These days, the morning temperatures in my area are gradually dropping like tree leaves. And thus begins a tradition for many: warming our cars before we depart each morning.

The trouble with this habit is that it wastes gas — a parked, running car gets zero mpg. You might as well burn your money. Plus, warming up is totally unnecessary — modern engines don't need to be warmed up before you start driving, unless the outside temperature is below freezing. The best way to warm up an engine is to drive it, gradually increasing in speed; no jack-rabbit starts. Even if it's below freezing outside, an engine really only needs 30 seconds to a minute of warm-up.

Nevertheless, the myth that it's best to warm up your car before leaving is widespread. One of my neighbors does this religiously — nearly every morning this time of year, I see his car running, parked in his driveway. Whether I'm running behind and leave at 7:25, or I'm on time and depart at 7:15, his Honda Civic is warming up, burning gas and pushing out carbon dioxide. Rather than just scrape off the bit of frost on his windows, he leaves his car running, with the defroster running full blast. It's too bad, because odds are that Civic isn't getting nearly as good of gas mileage as it could. (Oddly enough, I drive the same car, maybe even the same model year.)

So, spread the word — there's no need to warm your car every morning. Doing so wastes gas and money, and spews more global warming emissions into the atmosphere. I'll see you outside in the morning, scraping the frost off our windows, without our cars running.

For more info, read Should I Let my Car Warm up Each Morning? 

Last week in Washington, D.C., 20 teams from colleges and universities participated in the 2007 Department of Energy Solar Decathlon competition. The decathlon is just what it sounds like: 10 contests that all focus on creating a completely solar-powered, attractive and energy-efficient home.

Teams from all around the country and places as far away as Spain and Germany spent months preparing for, designing and constructing their solar-powered homes. 20 competitors put their homes to the test on the National Mall. Judges assigned scores in ten different contests, including architecture, engineering, lighting, and comfort. In addition, teams had to use the energy produced by their homes to power electric vehicles. They were awarded points based on how many miles they could get out of their cars.

Technische Universitat Darmstadt from Germany took first place in the contest, which wrapped up Oct. 20. They were followed by the University of Maryland and Santa Clara University. The Darmstadt team won the architectural, lighting and engineering contests, and was one of seven teams to score a perfect 100 in the energy balance contest.

Final scores and standings of the competition can be found here.

Alternative energy may well be the greatest challenge facing today's generation, and the Solar Decathlon is a way for students to learn about solar energy today what they can teach their peers and children tomorrow. The Solar Decathlon is already accepting submissions for 2009's contest.

Sometimes it's easiest to understand energy issues by watching them unfold one power plant at a time. During the last week, I've been hearing a lot about one particular power plant here in Kansas.

Last week, it made national headlines when a state official rejected a proposal for a coal-fired power plant because it would have produced too many greenhouse gases. And as many of the people who opposed the plant have pointed out, why would we want to build a new coal-fired plant, when the state is such a great location for new wind energy projects?

But as I learned at the state renewable energy conference I attended last month, the decisions of whether to build new coal- or wind-powered electric plants are even more closely related than you might think. In fact, several proponents of wind power at the conference spoke up in favor of the new coal plant because it would require upgrades to transmission lines that are also needed to develop new wind energy projects.

What happens now? Much of the national media agreed that the decision to reject a coal-fired power plant because of greenhouse gas pollution was a significant first. Meanwhile, wind power is still being developed here in Kansas. In fact, a few weeks ago one of our big state utilities announced the locations of three new wind-powered electric plants. But wherever you are, building big wind energy projects does depend on having high-power transmission lines in the right locations, so it's an issue we're likely to hear a lot more about in the future.

What's the state of wind power where you live? Check out this helpful map from the American Wind Energy Association to see wind energy projects across the United States.

More links related to the Kansas coal plant decision:

The New York Times, Scientific American, Grist, Worldwatch

The 2007 Solar Decathlon winners were announced recently. The Technical University of Darmstadt (Germany) was the overall winner. Two interesting features are the oak louvers on the windows and the convertible floors that open to provide 'bedrooms.' You can download construction drawings for the homes if you'd like more details (and floorplans).

One of the most promising technologies for the future is also one of the simplest and least expensive: passive solar design. The concept is simple. You can build a house that maintains a more constant, comfortable temperature and reduce your energy bills simply by designing a home to maximize natural heating and cooling.

Last Saturday, I was able to visit three different passive solar homes on a local homes tour that was part of the larger National Solar Tour. The tour confirmed what I've always heard about passive solar designs: They can be beautiful homes.

• In our region, one of the most recognizable features of passive solar houses is that they're designed with lots of south facing windows to collect light and heat during the winter. That almost automatically creates comfortable, inviting living spaces with lots of natural light.
• Passive solar designs also have to be well insulated, and they're constructed with a lot of heavy building materials such as brick and stone that transmit heat slowly. That leads to sturdy, substantial walls and a home that feels snug because it's tightly constructed.
• Another feature of passive solar homes is wide overhangs on the exterior of the house, which provide shading during the summer, and incidentally make a home look attractive from the outside, too.

But the real beauty of passive solar is that's an easy way to save energy. In one of the houses on the tour we were told that either the heating or cooling system could go out and the homeowners probably wouldn't notice it for about a week because the house naturally maintains a constant temperature. 

Those features didn't necessarily make the home more expensive either. The builders said that the cost of the house was about 15 percent higher than the cost of conventional construction— but they'd also added some special features unrelated to the passive solar design that had driven up the cost. Even so, the owners reported that their energy bills are so low that they'll quickly recover the extra costs.

If you'd like to learn more about passive solar design you can find a helpful article explaining the basic principles here. You can also view photos of homes from the National Solar tour by visiting our online photo gallery.