Energy

1. Energy

2. The main source of electricity generated in NZ. • Fossil fuels • Hydro dams • Geothermal • Wind turbines • Hydro power. • coal

3. Hydro-electric power plant works. • The theory is to build a dam on a large river that has a large drop in elevation. The dam stores lots of water behind it in the reservoir. Near the bottom of the dam wall there is the water intake. Gravity causes it to fall through the penstock inside the dam. At the end of the penstock there is a turbine propeller, which is turned by the moving water. The shaft from the turbine goes up into the generator, which produces the power. Power lines are connected to the generator that carry electricity to your home and mine. The water continues past the propeller through the tailrace into the river past the dam. By the way, it is not a good idea to be playing in the water right below a dam when water is released!

4. Geothermal power • Hot rocks underground heat water to produce steam. • We drill holes down to the hot region, steam comes up, is purified and used to drive turbines, which drive electric generators. • There may be natural "groundwater" in the hot rocks anyway, or we may need to drill more holes and pump water down to them. • The first geothermal power station was built at Landrello, in Italy, and the second was at Wairekei in New Zealand. Others are in Iceland, Japan, the Philippines and the United States.

5. How a wind power plant works • Wind is a form of solar energy. Winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetation. Humans use this wind flow, or motion energy, for many purposes: sailing, flying a kite, and even generating electricity. • The terms wind energy or wind power describe the process by which the wind is used to generate mechanical power or electricity. Wind turbines convert the kinetic energy in the wind into mechanical power. This mechanical power can be used for specific tasks (such as grinding grain or pumping water) or a generator can convert this mechanical power into electricity. • So how do wind turbines make electricity? Simply stated, a wind turbine works the opposite of a fan. Instead of using electricity to make wind, like a fan, wind turbines use wind to make electricity. The wind turns the blades, which spin a shaft, which connects to a generator and makes electricity

6. Fossil fuel • Coal, oil and gas are called "fossil fuels" becausethey have been formed from the organic remains ofprehistoric plants and animals

7. Electricity around new Zealandhow is electricity sent around the country on the transmission grid? • 11,800km of high voltage lines,178 substations. • There are 41,000 towers and poles on over 45,000 properties