GM has announced that it will sell the much-anticipated Chevrolet Volt--an electric car with a gas generator for extending driving range--for $41,000, which is about what people had been expecting. The automaker notes that with a federal tax credit, the actual cost to consumers is $33,500.

GM starts taking orders for the car today. It will be available initially in California, New York, Michigan, Connecticut, Texas, New Jersey and the Washington D.C. area. To buy one, you need to go to a Volt dealer, which you can find at http://www.getmyvolt.com.

The car costs more than the Nissan Leaf, which is also coming out this year. That car will sell for $32,780, or $25,280 after the tax rebate. Both are far more expensive than GMs new, more fuel efficient sedan called the Cruze, which costs $16,995 and is similar in size to the Volt.

With the Cruze, you can get 40 miles per gallon (with the Eco version). The Volt offers 40 miles of electric range with a charge, and 300-miles more with a range-extending gas generator. The Leaf offers 100 miles of gas-free driving range between charges.

If solar power is ever going to be a major source of electricity, researchers, engineers, installers, and solar panel array owners are going to have to pay closer attention to one essential component of the these systems--the inverter.

According to a study of solar arrays in actual operation, poorly designed or faulty inverters--devices that convert the DC power produced by solar panels to AC power that can be used in buildings or sent over the grid--can dramatically lower net power output. In one case, the inverters consumed hundreds of watts at night, decreasing overall power output by 40 percent. High temperatures caused inverter faults, and because the inverters had to be reset manually, about half the time when the sun was shining the array was producing no power.

What's more, the common practice of linking all the solar panels in an array to one inverter means that if there is a problem with one panel in the array, the output of the whole system goes down. So, because of inverter-related problems, solar arrays might produce nowhere near what they're supposed to, and solar power may prove even more expensive than expected.

One option is to install automatic disconnect circuits, which can cut down on parasitic losses. Presumably inverters that reset automatically after temperature faults--or that can operate better in high temperatures--would also help. Several companies are also starting to develop micro inverters or other electronics that can be installed at each solar panel so that if one panel has problems, the rest aren't affected.