Can Renewable Energy Be Used For Electricity?

Renewable energy comes from natural sources that are constantly replenished, such as sunlight, wind, rain, tides, waves, and geothermal heat. Renewable energy is critical because it provides power while reducing our dependence on fossil fuels like coal and oil, which release harmful greenhouse gases into the atmosphere when burned. Renewables also provide a sustainable way to generate electricity over the long term, unlike finite sources like fossil fuels which will eventually run out. In this content, we will outline the key types of renewable energy sources, discuss their advantages and challenges, examine renewable energy’s current role for electricity generation, highlight major renewable technologies like solar and wind power, and look at the future potential for renewables to continue growing as a vital energy solution. The goal is to leave readers feeling informed about how viable renewable energy can be for producing electricity to meet humanity’s needs in an environmentally friendly manner.

Table of Contents

Types of Renewable Energy Sources

There are several major types of renewable energy sources that are used to generate electricity:

Solar Energy – This uses photovoltaic cells or solar thermal technology to harness energy from the sun and convert it into electricity. Solar panels can be installed on rooftops or as large solar farms. [1]
Wind Energy – Wind turbines use the kinetic energy of wind to generate mechanical power which is converted into electricity. Wind farms can consist of many individual wind turbines. [2]
Hydropower – Flowing water from dams and reservoirs is used to spin turbines connected to generators that produce electricity. Hydropower is one of the oldest sources of renewable energy.

Geothermal Energy – This taps into the natural heat beneath the earth’s surface to generate steam which drives a turbine to produce electricity.
Biomass – Organic matter like plants, wood, and waste are burned to generate heat and electricity. It is considered renewable if the biomass is replanted.

Of these, solar and wind energy are the most widely used renewable sources for electricity generation currently.

Advantages of Renewable Energy

Using renewable energy provides many benefits compared to fossil fuels like coal, oil, and natural gas. Some key advantages include:

Reduces Greenhouse Gases

Renewable energy sources produce little to no greenhouse gas emissions, which are the leading cause of climate change. According to the EPA, the electricity sector accounted for 25% of global greenhouse gas emissions in 2017. Switching to renewables can help reduce these emissions and their impact on climate change (UCSUSA).

Improves Energy Security

Renewable energy can improve energy security by relying on domestic resources rather than imported fossil fuels. This reduces vulnerability to price fluctuations and supply disruptions. The more renewable energy is used, the more energy independence a country can achieve (EPA).

Cost Savings

Renewable energy technologies have become more cost-competitive with fossil fuels. The costs of solar and wind power have declined significantly in the last decade, making them cheaper sources of new electricity generation. Using renewables can hedge against fossil fuel price volatility (UN).

Job Creation

Expanding renewable energy can create new jobs in manufacturing, installation, and maintenance. According to the International Renewable Energy Agency, the sector employed 11 million people globally in 2018, and employment could reach over 40 million by 2050 (UN).

Challenges of Renewable Energy

While renewable energy has many benefits, there are some challenges with implementing renewable energy sources on a large scale. One of the main challenges is intermittency. Renewable sources like solar and wind are weather-dependent and have natural variations in their energy production throughout the day and year. This can make it difficult for grid operators to match electricity supply with demand [1][2].

Another major challenge is the high upfront costs of building large-scale renewable energy projects. The initial investment to build a renewable energy power plant like a large wind or solar farm can be very capital intensive. However, once built the marginal cost of producing electricity is very low. This makes the levelized cost of renewable energy competitive over the lifetime of a project [3].

The need for storage solutions is also a challenge. Since the energy supply from renewables can fluctuate throughout the day, energy storage technologies like batteries and pumped hydro can help mitigate this intermittency. Developing cost-effective and scalable energy storage is an active area of research and development [2].

Current Use of Renewables for Electricity

The use of renewable energy sources for electricity production varies greatly by country. According to World Bank data, the share of renewable energy in total final energy consumption reached 13.5% globally in 2019 [1]. Some countries generate a much higher percentage of their electricity from renewables than others.

As of 2021, the countries with the highest percentages of renewable electricity were Iceland (77%), Norway (98%), Costa Rica (99%), Paraguay (100%), and Ethiopia (100%) [2]. The growth in renewables has been significant in recent years. Between 2010-2020, the share of electricity generated from renewables increased substantially in countries like Denmark (from 48% to 64%), Germany (from 16% to 42%), and Spain (from 31% to 42%) [3].

The countries producing the largest total amounts of renewable electricity are China, the United States, Brazil, Canada, and India. Overall, renewables accounted for 29% of global electricity generation in 2020 and are projected to reach new highs in the coming years.

Solar Energy

Solar energy is one of the most common forms of renewable energy used to generate electricity. There are two main technologies used to convert sunlight into usable electricity – photovoltaics (PV) and concentrated solar power (CSP) (https://www.energy.gov/eere/solar/how-does-solar-work).

Photovoltaic systems use solar panels made up of solar cells containing photovoltaic materials that convert sunlight directly into electricity. The most common PV material is silicon. As photons from sunlight hit the solar cell, they transfer their energy to the electrons in the PV material, causing them to flow and generate a DC current (https://www.nationalgrid.com/stories/energy-explained/how-does-solar-power-work). Inverters then convert the DC current into AC current that can be fed into the electrical grid.

Concentrated solar power systems use mirrors to focus sunlight onto a receiver containing a fluid. The concentrated light heats the fluid, which creates steam to spin a turbine and generate electricity. Unlike PV, CSP requires the sun’s energy to be converted first into heat and then into electrical energy.

One challenge with solar energy is integrating it into the existing electric grid infrastructure, which was built for consistent power generation from fossil fuels. However, solutions like battery storage and smart inverters are helping grid operators manage the variability from solar generation.

Wind Energy

Wind energy has become one of the fastest-growing renewable energy sources worldwide, thanks to advancements in turbine technology and reductions in cost. In 2021, according to the U.S. Department of Energy, wind energy accounted for 9% of utility-scale electricity generation in the United States.

Most wind turbines are installed on land (onshore) but offshore wind capacity is expanding rapidly. According to the DOE, at the end of 2021 the total U.S. installed wind power capacity was over 135 gigawatts (GW), with only 42 megawatts (MW) of that from offshore wind. However, many offshore wind projects are in development. The DOE reports at least 34 GW of proposed offshore wind capacity in the U.S.

The capacity factor of wind power measures a wind project’s actual production over a period of time as a percentage of its potential production if it operated at full capacity 100% of the time. Onshore wind projects generally have capacity factors of 35-45%, while offshore wind projects can achieve 45-55% due to stronger and more consistent winds. In comparison, solar PV capacity factors are around 25% and natural gas power plants 60-90%.

For more details see:
How Do Wind Turbines Work?, U.S. Department of Energy

Wind Energy Basics, U.S. Department of Energy

Hydropower

Hydropower is one of the oldest and largest sources of renewable energy that uses the natural flow of water to generate electricity. According to the U.S. Energy Information Administration (https://www.eia.gov/energyexplained/hydropower/), hydropower provided 6.3% of total U.S. utility-scale electricity generation in 2020 and 37% of generation from all renewables. There are three main types of hydropower facilities: dams, run-of-river, and pumped storage.

Dams are the most common type of hydroelectric power. Dams use reservoirs to store water that is released to power turbines and generate electricity. According to the U.S. Department of Energy (https://www.energy.gov/eere/water/hydropower-basics), hydroelectric dams accounted for over 90% of U.S. hydroelectric generation in 2019. Advantages of dam projects include ability to generate large amounts of electricity to meet demand. Drawbacks include impacts on fish migration and sedimentation patterns.

Run-of-river projects generate power from the natural flow of rivers without the use of dams or reservoirs. They have a lower environmental impact but generate less power. Pumped storage facilities pump water uphill to a reservoir during off-peak hours then release it through turbines during high demand periods. This allows stored energy to balance electricity needs.

Other Renewable Sources

Geothermal power plants tap heat from the Earth to produce steam and generate electricity. Geothermal reservoirs of hot water are accessed by drilling wells miles into the Earth’s crust. The steam rotates a turbine that activates a generator, which produces electricity. According to the National Renewable Energy Laboratory (NREL), geothermal power provided 0.4% of total U.S. utility-scale electricity generation in 2020. The western states of California, Nevada, and Utah lead geothermal electricity production in the U.S.

Biomass power is generated by burning organic matter such as wood, agricultural waste, or garbage in power plants to produce steam for turning turbines. According to the U.S. Energy Information Administration, biomass accounted for 1.4% of total U.S. electricity generation in 2020. Biomass is renewable as long as the fuel source is replanted at a sustainable rate.

Tidal power utilizes the daily flow of tidal currents to run turbines for electricity generation. Despite having some of the highest tides in the world, tidal power currently provides a very small fraction of U.S. electricity. However, tidal power stations are in operation in South Korea, France, Canada, Russia, and China.

Future of Renewables

Many experts project strong growth in renewable energy production in the coming decades. This is driven by several key factors:

Governments and corporations around the world are setting ambitious decarbonization goals to combat climate change. Renewables like solar, wind and hydropower produce little to no greenhouse gas emissions, making them critical for reaching these climate targets.

The costs of renewables continue to fall dramatically thanks to technology improvements, economies of scale and competitive bidding. In many regions, building new renewable energy is now cheaper than operating existing fossil fuel plants. This cost competitiveness will drive more adoption.

Supportive policies like tax incentives, feed-in tariffs and renewable portfolio standards provide a policy boost for renewable energy. Many countries are working to enact more supportive policies to encourage the energy transition.

If current growth trends continue, renewables are expected to supply over 50% of global electricity by 2050, compared to under 30% today. Major projections suggest renewables will likely dominate future growth in electricity generation as economies move to reduce carbon emissions and take advantage of inexpensive renewable power.