Renewable energy is a form of energy that is produced from natural resources like wind, geo-thermal heat, sunlight, and tides. Rainwater may also be converted into energy suitable for commercial use. Renewable energy sources currently contribute to approximately 18% of total global energy consumption.
Renewable energy generating projects can be principal sources of power or act as supplementary power generating units. The alternative energy source is suitable for rural areas where transmission and distribution of energy can be expensive and even difficult. Renewable energy is particularly suitable for farmers and small businesspersons who require electrical power at certain predetermined intervals.
Renewable energies play an important role in the global commercial energy map. Alternative energy sources are employed to meet energy gaps like peaking power and base load power. The quality of supplied power from conventional sources are also improved with supplementary power generating units. Global wind power generating capacity currently stands around 100GW. Solar power plants contribute more than 2,000 MW per year.
An overwhelming renewable energy source is biomass. Biomass includes animal and plant matter, and biodegradable wastes like human excreta, manure, slaughterhouse waste and standard sewer content. Another major renewable energy source is hydro power. The scope of hydro power includes not only standard hydroelectric dams but also micro hydro systems that produce about 100kW of power. Tidal power generating units capture energy from natural tides of oceans. Turbines are used to tap the immense aquatic power source. Wave power systems generate electrical energy from ocean waves.
Biomass can be utilized to generate biofuel of great economic value. Renewable energy products like biodiesel and ethanol can be used as an energy source in boilers and internal combustion engines. Vehicle engines require no engineering modifications to accommodate the alternative fuel. Ethanol is a favorite among environmentally friendly biofuels. This chemical is manufactured by processing cornstalks, sugarcane, sugarbeets, and corn.
Renewable energy suffers from intermittent generation capability. For example, the wind required for wind power generating units may not be available at all times. The energy produced is thus stored to meet future energy demands. This system contributes to better utilization of power. All illustrative examples are the usage of solar energy in lighting public roadside lamp posts during nighttime. The different energy storage technologies are:
» Compressed air
» Batteries
» Pumped hydropower
» Superconducting magnetic energy
» Flywheels
» Super capacitors
Batteries are extremely popular for long and short term storage of electrical energy. Advanced battery technologies like lithium polymer, nickel metal hydride, and lithium ion are more efficient than common lead-acid batteries. Pumped hydropower employs off-peak electricity to pump water from a lower level reservoir to another reservoir situated at a higher elevation. The water is released when electricity generation is required. Water flowing under gravity is passed through hydraulic turbines to generate electrical power.