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Renewable energy sources and how they work

Written by
Poppy Stringer
5
min read
September 11, 2023

In an era marked by environmental concerns and the growing need for sustainable energy solutions, renewable energy sources have emerged as a promising answer to our energy demands. With countries such as the UK and the US aiming to be net zero by 2050 strategies such as renewable energy are crucial in making this a practical reality. Unlike traditional fossil fuels that contribute to pollution and climate change, renewable energy harnesses the power of natural processes to generate clean and abundant power. 

In this blog, we will explore 

  1. What is renewable energy? 
  2. The Top 5 common renewable energy sources
  3. How they work 
  4. Are there any drawbacks? 

Renewable energy is defined by the United Nations as energy derived from natural sources that are replenished at a higher rate than they are consumed. Unlike fossil fuels (such as coal, oil, and natural gas), which are finite and non-renewable, renewable energy sources are abundant and can be sustained over the long term. These sources of energy have a significantly lower impact on the environment in terms of greenhouse gas emissions, air pollution and carbon footprint. 

The top 5 most common types of renewable energy sources include:

Solar energy 

Solar energy works by capturing the sunlight that falls on solar panels, which are made up of tiny units called solar cells. These solar cells are made from materials that generate electricity when they're exposed to sunlight, they capture the heat of the sun to generate power. So when sunlight hits these cells, it creates a flow of electricity which can then be used to power our homes, which is why it is becoming more and more common to see panels lining the roofs of people’s homes and even corporate buildings.

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It is one of the most common and promising sources of renewable energy due to its abundance and renewability‚ÄĒharnessing energy from the sun ensures a constant and virtually limitless supply.¬†

Whilst installing solar panels in a small home in Britain typically costs around £7,000 and on a larger house it would cost around £11,000, once installed they have minimal upkeep. It is also estimated solar panels can save up to 64% on a household electric bill, so whilst it is a large upfront cost it is a worthwhile investment. 

However, the amount of sunlight can vary from season to season and from day to day which means most solar panels require a backup storage solution such as batteries to prevent electricity loss when the weather is less accommodating. 

Wind energy 

This is another abundant source of energy, mechanisms such as wind turbines harness the kinetic energy of the wind to generate large amounts of electricity. The wind spins the blades of the turbine which turns a rotor connected to a generator which creates a flow of electricity which, much like solar energy, is then used to power factories or local towns.

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It is a very clean source of energy, producing little to no direct emissions and wind farms can be established both onshore and offshore making it a flexible and versatile energy source. 

Currently, China, the US and Germany are leading in the generation of renewable wind energy. China currently holds over ¬ľ of the world's wind power capacity and has the largest onshore wind farm in the Gansu Province. The world's second-largest wind farm can be found in California at the¬†Alta Wind Energy Centre. In Europe, Germany has the highest wind capacity and is home to the¬†Nordsee Offshore Wind Farm¬†which provides energy for over 400,000 homes.

However, like solar energy, wind is weather and location-dependent dependent which can cause fluctuations in energy generation, backup electricity storage is often also necessary in buildings primarily reliant on wind energy.

Hydropower 

Hydropower capitalises on the kinetic energy of flowing water to generate electricity. 

Hydropower facilities typically involve the construction of dams across rivers to create reservoirs. As water is released from the reservoir, it flows through turbines. The turbines are turned by the water's force, converting the kinetic energy into mechanical energy. This mechanical energy is then transmitted to generators, which produce electricity. The water continues downstream after passing through the turbines, maintaining the river's natural flow.

It is another great form of clean energy and unlike wind and solar energy, hydropower facilities have the ability to store potential energy in reservoirs which enables quick response to changes in energy requirements.

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Here are 4 of the most common hydropower systems and the countries they can be found in; 

  1. Large Hydroelectric Power Plants: These are large-scale hydroelectric facilities that generate a significant amount of electricity. They typically involve the construction of large dams to create reservoirs, which are then used to release water through turbines to generate electricity. Countries like China, Brazil, Canada, and the United States have large hydropower plants that contribute significantly to their electricity generation.
  2. Small Hydropower Plants: Small hydropower plants are often built on rivers or streams, and they have a lower capacity compared to large hydroelectric plants. They are suitable for rural and remote areas where large-scale infrastructure may not be feasible. Many countries, including India and some European nations, have small hydropower projects.
  3. Run-of-River Hydropower: Run-of-river hydropower plants do not require the construction of large dams or reservoirs. Instead, they divert a portion of the river's flow to generate electricity. These systems have a lower environmental impact and are found in countries like Canada, Norway, and Chile.
  4. Pumped Storage Hydropower: Pumped storage facilities use surplus electricity to pump water from a lower reservoir to an upper reservoir during periods of low demand. When electricity demand is high, water is released from the upper reservoir to the lower reservoir, passing through turbines to generate electricity. Countries like Japan and the United States have pumped storage facilities to help stabilize the grid.

Hydropower does also have its drawbacks. There is a negative environmental impact as the construction of dams and reservoirs can significantly alter ecosystems, disrupt aquatic habitats, and impact local wildlife populations. 

Biomass energy 

Biomass energy harnesses the energy stored in organic materials like wood, agricultural residues, and even organic waste. 

Energy is generated through various processes, including combustion, gasification, and fermentation. In combustion, organic materials are burned directly to produce heat, which can be used for space heating, industrial processes, or electricity generation. In gasification, biomass is heated in a low-oxygen environment, producing a gas that can be used for electricity or heat. Fermentation involves converting organic materials into biofuels like ethanol and biodiesel, which can replace traditional fossil fuels in transportation.

However, there this a major drawback to this method, it releases CO2 which does seem counterproductive for the cause but these fuel sources are still considered renewable because they can be regrown and absorb as much carbon as they emit across their lifespans.

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Another interesting system of generating biomass energy from natural sources is deriving energy from rotting food and manure. This technology harnesses the inherent energy stored in organic waste materials, such as kitchen scraps, agricultural residues, and livestock manure, and transforms them into a valuable source of power.

 Through a process known as anaerobic digestion, microorganisms break down these organic materials in an oxygen-free environment, producing biogas as a byproduct. This biogas, primarily composed of methane, can be captured and used for electricity generation, heating, or as a transportation fuel, offering a clean alternative to fossil fuels.

Nuclear Energy

Nuclear energy is generated through the process of nuclear fission, where the nucleus of an atom is split, this generates large amounts of heat. This heat is then used to produce steam, which drives turbines connected to generators, ultimately generating electricity. 

This usually takes place in nuclear power plants which emit minimal greenhouse gasses, contributing to efforts to combat climate change. Additionally, nuclear power is not subject to the variability of weather conditions like solar and wind, providing a stable energy source.

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However, a major issue with this strategy is the release of radioactive waste, such as uranium mill tailings, used reactor fuel, and other radioactive wastes. These materials can remain radioactive and dangerous to human health for thousands of years.

Conclusion

Renewable energy sources offer a myriad of benefits, including reduced greenhouse gas emissions, energy security, and job creation. However, each source comes with its own set of challenges and considerations. Factors such as location, infrastructure, technology advancements, and environmental impact play pivotal roles in determining the viability and adoption of these sources.

As we strive to transition away from fossil fuels and towards a more sustainable energy future, the diversity of renewable energy sources ensures that we have a range of options to suit different geographic, economic, and environmental contexts. By harnessing the power of the sun, wind, water, and Earth itself, we are moving towards a cleaner, greener energy landscape that promises a more sustainable world for generations to come.

Poppy Stringer

Our eco-conscious blog writer. Passionate about sustainability, she's on a mission to combat ecosystem decline with insightful blogs, driven by her concern for the planet's future.