What Is Renewable Energy And Why Is It Important?

What is Renewable Energy?

What is renewable energy and why is it important?

Renewable energy is energy generated from natural resources that are constantly replenished, such as sunlight, wind, rain, tides, waves, and geothermal heat. Some of the main types of renewable energy include:

  • Solar energy – This harnesses energy from the sun through technologies like solar panels that convert sunlight into electricity.

  • Wind energy – Wind turbines convert the kinetic energy from wind into mechanical power that can generate electricity.

  • Hydropower – Capturing the energy from flowing water and using it to generate electricity is how hydropower works.

  • Geothermal energy – Using the internal heat from the Earth’s core to directly produce heat or electricity is geothermal energy.

  • Biomass – Organic material like plants and animal waste can be used to generate energy through combustion or conversion into biofuels.

The key aspect that makes renewable energy different from fossil fuels is that renewable resources are not finite like coal, oil, and natural gas. Sources of renewable energy are naturally replenished, while fossil fuels take millions of years to form.

According to the U.S. Energy Information Administration, “Renewable energy is derived from natural processes that are replenished constantly” (https://www.nationalgeographic.org/article/renewable-energy-explained/). This perpetual availability makes renewable energy an important sustainable alternative to non-renewable fossil fuels.

Why is Renewable Energy Important?

Renewable energy is important because it reduces reliance on fossil fuels, reduces greenhouse gas emissions, and provides a sustainable energy source. Fossil fuels like coal, oil, and natural gas are finite resources that will eventually run out. Burning these fuels also produces greenhouse gases like carbon dioxide that contribute to climate change. In contrast, renewable energy comes from naturally replenished sources like the sun, wind, water, plants, and Earth’s heat. These energy sources are constantly renewed and will never run out.

Shifting to renewable energy is key to reducing global greenhouse gas emissions and preventing the worst impacts of climate change, according to the World Wildlife Fund. Renewable energy has grown rapidly in recent years. Globally, renewable energy accounted for 29% of all electricity generation in 2020 and is on track to reach 50% by 2050, according to the International Renewable Energy Agency. Widespread adoption of renewables can help lower greenhouse gas emissions from the electricity sector.

Renewable energy systems generally have low operating costs once installed, making them a sustainable long-term energy supply. The more that renewable energy is incorporated into the grid, the less society has to rely on imported fossil fuels that fluctuate in price and availability. Local sources of renewable energy can also benefit energy security and access in remote areas. Overall, transitioning to renewable energy is essential for building sustainable, low-carbon energy systems now and into the future.

Solar Energy

Solar energy utilizes energy from the sun to generate electricity or heat. There are two main technologies for harnessing solar energy:

Solar photovoltaic (PV) uses solar panels containing photovoltaic cells to convert sunlight directly into electricity. Solar PV has seen rapid growth in capacity globally, with total installed capacity reaching 846 gigawatts by the end of 2022 according to the International Renewable Energy Agency (source). The United States is one of the leading countries for solar PV adoption, with over 130 gigawatts of installed capacity as of early 2023 according to Wikipedia (source).

Solar thermal systems use the sun’s energy to heat water or another liquid which can then be used for domestic hot water, space heating, or electricity generation. Solar thermal is commonly deployed for residential water and space heating.

Solar energy offers a clean, renewable source of electricity and heat that produces no direct carbon emissions. As solar technology costs have fallen dramatically and efficiency has improved, solar adoption has grown rapidly to meet rising energy demand and climate change goals. Key markets like the U.S., China, Japan and Europe are expected to install hundreds of additional gigawatts in the coming decades.

Wind Energy

Wind energy harnesses the power of the air flowing across the earth’s surface. Wind turbines convert wind’s kinetic energy into electricity using rotating blades connected to a drive shaft and generator. Most commercially available wind turbines have 3 blades mounted horizontally on top of a tall tower with heights up to 150 meters.[1]

Wind turbines can be located on land (onshore) or in the ocean (offshore). Onshore wind is the most widely used form of wind energy, while offshore wind is a newer and rapidly growing technology. At the end of 2021, global onshore wind capacity was estimated at 837 GW and offshore capacity was 57 GW.[2] The top countries for total installed wind capacity are China, the United States, Germany, India, and Spain.[3]

Wind power capacity continues to expand rapidly worldwide. Falling costs and technological advances have made wind energy competitive with fossil fuels in many markets. Offshore wind in particular offers enormous potential, especially in coastal regions. However, wind’s variability can pose grid integration challenges at high penetrations, requiring complementary sources or storage.


Hydropower is a renewable energy source that utilizes the natural water cycle of evaporation and precipitation to generate electricity. Water flowing down from higher elevations spins a turbine connected to a generator to produce power. Hydropower is a mature renewable technology that currently provides about 16% of the world’s electricity and over 70% of all renewable electricity.

Most hydropower facilities use dams on rivers to store water in reservoirs. When power is needed, operators open gates to release water from a higher elevation through turbines and generators. The kinetic energy of the flowing water spins the turbine blades which powers the generator to produce electricity. Pumped-storage hydropower works by pumping water uphill into a reservoir when energy demand is low so this stored energy can be released to generate power when demand is high.

According to the 2022 Hydropower Status Report, global installed hydropower capacity rose by 26 GW in 2021 to reach 1,360 GW. The International Energy Agency forecasts hydropower capacity will increase by 17%, or 230 GW, between 2021 and 2030 as countries seek to expand renewable energy and electrification.

Geothermal Energy

Geothermal energy taps into the natural heat from the earth’s core to generate renewable power. It utilizes geothermal energy reservoirs located in the earth’s crust that contain hot water or steam.[1]

Geothermal power plants drill wells into these underground reservoirs to pump the steam or hot water to the surface. The steam rotates turbines that activate generators, which produce electricity. After being used, the steam is returned to the reservoir.[2]

In 2021, the global installed geothermal electricity capacity was 16.9 gigawatts, with the United States and Indonesia leading capacity.[3] Geothermal energy is considered renewable since the water is replenished in the reservoir, allowing it to be sustainably used as a clean energy source.

Biomass Energy

Biomass energy uses organic matter such as plants, wood, and waste as a fuel source. Some examples of biomass include crops, sewage, forest residues, and food waste. Biomass contains stored energy from the sun, and when burned it releases this captured energy as heat. Biomass can be directly combusted to produce heat or converted into other useable forms of energy like methane gas or transportation fuels.

According to the Environmental Protection Agency (EPA) and the USDA, increasing biomass energy capacity has several benefits such as reducing greenhouse gas emissions by utilizing waste materials, enhancing energy security by relying on domestically available fuels, and supporting local economies and agriculture. As of 2019, the global installed capacity of biomass power plants was 121 gigawatts, with the leading countries being the U.S., Germany, China, and Brazil (Statista). The potential to further expand biomass energy production exists in many regions with abundant agricultural or forestry resources.

However, utilizing biomass sources sustainably is an important consideration. Overharvesting biomass feedstocks can disrupt ecosystems and lead to soil erosion or nutrient depletion. Converting waste into energy must also be balanced with maintaining soil fertility through practices like composting. Overall, biomass offers a renewable energy source that can supplement fossil fuels, but it requires careful management to avoid unintended environmental consequences.

Challenges of Renewable Energy

While renewable energy sources like solar, wind, hydropower and geothermal provide clean and sustainable energy, they also come with some challenges that need to be addressed for them to reach their full potential. Some of the main challenges facing renewable energy are:

Intermittency: Many renewable energy sources like solar and wind are intermittent – they are not available at all times. The sun doesn’t shine at night and calm weather can mean little to no wind energy. This intermittency can make it difficult to integrate large amounts of renewable energy into the existing electric grid which requires reliable power at all times. Energy storage solutions are needed to store the energy when available and discharge it when production drops.

Storage: The intermittent nature of renewables increases the need for energy storage to capture and store energy when it is plentiful for use when production falls. While progress is being made, affordable and scalable energy storage is still a challenge. Better energy storage technology is required for the growth of renewable energy. Overcoming Barriers to Renewable Energy Adoption – Energy5

Transmission: Many of the best renewable energy resources are located far from the areas of electricity demand. New transmission infrastructure is needed to transport the electricity from areas of generation to areas of use. Building new transmission lines faces challenges like high costs, regulatory issues, and public opposition.

Costs: While costs of renewable energy have fallen dramatically, the upfront capital costs of building renewable plants remains higher than conventional power plants. Technologies like solar PV and wind turbines require significant initial investments. Lowering costs through technological improvements and scale can increase adoption of renewables.

Growth of Renewable Energy

The capacity and share of renewable energy sources in the global energy mix has increased significantly in recent years. According to the Renewables 2022 Global Status Report from REN21, the renewable energy share of total final energy consumption reached 11.7% in 2020, and renewable power capacity saw its largest ever annual increase in 2021, reaching over 3,000 GW. In particular, solar and wind capacity have grown exponentially.

The International Renewable Energy Agency (IRENA) reports that global renewable power capacity has more than doubled within this decade alone. IRENA’s statistics show renewable energy supplied over 26% of global electricity generation in 2018, and is on track to reach over 45% by 2030.

The massive growth is driven by continuously improving competitiveness of renewables versus fossil fuel energy. The levelized cost of electricity has declined substantially for solar and wind power in the last decade, making renewables the cheapest option for new power generation capacity in most major markets. Government policies, investment flows, and corporate procurement of renewables have also catalyzed rapid capacity additions.

According to BloombergNEF, experts project that renewable energy capacity will grow over 60% between 2020 and 2030 under the current policy environment. With stronger climate policies and declines in renewable energy costs, growth could further accelerate to meet the world’s expanding energy needs while also transitioning away from fossil fuels.

The Future of Renewable Energy

The future looks bright for renewable energy. Projections show massive growth in renewable energy capacity in the coming years and decades.

According to the International Renewable Energy Agency (IRENA), renewable energy could supply over 50% of global electricity by 2030 and close to 90% by 2050. The share of renewables in total final energy consumption could double from 18% in 2018 to 36% in 2030 and reach 86% by 2050.[1]

Solar and wind energy are expected to lead this renewable revolution. The International Energy Agency (IEA) projects that solar photovoltaic capacity will increase by over 5,000 GW between 2020 and 2040 under a sustainable development scenario, a nearly 20-fold increase. Wind capacity may triple in the same period to over 2,600 GW globally.[2]

Innovations are also driving down the costs of renewables, making them increasingly competitive with fossil fuels. The global weighted-average levelized cost of electricity (LCOE) could decline by up to 35% for solar photovoltaics and 15% for onshore wind between 2020 and 2030.[3]

The growth of renewables will play a pivotal role in mitigating climate change and reducing carbon emissions. According to the United Nations, the share of renewables in the global energy mix needs to grow from the current 26% to at least 65% by 2050 to limit global warming to 1.5°C above pre-industrial levels.[4] Countries around the world are ramping up investments in renewables to meet their climate goals and build sustainable energy systems.

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