You know that saying, “there’s nothing new under the sun?” Well, it’s true for solar energy too. Although the modern photovoltaic movement began over 165 years ago, the history of solar power actually began thousands of years earlier.

Early Solar Energy History

The Ancient Greeks, who already worshiped the sun, built their homes to maximize it too. Using basic passive solar design techniques, Greek homes stayed naturally cool in the summer and warm in the winter. The Ancient Romans also valued the sun—so much, in fact, that in the 6th century CE Emperor Justinian granted “sun rights” to ensure his citizens access to sunrooms and homes were built to make use of light and heat from the sun. Similarly, the Ancient Chinese oriented their homes towards the south to provide light and warmth. Across the Atlantic Ocean, the Anasazi Indians were building southerly-facing cliff dwellings to heat their homes.

These passive solar design techniques have fallen into disuse in modern America, but are regaining popularity in the twenty-first century.

Modern Solar Energy History

In 1839, 19-year-old French physicist Edmund Becquerel changed solar energy history forever when he discovered the photovoltaic effect—that some special materials produced an electric current when exposed to sunlight. This finding started a whirlwind of activity around the globe, with scientists discovering photoconductivity in selenium, copper, and cadmium. Einstein contributed in 1905, writing a paper explaining the photovoltaic effect and winning a Nobel Prize for it in 1922. Still, solar power history at this point was confined to research.

Commercial Solar Energy History

The breakthrough came in 1954, when Bell Laboratories created the first high-power silicon photovoltaic cell. Although only 4.5% efficient, it was a big event in solar energy history, with the New York Times calling it “the beginning of a new era, leading eventually to the realization of harnessing the almost limitless energy of the sun for the uses of civilization.” Bell Laboratories licensed the technology to other companies, and by 1960, one called Western Electric had increased its efficiency to 14%. Although used primarily by NASA to power satellites, photovoltaic cells began making their way into consumer electronics and homes.

The US government became serious about solar on October 17, 1973, when the Arab Oil Embargo doubled fuel prices almost overnight. With new government funding to help offset western oil dependence, the cost of photovoltaics dropped 80%. Unfortunately, oil prices eventually did too, and the U.S. government reduced its support for alternative energies, leaving many advocates discouraged.

To help increase adoption, Germany launched an unprecedented $500 million “100,000 Solar Roofs” program in 1990. Japan followed suit four years later in 1994, launching its own “70,000 Solar Roofs” campaign. And after funding two smaller rebate programs in 1998 and 2002, California launched the biggest program yet in solar energy history: a $3.3 Billion, Million Solar Roofs Program in 2007.

With this and other help, the market continues to grow by a staggering 50% in California. There’s never been a better time to buy solar, and with the creation of Renewzle’s solar comparison shopping site in 2008, finding the right installer has never been easier. Get started today!

By Arlie Krigel

Wind power is one of the cleanest—yet oldest—forms of energy. Once only found on rural farms, wind turbines are making their way into backyards, modern landscapes, and many, many, business plans. How wind power became one of the fastest growing energies in the world, and where it goes in the future has a lot to do with its historical roots, complicated mechanics, and consumer interest from people like you.

Wind Power History

The history of wind power began in 500 BCE, with wind-powered sail boats along the Nile River. From there, wind power history progressed to China and then Persia, where farmers used windmills to pump water in 200 BCE.

As the technology improved over time, so did windmill applications and fame. By the 12th century, European crusaders had brought wind power technology back home, creating wheat and corn-grinding windmills. These lasted for many years, until Danish scientists created a rudimentary electric version in 1890. These wind turbines were used extensively in the US frontier and other rural country sides, until oil shortage created a new surge of interest in the 1970s. With the government help and consumer interest, modern wind turbines have been spinning ever since.

How does wind power work?

Wind turbines use wind to make electricity. Wind propels the blades, which rotate a shaft, which attaches to a generator to create the power. Size does matter for wind turbines too: in general, the bigger the wind turbine, the more efficient it is. Many commercial wind turbines are often grouped together in patches, called wind farms. But how is a homeowner supposed to install a bunch of giant wind turbines? The answer is small wind.

Wind power for your home

Small wind is the industry name for 100 kilowatt capacity turbines and below. Smaller in both size and capacity, they’re perfect for homeowners and businesses looking to cut bills or become energy independent. Small wind turbines do require sufficient wind speeds and space, however, so they’re not ideal for everyone. You can read more about residential wind power at Renewzle with our articles on Top Five Small Home Wind Turbines and Home Wind Power Options.

Future of Wind Power

The wind industry is going to continue expanding: oil tycoon T. Boon Pickens recently announced a plan to invest $10 billion in the world’s largest wind farm, located in Texas, cities are changing zoning laws to allow wind turbines within city limits, many states are expanding their wind power capacity, and new technology is being developed like a new invention called the Windbelt, which will hopefully create a wind machine ten to thirty times more efficient the ones we have now. There’s never been a more exciting time in wind power history.

Also, ask your congressperson to extend the Renewable Energy Tax Credit, the main federal tax credit supporting wind power generation.

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Renewzle plans to expand its calculator functionality to small wind, to continue to help consumers like you become energy efficient and independent. To find out when Renewzle enters other renewable fields like small wind, join our mailing list.

By Arlie Krigel

All about Solar Ovens

Solar ovens are an inexpensive, easy, and fun alternative to conventional cooking. Also known as solar cookers, solar ovens require no electricity and are used around the world by citizens in developed and developing countries alike.

A good solar oven can cook just about anything on a sunny day, from a sizzling hot stir-fry to a slow-cooked stew. But even a simple solar oven can bake brownies or bread. All it takes is some recycled cardboard, old pieces of foil, and a healthy dose of patience and sunlight.

How solar ovens work

Solar ovens use shiny reflectors to direct sunlight into dark boxes and pots. There, the light is trapped and transformed into heat. Although several hundred different versions use these principles, three main types of solar cookers exist.

• Solar Box Cookers: The simplest, most common solar ovens. Often made out of cardboard boxes and foil-lined reflectors, these solar cookers reach low to medium temperatures of around 200 to 350 degrees Fahrenheit. They’re the most similar to real ovens, since they heat up slowly and have room for multiple pots and pans.
• Parabolic Solar Ovens: The hottest, most dangerous solar ovens. More like stoves than ovens, these complex solar cookers use a parabolic shape to reflect all sunlight onto a single point, creating an intense heat of over 600 degrees Fahrenheit. They heat up quickly, but require frequent readjustment and are difficult to construct.
• Solar Panel Cookers: A combination of box and parabolic cookers. Lightweight and portable, these solar ovens are ideal for backpacking and small spaces. They use foil-lined cardboard walls to reflect sunlight into dark pots, which are then enclosed in inflated oven bags to build up heat.

Ready to start cooking? Make or buy your own solar oven

In just a few hours, you can build your own powerful solar oven out of recycled household materials like cardboard, foil, plastic bags, and glue. But if building makes you wary, there are also many great commercial solar ovens available for purchase too.

Happy cooking!

Although they sound like they are different terms for the same thing, geothermal energy and ground source heat pumps are two different systems, with little in common other than that they are making use of what lies below the surface of the Earth. They do it in very different ways, however.

A geothermal energy system uses heat from below the surface of the earth as an energy source, much like solar panels capture sunlight and convert it into useful energy (electricity or hot water). A geoexchange system with a ground source heat pump (GSHP) is more akin to a hybrid automobile. It is not a method for generating energy, but a method for more efficiently using energy. It still takes energy input to operate a GSHP system, but a GSHP can be as much as 300% to 400% more efficient when compared to highly efficient furnaces, which are typically in the high 90s for efficiency percentage.

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The April/May issue of Home Power magazine features a story by Kelly Davidson entitled “The Best States for Solar” that features criteria for selection one would not expect. It’s not the number of sunny days nor the latitude that makes a good solar state, but strong incentives, regulatory policies that are looking ahead, and strong support for setting renewable energy usage targets. Listed alphabetically, they are:

1. California — Its California Solar Initiative calls for a $3.3 billion, ten-year program that will help CA hold its position as the leading producer of solar technologies in the US, and one of the largest solar markets in the world

2. Colorado — 300 sunny days per year help, but this state maximizes its solar assets by offering rebates, loans, and tax exemptions for PV systems while spurring growth of green collar jobs by encouraging solar tech and PV manufacturing.

3. Connecticut — The Connecticut Clean Energy Fund provides solar incentives, while the state’s RPS (renewable portfolio standard) requires that 27% of the the state’s electricity come from renewable sources by 2020.

4. Maryland — The state has jump-started its support of solar energy with increased rebates, causing total installed solar capacity to jump to 1MW. (more…)

The Solar Thermal Edition

In my first post about the feast or Famine Cycles of American Clean Energy Development, I discussed renewable energy more broadly and used the example of wind to show my point. I also touched upon the up and down nature of federal funding for renewable energy deployment in the late 70s and early 80s. With that said, the following examination adds some more context with a historical-institutional perspective of what went down in the early 80’s, how, and why. And in the spirit of some of the earlier posts this week that covered the technology of solar thermal, and the practical application of solar thermal technology to entire neighborood developments, I have decided to follow suit by writing about solar thermal as well. I hope to show that the decline and slow fazing out of federal support for solar thermal research and development during the Reagan and George Bush administrations has had a substantial effect on where the industry is today. (more…)

They have been around for centuries, but they are quickly becoming the darlings of the eco-friendlies and clean energy nuts. Windmills, or in this case, wind energy generators, come in all shapes and sizes. But, how feasible and cost-effective would it be for you to integrate a small wind system at your home, cabin, or camp? It might actually be easier than you might think. And if the small-wind tax credit somehow holds onto its tenuous place in the farm bill, it might just be cost-effective for you to invest one that can help defray, or even eliminate your monthly electricity bill. (more…)

What if you could produce clean solar energy night and day, rain or shine, and never hit the bank for a single P.V. solar panel? Photo voltaic panels can be pricey, so the solar industry is always trying to lower costs and boost efficiency in the quest to compete with coal. One fast-growing, cost-effective solar technology uses heat to generate energy 24 hours a day, and it can store energy without batteries. In this post I’m going to investigate solar-thermal technologies.

It’s called “Concentrated Solar Power” or C.S.P. The idea is simple; no complex chemistry or fancy silicon wafers required. Glorified mirrors shaped like satellite dishes (or parabolic troughs) direct the sun’s rays towards a reservoir. The concentrated solar heat boils water into steam, and steam powers a turbine. When the water cools off it’s collected and cycled back through the system. The mirrors can even track the sun across the sky to maximize efficiency. Water is not the only fluid that can be used, but its unique properties have made it popular. More on that below. (more…)

Since the energy crisis of the late 1970s, the federal government has employed various policy mechanisms to support renewable energy development. Driving through the neighborhoods that were developed in the late 70s and early 80s, it’s not hard to notice all of the old rooftop solar water heating arrays that were installed because people were taking advantage of a tax credit made available by the Carter administration. But the tax credit expired after Reagan took office, which is why I don’t see rooftop solar hot water nearly as much anymore (at least not recently installed).

The same thing will happen if the renewable energy tax credits expire (more…)

Solar thermal technology provides space heating and hot water and is a frequently forgotten member of the solar family. These highly effective systems are popular in many parts of the globe, from China to Greece to Zimbabwe. They displace the use of the existing hot water heater and heating equipment, typically saving either natural gas or electricity.Solar thermal is a more mature technology than solar photovoltaic systems that produce electricity. It has been used for centuries for water heating. In fact, even Leonardo Da Vinci owned one.

When considering the installation of such a system, it is important to consider the following items.

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