Simply put, Renewable energy is energy derived from natural processes that are replenished constantly. In its various forms, it derives directly from the sun, or from heat generated deep within the earth. Included in the definition is electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and biofuels and hydrogen derived from renewable resources.
Present renewable energy sources supply about 18% of current energy use (see figure 1 & 2) and there is much potential that could be exploited in the future.
As the simple drawing will show, the technical potential of renewable energy sources is way beyond the current and even future global primary energy requirement.
Hydropower
Using renewable sources of energy has significant benefits to people. Renewable sources of energy are derived from natural processes that are replenish constantly. Compared to other sources of energy which uses oil, coal and nuclear technology to generate electricity renewable sources are a lot safer and environmental friendly.
| Worldwide, hydro power plants produce about 24 percent of the world’s electricity and supply more than 1 billion people with power. The world’s hydro power plants output a combined total of 675,000 megawatts, the energy equivalent of 3.6 billion barrels of oil, according to the National Renewable Energy Laboratory. |
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In the Phillipines, there are a handful of hydro power plants dispersedly located at the various countrysides of Luzon, Visayas and Mindanao. Almost all of the large hydroelectric power plants, which range from over 50 MW are connected to the main transmission grid, while most of small, (10 to 50 MW) and mini (101 to to 10 MW) are embedded to the local distribution system. The total installed generating capacity at the Phillipines is 15,937 MW. Hydro power plants accounts for about 3,289 MW (20.64%). On the other hand, the gross power generation is 59,612 GWh, hydro power acounts for about 8,563 GWh (14.36 %).

In this article, we’ll take a look at how falling water creates transforms energy into electricity known to us as hydropower. You will also get a glimpse at one unique application of hydropower that may affect your daily life.
| When watching a river roll by, it’s hard to imagine the force it’s carrying. Hydropower plants harness water’s energy and use simple mechanics to convert that energy into electricity. Hydropower plantsare actually based on a rather simple concept, water flowing through a dam turns a turbine, which turns a generator. |
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Here are the basic components of a conventional hydropower plant
1. Dam - Most hydropower plants rely on a dam that holds back water, creating a large reservoir.
2. Intake - Gates on the dam open and gravity pulls the water through the penstock, a pipeline that leads to the turbine. Water builds up pressure as it flows through this pipe.
3. Turbine - The water strikes and turns the large blades of a turbine, which is attached to a generator above it by way of a shaft.
4. Generators - As the turbine blades turn, so do a series of magnets inside the generator. Giant magnets rotate past copper coils, producing alternating current (AC) by moving electrons.
5. Transformer - The transformer inside the powerhouse takes the AC and converts it to higher-voltage current
6. Power lines - Out of every power plant come four wires: the three phases of power being produced simultaneously plus a neutral or ground common to all three.
7. Outflow - Used water is carried through pipelines and re-enters the river downstream.
The water in the reservoir is considered stored energy. When the gates open, the water flowing through the penstock becomes kinetic energy because it’s in motion. The amount of electricity that is generated is determined by several factors. Two of those factors are the volume of water flow and the amount of hydraulic head. The head refers to the distance between the water surface and the turbines. As the head and flow increase, so does the electricity generated. The head is usually dependent upon the amount of water in the reservoir.
*Article-contribution by Manila Electric Company