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Published on February 11th, 2008 | by Michelle Bennett

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Clean Energy Intro: What is an Inverter?

February 11th, 2008 by  


An Emphase Micro-InverterWhen we think about “clean” energy, we envision big, dark solar panels out in a field or on a roof. Or maybe wind turbines with those big whooshing propellers. What we don’t often think about are the other components that make solar panels and other technologies possible and practical for everyday use.

One very important component of these systems is the inverter. Inverters make it possible to hook your solar panels (or other energy dynamo) into batteries, your electrical system, and/or feed electricity back into the grid. An inverter’s most important task is to convert D.C. (direct current) electricity into A.C. (alternating current). In case you’ve forgotten your high school chemistry, A.C. is all the rage with the power company. Depending on the type of inverter you buy, they can pump all the excess electricity you produce into batteries or back into the power grid. And yes, the power company will pay you for the energy you send them.

So is there a catch? Well, all good things cast a shadow. You may be aware of solar panel efficiency, meaning how much power a panel can produce from sunlight. Inverters have efficiency ratings too. An inverter with 50% efficiency will successfully switch half of the D.C. current into A.C. current. That also means that half of that energy is wasted, but fear not! Most inverters have efficiency ratings in the lower-90% range. New breakthroughs in inverter technology could reduce the cost and boost the efficiency above 98% Speaking of cost, unfortunately inverters will cost you a pretty penny. They start in the $2,000 range. Inverters are rated (and priced) by their capacity, meaning how much power you can pump through them, so keep that in mind if you decide to buy one. The last issue is interference: inverters might interfere with your AM radio, walkie-talkies or even cell phones. Clever placement and some fancy wire work will reduce this.

Because of cost and efficiency concerns, one solar company decided to bypass inverters all together. Enphase Energy is trying to build solar panels with built-in micro-inverters that will cost less and offer more. On top of providing A.C. power, the micro-inverters will also include a communication feature that will alert the company if your panel needs maintenance. One less thing to worry about is OK with me!

Inverters are not just used for solar panels. Any device that produces or uses D.C. electricity needs an inverter to work with the power grid. That includes wind turbines and fuel cells. Some people with off-grid cabins in the wilderness forgo A.C. power all together and buy light bulbs, appliances, etc. that run on D.C. power. While this does remove a major step in their energy-producing process, it’s not particularly popular. D.C. power is low-voltage, so powering larger appliances becomes tricky. If you have more than a mile of wiring in your wilderness “cabin”, D.C. is a poor choice. It loses power as it travels over long distances.

Inverters bridge the gap between basic electrical production and practical energy use. They’re always getting smaller, less expensive, and more efficient as innovations and discoveries improve the technology. Now you know about inverters. Congratulations! I’ve included a few useful links below in case you’re curious about the details.

Wikipedia.org: Inverter

What’s the difference between AC and DC current?

Solar Expert.com: Inverter Basics

Solar Panel Info.com: Inverter Details

 

Image Credit: Enphase Energy




 

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About the Author

is an environmentalist who loves to write. She grew up across the southeastern USA and especially love the Appalachian mountains. She went to school in the northeast USA in part to witness different mindsets and lifestyles than those of my southern stomping grounds. She majored in English Lit. and Anthropology. She has worked as a whitewater rafting guide, which introduced her to a wilderness and the complex issues at play in the places where relatively few people go. She also taught English in South Korea for a year, which taught her to take nothing for granted.



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