This question doesn't have a simple answer.
If a person doesn't own their property yet, they can save thousands of dollars per acre by buying off-grid property. My 12 acres in southern Utah cost me $28,000 per acre, I could have (and now wish I had) gone twenty miles down the road and bought similar property for about $4,000 per acre or less. The difference would have bought a pretty fancy RE system. Property taxes would have been a lot less too. And even though the grid power lines go right past my driveway, it still cost me $5,000 to have the power brought from the street to my house, and that doesn't include the $10 a foot they wanted to charge me for digging the trench for the electrical wires. My wife ended up digging that trench using our backhoe, took her three weeks to dig it because of all the rocks.
Secondly, the payback time for any RE system depends on utility rates. Mine are cheap now, about $90 a megawatt-hour, but I fully expect them to rise dramatically. Think cap and trade. It's coming as soon as the rest of the world starts to believe that global warming really is happening. Gotta save the polar bears.
Third, FITs are coming. Those are feed-in tariffs. Basically FITs require utilities to pay four or five times the going rate for power supplied to the grid by distributed generators (people with wind turbines and/or solar panels). FITs are revenue neutral to the utility because the cost is passed along to the folks who don't feed any power to the grid. FITs are already the law of the land in many places, especially in Europe. Australia and Canada have them; Gainesville, Florida has them; California is going after FITs in a big way. They're coming as soon as the rest of the world wakes up.
I'm a firm believer in FITs because they promote distributed generation of electrical power. About half of the electrical power generated in a typical coal-fired power plant is lost in transmission lines before it even gets to the ultimate users. A million homes each supplying a kilowatt of power to the grid would replace one big old stinky coal fired 2,000 megawatt power plant, because with distributed generation the power is consumed very close to where it is generated. The electrical power that my wind turbines and solar panels generate is likely used by other houses right in my neighborhood. FITs will greatly reduce the payback period for wind turbines and solar panel installations.
Here's another scenario that greatly impacts the payback period of residential RE installations, at least those with battery back-up. One of these days the Iranians or some other bunch of terrorist jerks is going to sail a tramp steamer (or a sailboat) into New York harbor and set off a nuke. The ultimate suicide bomb. When that, or some similar catastrophe happens, the economy will shut down for at least six months (it almost shut down in September 2008 even without the help of terrorists). The grid will go down for an extended period of time. When that sad event happens, the payback time for my RE system is about three days, because that's about how long my freezers will last without electrical power. I give this a 3% chance of happening in my lifetime.
It bothers me somewhat that so many people are so concerned about the payback time for RE systems. We don't worry about the payback period for our $44,000 pickup trucks, even though we could drive a compact car and hire somebody to haul all the big stuff for much less than the pickup truck cost. You have to have a more noble reason than making money to justify an RE system. How about the fact that every kilowatt-hour of electricity you generate offsets the release of 2.2 pounds of greenhouse gasses?
Posted on: December 12, 2010, 09:18:54 AMPosted by: ghurd
If it is not windy, it is often sunny.
And if it is available, hydro works 24/7.
All 3?
You don't necessarily need a flowing water source such as a stream or a spring to use hydro. My place has no stream, but it does have a 400 foot cliff. I'm building a 40,000 gallon water tank at the top of the cliff, and another one at the bottom. A 1.5 kw Exmork microhydro will connect the two tanks. When the sun shines and the wind blows hard, the excess power will be used to pump the water from the lower tank to the upper tank. When the top tank is full, and the sun isn't shining, and the wind isn't blowing and I need power, the hydro comes on. Think of the two water tanks as a big, 2,000 amp-hour battery with no lead, never needs to be replaced like batteries do, can be discharged to a 100% DOD without shortening its life, and the top tank will double as a swimming hole in the summer. Both tanks will serve as an emergency water source when the economy shuts down and the community water system dies. Need lots of water to keep the plants in the greenhouse alive when the grocery store shelves go bare.
Sorry to end on such a gloomy note, but that's all I have to say about payback time for wind turbines.
poco