cells should start with the fact that they require hydrogen, which costs energy to produce. This is a bad thing if the energy comes from coal-fired electric plants. The compensating factor is that hydrogen-storage technology is well developed. Serious methods for large amounts of electricity storage still need to be perfected.
In the hydrogen economy (which seems less likley than a few years ago) I envision the future 'gas' station to be equipped with a device to produce hydrogen from natural gas and a tank to store it. The motorist drives up to the station, plugs into the tank, and fills up his car. Thus the much-talked-about distribution system for hydrogen is easily provided.
The 'gas' station has advantages over other future technologies. Ethanol will still have to be delivered by tanker truck, which is expensive. Charging of electric cars en-route will be slow, unless the technology improves.
In the hydrogen economy (which seems less likley than a few years ago) I envision the future 'gas' station to be equipped with a device to produce hydrogen from natural gas and a tank to store it. The motorist drives up to the station, plugs into the tank, and fills up his car. Thus the much-talked-about distribution system for hydrogen is easily provided.
The 'gas' station has advantages over other future technologies. Ethanol will still have to be delivered by tanker truck, which is expensive. Charging of electric cars en-route will be slow, unless the technology improves.
Tuesday, October 28, 2008
More on Electrical Usage
According to recent postings on Cleantechnica.com, large wind turbines need to generate about 3kW to supply a home (a planned wind farm in KS has a capacity of 250MW and will satisfy the needs of 85,000 homes). A small rooftop turbine works out to 6 kW/home, due to the lesser efficiency of smaller blades. The small rooftop model seems terribly expensive ($6.70 per kW), so I'll stick with the 3 kW/home number.
They also state that the average home uses 670 kWh/mo, which is 70% higher than our usage (see yesterday). This means almost 800,000 homes could be served with a 1000 MW coal plant.
They also state that the average home uses 670 kWh/mo, which is 70% higher than our usage (see yesterday). This means almost 800,000 homes could be served with a 1000 MW coal plant.
Monday, October 27, 2008
Electricity per month
We use about 400 kWh per month. A 1000 MW coal plant produces about 520 million kWh/per month (70% time on line, which amounts to about 1.3 million homes supplied if they are all like us). I expect (need to check) that our usage is below average and that the estimate that a 1000 MW coal plant can supply one million homes is not far off.
Saturday, October 25, 2008
Coal vs. Wind
I'm having a problem sorting out relative efficiencies of various electricity generation methods. For example, a 1000 MW coal plant is supposed to provide enough electricity for 1 million homes (this may be high, but I don't have good numbers). The power is then about 1kW/home. But only about 1/3 of the chemical energy of coal is converted to electricity.
Wind turbines need about 3 kW/home. So the efficiency of harnessing wind to produce electricity is in the same ball park as the efficiency for coal.
Wind turbines need about 3 kW/home. So the efficiency of harnessing wind to produce electricity is in the same ball park as the efficiency for coal.
Tuesday, October 7, 2008
More Solar Economics Data
There was a report in Sunday's Columbus Dispatch about a solar home with a claimed 10-12 year payback. The owner paid $41,500 and received State and Federal grants reducing that to $21,500. He has net metering.
In his best month, he generated 806 kWh, which provides 115,200 kWh over 12 years. At $0.10.kWh, this comes out to around $11,000 worth of electricity produced - I don't see how he can break even.
Refs:
"Solar power users amass savings by folllowing the sun", Columbus Dispatch, 08 Oct. 2008
Stowell web page:
In his best month, he generated 806 kWh, which provides 115,200 kWh over 12 years. At $0.10.kWh, this comes out to around $11,000 worth of electricity produced - I don't see how he can break even.
Refs:
"Solar power users amass savings by folllowing the sun", Columbus Dispatch, 08 Oct. 2008
Stowell web page:
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