1. By kevin p., caroline b., Lucy P., and sarah d.
Hydroelectric power
By kevin p., caroline b., Lucy P., and sarah d.

2. diagram

3. Process
Hydroelectric power harnesses the power of seasonal water flows, water pressure, and gravity to produce reliable amounts of electricity over short to medium amounts of time.
A dam is built first to block water flow, creating a deeper lake with a tunnel at the bottom. When electricity needs to be generated, water is run through this tunnel, pushed downwards by gravity and by the water pressure from the lake above.
The water travels through the tunnel, gaining speed until it reaches a turbine, which it spins before being emptied into the outflow river. Spinning the turbine creates mechanical energy, which is then turned into electricity through the use of a generator.
This electricity is then transferred through power lines into the electric system at a high voltage.

4. Advantages
Capable of reliably delivering power over a short-medium amount of time, depending on the season
Completely renewable, and dams can be built which have positive environmental effects on the local watershed (creating a lake)
Cost effective and able to work for a very long time after construction
Domestic source of energy, meaning that it reduces dependence on other, foreign sources of energy

5. Disadvantages High setup cost and intensive construction
Seasonal power availability; less electricity generated during summer months or draughts
Must be constructed on a river or other source of flowing water, which is scarce in some areas
Requires hills/mountains to provide water pressure and downward momentum, meaning that only certain geographical areas are capable
Cannot reliably produce power over a long period of time

6. Conditions
Must be built on a river/lake with flowing water and a hill to provide motion through gravity and water pressure
Must be a reliable, constant source of water or the dam cannot operate during some seasons
High setup cost means that dams take years to build and are not always able to be built

7. Locations
Hydroelectric power is most abundant and developed in China, with Canada and Brazil also ranking above the US
Chinese hydroelectricity accounts for 32% of worldwide hydroelectricity
The Pacific Northwest is the more popular location for hydroelectric power in the United States, as we have a very reliable source of water and a big river (the Columbia)
Hydropower makes up 7% of US power and 16% of power worldwide
2/3 of Potential spots worldwide for hydroelectric power are undeveloped
Source:

8. efficiency
The best hydroelectric plants can be up to 90% efficient, meaning that they convert 90% of the water’s kinetic energy into power that we can use.
This is significantly better than the best gas-powered electricity plants, which are at best 50% efficient.
Hydropower is also much less expensive to maintain- power in Wisconsin costs less than 1 cent per kWh, and nationally hydroelectric power is about 1/3 the price of fossil fuel power.
Source:

9. Fun Facts! In 1995, all of Idaho’s electricity came from Hydropower.
99% of renewable energy is made from hydropower.
Washington, Oregon, and California account for over 50% of the electricity generated in the US
70% of Washington’s energy is from hydroelectric power
The construction of dams and artificial lakes along with fish ladders provides new habitats for organisms and allows for bigger and healthier ecosystems.
All statistics are from sources on previous slides.