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.