What is green energy?

Green energy explained 

Green energy, renewable energy and clean energy are often taken to mean the same thing. While they definitely overlap in some areas, there are also key differences between each of the terms. That’s what we’re going to explore now as we consider the similarities and differences between the three different energy types.

Green energy
Green energy is energy that comes from clean, environmentally friendly and natural sources. 

To be considered green, an energy source needs to be either a zero-carbon or low-carbon form of energy that is generated from naturally occurring power. A couple of good examples of green energy are solar power and wind power, both of which generate electricity without creating any emissions. This is in contrast to brown energy — such as gas, coal and oil — which releases harmful greenhouse gases that contribute to global warming.

Renewable energy
Renewable energy is energy that comes from sources that are easily replenished or recycled.

While most forms of green energy are renewable, not all renewable energy sources are green. Biomass energy is a good illustration of this point. Biomass power plants burn wood waste, sawdust and other organic waste to create energy. While this energy source is constantly renewed, biomass energy releases greenhouse gases and is not green energy in the strictest sense.

The same is true for geothermal energy. Thermal energy stored below the earth's crust is a renewable source of energy. But given the environmental impact of drilling to access it, geothermal energy can't really be considered a green energy source.

Clean energy
Clean energy is energy that is created without releasing any emissions.

This includes many forms of green energy and renewable energy — solar, wind and hydroelectric can all be considered green and clean. But it also includes nuclear energy, which is clean because it doesn’t produce any carbon emissions. The uranium and plutonium used in nuclear power are not renewable. And the radioactive nuclear waste created means nuclear isn’t usually thought of as being a green energy source.

Top 3 green energy sources 

You’ve seen some of the subtleties between the different types of energy sources. While there are many forms of renewable energy and clean energy, only a handful of energy sources are environmentally friendly enough to truly be called green energy sources. Let’s explore the top 3 green energy sources in more detail.

Solar power
Solar energy uses the power of sunlight to produce electricity. Energy from the sun is converted into electricity for homes and businesses. 

Solar power is generated using solar panels, large flat surfaces made of silicon or a similar semiconductor material. Solar panels can be fixed on the rooftops of buildings or may form part of large solar farms stretching across rural land.

Sunlight is actually made up of small packets of energy called photons. When a photon reaches a solar panel it releases energy, which produces an electric charge. This charge is captured in the wiring of the solar panel and converted into the alternating current (AC) we need for our household electricity supplies.

Solar power is a green energy source because the sunlight it requires to generate power is renewable and available in infinite supply. Since no carbon dioxide or other greenhouse gases are released in the generation of solar power, it’s also a very clean form of energy. 

Even in climates that are not always the sunniest — something we know a little bit about here in Northern Ireland — solar energy can still be generated. On cloudy days, solar panels can still harness the power of any daylight, though not as much electricity can be generated as would be the case with clear skies and blazing sunshine. 

Wind power 
Wind power harnesses the strength of the wind to generate power. The natural power of the wind can be converted into the electricity we need to power residential and business properties.

To generate wind power, large wind turbines are built. They are usually placed in exposed areas, such as in hilly, mountainous or coastal locations. Some homes and businesses install a single wind turbine, which can be particularly useful for properties that use a lot of energy. But the majority of wind power comes from turbines that form part of large wind farms. They can either be onshore wind farms, which are usually found at high altitudes in rural areas, or offshore wind farms, which are located on floating platforms at sea. 

In all cases, the power of the wind turns the rotary blades of the turbine, which turn a generator to create electricity. Wind turbines need only wind to drive them — something that happens naturally and is available in limitless supply. With no greenhouse gases released in the process, wind power is a green, renewable and clean energy source.

Since we’ve got plenty of uplands and no shortage of gusty conditions, wind power is the most common form of green energy in Northern Ireland.

Hydroelectric power
Also known as hydropower — uses the natural power of water to generate electricity. Fast-flowing water travelling from a higher elevation to a lower elevation is channelled to turn turbines. The turbines power a generator that produces a supply of electricity.

Most hydroelectric power stations are located on dams, where water can be released from behind a dam to drive the turbines as needed. Water is also used to generate electricity on rivers and tidal systems. The plants need to be built in places where a substantial amount of water is flowing quickly or the potential for it to do so can be created.

Hydroelectric power can operate on a relatively small scale or the industrial scale of some of the world’s largest reservoirs. It is considered to be a form of green energy because it uses natural, renewable sources and does not create any emissions. The impact of mega-dams and large hydropower projects on the local ecosystem means the largest hydroelectric power plants are no longer considered to be as ‘green’ as solar power and wind power.

But recent improvements in the quality of generators mean micro hydro projects are now viable at dams, sluices and mill wheels in Northern Ireland. Similar hydropower infrastructure was a key part of electricity generation in rural parts of Northern Ireland in the first half of the 20th century.

Why is green energy important?

Green energy has an important role to play in providing sustainable and environmentally friendly energy for the future. It can also have a positive impact on our society as a whole. Some of the important things green energy can do for our communities include:

• Ending our dependence on fossil fuels and helping to tackle climate change.

• Improving air quality and cutting respiratory illnesses that are linked to air pollution.

• Making electricity generation something that can be achieved at a local level.

• Bringing stability to global energy prices by limiting the impact of geopolitical crises, supply chain problems and price spikes.

• Creating jobs in the building and management of new green energy plants.

• Increasing the resilience of electricity supply by removing the risk of central or national distribution problems.

• Lowering energy prices worldwide by increasing supply and stability. 

Examples of green energy in practice 

Green energy is already delivering on some of those improvements in various areas of our lives. There are lots of ways to incorporate green energy at home, at work and on the move.

Green energy for homes - Many households now have solar panels installed on the roof of their homes. This allows them to generate their own electricity and often sell excess power to the network. Even if you can’t generate your own green energy, you can choose an electricity tariff that promises 100% green energy for your home. 

Green energy for business - Solar panels are also a common sight on business premises, while some companies choose to install wind turbines on site. This helps to lower overheads while also demonstrating corporate social responsibility. 

Green energy for travel - Electric cars, buses and vans powered by green energy sources are already cutting emissions from our roads. This can be used to improve air quality, cut costs and reduce carbon footprints.

Power NI Go Green 

We’re committed to helping households across Northern Ireland to use green energy. That’s why we’ve created our Power NI eco energy tariffs, which deliver 100% renewable electricity to your home. Our green energy plans help you to reduce your carbon footprint by cutting your use of fossil fuels.