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Introduction

Wind, solar, and hydroelectricity are three emerging renewable sources of energy.

Renewable energy is energy that is collected from renewable resources, which are naturally replenished on a human timescale, such as sunlight, wind, rain, tides, waves, and geothermal heat. Renewable energy often provides energy in four important areas: electricity generation, air and water heating/cooling, transportation, and rural (off-grid) energy services.

Based on REN21's 2017 report, renewables contributed 19.3% to humans' global energy consumption and 24.5% to their generation of electricity in 2015 and 2016, respectively. This energy consumption is divided as 8.9% coming from traditional biomass, 4.2% as heat energy (modern biomass, geothermal and solar heat), 3.9% hydro electricity and 2.2% is electricity from wind, solar, geothermal, and biomass. Worldwide investments in renewable technologies amounted to more than US$286 billion in 2015, with countries like China and the United States heavily investing in wind, hydro, solar and biofuels. Globally, there are an estimated 7.7 million jobs associated with the renewable energy industries, with solar photovoltaics being the largest renewable employer. As of 2015 worldwide, more than half of all new electricity capacity installed was renewable.

Renewable energy resources exist over wide geographical areas, in contrast to other energy sources, which are concentrated in a limited number of countries. Rapid deployment of renewable energy and energy efficiency is resulting in significant energy security, climate change mitigation, and economic benefits. The results of a recent review of the literature concluded that as greenhouse gas (GHG) emitters begin to be held liable for damages resulting from GHG emissions resulting in climate change, a high value for liability mitigation would provide powerful incentives for deployment of renewable energy technologies. In international public opinion surveys there is strong support for promoting renewable sources such as solar power and wind power. At the national level, at least 30 nations around the world already have renewable energy contributing more than 20 percent of energy supply. National renewable energy markets are projected to continue to grow strongly in the coming decade and beyond. Some places and at least two countries, Iceland and Norway generate all their electricity using renewable energy already, and many other countries have the set a goal to reach 100% renewable energy in the future. For example, in Denmark the government decided to switch the total energy supply (electricity, mobility and heating/cooling) to 100% renewable energy by 2050.

While many renewable energy projects are large-scale, renewable technologies are also suited to rural and remote areas and developing countries, where energy is often crucial in human development. Former United Nations Secretary-General Ban Ki-moon has said that renewable energy has the ability to lift the poorest nations to new levels of prosperity. As most of renewables provide electricity, renewable energy deployment is often applied in conjunction with further electrification, which has several benefits: Electricity can be converted to heat (where necessary generating higher temperatures than fossil fuels), can be converted into mechanical energy with high efficiency and is clean at the point of consumption. In addition to that electrification with renewable energy is much more efficient and therefore leads to a significant reduction in primary energy requirements, because most renewables don't have a steam cycle with high losses (fossil power plants usually have losses of 40 to 65%).

Renewable energy systems are rapidly becoming more efficient and cheaper. Their share of total energy consumption is increasing. Growth in consumption of coal and oil could end by 2020 due to increased uptake of renewables and natural gas.

Selected article

A mandatory renewable energy target is a government legislated requirement on electricity retailers to source specific proportions of total electricity sales from renewable energy sources according to a fixed timeframe. The additional cost is distributed across most customers by increases in other tariffs. The cost of this measure is therefore not funded by government budgets, except for costs of establishing and monitoring the scheme and any audit and enforcement actions.

At least 66 countries, including 27 EU countries have renewable energy policy targets of some type. The EU baseline target is 20% by 2020. While the USA does not have a national RET, 29 of its states do. Similarly Canada has 9 state RETs but no national target. Targets are typically for shares of electricity production, but some are defined as by primary energy supply, installed capacity or otherwise. While some targets are based on 2010-12, many are now for 2020 which ties in with the IPCC suggested greenhouse gas emission cuts of 25 to 40% by Annex I countries by 2020, although some are for 2025.

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View of a photovoltaic panel installation in Parc del Forum, Barcelona, Spain
Photovoltaic panel installation in Parc del Forum, Barcelona, Spain

Selected biography

Stefan Krauter 2005.jpg

Stefan Krauter is Professor and Entrepreneur in the area of Renewable Energies. His activities in research, teaching and business are directed to establish a global sustainable energy supply. He specialized in the direct conversion of sunlight into electricity - photovoltaics.

He initiated and organized in Rio de Janeiro several congresses (RIO 02/3/5/6/9 - World Climate & Energy Events) and the Latin America Renewable Energy Fair (LAREF), to sustain the vision of the UNCED Earth Summit of Rio 1992 in that area.

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Did you know?

... that REN21, the Renewable Energy Policy Network for the 21st Century, is a policy network that provides a forum for international leadership in renewable energy policy, in order to share knowledge and facilitate the rapid growth of renewable energy technologies in developing countries and industrialised economies ?

The network launched in June 2005, operates from offices in Paris, France, and is provided by the United Nations Environment Programme and the Deutsche Gesellschaft für International Zusammenarbeit in collaboration with the International Energy Agency. Since 2005 REN21 has produced an annual Renewables Global Status Report, with Eric Martinot and Janet Sawin as lead authors.

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  • "Renewable energy is proving to be commercially viable for a growing list of consumers and uses. Renewable energy technologies provide many benefits that go well beyond energy alone. More and more, renewable energies are contributing to the three pillars of sustainable development – the economy, the environment and social well-being – not only in IEA countries, but globally."
  • "Renewable energy is 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."

International Energy Agency, Renewable energy... into the mainstream, 2002.

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