Renewable Energy

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Renewable energy is energy which comes from sources which are naturally replenished, such as solar, wind and geothermal heat.  Global warming concerns, high oil prices and increasing government support and incentives are all contributing to the rapid commercialization of the renewable energy industry.  Advances and improvements with the technology and installations of renewable systems are making it more accessible and affordable to individuals.

To help give you a better idea of the renewable energy options out there and how they work, we’ve included definitions of the various types of renewable energy, thanks to online resources like Wikipedia and The US Energy Information Association.   As always, if you have an idea for us, let us know by contacting us!

Solar Power

Perhaps the most commonly known form of renewable energy is solar power.  Solar energy is the sun’s rays that reach the earth and can be converted to other forms of energy like heat and electricity.  There are several different types of solar power, the most common being 1.) Passive Solar 2.) Solar Thermal (solar hot water) 3.) Photovoltaic (solar electric).  Each have a unique set of advantages and disadvantages.

Passive solar technologies are means of using sunlight for useful energy without use of active mechanical systems.  Think of what happens to your car if you’re parked in the sun or the temperature of your pool water if it’s exposed to direct sunlight.  The inside of your car gets heated by the direct sun and the water in your pool does too.  Click here for more about passive solar.

When converted to solar thermal (or heat) energy, solar energy can be used to heat water for use in homes, buildings, or swimming pool or heat spaces, like the inside of homes, greenhouses, and other buildings.  Concentrating solar power plants use heat from thermal collectors to heat a fluid to produce steam, which is then used to power a generator. This method is used in solar thermal power plants by utilizing either a parabolic trough (which is the most common), a solar dish or solar power tower. Solar thermal heat can also be used to heat water used in homes and swimming pools and for heating inside a home or building and these can be classified as either passive or active systems.  Click here for more info.

Photovoltaics (PV) is a method of generating electrical power by converting solar radiation into direct current electricity using semiconductors that exhibit the photovoltaic effect. Photovoltaic power generation employs solar panels comprised of a number of cells containing a photovoltaic material. Materials presently used for photovoltaics include monocrystalline silicon, polycrystalline silicon, amorphous silicon, cadmium telluride, and copper indium selenide/sulfide. Due to the growing demand for renewable energy sources, the manufacture of solar cells and photovoltaic arrays has advanced considerably in recent years.  To learn more about Photovoltaics click here and for a guide for going solar, visit our Going Solar resource page!

Wind Power

Wind energy is the conversion of wind energy into a useful form of energy, such as using wind turbines to make electricity.  To understand wind power, it’s important to first understand how wind is created.  Wind is air motion that is caused by the uneven heating and cooling of the earth’s surface by the sun.  Different parts of the earth heat and cool at different rates (think night and day and water and land), causing different parts of the atmosphere to heat and cool differently.  Hot air rises, reducing the atmospheric pressure at the earth’s surface, and cooler air is drawn in to replace it, creating wind.

Much like the old windmills, today’s wind turbines use the blades to collect kinetic energy.  As the blades turn, they turn a shaft which turns an electric generator.  One of the problems wind turbines have, is what to do when the wind isn’t blowing.  That is why the placement of wind turbines is important in relation to the amount of energy it will produce.

The amount of energy being produced by wind doubled from 2006 to 2008, thanks to new technologies, which have decreased the cost of producing electricity and increase of tax breaks for renewable energy.  Perhaps you have noticed an increase in “wind farms” or wind power plants (like the one pictured).  The top five wind power producing states are Texas, California, Minnesota, Iowa, and Washington.

Geothermal

Geothermal energy is heat from within the earth and is generated in the earth’s core.  Some methods of extracting geothermal energy use the earth’s heat near the surface, while others require drilling miles into the earth.

Geothermal power is cost effective, reliable and sustainable.  The US is the world leader of geothermal electricity production, most of which comes from geothermal power plants.  These plants use either steam directly from a geothermal reservoir,   high pressure hot water which is converted into steam, or transferred heat from geothermal hot water to another liquid to turn the generator turbine to produce energy.

Another method of harnessing and applying geothermal energy is through a geothermal pump.  As we here in Chicago can attest to, temperature changes day by day and season by season.  But, temperatures just 10 feet below the earth’s surface hold pretty steady at 50 – 60 degrees.  For most areas, you can feel proof of this fact by feeling the soil, which is typically warmer than the air during the winter and cooler than the air in the summer.  Geothermal heat pumps use those constant temperatures to heat and cool buildings and homes. They transfer heat from the ground into buildings in winter and reverse the process in the summer.

Chicago Area Geothermal Providers
For more information about installers, check out www.geoexchange.org

Hydro Power

Hydropower is one of the oldest forms of energy and years ago, it was used to turn a paddle wheel for things like grinding grain.  It generates energy from moving water and is the renewable energy source that produces 19% of the  electricity in the United States, with most of the of it in the West.

Hydropower is generated in 3 different ways; hydroelectric power (the most common form and produced using dams), tidal power (produced by currents) and wave power (the newest form, using the power of the wave).  As I mentioned before, the most common type of hydropower is hydroelectric power and most hydroelectric plants have a dam and a reservoir where the water can come in one end and out the other to the river below.  There is about 2,400 electricity producing dams in the United States and they produce energy by using the fall of the water to turn turn a turbine which then turns the shaft in a generator.  Some of the benefits of using hydropower is that it is a clean and domestic fuel source.

Biomass

Biomass is a renewable energy source derived from living, or recently living organisms, such as wood, waste, alcohol fuels, crops and landfill gases.  When burned, the chemical energy in biomass is released as heat.  Wood waste or garbage can be burned to produce steam for making electricity, or to provide heat to industries and homes, but burning stuff isn’t the only way to release it’s energy.  Biomass can be converted to other forms of energy, like methane gas or transportation fuels, such as ethanol and biodiesel.  Landfill, human and agricultural waste release methane gas, the main component of natural gas.  Corn and sugar cane crops can be fermented to produce ethanol, which can be used as a transport fuel and because it contains a higher percentage of oxygen than petroleum based gas, it burns more completely, reducing greenhouse gas emissions by as much as 46%.  Biodiesel can be made from vegetable oils, animal fats, or greases, but most is made from soybean oil. About half of biodiesel producers are able to make biodiesel from used oils or fats, including recycled restaurant grease.  This kind of fuel will run in regular diesel vehicles without making any changes to the engines and can also be stored and transported using diesel tanks and equipment.

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