Do You Know Renewable Energy?

According to the latest data from the Energy Information Agency the United States gets 7% of its total energy supply from renewable energy sources. Now, that includes hydropower. When you take that out of the equation and focus on wind power, solar power, etc., that number drops to about 4.5%.

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Planet Green: Renewable Energy

Even though it may be tempting to stick up a small-scale wind turbine on top your house, frankly, if you're in an urban or even densely developed town these turbines really aren't that efficient, with some studies showing that they may never even pay back the energy used to create them, and often manufacturers overstate their efficiency. That's different in rural areas when wind speeds are more consistent and less disturbed by surrounding buildings, by the way.

If you live in someplace appropriate for them, check out:
Hot Home Wind Turbines You Can Actually Buy

Biodiesel can be a great thing, but most of the claims of it being truly carbon neutral have to be taken with a grain of salt. Sometimes that's the case, and if you're using waste vegetable oil it's a great use of a waste product. However, in some cases, like when palm oil grown on plantations which used to be rainforest is used, the biodiesel actually can have a carbon footprint up to eight times that of petroleum-base diesel.

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How to Make Your Own Biodiesel or Find It Nearby
25 Things You Need To Know about Biodiesel

OK, so this one's a giveaway. But in case you just used some basic test question parsing ability to answer, with a green power program you sign up with your utility for a cost of perhaps an extra $100 per year. You still get your normal utility bill, but instead of buying fossil fuel generated energy, you buy part of the energy produced by a wind farm or biomass plant that your utility contracts with. The actual electricity coming into your house is no different than your neighbors', but it's effectively carbon neutral as it was generated from a renewable source.

Here's how to do it:
Buy Renewable Energy From Your Power Company

If you picked B, you're sort of right—give yourself an honorary half point. Sometimes people refer to solar water heaters as solar thermal, but when it comes to renewable energy solar thermal also refers to large commercial power plants which use mirrors known as heliostats (there are a couple variations on this) to focus the heat of the sun onto a receiver containing a liquid. This liquid boils, creates steam and turns a turbine to generate electricity.

While most commercial wind turbines have three large blades connected to a center point like a propeller, on a smaller scale a number of people are experimenting and producing wind turbines with blades rotating on a vertical axis. One example is the Wind Spire by Mariah Power.

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DIY Vertical Axis Wind Turbine (Video)

OK, this is a very rough estimate, and largely depends on location of the wind turbines and the local wind conditions, but due to all that commercial wind turbines only end up producing about one-third of the power that their rated capacity indicates. Sometimes this is played up as a serious limitation of wind power, but when enough different renewable energy sources are linked together via a smart grid, this can be minimized.

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Queen of England Buys World's Largest Wind Turbine (7.5 Megawatts!)

Though solar panels normally look like what you expect them to and what you're familiar with, a number of manufacturers are working on making solar panels blend in more with the roof of a house. Though these solar power tiles aren't identical in power output to conventional solar panels, and frankly don't entirely blend in, if you live in someplace where building appearance is regulated (such as historic districts) these panels may be the answer.

In the past year you've probably heard a lot about second generation biofuels, and perhaps a good deal of that has centered around their benefits over first-generation fuels, and perhaps it's all got you a bit confused. Fair enough as second-generation is a slightly vague term. All of the following qualify: Fuels made from agricultural and construction waste products such as cellulosic ethanol; crops grown specifically for biofuel but grow in places that normal food crops can't, such as jatropha; biofuels made from algae. Not all of these are perfect by any means, but all are better than first-generation fuels.

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How Much Electricity Will Venice Get From Algae

When you hear someone promote geothermal power this is not in any way the same thing as a geothermal heat pump like you might install in your house. In fact the proper term is a ground source heat pump. Geothermal power is an entirely different thing and is used to generate electricity. Our colleagues over at How Stuff Works have a good summary.

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5 Ways Geothermal Power is Heating Up Around the World