Group items matching

in title, tags, annotations or url

Geothermal energy has been used for thousands of years in some countries for cooking and heating. It is simply power derived from the Earth's internal heat.This thermal energy is contained in the rock and fluids beneath Earth's crust. It can be found from shallow ground to several miles below the surface, and even farther down to the extremely hot molten rock called magma.These underground reservoirs of steam and hot water can be tapped to generate electricity or to heat and cool buildings directly.A geothermal heat pump system can take advantage of the constant temperature of the upper ten feet (three meters) of the Earth's surface to heat a home in the winter, while extracting heat from the building and transferring it back to the relatively cooler ground in the summer

There are three types of geothermal power plants: dry steam, flash, and binary. Dry steam, the oldest geothermal technology, takes steam out of fractures in the ground and uses it to directly drive a turbine. Flash plants pull deep, high-pressure hot water into cooler, low-pressure water. The steam that results from this process is used to drive the turbine. In binary plants, the hot water is passed by a secondary fluid with a much lower boiling point than water. This causes the secondary fluid to turn to vapor, which then drives a turbine. Most geothermal power plants in the future will be binary plants.

It can be extracted without burning a fossil fuel such as coal, gas, or oil. Geothermal fields produce only about one-sixth of the carbon dioxide that a relatively clean natural-gas-fueled power plant produces.

All renewable energy (except tidal and geothermal power), and even the energy in fossil fuels, ultimately comes from the sun. The sun radiates 174,423,000,000,000 kilowatt hours of energy to the earth per hour.

The sun radiates 174,423,000,000,000 kilowatt hours of energy to the earth per hour.

Currently, most hydrogen is made from natural gas through a process known as reforming. Reforming separates hydrogen from hydrocarbons by adding heat. Hydrogen can also be produced from a variety of sources including water and biomass.

Because the energy is generated right near the plant, it saves on processing and transportation costs compared to other types of fuel.

The initial costs of geothermal energy are high -- wells can cost $1 to $4 million each to drill, and installation of a home geothermal pump system can run as much as $30,000

However, a home geothermal energy pump can cut energy bills by 30 to 40 percent and will pay for itself within 5 to 10 years

A generator is basically an electric motor working in reverse.

In contrast to tidal power, ocean wave energy plants do not make use of the energy difference between high tide and low tide, but generating energy from continuous wave motion. So, wave energy generation is the conversion of the forces from the motion of waves into usable energy.

Wave energy is considered a form of hydropower, although it is the wind blowing over the surface of the ocean causing waves. So in many ways, wave energy is also wind energy - with all the pros and cons.

There were 140,000 fuel cell stacks shipped globally in 2010

although, as of 2010, no public company in the industry had yet become profitable

Hydrogen has the highest energy content of any common fuel by weight,

PEM Fuel Cell Applications

All Soymet biofuel products have zero petroleum toxins and lower emissions. Primary byproducts are carbon dioxide and water vapor. These biodiesel fuels burn cleanly and produce the same amount of energy as conventional diesel fuels.

Tidal energy is most sustainable and beneficial as a tool in a larger tool belt of renewable energy sources needed to meet our energy demands.

Unlike other renewable energy sources, biomass can be converted directly into liquid fuels, called "biofuels," to help meet transportation fuel needs

Today, ethanol is made from starches and sugars, but NREL scientists are developing technology to allow it to be made from cellulose and hemicellulose,

But as much as it poses a health risk, a group of researchers from the National Renewable Energy Laboratory point out that the relative risks are still light when compared to the use of fossil fuels