Wind energy of about 7 kwh at home?
Thursday, September 2nd, 2010 at
3:43 am
I want to generate electricity of about 7 kwh per day at home with 240 volts. Is it possible? Wind energy? What would be estimated cost?
Filed under: Wind Power
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If I remember correctly, a 1 kW wind turbine unit costs about $6,000 installed. A 2.4 kW wind turbine costs about $18,000 installed. You would likely need a tall tower to place this on as well — maybe 60 to 100 foot tall. The wind varies, so you get an actual "capacity factor" of about 20 to 25% — meaning that the 1 kW unit will not average 1kWh each hour, but closer to 20% of that or about 200 to 300 Watts. That is only about enough to power a small TV or maybe 2 or 3 light bulbs — and all intermittntly — when the wind is blowing.
So instead of paying $6,000 for the 1 kW unit, now you need to look at the $18,000 larger 2.4 kW wind unit. So this one will output an average of about 600 or 800 Watts. This might power a small microwave. Or it could power several light bulbs and a small TV at the same time — you can watch American Idol with 1 or 2 lights on. But not much else.
(BTW — your request for 7 kWh per day is about 300 Watts per hour on average — which is about the output of the smaller 1 kW unit)
The wind speed varies all over the country. You really need an area that has an average wind speed of 14 mph to make wind power economical. It takes at least a 7 to 8 mph wind just to turn the turbine blades. Some parts of Iowa, Texas, Oregon and California are prime areas — not the entire state — just portions of it. So depending on where you live, the wind may not be strong enough to even turn the turbine blades — then no power — no American Idol.
You may be able to purchase a bank of batteries. This will allow you to watch TV or use the microwave when the wind is not blowing. It may take many batteries — 50 to 100 batteries — similar to car batteries. This would be about $100 each, so now you have another $5,000 to $10,000 in batteries that will last about 5 years — then they will have to be replaced again — for another $5 to $10K. And add in another $5000 for an electronic inverter, to convert 12 Volts DC to 120 Volts AC ……. It starts getting to be a very expensive proposition.
The wind turbine will last maybe 15 to 20 years. The batteries and replacement batteries will cost you about $20 to $30,000 over those 20 years. So you will have about $40,000 to $50,000 invested in your wind turbine for 20 years of power.
But what does your current power bill come to? Let’s say a maximum of $100/ month. That is $1200 per year. Or $12,000 per 10 years. Or $24,000 for 20 years. So it costs you much less to just buy your electric the way you have, and not have to "prepay" $50,000 upfront for a wind turbine, and worry about maintenence and broken parts, and replacing failed batteries.
Bottom line — it does not pay off and is a headache. Solar power/ PV power is essentailly the same proposition — it will never pay off. That is why we have so little "green power". It is not economical. You probably pay something less than $0.10 to 0.15 per kWh from the electric company. It is cheap. Unless power ever gets up to $0.50 to $1.00 per kWh — the economics for wind or solar will never pencil out. Hope this helps.
7 kW-hours / 24 hours = 290 watts, a pretty low power level. Are you sure that is what you want? or do you want average power level of 7000 watts? a big difference.
But the wind only blows part of the time, and that percentage could be less than 10%, depending on your location. so is that 290 watts a peak or an average power?
So you need to tell us what power you actually want, and what are the typical wind values in your location? Do you want batteries to store power when there is no wind? For how long a period do you want to operate on batteries alone (this can get very expensive as batteries are not cheap).
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As Richard has very thoroughly explained, wind power is not cost effective in areas where the grid is available. Wind power is the way to go when you need to provide a lot of power in a remote location where gas or diesel cannot be delivered,and where there is little sunlight. A good example would be a weather station on an island in a polar region. Very interestingly, I noticed that when 16 year old, Jessica Watson sailed around the world, she had to run her engine now and again to keep the batteries charged, in spite or having what looked like a windmill on the stern and a photo-voltaic array on the roof.