I like solar calculators, and this is an interesting one to explore.

The PV Watts1 calculator from the National Renewable Energy Laboratory (NREL) is a simple solar calculator that can help you figure out how much electricity you can generate with a PV system at many locations around the world. (Disclaimer here.)

When you use the calculator, it gives you a measurement of solar radiation in kilowatt-hours per square meter, which is also known as peak sun hours. (Here’s a very detailed explanation of that concept from the U.S. Department of Energy.)  

I used the calculator to compare peak sun hours and kWh of electricity generated for several different locations. You should know that I used all the default settings on the calculator, so the measurements below assume a 4 kilowatt PV system and a fixed tilt, south-facing PV array.

OK, here we go!

• According to this calculator, here in Topeka, Kan., we get an average of 4.95 peak sun hours per day. Over the course of a year that would add up to 5,238 kWh a year, which is worth $403.33 at local electricity prices.

• How about a sunnier location? Well, it looks like Albuquerque, N.M., has 6.48 peak sun hours per day, which produces 6,726 kWh a year for a value of $585.16 in electricity. 

• Or, for less sun, we could look at the Northwest. Famously rainy Seattle, Wash., gets 3.76 peak sun hours a day for 3,879 kWh a year, and $248.26 worth of electricity.

• What about outside the United States? Stockholm, Sweden gets 2.98 peak sun hours a day, and generated 3102 kWh a year. Cairo, Egypt gets 5.66 peak sun hours, and generates 5727 kWh a year.

You can take a look at your location and see how it compares. There’s also a PV Watts 2 calculator, which is more complicated to use, but will allow you to select any location in the United States.

Pictured Above: A PV array in Manchester, Wash., near Seattle. Photo by DOE/NREL/JOHN GROBLER

Many of our readers are interested in renewable energy, and for some of you there’s a simple and easy way to get your electricity from renewable sources — many utilities offer a green power option.

If you’re looking for more information on green power in the United States, the U.S. Department of Energy has some helpful information about green power programs, including a map and chart showing where they’re offered.

We’d like to hear more about your experiences with green power. Is it available where you live? How does the price compare to what you would otherwise pay for electricity? Why have you — or haven’t you — chosen this option? You can share your thoughts by posting a comment below.

Photo by Istockphoto/Nicholas Homrich

Many people dream about powering their homes with solar energy, but aren’t ready to make the investment in solar panels just yet. But chances are you’re already using solar power at home, even if it’s only in a small way.

There are a growing number of small, inexpensive solar-powered gadgets available that fit nearly every budget. That includes not only the familiar solar calculator, but a growing array of solar flashlights, radios, cell phone chargers, outdoor motion lights and more. Solar-powered products also are useful around the homestead, for example, for solar-powered electric livestock fencing.

Over the last couple of weeks, we ran a poll asking people if they were using these small solar-powered products and a surprisingly large number of people —almost 90 percent — said yes!

Now we’d like to know more about what you think of these solar gadgets, including what products you’re using and why — or why not. For example, do you have a solar cell phone charger or radio around because it’s a good backup for emergencies? Are you using solar motion lights because they’re convenient? Do they save you money?

Beyond that, what do you think about these small solar products in general? Are they gimmicky? Interesting? Useful?

Share your thoughts by posting a comment below.

The following information is condensed from a presentation by Brent Summerville, Technical Director of the Small Wind Certification Council.

Small wind can be very rewarding — creating your own electricity from home wind turbines allows you to enjoy energy security, become more connected to weather patterns and the rhythm of the seasons, and interact with your community by hosting curious visitors wanting to learn more about your efforts in sustainability. As Wendy Milne describes in her article, Choosing Renewable Energy, “The aesthetics of wind turbines are irresistible, and we steal a glance at ours almost every time we walk between the house, garden and workshop.”

If you are interested in creating home wind power, start by visiting the US government website for Energy Efficiency and Renewable Energy (EERE). This will help you to find state-specific information on a variety of issues such as installation, maintenance and pricing as well as providing you with wind resource maps, for optimizing the placement of your turbine,and contact details for local organizations and authorities. If money is tight and you'd prefer a DIY project, consider building your own wind generator; it will be sturdy, not so expensive, and less efficient than a commercially available unit — but it will be yoursand it will create energy.

Here are a few extra resources to help you out:

Database of State Incentives for Renewables & Efficiency: Click on "FED" for Federal incentives or click on any state for state incentives
Home Power Magazine (click on The Basics and Wind Electricity)
American Wind Energy Association

Build your own:

Windstuffnow.com (parts and information)
Otherpower.com (information and plans for sale)
Axial Flux Windmill Plans (plans available for purchase)

These days, many people are trying to use less energy at home. Not only is saving energy good for the environment, it can save you a lot of money on your electric and heating bills. So what are you doing to save energy at home? Have you turned down your thermostat this winter? Installed compact-fluorescent light bulbs? Added insulation to your attic? Tell us what you’re trying and how well you think it works by posting a comment below.

Need inspiration? Here are a few articles with some simple ideas for saving energy: How to Make Your Home Energy Efficient, Easy Projects for Instant Energy Savings, and Bright Ideas for Home Lighting.

While they provide a beautiful, clear picture, plasma screen televisions are a huge detriment to the environment, and California could be the first state to ban them. Earlier this month state regulators in California began drafting a plan to remove all plasma screen televisions from retail shelves. Plasma screen and LCD TVs gluttonize electricity and account for 10 percent of all Californians’ electric bills, according to the Los Angeles Times. The new rules, which are expected to go into effect by mid-2009, would only give consumers the option of choosing a more energy-efficient model.

Last year California was ranked number one in energy efficiency by the American Council for an Energy-Efficient Economy. Officials say the standards, once fully in place, would reduce the state's annual energy needs by an amount equivalent to the power consumed by 86,400 homes. The LA Times says that during peak TV viewing times, such as during the Super Bowl, the electricity used to power those TVs is the same amount used to power the San Onofre nuclear power station at full capacity. 

But California isn’t the only place banning plasma screens from stores. The European Union is also putting a ban on certain energy-draining plasma screen televisions. The Daily Mail says the legislation should pass this spring and will remove the most energy-consuming televisions from store shelves and will place a label on all other TVs encouraging energy efficient choices.

PHOTO BY ISTOCKPHOTO/OLAF LOOSE

Sure, most people know that you can produce electricity with photovoltaic (PV) panels. But have you ever wondered exactly how solar cells generate electricity?

There’s a great, very detailed explanation of the whole process on the How Stuff Works website.

Or, here’s another idea. You can skip the article and jump straight to this solar cell quiz (also from How Stuff Works). You can learn a lot just by guessing, because the quiz format explains the answer right after each question.

If you're brave enough to share your quiz score (and whether or not you read the article) post it in the comments section below. My quiz score was 7/10 after reading the article. Think you can beat that? Go ahead, give it your best shot!

PHOTO BY ISTOCKPHOTO/JOEY CHUNG

Here in Kansas we got some unexpected good news this week. There’s new momentum at the state level to pass new regulations to promote renewable energy. (Kansas has lagged behind most other U.S. states on this.) For any fellow Kansans out there, here’s an article from the The Lawrence Journal World with more details.

For others in the United States, here’s how you can find out more about what your state is doing to promote renewable energy. Follow the links below to see how your state compares in two key areas:

1. Does your state have a net metering law?

These laws affect the price homeowners get paid for any electricity they produce. Check out the Department of Energy’s EERE Website for more on how net metering policies work, including this handy map which shows which states have net metering laws. (Hint: All but eight states do.)

2. How about a renewable portfolio standard?  

These are goals the states set to mandate how much of their electricity must come from renewable sources. So far, 24 states have RPS policies. You can find out which ones by checking out this map, as well as this table, to see which states are setting the highest goals. (As usual, California is at the head of the class on renewable energy, but many other states have set ambitious goals.)

I’m looking forward to the day that Kansas is on these lists.

To find out about other renewable energy-related activities that are happening in your state, check out this EERE page of State Activities and Partnerships.

BY BOJAN FATOR/ISTOCKPHOTO

I’d love to be able to say that my electricity comes from solar panels or a backyard wind turbine, but nope, I must admit, it comes from the grid. (My household does purchase green tags to offset our electricity use, but that’s another story.)

But here’s an interesting question: If your electricity comes from the grid, how can you find out what fuels it comes from? Different energy options have different costs and benefits. For example, is it possible that your utility gets some of its power from a wind farm? How about a nuclear power plant? How much of it comes from coal?

You can find out by using this nifty feature on the EPA web site. If you live in the United States, all you have to do is type in your ZIP code and identify your utility, and it gives you a couple of handy graphs and links that tell you which fuels the electricity comes from in your region, how that relates to pollution and how it compares to national averages.

When I typed in my ZIP Code, it showed that here in northeast Kansas our electricity comes predominantly from coal — which unfortunately is associated with a lot of greenhouse gas pollution. And you can see from the graph that our fuel mix does in fact produce more carbon dioxide pollution than the national average.

So if you’d like to find out where your electricity comes from, just try the link and find out. And if you haven’t already, now is a great time to learn more about green power options from your utility, or other renewable energy options for your home.

Last week, I wrote about measuring the electricity my computer was using by plugging it into an electrical meter called a Kill a Watt.

This week, I decided to try my hair dryer with the Kill a Watt, and holy cow. So my computer was drawing about 92 watts. My hair dryer on low used 402 watts. Switch it to high, and it goes to 1440 watts!

Why is that number so high? Well, the hair dryer is producing heat, and that can consume a lot of electricity. Here’s a great list from the Department of Energy with the typical wattages of many appliances. Some of the big electricity users are obvious: your water heater, your refrigerator, dishwashers. But some of the smaller appliances on the list that are unexpectedly high produce a lot of heat: irons, toasters and hair dryers, for instance.

On the other hand, just because an appliance uses a lot of electricity while it’s on doesn’t mean much, because it all depends on how long you leave it on. Remember, your electric bill is based on kilowatt-hours, and that’s electric use over time. And while I use my computer for many hours a day, I typically spend five minutes or less drying my hair. So where am I using the most electricity?

Hair Dryer vs. Computer: Here’s How It Breaks Down

So, I’ve left the Kill a Watt plugged into my computer for 10 days now, and the meter shows that during that time the computer has used 13.5 kilowatt-hours of electricity.

Have I used that much electricity over the last 10 days while drying my hair? Not even close. 1.5 kilowatt-hours is a better guess, because I've probably spent a total of an hour* drying my hair over the last 10 days.

So, yes, I’m using far more electricity with my computer than with my hair dryer.

Want to do some more math? You can find out how all that translates to greenhouse gas emissions here.

*Update 11/26/08

OK, it's true. An "hour" was just a lazy guesstimate on my part. I didn't really intend to measure how long I spent drying my hair over 10 days with the Kill a Watt. I mean, these numbers are close enough, right?

But now certain family members have challenged whether I really spend only five minutes a day drying my hair. Maybe I'm using a lot more electricity with the hair dryer than what's recorded here. All right, so now it's on. I'm measuring the exact electricity use of the hair dryer with the Kill a Watt for 10 days to prove that yes, the hair dryer still winds up using less electricity than the computer. When I have an update, I'll post it here. Stay tuned!

Update: 1/19/09

Well, I finally finished counting this up, and I'm happy to report that after 10 days of drying my hair, I had only spent a total of 32 minutes with the hair dryer on. The total on the Kill a watt was .68 kilowatt-hours. As expected, that's far less than the 13.5 kilowatt-hours my computer used over a 10 day period. So yes, I use far less electricity drying my hair than I do running my computer.

What's the point of this story? Just that if you're trying to understand how much electricity you're using, you need to know two things: the wattage of an appliance and how long you're leaving it switched on. Low wattage appliances or electronics can surprise you with how much electricity they consume over time.

Photos by Megan Phelps

How much electricity is your computer using right now? It’s surprisingly easy to find out using a simple electrical meter, such as a Kill a Watt. Right now, I have a Kill a Watt hooked up to my PC, and it shows that I’m using 92 watts of electricity.

 Actually, the figure fluctuates, depending on how hard I’m making the processor work at any given moment. But since I plugged this particular meter into my computer 39 hours ago, it’s used about one kilowatt-hour of electricity.  So what does that mean? What exactly is a kilowatt-hour anyway? Here’s a quick review:

• One kilowatt-hour is equal to one kilowatt consumed over one hour. And one kilowatt is equal to 1,000 watts. (For more energy measurements check out this handy chart from the Energy Information Administration.)

• On your electric bill, you’re charged based on the number of kilowatt-hours (kWh) you consume. For the United States, the average cost of one kWh is about 10 cents.

• For even more math fun, you can consider that this one kilowatt-hour is equal to roughly 2 pounds of greenhouse gases, because electricity in the area where I live comes primarily from coal.

So here’s another interesting question: How does my computer compare to other computers? Well, last week we hooked up a Kill a Watt to another editor’s computer, and his laptop was only drawing about 30 watts of electricity. Humph. Oh well, I suppose it’s not a competition.

But the possibilities for measuring and figuring out how to reduce your energy use are endless. For some great ideas, check out this article from Gary Reysa, with his Eight Great Energy Saving Projects. He measured the energy savings of eight different projects and calculated the dollar savings and reduced carbon emissions for each one. You can find even more of these projects on his Web site, BuilditSolar.com.

Photo by Megan Phelps

A couple weeks ago, we told you about a new, funky kind of solar panel that’s about to hit the market (Solar Panels Get a Make-over). A few months ago, we told you about a completely different kind of solar energy with gobs and gobs of potential — utility scale CSP, or concentrating solar power (Solar Thermal Power Coming to a Boil). We’ve also recently sung the praises of solar power potential in Solar Power Could Provide 10 Percent of U.S. Electricity by 2025. Clearly, we’re crazy for solar around here!

But can you handle even more good solar news?

A team of researchers at MIT has invented an award-winning solar electric system that is vastly more efficient than typical solar panels. And believe it or not, it should be vastly more affordable, too. Props go to associate professor of electrical engineering Marc A. Baldo, graduate students in electrical engineering Michael Currie, Jon Mapel and Timothy Heidel, and postdoctoral associate in the Research Laboratory of Electronics at MIT, Shalom Goffri. (Mad props also to the National Science Foundation, for supporting the research!)

The team’s “solar concentrator” collects the sun’s energy over a large dye-coated glass or plastic surface, such as a window, and gathers it at the edges. Therefore, expensive photovoltaic cells are only necessary around the glass panel’s edges. And the concentrated light actually multiplies the electrical output of each cell by up to 40 times. The best news may be for homeowners who already operate a solar electric system, because they’ll be able to boost their system efficiency significantly with even an inexpensive retrofit. Covalent Solar, the company founded by Currie, Mapel and Goffri, expects to be able to bring this technology to market within three years.

Watch professor Marc Baldo explain how these solar concentrators work:

New whiz-bang technologies are always cool, but the best news behind this development is about affordability. Says the research team: “Unsubsidized solar electricity is over three times as expensive as the average grid prices for electricity derived from conventional energy sources, according to the U.S. Department of Energy. Dramatic cost reductions are needed. Clean, renewable electricity at affordable prices would be an attractive alternative to conventional electricity and the related fossil-fuel dependence, greenhouse-gas emissions and peak-time grid constraints.”

Further Resources:

* You can read the full report about the team's solar concentrator technology in the July 2008 issue of Science magazine: High-Efficiency Organic Solar Concentrators for Photovoltaics.

* Wish you were smarter? Catch more cool videos at MIT TechTV or participate in MIT classes through their free service, MITOpenCourseWare.

* Check out the January/February 2009 issue of our sister magazine, Natural Home, for more about solar concentrators.

Curious about whether your home is a good candidate for solar power? Check out Roofray, a handy tool that takes advantage of Google’s complex map data to project your home’s solar power potential. Roofray also makes educated guesses about energy bill savings and installation costs for your location.

How much electricity do you use each month? Have you ever wondered how your electric bills compare to other households?

These are the average figures for electricity bills in the United States, according to this handy page of statistics from the Energy Information Agency (EIA).

 * The average residential monthly bill is $95.66

 * Average residential monthly use is 920 kilowatt hours (kWh)

 * The average price paid per kWh is 10.4 cents, so about a dime. (Here’s a further breakdown by state.)

Are your electric bills above or below these averages? Are you taking steps to reduce your electricity use? You can share your thoughts by posting a comment below.

Photo by Thorsten Christian Pohlmann/Istockphoto

Wind turbines come in all sizes, but if you’re trying to understand exactly how big a wind turbine is some of the terms are unfamiliar. What’s a kilowatt exactly? How is that different from a megawatt?

There’s a handy cheat sheet here that explains all the measurements, but I find them a little hard to visualize. Fortunately, there are a lot of great photos out there on the Web! Below are a few wind turbine photos as a frame of reference. You can find many more wind turbine photos online by visiting the Web site of the National Renewable Energy Lab.

Small Wind Turbines

The smallest home wind systems are equal to about a kilowatt. For example, the wind turbine pictured in this cornfield is a 1 kilowatt wind turbine.

Another common size of small wind turbine is a 10 kilowatt turbine, such as the one pictured by this house.

For a better sense of what sizes wind turbines come in, check out this page from the American Wind Energy Association. It has a list of manufacturers of small wind turbines (defined here as anything 100 kilowatts or less), and the models they produce, with links to more information.

Big Wind Turbines

On the other hand, some of the commercial scale wind turbines are closer to a megawatt (1,000 kilowatts.) The wind turbines pictures along this road are 1.5 megawatt wind turbines.

If you want to get a better sense of what megawatts means, check out this handy map from AWEA that shows commercial-scale wind projects in the United States. Click on the links to different states and you can find out exactly where new wind projects are being built and how many megawatts they are.

 Photos courtesy DOE/NREL

So how big is that wind turbine exactly?

When you’re talking about wind, it helps to get familiar with the terms kilowatts and megawatts. There’s a handy cheat sheet here that explains all the measurements, but I find them a little hard to visualize, so I thought I’d post a few pictures as a frame of reference.

What does a 1 kilowatt turbine look like? Something like the photo above of a wind turbine in the cornfield. For more perspective on the various sizes of small wind turbines, check out this page from the American Wind Energy Association with more information about the various models of small-scale turbines and their relative sizes.

On the other hand, some of the commercial scale wind turbines are closer to a megawatt. The large wind turbines pictured next to the road are 1.5 megawatt wind turbines. (1 megawatt is equal to 1,000 kilowatts.)

For a better sense of what a megawatt is, check out this handy map from AWEA that shows the number of installed megawatts by states. Click on the links to different states and you can find out exactly where new wind projects are being built and how big they are.

Photos Courtesy DOE/NREL

Wouldn’t it be great if more of our electricity came from wind and solar power? There are a lot of good reasons the United States should start generating more electricity from renewable sources. But what will it take to make that happen?

One thing we are likely to need is an upgraded, expanded electric grid with more transmission lines extending to the sunniest and windiest parts of the country. Today, there’s a great article in the New York Times that does a good job of explaining the connections between transmission upgrades and developing renewable energy.

You can find another good discussion of the need for grid improvements here in this recent article from Renewable Energy World. It was originally published by the American Wind Energy Association, and includes many details about how upgrades to the grid could help speed up the development of wind energy.

 It’s also worth mentioning that some individual states are already leading the way with transmission upgrades — notably Texas.

Do you think the United States needs to upgrade its electrical grid? Tell us your thoughts by leaving a comment below.

Photo by Tom Wald/Istockphoto

Renewable energy has been in the news lately, as the U.S. presidential candidates have been discussing their energy plans, and many other people have been talking about renewable energy, including T. Boone Pickens and Al Gore.

Yesterday, Bill Clinton weighed in with his own recommendations for what the U.S. government should do to promote renewables and combat climate change when he spoke at the National Clean Energy Summit in Las Vegas.

There’s a great summary of Clinton’s top 10 recommendations for cleaner energy here on Earth2Tech. Just a few of the measures he suggested were making improvements to the electrical grid, establishing a carbon cap and trade system, and renewing tax credits for producing renewable energy for the next six to 10 years.

This week, there’s a nice article from Worldwatch with statistics on exactly how fast renewable energy is growing in the United States. The good news is, it’s growing rapidly — especially electricity from wind and geothermal.

But it made me wonder, exactly how much of our electricity already comes from renewable sources? Well, according to this fact sheet from the Energy Information Administration (EIA), it’s about 8.5 percent, and almost all of that is from hydropower — 6 percent.

Where are we going? One EIA projection says that we could be at 12.6 percent renewable electricity by 2030. Not very inspiring, is it? However, the U.S. Department of Energy also projects that we could produce 20 percent of our electricity from wind by 2030 if we address several challenges, including the need for additional transmission lines.

On the other hand, Al Gore recently challenged the country to set the audacious goal of getting 100 percent of our electricity from renewables within 10 years, so by 2018. It’s easy to see why he compared it to the challenge of putting a man on the moon: That would be a huge leap forward from where we are now. But it might be just the push we need to make the transition to renewable energy.

What about the presidential candidates? On his campaign Web site, Barack Obama specifically calls for 10 percent of our electricity to come from renewable sources by 2012, and 25 percent by 2025. (On his Web site, John McCain doesn’t suggest a specific goal for renewable electricity, but does say he favors support for renewables, including through tax credits.)

What kind of goals for renewable energy do you think the United States should aim for? Share your comments below.

Which countries have installed the most wind power? It used to be Germany, followed by Spain. But the United States is now in the lead, according to estimates from the American Wind Energy Association. You can read more about it here in the Financial Times, or here, on Live Science.

 Looking for more statistics on wind energy around the world? A good source for this kind of information is the Global Wind Energy Council. Here’s their 2007 Global Wind Report (pdf).

Texas is already the U.S. leader in wind power with about 5,300 megawatts of installed wind capacity, but that lead is likely to get even bigger thanks to a new multi-billion dollar transmission upgrade that was just approved by Texas regulators.

Transmission capacity is a frequent stumbling block for windy parts of the world that want to put up more wind turbines. That’s because utility-scale wind projects require high voltage lines to carry the electricity where it’s needed. The transmission upgrades in Texas will make it much easier to build new wind power projects because they will help connect windy West Texas with the state’s largest cities.

Read More:

Texas Approves a $4.93 Billion Wind-Power Project, New York Times, New York Times

Texas to Spend $4.93 Billion on Transmission Lines for Wind Power, EERE

Yesterday, Al Gore gave a speech challenging the United States to set a surprising new goal: To produce 100-percent of our electricity from renewable and carbon-free sources within 10 years.

Here’s the text of the speech, and you can check out video highlights below. It’s already gotten a lot of attention, and there’s a nice roundup of reactions to the speech from the blog Gristmill.

Tell us what you think. Is this goal far too ambitious, or is it achievable? Is setting this kind of challenge just the thing we need to start thinking seriously about renewable energy, or should we be aiming for more realistic goals?

More on this Topic:

An Inconvenient Truth

What You Can Do To Help Solve the Climate Crisis

Can you afford solar-electric panels, or a backyard wind turbine? For a growing number of people, the answer is yes.

But how you answer that question depends a lot on your state's net metering laws, because this one policy makes it much easier to pay for home solar or wind-electric systems.

That’s because net metering policies allow you to sell any extra electricity you produce back to the utility at the retail rate. It’s a simplified billing process where when you’re drawing electricity from the grid, your electric meter spins forward; when you’re producing electricity that you’re not using, your meter spins backward.

If you don’t have net metering, the utility can charge you more for the electricity you buy than you get for the electricity you produce. For a grid-connected wind or solar system, that makes a huge difference in how quickly the system pays for itself in reduced electric bills.

Currently, most U.S. states have net metering laws, although they don't all make it equally easy to connect to the grid. For more specifics on state policies, check out this list from the Database of State Incentives for Renewables and Efficiency (DSIRE). Only eight states don’t have net metering laws: Alaska, South Dakota, Nebraska, Kansas, Tennessee, Mississippi, Alabama and South Carolina.

Fortunately, more states are passing net metering laws all the time. So if you want net metering and don’t have it, let your state legislators know!

Photo by Michael Braun/Istockphoto

If you're concerned about climate change, and want to reduce carbon emissions, you might be surprised how easy it is to figure out how much carbon dioxide is produced by, say, driving to work. Sure, there are a lot of carbon calculators out there where you can plug in all the numbers on how much you drive, and how much electricity you use. But it's also surprisingly easy to estimate yourself.

Here’s how you can do it. If you go to the EPA carbon calculator it gives you recognizable units, like gallons and pounds. (And slightly more confusing units like carbon dioxide equivalent.  Essentially, they’re adding the other greenhouse gases into the number for carbon dioxide. But there’s more about that on the calculator page.)

It’s very simple to use, so here are results I got from spending a few minutes with the EPA calculator and playing with the numbers.

* Every gallon of gas burned produces about 22 pounds of carbon dioxide equivalent. (So for simplicity, let's round down to 20.)
* Every therm of natural gas burned produces about 11 pounds. (I think it’s fair to round down to 10.)
* Every kilowatt hour (kWh) of electricity produces about 1.7 pounds.
(If rounding up to 2 seems too painful, consider where your electricity comes from. If it comes from coal, yep, round up to 2. For natural gas, you can figure 1 pound. There are some statistics that help justify those numbers here.)

So when you fill up your gas tank, you have a number in gallons. Take it times 20 and you're awfully close to knowing how much carbon dioxide burning that tank of gas will produce. Same thing goes for your electric bill. Take a look at the number of kilowatt hours. Double it (in most cases) and you’re looking at pounds of greenhouse gas emissions.

Want to think more about pounds of carbon emissions and how to lose them? Here are a few related articles:

Eight Projects for Instant Energy Savings, Mother Earth News 

On Carbon Calculators, Grist 

What Makes a Pound of Carbon Dioxide, The Green Guide

Many people using renewable energy at home will tell you that if you're interested in installing a solar or wind system to generate electricity, a good first step is to start cutting your electricity use. For example, you might want to start by installing compact fluorescent light bulbs, getting in the habit of turning off lights when you leave the room, plugging all your appliances into easy to shut off power strips, or any of dozens of other proven ways to cut your electricity use.

Why Energy Efficiency is Exciting To be honest, cutting your energy use doesn't have the romantic appeal of immediately installing solar panels or a wind turbine to generate all your electricity, but I think there are two good reasons to get excited about the idea.

1. You can start doing it today. Renewable energy systems are an investment, and financial or other personal circumstances may prevent you from purchasing one right now. But there are lots of simple, painless ways you can start cutting your electricity use around your home right now.

2. It can save you a bundle of cash down the road. The size of a renewable energy system to meet all your electric needs varies a lot, depending on how much electricity you use. If you cut your use of electricity first, you can buy a smaller, less expensive system that still meets your needs.

No, Seriously... It Saves Thousands of Dollars I've written before about how useful the Find Solar Web site is for getting rough estimates of the cost of a solar-electric system. You don't even have to have exact numbers from your electric bill to get an idea of how much a PV system for your home might cost.

On the other hand, if you do have the exact numbers from your electric bill, you can enter them into the site's solar calculator to get a better estimate. You can also tweak those numbers to get a rough idea of how much it would cost to install bigger or smaller PV systems. (Because if you use more electricity, it will likely take a bigger and more expensive electric system to meet your needs.)

Crunching the Numbers It's easy to find out how much electricity you use each month. You can request these figures from your utility, or, if you pay your bills online, you can probably get them just by logging into your account. Then plug those numbers into the Find Solar calculator in the spot for average monthly electricity use.

I found the estimate for a PV system based on my average electricity use, and it was $16,000. Yikes. But that's the average. If I plugged in the number from the month I used the least electricity, the estimate goes down to $8,000. If I use the number from the month I used the most electricity last year, the estimate goes up to $34,000. Yep, that's a breathtaking difference in price.

(Don't panic when you look at the largest number. Remember that for a grid-tied system you don't have to generate all your own electricity. You could buy the smallest system, it just might not meet all your needs for electricity. You'd have to buy the rest from your electric utility at the usual price.)

How to Start Saving Electricity The cost difference between a small PV system and a larger one is even more thought provoking when you consider that many steps to use less electricity at home are surprisingly easy and inexpensive.

Ready to go home and look for more ways to save electricity? Check out a few ideas for places to start here!

When I first heard about the Find Solar Web site, I was skeptical. (Oh sure, it provides everything you need to know to buy solar panels in one place. What are the odds of that?)  But I was pleasantly surprised: This Web site is remarkably thorough and easy to use. In fact, if you're in the market for a solar energy system, you might as well skip the rest of what I have to say, and go straight to the Find Solar site.

On the other hand, if you're as skeptical as I was, keep reading and let me try to convince you that Find Solar is a wonderful source of information. Here are some of the Web site's best points:

  1. It's not a corporate site. When I first glanced at the Find Solar site, I was afraid it might all be the work of one company that sells solar panels, but that's not the case at all. According to their 'About us' page, Find Solar is a partnership between the American Solar Energy Society (ASES), Solar Electric Power Association (SEPA), U.S. Department of Energy, and on the software side of things Energy Matters LLC.

2. It covers all forms of solar power. Not only is there information on photovoltaic systems, there's also info on solar space heating and water heating. (There are also listings for companies that sell wind turbines, but the site is definitely geared toward people interested in solar.)

3. It has all the local information you need. Just fill in your state and county and you can get all the relevant details about incentives available in your area, and info on local retailers and installers. The information is detailed but easy to follow.

For example, I was in the section that helps you find local solar professionals. I did a quick search and found that there's one solar retailer in my town, and there are four others within a 100 mile radius. For each company, the site lists not only contact information, but also customer reviews, associations the business is a member of, and the number and types of solar systems they've installed. It's all very handy.

4. Getting an estimate is remarkably painless. I hate filling out online forms, but this one's easy. To get an estimate on a PV system, all you have to know is what county you live in, what utility company you use and about how much you pay each month for electricity. Then you click a button and it gives you an estimate that takes into account any local incentives.

5. There's good, general background information. If you're in the market for a renewable energy system, chances are you have a few questions about how it works. I was happy to see that Find Solar answers many of those questions with an extensive list of FAQ, which you can search by keyword.

Yes, it's that good! Whether you're actively looking for a solar energy system, or just exploring your options, I definitely recommend this site as a starting place.