Geothermal Power Matthew Duarte Josh Ku-ha! Jerry Lu

Source of Geothermal Power The word, Geothermal, comes from two Greek words, “geo” which means “Earth” and “thermal” which means “heat”. Available anywhere (to some extent). Geothermal energy comes from underground heat sources such as hot rocks that heats water producing steam. Geothermal energy is indirectly sourced by the sun also the sun shines on the ground and is absorbed by the ground.

Efficiency & Cost The approximate efficiency rate of geothermal power plants is 16%. At geysers, geothermal power costs about $0.03-$0.035 per kilowatt-hour. At geothermal power plants, geothermal power costs about $0.01-$0.03 per kilowatt-hour. Although, geothermal power plant are energy efficient, they aren’t cost efficient. Most of its expenses lean towards the beginning of its construction rather then the fuels that run them. The initial cost for the field and power plant is about $2500 per installed kilowatt. At smaller power plants, it costs $ $5000.

Equipment (extraction) The most common current way of capturing the energy from geothermal sources is to tap into naturally occurring "hydrothermal convection" systems where cooler water seeps into Earth's crust, is heated up, and then rises to the surface. The 3 types of extraction are Dry Steam Power Plant, Flash Steam Power Plants, and Binary- Cycle power plant.

Dry Steam Power Plant In the simplest design, the steam goes directly through the turbine, then into a condenser where the steam is condensed into water.

Flash Steam The second design very hot water is depressurized or "flashed" into steam which can then be used to drive the turbine.

Binary Cycle Power Plant In the third design is when hot water is passed through a heat exchanger, where it heats a second liquid—such as isobutane—in a closed loop. The isobutane boils at a lower temperature than water, so it is more easily converted into steam to run the turbine.

Equipment ( Use) Geothermal energy can be used for heating homes. Geothermal heat pump system can heat or cool a house almost anywhere. They can heat houses by taking heat from the ground and transfer the heat into the house To cool houses in the summer it takes the heat in the house and transfers it into the ground. Average Life span of heating pump is 22 years Geothermal heat pump systems work so efficiently is because the sun shines on the ground heating it. Earth absorbs 50% of the sun light There are different types of heating systems. Horizontal Loops which are used where adequet land is available ranging from 100 – 500 feet in range Vertical Loops which is used when land is limited. Pump goes underground feet down. Pond Loops can be used next to a lake where pipe is placed at bottem of lake.

Consumption/Usage There are 40 countries that extract enough energy from geothermal sites to produce 1% of world’s energy. Currently the United States is the world’s largest producer of geothermal electricity followed by the Philippines ( supplying 27% of its electricity). Geothermal energy supplies electricity for 6 million people in the United states. Supplying 6% of California’s electricity It can also be use to heat and cool buildings.

Advantages and Disadvantages Advantages Very high- efficiency Lower CO2 emissions than fossil fuels Low land use Moderate environmental impact Low land disturbance Low costs at favorable site Disadvantages Not a wide-spread source of energy High installation cost Can run out of steam Suited of particular regions May release hazardous gases