Renewable energy
Renewable energy is useful energy that is collected from renewable resources that are naturally replenished on a human timescale. Examples of renewable energy sources include carbon neutral sources such as sunlight, wind, rain, tides, waves, and geothermal heat, as well as hydroelectric and wind energy. This form of energy source contrasts with fossil fuels, which are being depleted at a rate that is significantly greater than their ability to replace themselves. Although the vast majority of renewable energy is sustainable, some of it is not, for example, some biomass is not environmentally friendly.
Electricity production, air and water heating/cooling, transportation, and rural (off-grid) energy services are all examples of how renewable energy may be used to deliver energy in four crucial sectors.
According to the REN21 2017 study, renewables contributed 19.3 percent to humans' worldwide energy consumption and 24.5 percent to their power production in 2015 and 2016, respectively, according to the United Nations Environment Programme. With traditional biomass accounting for 8.9 percent of total energy consumption, heat energy (modern biomass, geothermal, and solar heat), hydropower accounting for 3.9 percent, and the remaining 2.2 percent being electricity generated by wind, solar, and other forms of biomass accounting for the remaining 2.2 percent of total energy consumption. In 2017, global investments in renewable energy totaled US$279.8 billion, with China accounting for 45 percent of total global investments and the United States and Europe each contributing for roughly 15 percent of total global investments. Approximately 10.5 million employment were predicted to be linked with the renewable energy businesses worldwide, with solar photovoltaics being the biggest employer in the renewable energy industry. Energy systems based on renewable sources are becoming more efficient and cost-effective, and their percentage of overall energy consumption is growing. As of 2019, renewable energy sources accounted for more than two-thirds of all newly built power capacity globally. Because to rising use of renewable energy and natural gas, the growth in coal and oil consumption might come to a halt by 2020. As of 2020, photovoltaic solar and onshore wind will be the most cost-effective methods of constructing new electricity-generating facilities in the vast majority of nations.