Green Energy

What is a renewable energy source?

A renewable energy source means energy that is sustainable - something that can't run out, or is endless, like the sun. When you hear the term 'alternative energy' it's usually referring to renewable energy sources too. it means sources of energy that are alternative to the most commonly used non-sustainable sources like coal.

Types of renewable energy

Alternative or renewable energy comes from natural processes that (unlike those listed above) can reliably produce cheap energy with minimal impact to the environment.

The most popular renewable energy sources currently are:

Solar energy
Wind energy
Hydro energy
Tidal energy
Geothermal energy
Biomass energy
How these types of renewable energy work

1) Solar energy

Sunlight is one of our planet’s most abundant and freely available energy resources. The amount of solar energy that reaches the earth’s surface in one hour is more than the planet’s total energy requirements for a whole year. Although it sounds like a perfect renewable energy source, the amount of solar energy we can use varies according to the time of day and the season of the year as well as geographical location. In the UK, solar energy is an increasingly popular way to supplement your energy usage. Find out if it’s right for you below by reading our guide to solar power.

2) Wind energy

Wind is a plentiful source of clean energy. Wind farms are an increasingly familiar sight in the UK with wind power making an ever-increasing contribution to the National Grid. To harness electricity from wind energy, turbines are used to drive generators which then feed electricity into the National Grid. Although domestic or ‘off-grid’ generation systems are available, not every property is suitable for a domestic wind turbine.

3) Hydro energy

As a renewable energy resource, hydro power is one of the most commercially developed. By building a dam or barrier, a large reservoir can be used to create a controlled flow of water that will drive a turbine, generating electricity. This energy source can often be more reliable than solar or wind power (especially if it's tidal rather than river) and also allows electricity to be stored for use when demand reaches a peak. Like wind energy, in certain situations hydro can be more viable as a commercial energy source (dependant on type and compared to other sources of energy) but depending very much on the type of property, it can be used for domestic, ‘off-grid’ generation.

4) Tidal energy
This is another form of hydro energy that uses twice-daily tidal currents to drive turbine generators. Although tidal flow unlike some other hydro energy sources isn’t constant, it is highly predictable and can therefore compensate for the periods when the tide current is low. Find out more by visiting our marine energy page.

5) Geothermal energy

By harnessing the natural heat below the earth’s surface, geothermal energy can be used to heat homes directly or to generate electricity. Although it harnesses a power directly below our feet, geothermal energy is of negligible importance in the UK compared to countries such as Iceland, where geothermal heat is much more freely available.

6) Biomass Energy

This is the conversion of solid fuel made from plant materials into electricity. Although fundamentally, biomass involves burning organic materials to produce electricity, this is not burning wood, and nowadays this is a much cleaner, more energy-efficient process. By converting agricultural, industrial and domestic waste into solid, liquid and gas fuel, biomass generates power at a much lower economical and environmental cost. The cost of renewable energy In 2016, global renewable energy capacity grew by a record amount while its cost fell considerably. This improvement was largely due to a drop in the cost of both solar and wind energy. 161 GW of renewable energy capacity was installed worldwide in 2016 - a 10% rise on the preceding year and a new record as reported by REN21, a global renewable energy policy network covering 155 nations and 96% of the world’s population. New solar installation provided the biggest boost - half of all new capacity. Wind power accounted for a further third with hydropower accounting for 15%. New solar capacity exceeded all other electricity producing technology for the first time ever. Although traditional fossil fuels such as oil and gas still provide 80% of global electricity output, renewables are rising fast. Christina Figueres, the former UN climate chief said “The economic case for renewables as the backbone of our global energy system is increasingly clear and proven. Offering greater bang-for-buck, renewables are quite simply the cheapest way to generate energy in an ever-growing number of countries. Renewable energy and your home The advantages of using renewable energy in a domestic setting are persuasive: Cut your electricity bills: Once you’ve paid for the costs of installing a renewable energy system, you can become less reliant on the National Grid and your energy bills can be reduced. Get paid for the electricity you generate: The UK Government’s Feed-in Tariff pays you for the electricity you generate, even if you use it. Sell electricity back to the grid: If you are generating enough energy to export an excess back into the National Grid, you can receive an additional payment from the Feed-in Tariff scheme. Reduce your carbon footprint: Green, renewable sources of energy don’t release carbon dioxide or other harmful pollutants into the atmosphere. According to the Energy Saving Trust's Solar panels page, a typical solar PV system could save around 1.5 - 2 tonnes of carbon per year. Renewable energy facts:
1. Solar PV could account for 5% of global demand by 2020 and up to 9% by 2030(1)
2. By the year 2050, our energy needs can be met by 95% renewable energy(1)
3. Price Waterhouse Cooper predicts that Africa could run on 100% renewable energy by 2050(1)
4. Over the last four decades, the price of solar PV panels has declined 99%(2)
5. A US study showed that renewable energy creates three times more jobs than fossil fuels(3)
6. Investment in renewable energy has surpassed fossil fuel investment. The global renewable energy market is now worth over $250 billion