Renewable Energy Sources: Geothermal and Tidal Power
Geothermal and Tidal Energy Sources
The heat for geothermal power comes from ongoing radioactive decay and primordial heat left over from the formation of the Earth. The energy can be tapped anywhere on the Earth’s surface, but it is best in volcanically active areas.
Radioactive Decay
The decomposition of species gives rise to uranium-235 and thorium-232. This process continually replenishes geothermal energy.
Primordial Heat
As the name implies, primordial heat has existed since the creation of the Earth 4.6 billion years ago when the energy and mass from colliding cosmic matter produced a planet. This heat is cooling inside to form the crust and giving life to it.
Types of Geothermal Resources
- Conventional Hydrothermal Geothermal Resources
- Geopressurized Reservoirs
- Rock Reservoirs
Tidal Energy
With the help of turbines, incoming tides can be manipulated to generate electricity. The second way to exploit tidal energy is by sinking turbines to the seafloor where fast-flowing currents turn generator blades, much like wind does with a wind turbine. Tidal energy harnesses the natural ebb and flow of the tides to produce power. Tides are created by the gravitational pull of the Moon and Sun, combined with the rotation of the Earth. Tidal energy can be harnessed both in the sea and in tidal rivers and estuaries.
Movable flood gates, called sluice gates, on the dam allow incoming tidal waters to fill up in a reservoir. Once the water reaches its maximum level, the gates close and trap the water. The water in the artificial estuary is called the hydrostatic head. As the tide ebbs, a gradually increasing head differential is created between receding water levels and the fixed level within the barrier. When the head differential has reached the desired value, the potential energy created can be converted into mechanical energy or electrical energy simply by opening the gates and allowing the water to flow through the turbine. A proper site for this type of technology should have a sufficient tidal range in addition to the location of a natural bay.
Incineration
Fuel wastes are burned, and heat is generated to produce electricity (through an energy power plant) or heating.
Fermentation of Organic Wastes
This process is similar to that of biomass, and the goal is to obtain biogas.