First of all it works better to spread them out, this vastly reduces the size and complexity of the grid we need to move all the power around. It also solves the problem of what to do in a calm day in North Dakota. Someplace the wind is blowing, so if we plant some in each state, we will always have some wind power. Secondly, Bravo makes a good point that wind power is very low density. What that means is it takes a 400 foot tall tower and a 500 foot diameter blade to make the same 5 MW as a hydro power plant that might fit in a small house. Hydro power is high density, and a much cheaper way to make power. Problem is, we have already built dams in all the good spots, like Lake Mead and the Columbia River Gorge. Lastly, one of the reasons we have gotten into this energy predicament is through overreliance on very few sources, like oil and coal. The best resource to power the country is a diverse one. I’m a big supporter of renewable energy, like wind and solar, but I would be quite happy to see wind get maybe 10 or 20 % of our grid power. I’d like solar to get another 10, hyrdro to hold the piece it has now, and there would still be room for some coal and nuclear. This way, if there is any problem with one source, the others can pick up the load, and by using all available sources, we can place the ones that work best in each location. Hydro is best in the West and Northwest. Coal plants could be located next to the mines. Solar in the Southwest, and wind on higher grounds, where the wind blows. This is the cheapest and most efficient way to power our globe.

We live in a home that is powered by the wind and sun, has been for 11 years now. We’ve learned a great deal about renewable energy along the way, made some mistakes, and have a pretty good handle on what works where, and what doesn’t. Powering a home in Seattle with solar would be like replacing your family car with a fleet of bicycles. It would work great for getting to school, but that trip back from the lumber yard would be a killer. Seattle, with all its jungle like foliage, has great biomass potential, something else that we’ve barely scraped the surface on, but it would be a waste to export that technology to the desert southwest.

One of the most promising ideas to come along lately is a project the Germans are doing in the Sahara Desert. Using solar concentrators, they are going to heat oil to several hundred degrees, then store the heated oil in huge insulated tanks. When electricity is needed, a pump forces water through a coil in the tank, which heats up the water and makes steam. The steam is used to turn a turbine generator that makes electricity. The really great thing about it is that with all that hot oil, it will work all night too. So now we have access to solar power at night, pretty slick. Google the phrase, "North African Solar Project," to check it out. I’ll list some other sources below for you to research as well. Good luck Lamb, and take care, Rudydoo

If you were to just perform the simple math, then 1.5 MW divided by 1.2 kW would be 1250 homes.
But there is a "Capacity Factor" involved, and this question can not be accurately answered that way. The Capacity Factor of wind power is about 25% in the very best locations. Wind Power is not consistent. Where do the homes get power when the wind is not blowing? They don’t. The days when you need the most power for your A/C loads —- on very hot days, you likely won’t have any wind power. Hot days are hot for a reason — the reason being there is no breeze or wind to keep things cool. If there was a wind — the day wouldn’t be hot — it would be much cooler.

Wind Power has a Capacity Factor in its very best locations of about 25%. So if you put that 1.5 MW wind turbine in the best location, it would only produce an average of about 375 kW over the course of a month. The 375 kW x 720 hrs/ month = roughly 270,000 kWh each month. An average home will use about 500 kWh each month. So it will produce about enough energy to power 540 homes on average.

In addition to the cost of the wind turbine to provide power — you still need to invest big dollars into another natural gas turbine peaking power plant to produce reliable power when the wind is not blowing. Also wind turbines don’t really make economic sense unless you have wind speeds that average about 12 or 13 mph. Not many locations meet that criteria. It takes a wind speed of about 7 or 8 mph just to turn the blades of the wind turbine.

If there is no requirement for a dependable source of power, and power can be utilized when ever the wind is blowing — maybe agricultural water pumping for livestock ponds — then wind would maybe make sense. Wind just is not a dependable or consistent source of power.

If you need some documentation, I’d say skip the postings online and go to the source, the American Wind Energy Association. They are a non profit group advocating and assisting in the research and education relating to wind power. I will list their website below, but if you want to cut to the chase and see the actual math involved, google the phrase, "Wind Turbine Power Equation," and look for a link to the AWEA.ORG website, that will take you straight to the page that explains everything you are asking about here.

Wind power is finally coming into its own in most places in the world. If you took a plane ride across the US 10 years ago, you might have seen one or maybe 2 wind farms. Today, you would likely see at least a dozen. Many are not finished yet and not online, but they will be soon. Wind power in the US alone is doubling each 2 years. We live in a home today that is powered by the wind and sun. It has been quite a learning experience for us, some things we learned the hard way. Many people still ask me what the payback is on our equipment. I really doubt we’ll ever see our investment back in dollars, but as Oscar Wilde says, "The reward for having done something well is having done it." Many people grow tomatoes in their garden even though it’s cheaper to buy them at the store, we just grow electrons in ours. When you’re done getting the wind turbine power equation info you need, check out some of the other sites too, it’s a very interesting field, and becoming more popular each day despite the amount of misinformation that still revolves around it. Good luck Nettle, and take care, Rudydoo

By the way I live in middle Tennessee we are in zone 4 so we get 4.5 hours of direct sun and I dont now about average wind speeds.

So basically to get 50 KWH in 4.5 hours, you would need 12 KW of panels. At about $10 a watt installed, that would cost you $120,000. I think a wind turbine would be less expensive but you’ll have to check to see if your neighbours will let you have one.

You should work on insulating your home first to try and get your power usage down. If you have airconditioning, you may want to consider running an absorption chiller off hot water from some evacuated tube solar collectors. Running absorption based air conditioners directly off solar heat is a bit of a toss up since small scale chillers are expensive but the solar thermal collectors are cheap compared to photo-voltaics.

But a city has infrastructure, like street lights and business, etc. I’d, at a guess, add a factor of 3 for that, so we get to 1.2 GW

Large wind turbines come in a range of values. The large ones are in the 1-3MW. Take 1.5 MW as an average. But typical usage of a wind turbine is 20%, so we need to multiply by 5.

So number needed is 1200 MW / 1.5 MW = 800 turbines. Multiplied by 5, that is 4000 units.

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After researching this subject I come to have a new respect for our utility companies. Electricity is the best bargain I ever get for only 8 cents per KWH. We are spoiled.