What Is Renewable Short Answer?

Definition of Renewable Energy

Renewable energy is defined as energy that comes from sources that are naturally replenished on a human timescale. The most common renewable energy sources are solar, wind, geothermal, biomass, and hydropower. Unlike fossil fuels, which are finite resources, renewable energy sources quickly replenish themselves and can provide energy almost indefinitely. The key aspect that makes energy “renewable” is that it comes from an ongoing natural process that is not significantly depleted or used up by harnessing it for human needs.

Some key characteristics of renewable energy sources:

  • They are replenished naturally within a short period of time.
  • They come from ongoing natural processes such as sunlight, wind, water flows, plant growth, and geothermal heat flows.
  • The energy can be harnessed sustainably without depleting the source.
  • They produce much less pollution and carbon emissions compared to fossil fuels.

Overall, renewable energy provides clean and sustainable power from sources that will not run out for the foreseeable future. This makes them essential alternatives to non-renewable fossil fuels.

Types of Renewable Energy

There are several major types of renewable energy sources that are in use today: (National Grid, 2022)

Solar Energy

Solar energy comes directly from the sun and is captured and converted in a few ways. Photovoltaic cells convert sunlight directly into electricity, while concentrated solar power systems use lenses or mirrors to focus sunlight to drive traditional steam turbines or engines that create electricity. (UN, n.d.)

Wind Energy

Wind turbines convert the kinetic energy in wind into mechanical power that runs a generator to produce electricity. Wind farms with many turbines in one location can provide power to the grid.


Hydropower harnesses the energy of falling or fast-moving water to produce electricity. Hydroelectric dams use water’s energy to drive turbine generators, and new systems can extract energy from waves and tides.

Geothermal Energy

Geothermal energy taps into underground reservoirs of hot water or steam to power turbines at the surface. This heat energy can be used directly or converted to electricity.

Biomass Energy

Biomass refers to any organic material from plants or animals that can be used as an energy source. Biomass can be burned to produce heat and electricity or converted into gases or liquids for energy.


Renewable energy provides substantial benefits for our climate, health, and environment compared to fossil fuels. Some key benefits include:

Clean energy generation that produces little to no greenhouse gas emissions or air pollution. Sources like solar, wind, geothermal and hydropower emit no carbon dioxide or other pollutants when generating electricity.

Sustainability and resource independence. Renewables rely on continuously replenished resources like sunlight, wind, water, and geothermal heat. This provides energy security and reduces dependence on finite fossil fuel reserves.

According to the EPA, generating energy from local renewable sources like solar or wind rather than imported fossil fuels keeps energy dollars in local communities. The EPA notes local renewables can create jobs and grow the local economy.

Renewable energy production is rapidly expanding and has great potential to displace carbon-intensive energy sources. The Union of Concerned Scientists reports that 18.7% of U.S. energy came from renewables in 2019, up from 11% in 2009 and on track to hit 30% by 2030.

Current Usage

Renewable energy sources currently provide about 13.1% of total U.S. energy production and 12.9% of total U.S. electricity generation as of 2021 according to the U.S. Energy Information Administration. This includes hydropower, biomass, biofuels, wind, geothermal, and solar energy sources. Globally, renewables accounted for 13.8% of total final energy consumption and 26.2% of global electricity generation in 2018 according to the U.S. Renewable Energy Factsheet. The percentage varies significantly by country. For example, Iceland generates 100% of its electricity from renewable sources due to abundant geothermal and hydropower resources. In Europe, renewable energy provided 19.7% of gross final energy consumption in 2019 with Scandinavian countries leading the way. China is also rapidly expanding its renewable energy capacity, contributing 26.4% of global renewable power capacity additions in 2020.

Growth Potential

There is immense potential for renewable energy expansion globally. According to the International Energy Agency (IEA), renewable capacity additions are set to increase by 107 gigawatts (GW) in 2023, the largest absolute increase ever. This will bring total renewable capacity additions to over 440 GW next year.

Many countries have set ambitious renewable energy goals as they aim to strengthen energy security and meet net zero emissions targets. For example, the IEA projects that global renewable power capacity will grow by 2,400 GW from 2022-2027, equal to the world’s entire current power capacity. This rapid growth is being driven by supportive government policies and falling technology costs.

However, there is still tremendous potential to scale up renewables even further. The IEA’s net zero pathway requires renewable capacity to expand at twice the pace seen over the last five years. This will require concerted policy action and investment worldwide.


While renewable energy usage is growing, it still faces some key challenges. One major challenge is intermittency and variability. As the IEA reports, renewable sources like solar and wind are intermittent, meaning they fluctuate based on weather conditions and time of day (IEA). This variability makes it difficult to integrate large amounts of renewable energy into the existing grid.

Another challenge is the need for better energy storage solutions. Renewable sources produce energy at certain times, but it needs to be stored effectively to provide continuous power generation (Regen Power). Developing grid-scale storage is complex and expensive.

Transmission infrastructure also poses a barrier. Many prime renewable energy sites are located far from major cities and demand centers. Building out transmission lines to transport this energy is costly and faces regulatory hurdles (Sustainable Review).

Lastly, despite decreasing costs, renewable energy remains more expensive than conventional sources in many contexts. More investment is needed to achieve economies of scale and fully close the cost gap.

Key Technologies

When it comes to renewable energy technologies, some of the key ones that are used widely today include solar panels, wind turbines, and hydroelectric dams.

Solar panels, also known as photovoltaic (PV) panels, generate electricity directly from sunlight. They’re often mounted on rooftops, but can also be installed on the ground as part of large solar farms. Solar PV is now one of the most rapidly adopted energy technologies in the world (source).

Wind turbines harness the power of the wind to generate electricity. They often consist of tall towers with blades that spin as the wind blows, turning a generator. Wind power is considered one of the lowest cost and most scalable renewable energy technologies available today (source).

Hydroelectric dams convert the kinetic energy from flowing water into electricity by passing it through turbines. While hydroelectricity provides only about 16% of the world’s electricity, it is a mature technology that offers stability to electricity grids (source).

Notable Renewable Energy Projects

Some of the largest and most notable renewable energy projects around the world include:

The Longyangxia Dam Solar Park in China is currently the largest solar farm in the world, with a capacity of 1,300 MW. It contains over 4 million solar panels and spans nearly 10 square miles of land (Source).

The offshore Hornsea Wind Farm under construction off the coast of England in the North Sea will have a capacity of 1,200 MW when completed. It will consist of 174 wind turbines and be able to power well over 1 million homes (Source).

The Three Gorges Dam in China is one of the largest hydroelectric power stations in the world, with a capacity of 22,500 MW. The dam spans over a mile across the Yangtze River and contains 32 main turbines (Source).

Future Outlook

The future outlook for renewable energy is very positive, with continued strong growth expected according to the U.S. Department of the Interior (Clean Energy Future | U.S. Department of the Interior). Renewable energy sources such as solar, wind, geothermal and hydroelectric are becoming more cost competitive with fossil fuels, and improvements in technology are driving down costs further. Many governments around the world are implementing policies and incentives to accelerate the transition to renewables. There is still tremendous untapped potential for growth in renewables – currently under 15% of global energy comes from renewable sources according to the UN (Renewable energy – powering a safer future). With the right investments, policies and technological innovations, renewables are poised to continue their rapid growth in the coming decades.


In summary, renewable energy comes from naturally replenished sources such as sunlight, wind, water, and geothermal heat. The main types of renewable energy are solar, wind, hydroelectric, biomass, and geothermal. Renewable energy provides numerous benefits such as reducing greenhouse gas emissions, diversifying energy supply, stimulating economic growth, and improving public health. While renewable energy currently makes up a modest portion of global energy use, it has tremendous potential for future growth as costs continue to fall and technologies advance. Key challenges for renewable energy include variability, grid integration, and upfront costs. However, with supportive policies and sustained investment, renewable energy can play a major role in building a sustainable energy future and mitigating climate change. The transition to an energy system based on renewables is crucial for establishing energy security, meeting emissions targets, and building resilient infrastructure. With innovative technologies, smart policies, and public-private collaboration, a renewably-powered world is within reach.

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