Presently, carbon-based energy sources are utilized to a large extent, however, renewable sources of energy are slowly gaining importance due to concerns about climate change and environmental sustainability. Despite the current low prices of fossil fuel, renewable energy sources development is gaining momentum due to the initiative of the world leader to reduce carbon emissions. At the moment, the investment cost of renewable energy is still higher compared to carbon-based energy per unit of generated energy. Inefficiencies of current technologies are also a factor in the higher cost of renewable energy.
Renewable energy can be derived from natural sources that replenish themselves over some periods of time. These natural sources include the sun, wind, water movement, organic plant and biomass, and geothermal. The present technology of most renewable energy sources is not suitable to supply large base loads, particularly solar and wind due to energy storage requirements.
Some common sources of renewable energy:
Solar energy is the most abundant of all energy resources. Solar technologies can provide heat, cooling, natural lighting, electricity, and fuels for a host of applications. Solar technologies convert sunlight into electrical energy either through photovoltaic panels or through mirrors that concentrate solar radiation.
Wind energy harnesses the kinetic energy of moving air by using large wind turbines. Wind energy technologies have evolved over the last few years to maximize the electricity produced with taller turbines and larger rotor diameters. Many parts of the world have strong wind speeds, but the best locations for generating wind power are sometimes remote ones. Offshore wind power offers tremendous potential.
Geothermal energy utilizes the accessible thermal energy from the earth’s interior. Heat is extracted from geothermal reservoirs using wells or other means. The technology for electricity generation from hydrothermal reservoirs is mature and reliable and has been operating for more than 100 years.
Hydropower harnesses the energy of water moving from higher to lower elevations. It can be generated from reservoirs and rivers. Reservoir hydropower plants rely on stored water in a reservoir, while run-of-river hydropower plants harness energy from the available flow of the river. Hydropower currently is the largest source of renewable energy in the electricity sector. The infrastructure needed to create hydropower can also impact ecosystems in adverse ways. For this reason, many consider small-scale hydro a more environmentally-friendly option, and especially suitable for communities in remote locations.
Ocean energy derives from technologies that use the kinetic and thermal energy of seawater - waves or currents for instance - to produce electricity or heat. Ocean energy systems are still at an early stage of development, with a number of prototype wave and tidal current devices being explored. The theoretical potential for ocean energy easily exceeds present human energy requirements.
Bioenergy is produced from a variety of organic materials, called biomass, such as wood, charcoal, dung, and other manures for heat and power production, and agricultural crops for liquid biofuels. Most biomass is used in rural areas for cooking, lighting, and space heating, generally by poorer populations in developing countries. Energy created by burning biomass creates greenhouse gas emissions, but at lower levels than burning fossil fuels like coal, oil or gas.
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