Earth Day 2025: About Renewable Energy

Earth Day celebrated its 55^th year last month and discussed the solutions we need for clean energy. The theme this year was Our Power, Our Planet™.

Burning fossil fuels to produce electricity contributes to emitting greenhouse gases. Renewable sources are needed to fight climate change. Renewable energy comes from a natural source the replenishes, which often have a low- or zero-carbon footprint.

Renewable energy is often confused with ‘clean energy’ and ‘green energy’. While they are both renewable, meaning that they come from a source that cannot be depleted, they are different.

• Clean energy is electricity without emitting greenhouse gases. However, they can have a carbon cost, such as clearing an environment to create a dam, which can produce carbon emissions.
• Green energy come from natural sources that have no or limited environmental impact.

There are renewable energy options. In honour of Earth Day 2025, this blog post will discuss some of the pros and cons of the three biggest renewable energy sources.

Hydroelectric

Dams

Hydropower plants need to have dams to control water flow. Dams hold the water, forming a reservoir, and then flows through turbines, which then turn and produce electricity.¹ Electricity is generated at a constant rate.

Dams produce energy cleanly, with no greenhouse gases being emitted,¹ outside the production of the hydropower plant. Electrical dams also last longer than other renewable energy sources, such as thermal power plants. Manmade dams can, like the ones made by beavers, prevent floods, as the downward flow of water can be controlled by a dam.

However, making dams can force people from their homes. When the Three Georges Dam was built China, over a million people had to leave their homes. Dams do not just affect people but also fish.¹ Fish have adapted to the natural river flow, but dams can damage this.

While countries like Norway gets 98% of its energy from hydropower, it can be difficult in other countries. Countries like Belgium and the Netherlands have a flatter landscape, so it make producing energy there more difficult, though not impossible.¹

Tidal

Tidal power works like dams, with giant sluice gates being used to allow water to flow in and out of a bay or an estuary. When the tide comes in, the gates close to keep in the high tide. When the tide on the other side of the gate has fallen, the water is released through hydroelectric turbines.² The turbines turn, producing electricity.

Energy produced by tidal power is pollution free and uses the world’s natural power. For example, in the Bay of Fundy the tides life 14 billion tonnes of water, with 1.5 million mega watts being expended each time. Experts estimate that tidal power could supply 20% of Britain’s energy.²

However, tidal power can damage the ecosystems where they placed, typically in bays and estuaries. The local tidal range can also cause problems. If the total rise and fall of the tide is less than 5 m, then the power plant becomes inefficient.²

Wind

Often positioned out in the sea or in fields, the wind turns the sails of wind turbines. The energy produced goes into a generator and is turned into electricity.¹

Wind turbines do not emit greenhouse gases¹ once they have been built and installed. They can be built quickly¹ and is the fastest growing sector in the USA, with more than 100,000 workers in the field.

While wind farms can be expensive to install, the running and operating costs are low, with limited maintenance needed. They can also take up a lot of land space, but the wind turbines do not need a large amount of space individually, which means the land can also be used for other purposes, including farming.

The effectiveness of wind turbines depends on the weather. For example, if there is not enough wind, the sails will not be able to spin. Furthermore, they can be dangerous to flying wildlife. In Germany, 1.2 tonnes of insects are killed by wind turbines, along with a number of bats and birds.¹

Solar

Solar panels and collectors can convert sunlight into electricity and heat. When light shines on a solar cell, made to two layers of silicon, an electrical current is generated.¹

The sun is powerful and sends a lot of energy to the earth. It sends more energy to the earth in an hour than the entire world’s population uses in a year. Scientists have estimated that if we covered just 1% of the Sahara dessert with solar panels, we would be able to provide enough energy for the world.¹ With no moving parts, solar energy is reliable and efficient.

While solar energy is clean, making and installing solar panels involves greenhouse gases and hazardous materials. At the end of their use, solar panels need to be disposed of carefully to stop environmental harm.

Solar panels are not entirely efficient as they depend on the weather. Sometimes there is not enough sunshine and, surprising for the UK, there is sometimes too much. While the surplus can be stored, most houses are not equipped for storing extra energy.¹

Read more:

1. Masters, M. ‘What are we going to do about it?’, 123 Seriously Smart Things You Need to Know About the Climate (2020) London: Thames & Hudson Ltd, pp.115-143.
2. Gilpin, D. ‘Tides’, Nature’s Might Powers: The Mighty Oceans (2006) London: The Reader’s Digest Association Ltd., pp. 64-69.