An Introduction to Renewable Energy

There is something quite exciting about Renewable Energy, particularly for creating electricity. Harnessing the power of Mother Nature to create an energy source we can use feels very special. Whether you are plugging your phone in to charge from a solar-powered charger, or you're commissioning a huge utility-scale wind farm, it feels almost magical when you switch it on for the first time and realise your generating electricity quite literally out of thin air.

It is a very different form of energy production to a traditional approach. For the past one hundred years, the vast majority of our energy has come from fossil fuels. Whether we are burning it in our cars, heating our homes or using it to generate electricity, fossil fuels are providing us with a way of life that would have been unimaginable to our ancestors.

Of course, this energy comes at a cost. Air pollution in our cities is now regarded as an urgent public health issue, responsible for around 60,000 deaths per year in the UK. Greenhouse gases are changing the global climate, increasing the mean surface temperature of the planet and creating extreme weather systems, creating more powerful flooding, drought and tornadoes than ever previously recorded.

If we are going to move away from fossil fuels, what are we going to replace them with? The two biggest benefits of fossil fuels is that they provide an enormous amount of energy, and that the energy is controllable - we can have it when we want it. Renewable energy is different. Renewable energy provides us with electricity when Mother Nature decides to give it to us, rather than when we want to use it. That gives us a problem: there is no correlation between supply and demand.

Some renewable energy sources are more controllable than others: hydro-electricity production can be switched on and off quite literally like a tap, giving us a fair amount of control about when we use it. Wave power is more consistent and always provides some power, whilst tidal power is very predictable. Other sources are less predictable and more difficult to manage.

The answer is to develop a mix of power sources and to spread them around. Solar, wind, hydro, tidal and wave power all have a part to play. Combining these sources allows us to balance out our power generation capabilities. We can also use hydro power to create giant utility-scale energy storage facilities, storing huge quantities of energy and release it at a later time when it is required. Called Pumped Storage Hydroelectricity (PSH), it works by having two water reservoirs at different elevations. When demand for electricity is low, water is pumped from the lower reservoir to the higher reservoir. When demand is high, water is then released from the higher reservoir, through the hydro-electric turbines to the lower reservoir, generating electricity to handle the higher demand. Although the net result is less efficiency, the ability to store electricity in this way is a significant advantage: if it is windy in the middle of the night, for example, wind turbines can generate more electricity than there is demand for. By storing the energy in a pumped storage system, the energy can be stored for release, either later in the day or potentially months later, when it is needed.

Renewable Energy and the Environment

It is a simple fact that if we want to generate energy, there is going to be an impact on the environment. No form of electricity production is going to be entirely green.

In terms of carbon footprint savings, renewable energy systems have an obvious advantage over traditional forms of power production. There is no pollution at the point of use. It is not true, however, to say that the electricity produced is entirely carbon free: the carbon impact is in the production and transportation of the power generation equipment, the installation and maintenance of the system and the decommissioning of the system at the end of its life.

Compared to the carbon footprint of a traditional power station, these figures are very low. A typical wind turbine, for instance, is rated at 11g CO2e per kilowatt-hour of electricity produced, compared to 977g CO2e per kilowatt-hour for a coal-fired power station. Similarly, solar photovoltaic panels are rated at 44g CO2e for every kilowatt-hour of electricity produced over the lifetime of the panel.

There are other environmental factors to consider, too. Whilst fitting a handful of solar panels onto a roof of a house is unlikely to be a problem, a field of solar panels in a solar farm may cause problems of reflective dazzle that could affect nearby airfields. Installing solar panels on a vertical wall can also cause problems with dazzle that can affect the immediate surroundings including neighbours.

Wind turbines can cause more serious problems. The latest designs are much quieter than previous models, but noise levels do increase as wind speeds increase, which is likely to upset neighbours. Again, this is unlikely to be a problem if you are just installing one wind turbine, but if you are planning to install several large turbines, there is an issue: according to a recent US study in Maine, the constant noise from the rotating blades of multiple industrial wind turbines disrupts sleep patterns and can cause stress-related conditions, including depression, anxiety and other mental health problems.

Living or working in the shadow of a wind turbine can also cause problems. The constant flashing shade of a turbine over a prolonged period can cause headaches and migraines and trigger epileptic fits in sufferers. In the very early days of wind turbines, the reflection of the sun on rotating blades also caused issues. Today, turbines and blades are coated with a non-reflective paint finish to resolve these problems.

Hydro-electric power generation also has an environmental impact, particularly with regards to nature conservation and the water flow. A hydro installation needs to minimise the impact on wildlife, in particular swimming birds and fish. In some countries, you will require additional licences to install hydro-electric power as it is regarded in law that water running through a premises in a stream or river is not owned by the landowner.

Renewable Energy technologies

Solar Power

Solar Power

Find out how you can generate energy from the power of the sun.

Wind Power

Wind Power

Wind power is the fastest-growing renewable energy technology in use today.

Hydroelectric Power

Hydroelectric Power

Hydroelectric power harnesses the power of moving water.

Wave Energy

Wave Energy

How to harness the power of our oceans to generate renewable energy.