What is Renewable energy? Definition, Types, Facts, Benefits

renewable energy technologies

What is Renewable energy? Definition, Types, Facts, Benefits

Renewable energy, also known as green energy, is available from natural resources. Renewable energy derives its name from the fact that this energy is replenished faster than consumed.

Introductory image on renewable energy

In our discussions with sustainability industry colleagues, Renewable energy production has been gaining significance, especially with growing concerns about climate change, resource depletion, and environmental degradation impacting the earth.

In our view, the major factor why this is important is because it can act as an important lever for decarbonization and sustainable development. This makes it crucial for environmental sustainability.

In this detailed article, we comprehensively share with you the following:

  1. what is renewable energy
  2. the various types of renewable energy
  3. the benefits of using renewable energy
  4. how renewable energy contributes to sustainable development
  5. methods for adopting renewable energy at home
  6. ways renewable energy can power a safer future
  7. the role of renewable energy in achieving Goal 7 of the United Nations (UN) Sustainable Development Goals (SDGs)

So now let’s discuss each of these in detail.

If you want to learn all about renewable energy in just 1-minute, watch the video below.

What is Renewable Energy?

Renewable energy is a source of energy that is derived from natural sources. The name “renewable” comes from the fact that these are replenished naturally on a human timescale.

These sources do not emit any Greenhouse Gases (GHG), making them sustainable and environmentally friendly.

As per the United States Energy Information Administration, renewable energy is virtually inexhaustible. Currently, renewable energy is about 13% of the total primary energy consumption in the United States and its share is expected to increase through 2050.

In the United Nations Conference of the Parties (COP28) held in Dubai in November-December 2023, more than 130 Nations joined and agreed to triple the world’s installed renewable energy capacity to at least 11,000 GW by 2030.

This demonstrates the expected growth in renewable energy capacity addition going ahead. This can also be seen from the Renewable electricity capacity additions forecast available from the International Energy Agency.

Figure 1. Renewable Energy Capacity Additions Forecast, International Energy Agency

Forecast on renewable energy as per International Energy Agency

Source: IEA (2024), Renewable electricity capacity additions by technology and segment, 2016-2028, IEA, Paris https://www.iea.org/data-and-statistics/charts/renewable-electricity-capacity-additions-by-technology-and-segment-2016-2028, Licence: CC BY 4.0

Types of Renewable Energy

There are majorly the following types of renewable energy:

  • Solar
  • Wind
  • Geothermal
  • Hydroelectric
  • Biomass energy

We will discuss each one in detail below.

1. Solar Energy

Solar energy or solar power refers to the energy that we get from the sun’s radiation. There are two simple mechanisms by which solar energy is generated and used.

  1. The first is solar photovoltaic (PV) systems that convert sunlight directly into electricity using solar cells composed of semiconductor materials.
  2. The second is solar thermal energy which uses sunlight to generate heat. This heat can be utilized directly for heating water, heating closed spaces or producing steam that drives turbines for electricity generation.

a) Solar PV systems

They convert sunlight directly into electricity using semiconductor materials such as silicon. This is the most common form of solar power technology. When sunlight hits the PV cells, it excites electrons, generating an electric current. The electricity can then either be used or stored.

Men fixing solar panels

 

Solar PV generation has been seeing significant growth. As per the International Energy Agency (IEA), solar PV alone accounted for three-fourths of the renewable capacity additions worldwide in 2023. Going ahead, solar PV and wind are forecast to more than double by 2028 compared to 2022 as per IEA.

b) Solar thermal systems

The second way to produce solar power is through solar thermal systems. They harness the sun’s energy to generate heat, which can be used directly for heating applications or to produce electricity.

There are two main types:

  1. Low-Temperature Solar Thermal Systems: These systems are generally used for water heating or space heating at a maximum temperature of about 80 degrees Celsius. These systems can supply hot water for residential or commercial use or can be used for heating air or water for space heating in buildings.
  2. High-Temperature Solar Thermal Systems: These systems use mirrors or lenses to concentrate sunlight onto a small area to generate high temperatures above 100 degrees Celsius even up to 1,000 degrees Celsius. This heat is then used to produce steam that drives a turbine connected to an electricity generator.

We think that as solar technology advances, the efficiency and accessibility of these solar systems should only improve. And this should be the case as increased adoption of solar power into the global energy mix is crucial for reducing greenhouse gas emissions and promoting a sustainable future.

2. Wind Energy

Wind energy or wind power is a renewable energy that harnesses the wind’s kinetic energy to generate electricity. This type of energy is generated when wind turbines also known as windmills rotate as the wind blows across them.

This motion drives a generator inside the turbine’s nacelle, converting mechanical energy into electrical wind energy.

Windmills are strategically placed in locations with consistent wind speeds, such as onshore or offshore wind farms. This maximizes their efficiency and generates continuous electricity, which is then transmitted through power lines.

Wind energy as renewable energy

 

The world’s largest wind farm, the Dogger Bank Wind Farm is an offshore wind farm being developed off the North East coast of England. It is being developed in three phases – Dogger Bank A, B, and C. Each phase will have an installed generation capacity of 1.2 GW. The combined installed capacity will be 3.6 GW. The farm will be capable of powering up to 6 million homes annually.

3. Geothermal Energy

There is a lot of heat stored beneath the Earth’s surface. This heat can be used to generate electricity and other energy applications. Geothermal energy derives its name from the word Geo meaning “earth,” and thermal meaning “heat” in Greek.

As per an Encyclopedia entry in National Geographic, the Earth’s core, located 2,900 kilometres below the surface, is the hottest part of the planet, generating most of its heat through the radioactive decay of isotopes like potassium-40 and thorium-232. The core’s temperature rises with depth, known as the geothermal gradient.

Radioactive decay in the core causes temperatures to rise to over 5,000°C, radiating heat outward and warming rocks, water, gas, and other geological materials. When underground rock formations are heated to 700-1,300°C, they can become magma, which heats nearby rocks and underground aquifers.

Magma, molten rock permeated by gas and bubbles, heats rocks and underground aquifers through geysers, hot springs, steam vents, underwater hydrothermal vents, and mud pots, generating geothermal energy. This can be captured and used for heat or electricity generation and can be used to heat structures like buildings and parking lots.

We are sure you would have seen videos or photographs of a volcano. Now a volcano is an extreme example of geothermal energy escaping the earth’s surface. However, milder heat from fissures, hot springs, etc can be efficiently used.

Most of the Earth’s geothermal energy remains in the mantle, accessible through drilling and steam generation. Countries like Iceland and the U.S. have developed methods to tap into this energy source.

Geothermal heat

 

This is achieved by tapping into geothermal reservoirs, which contain hot water and steam. Geothermal power plants convert this heat into electricity, while geothermal heat pumps can be used for heating and cooling buildings.

4. Hydroelectric Energy

The next type of renewable energy is hydroelectric energy also known as hydropower. It is one of the oldest and most established forms of renewable energy produced by harnessing the energy of flowing or falling water.

Hydroelectric generating stations are often built on or near water sources. The amount of accessible energy in moving water is determined by the volume of water flow and the change in elevation (or fall, also known as head) from one location to another.

Conventional hydroelectric facilities include the following:

  1. Run-of-the-river systems use the force of a river’s current to provide pressure on a turbine. The facilities may include a weir in the watercourse to divert water flow to hydro turbines.
  2. The second is the storage-based system where water accumulates in reservoirs built by dams on streams and rivers, which are then discharged through hydro turbines to generate energy.

Generally, the bigger the water flow and higher the head, the more energy a hydroelectric plant can generate. In hydropower facilities, water runs through a pipe, or penstock, and then pushes against and rotates blades in a turbine, which spin to power a generator and generate energy.

You can see the following video to understand how hydropower is generated, its benefits, and concerns with hydropower.

Hydropower projects have many advantages as in addition to electricity generation, they can also help with development in remote areas where the project is located, flood control, irrigation support, and can even provide clean drinking water. They can also provide recreational opportunities such as fishing, swimming, and boating.

5. Biomass Energy

Biomass energy is derived from organic materials from plants and animals such as wood waste, agricultural residues, and waste. These contain stored chemical energy produced by plants through photosynthesis. These materials can be burned directly to produce heat or converted into biofuels such as ethanol and biodiesel.

Biomass can be converted into energy through direct combustion, thermochemical, chemical, and biological conversion. Direct combustion is the most common method used for heating buildings, water, industrial processes, and electricity generation. Thermochemical conversion involves pyrolysis and gasification, with temperature and oxygen content differences.

Biomass is derived from recently living organisms making it a crucial part of Earth’s carbon cycle. The carbon cycle is the process by which carbon is exchanged between Earth’s layers namely atmosphere, hydrosphere, biosphere, and lithosphere.

In contrast to fossil fuels such as natural gas, biomass comes from recently living organisms. However, biomass resources like plants and forests must be farmed sustainably to efficiently continue the carbon cycle.

Benefits of Renewable Energy Sources

Now let us move to the benefits that renewable energy such as solar energy and wind energy offer.

  1. Environmental Sustainability: Generating and using renewable energy in place of burning fossil fuels has a positive impact on the environment. Unlike fossil fuels, renewable energy sources produce minimal to no greenhouse gas emissions, which is important for moving towards Net Zero emissions. This helps in reducing the carbon footprint and mitigating climate change.
    As per the United Nations Environment Programme’s Production Gap Report (UNEP), fossil fuels, such as coal, oil, and natural gas, are the largest contributors to the global climate crisis. They account for more than 75 percent of global greenhouse gas emissions and nearly 90 per cent of all carbon dioxide emissions.
    Renewable energy can come as a hope in this alarming situation. As per the International Renewable Energy Agency (IRENA), about 90 per cent of the world’s electricity can and should come from renewable energy by 2050. This can provide hope against climate change.

    Group of diverse people planting tree saplings together, symbolizing sustainability and teamwork.
  2. Energy Security and Independence: Renewable energy can enhance energy security and reduce dependence on imported fossil fuels. For instance, India is the world’s third-largest net importer of crude oil and petroleum products. It imports over 80% of the crude consumed. By increasing its reliance on renewable energy India can significantly bring down its import bill and become self-reliant.
    This can reduce its vulnerability to geopolitical tensions and price fluctuations in the global energy markets leading to greater economic stability and resilience.
  3. Economic Growth and Job Creation: The renewable energy sector is a major employment generator and can boost economic growth. As per IRENA, the renewable energy industry employed 13.7 million people worldwide in 2022 up from 12.7 million in 2021. Renewable energy projects stand out as they can stimulate local economies, create new employment opportunities, and drive innovation in an entire economy.

    Man and Woman Near Table

  4. Contributes to Sustainable Development: Renewable energy is at the centre of goal 7 of the UN SDGs as it helps in reducing carbon emissions and limits climate change in line with the objectives of the Paris Agreement. The widespread adoption of renewable energy can help limit global temperature rise and prevent the most severe consequences of climate change.
  5. Energy Access and Affordability: According to the UN, about 675 million people still lacked access to electricity in 2021. Renewable energy can play a crucial role in bridging this gap. It can empower communities by providing access to clean and reliable electricity. Regions with limited access to traditional energy can use renewable sources such as off-grid solar and wind to get affordable and sustainable energy.
  6. Circular Economy: This is an important area, which is gaining significance as it can enable cross-industry resource utilization. Renewable energy such as generating biomass energy from bagasse or using Waste Heat Recovery Systems (WHRS) in cement plants can lead to utilization of resources that would have otherwise gone to waste. For example, the use of bioenergy from agricultural residues can reduce waste and provide a renewable source of energy.
    Oranges
  7. Sustainable Urbanization: Integration of renewable energy in urban planning and infrastructure can also facilitate sustainable urbanization. Varied examples of this can be seen as rooftop solar panels, district heating systems, etc. Sustainable urbanization can lead to healthier living environments, reduced greenhouse gas emissions, and more resilient cities.
  8. Rural Development: Renewable energy initiatives such as the installation of biomass gasifiers in rural areas lead to agricultural productivity and development of the rural areas. Small-scale solar and wind projects can provide electricity in regions where the electrical grid has yet not been reached. This in turn can provide electricity for irrigation, refrigeration, etc, improving the quality of life for the rural population.
  9. Technological Innovation: Research and Development (R&D) in renewable energy solutions is crucial and can lead to more efficient, cost-effective, and scalable systems that need to be definitely deployed going ahead. As per EcoEngineers, a carbon advisory and consulting firm based out of Iowa, United States, investment in applied R&D is crucial to meet the clean energy demands of a growing global population.
    These innovations can have broader applications, contributing to advancements in energy storage, grid management, and sustainable materials. This can also have cross-sectoral applications so that R&D in clean energy can benefit multiple sectors such as manufacturers of PV panels or farmers who produce biomass fuels.
  10. Public Health Improvement: Finally, the transition to renewable energy can lead to substantial public health benefits, eventually leading to reduced air and water pollution associated with burning fossil fuels. These improvements in public health can enhance the quality of life for communities and indirectly contribute to UN SDG 7, Good Health and Well Being, and UN SDG 6, Clean Water and Sanitation.

    How Renewable Energy Can Be Adopted at Home

    You can adopt renewable energy to enhance your eco-friendly living and contribute to a cleaner, more sustainable earth in multiple ways.

    1. Solar Panels: One of the easiest ways to adopt renewable energy at home is by installing solar PV panels on rooftops to generate electricity from sunlight. Depending on the size of the panel and the intensity of solar radiation, solar panels can significantly reduce or even eliminate your electricity bills.
      Many Governments offer incentives and rebates to encourage residential solar adoption, making it more affordable. For instance, the Indian Government offers multiple schemes such as the Jawaharlal Nehru National Solar Mission (JNNSM), Rooftop Solar Scheme, etc to promote the boost of the solar landscape in India.
    2. Solar Water Heaters: In addition to generating electricity, solar energy can be used to heat water. These water heaters use solar collectors to capture sunlight and convert it into heat, which is then transferred to a storage tank. They are cost-effective and environmentally friendly compared to conventional water heaters as they do not use electricity. This helps in reducing energy consumption and lowers electricity bills.
    3. Wind Turbines: With sufficient land and favourable wind conditions, you can use small wind turbines to generate renewable wind energy. These turbines can help you harness wind power and produce electricity using wind energy on a small scale for your needs. While the initial investment may be higher than solar panels, wind energy can offer a reliable and consistent source of energy, particularly if you live in windy regions.
      A small wind mill
    4. Biomass Stoves and Boilers: These offer a renewable alternative to fossil fuel-based heating systems. They burn organic materials such as wood pellets, agricultural residues, or other biomass to produce heat. It is, however, important to ensure that biomass is sourced sustainably to minimize environmental impacts.
    5. Geothermal Heat Pumps: These pumps use Earth’s natural heat to efficiently and sustainably heat and cool homes. They consist of a ground loop that exchanges heat with the ground and a heat pump that transfers the heat to the building.
      They can provide significant energy savings and reduce greenhouse gas emissions compared to traditional heating and cooling systems. You can check out several details about geothermal heat pumps in the video below.

      In addition to adopting renewable energy technologies, homeowners should also adopt energy efficiency measures to enhance sustainability. This can include simple ways such as upgrading insulation, installing energy-efficient windows and doors, using LED lighting, and investing in energy-efficient appliances.

      You should check out our guide on 101 easy ways to live more sustainably where we discuss energy efficiency in detail. Reducing energy consumption can complement renewable energy adoption and maximize environmental and economic benefits.

      How Can Renewable Energy Resources Power a Safer Future

      Renewable energy resources can power a safer future in the following 12 ways.

      How Can Renewable Energy Resources Power a Safer Future

       

      1. Reducing Greenhouse Gas Emissions: The burning of fossil fuels for energy is the primary source of carbon dioxide (CO2) emissions, which contribute to global warming and climate change. One of the most critical ways renewable energy production can power a safer future is by reducing CO2 emissions. This can significantly reduce CO2 emissions and limit the adverse effects of climate change, such as extreme weather events, sea-level rise, and loss of biodiversity.
      2. Enhancing Energy Resilience: Renewable energy can enhance energy resilience by diversifying the energy mix and reducing dependence on centralized power systems. Distributed renewable energy systems, such as rooftop solar panels and small wind turbines, can provide a decentralized and resilient energy supply. This can be particularly valuable during natural disasters or other emergencies, ensuring that communities have access to reliable power when centralized systems may be disrupted.
      3. In line with Goal 7 of the United Nations SDGs: Goal 7 of the United Nations Sustainable Development Goals (SDGs) Ensuring Access to Affordable, Reliable, Sustainable, and Modern Energy for All focuses on ensuring access to affordable, reliable, sustainable, and modern energy for all. Renewable energy plays a crucial role in achieving this goal by promoting clean and sustainable energy sources that benefit both people and the planet.
      4. Expanding Energy Access: Renewable energy helps expand energy access even to areas that still need to be connected to the electrical grid or are facing power shortages due to other factors. This can empower communities by providing access to clean and reliable electricity.
        As per IEA, over 760 million people globally still lack access to electricity. Renewable energy can play a crucial role in bridging this gap. As per the IEA’s World Energy Outlook 2023 report, “The pattern of investments in recent years has started to shift the world towards a more electrified, renewables-rich energy system. For every USD 1 spent on fossil fuels, USD 1.8 is now spent on a range of clean energy technologies and related infrastructure.” This is a positive change and will increase adoption of renewable energy in the coming years.
      5. An Inexhaustible Source of Energy: Renewable energy sources are virtually inexhaustible, unlike fossil fuels such as natural gas, which are finite and depleting. Renewable energy can become a stable source of sustainable and reliable energy. This long-term energy security can contribute to economic stability and resilience for global economies.
      6. Creating Jobs and Economic Benefits: The renewable energy sector has significant potential for economic growth and job creation. Investments in renewable energy have a multiplier effect and drive both direct and indirect economic benefits through infrastructure, research, and development.
        This can be in the form of direct jobs for instance wind turbine manufacturers and onsite installers. It can also create indirect jobs such as employment for people who are supplying raw materials for manufacturing clean energy equipment. This also has a cascading effect as the income earned through these jobs supports families and drives economic growth leading to improved living standards.
        man, work, desk
      7. Stabilizing Energy Prices: Renewable energy can help stabilize energy prices by reducing dependence on volatile fossil fuel markets. This can lead to more predictable and stable energy prices, benefiting consumers and businesses.
      8. Enhancing Reliability of the Energy Grid: Increasing the adoption of renewable energy can enhance the reliability of the energy grid. Distributed renewable energy systems, such as rooftop solar panels and small wind turbines, can provide a decentralized and resilient energy supply. This can be particularly valuable during natural disasters or other emergencies as these distributed sources allow disrupted areas to access reliable power when centralized systems are disrupted.
      9. Promoting Sustainability: Integration of renewable energy in urban planning and infrastructure facilitates sustainable urbanization. For example, rooftop solar panels and district heating systems can use renewable energy to enhance energy efficiency and reduce environmental footprints. Sustainable urbanization can lead to healthier living environments, reduced greenhouse gas emissions, and more resilient cities.
      10. Improving Public Health: The transition to renewable energy can lead to substantial public health benefits by reducing air and water pollution associated with fossil fuel combustion. Cleaner air can result in fewer respiratory and cardiovascular diseases, while cleaner water can prevent waterborne illnesses. These improvements in public health can enhance the quality of life for communities and reduce healthcare costs.
      11. Boost Technological Innovation: Increasing adoption of renewable energy technologies can stimulate technological innovation by driving research and development in several key areas such as solar photovoltaics, wind turbine efficiency, and energy storage solutions. This can also provide breakthroughs in materials science, engineering, software solutions, etc., creating a dynamic ecosystem of startups, research institutions, and industry collaborations.
      12. Reducing Environmental Impact: Lastly, renewable energy’s most significant benefit is its positive environmental impact. Unlike fossil fuels, renewable energy sources produce minimal to no greenhouse gas emissions, reducing the carbon footprint and mitigating climate change. They also lead to reduced air and water pollution, compared to conventional energy sources.

      The Role of Renewable Energy in Achieving Goal 7 of the UN Sustainable Development Goals

      Goal 7 of the United Nations Sustainable Development Goals (SDGs) aims to ensure access to affordable, reliable, sustainable, and modern energy for all by 2030. This goal acknowledges the crucial role that energy plays in human development and emphasizes the need for sustainable energy solutions to combat climate crises, enhance resilience, and promote economic growth.

      United Nations Building

       

      Renewable energy sources, such as solar, wind, hydro, and biomass, are crucial for achieving this goal due to sustainability, accessibility, and potential to mitigate environmental impact. Now we will break down and analyze each aspect of goal 7 and see how renewable can cater to that aspect.

      1. Universal Energy Access to Generate Electricity

      One of the primary objectives of Goal 7 is to ensure universal access to affordable, reliable, and modern energy services. Renewable energy such as solar energy and wind energy technologies have a significant role in expanding energy access, particularly in remote and underserved regions where traditional energy infrastructure may be lacking or economically unfeasible.

      Solar panels, for instance, can provide electricity to off-grid communities, enabling access to lighting, clean cooking facilities, and communication tools that improve quality of life and economic opportunities. Renewable energy solutions are also scalable, making them suitable for both rural and urban settings.

      Another type of renewable energy, wind turbines, and small-scale hydroelectric projects can be deployed to supply power to communities and contribute to electrification efforts, thereby reducing dependency on fossil fuels and extending energy access to those currently underserved. This makes renewable energy an important enabler for ensuring universal energy access.

      2. Climate Change Mitigation

      Another critical aspect of Goal 7 is increasing the adoption of renewable energy to mitigate climate change and its impacts. Fossil fuel burning is a major contributor to greenhouse gas emissions. Transitioning to renewable energy sources can reduce carbon dioxide and other greenhouse gas emissions. This in turn can limit global warming and its associated environmental and socioeconomic consequences.

      Solar power and wind power, in particular, have experienced significant technological advancements and cost reductions in recent years, making them increasingly competitive with traditional fossil fuel-based electricity generation. This competitiveness can encourage the widespread adoption of renewable energy solutions by governments, businesses, and households. This can accelerate the shift towards a low-carbon economy.

      3. Promoting Sustainable Development

      Renewable energy supports environmental sustainability and contributes to broader sustainable development objectives outlined in the SDGs. This diversification of energy sources can promote economic growth through the creation of new industries and job opportunities in renewable energy manufacturing, installation, and maintenance.

      Furthermore, renewable energy projects often have positive social impacts, such as improved health outcomes due to reduced air pollution from fossil fuel combustion. This can create a sustainable tomorrow for our future generations.

      Person's Left Hand Holding Green Leaf Plant

      Conclusion

      Renewable energy can play an important role in creating a sustainable tomorrow. Renewable energy sources like solar, wind, and hydroelectric power offer a path to reducing our carbon footprint along with boosting economic opportunities and energy independence.

      The upfront costs of renewable energy infrastructure, however, can be an entry barrier. This would require supportive policy frameworks, capacity building, and public awareness campaigns along with innovative financing mechanisms for increasing adoption.

      This would also lead to the fulfilment of UN SDG 7 by ensuring universal access to affordable, reliable, sustainable, and modern energy services.

      The societal benefits of embracing renewables are vast, ranging from increased energy independence to improved public health and resilience against energy shocks. By investing in renewable energy, we invest in our planet’s future, ensuring that generations to come can enjoy a cleaner, healthier environment.

      Each of us plays a vital role in advocating for and adopting renewable energy solutions in our homes, communities, and beyond. Together, we can drive the momentum needed to make renewable energy the energy source of the future.

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