As we continue to grow larger in numbers and advance technologically, the demand for energy is growing dramatically. This is not helped by the limited amount of fossil fuels that remain on the planet. As such, we are having to think outside of the box and come up with ways in which to power the world without dipping into our traditional energy sources: oil; gas; and coal. Currently around 85% of the energy consumed worldwide comes from fossil fuels. So, what is the other 15% made up of and what are we doing in order to make that mix more in favour of the renewables?
Wind energy refers to the generation of electricity through wind turbines much like those pictured above. These turbines use natural wind to generate energy. Wind energy is one of the most globally developing electricity sources, especially in the United Kingdom. In 2015 wind energy contributed around 11% of all electricity produced in the UK, which is a fantastic increase over recent years. Also, reports state that on Christmas Day 2016 wind energy was responsible for around 40% of all electricity generated in the UK that day as opposed to the 25% of the previous year.
Although wind energy is providing us with a fantastic alternative to fossil fuel electricity production, wind is variable. Meaning because of the erratic behaviour of wind, it would be very difficult to rely solely on wind for our electricity grid. In addition, although the UK is in a fantastic geographical location for wind levels, a large proportion of other countries in the world are not, meaning it wouldn’t be possible to replicate our infrastructure in many other locations. At present, the issue of wind erraticism in the UK is usually accommodated in the general operation of the grid, meaning other electricity sources compensate for those areas that are experiencing low wind levels. One of the increasingly popular solutions for this issue is locating wind farms offshore. Placing them offshore has the benefit of more reliable, high-wind levels; however, it is currently considerably more expensive to install and maintain.
The biggest on-shore wind farm currently in operation in the United Kingdom is Whitelee Wind Farm and is located just over 9 miles outside of Glasgow. It is owned and operated by Scottish Power, who have developed this 215 turbine farm, with a capacity of 539 megawatts (539,000 kW). This means that if the farm was to work at its full capacity, in one hour, it would have the means to power over 761,000 households in real-time or around 174 for a full year.
Although Whitelee Wind Farm has more turbines, it is not as big in terms of capicity and output as London Array. The London Array Project is the largest off-shore wind farm in the world and is located just off the Thames Estuary. It has a capacity of 630 megawatts (630,000 kW), meaning if it were to work at full capacity it would be able to power over 890,000 households in real-time per hour.
Solar energy refers to the conversion of sunlight into electrical energy. This is carried out by using solar panels, increasingly found on the top of people’s houses and in large open spaces in order to take in the optimal amount of sunlight. At any given moment the earth receives roughly 173,000 terawatts (173 trillion kW) from the sun, which is 10,000 times more energy than the whole world uses. This means if we were to be able to harvest just 0.01% of the sunlight we receive on earth, we’d be able to power the whole world using only solar power. There are, however, many reasons why this is not the case as of yet:
The equipment used to produce electricity through solar power is extremely expensive, meaning profit-focused energy companies highly prioritise production cost as opposed to sustainability.
Darkness, i.e. night time, is the arch-nemesis of solar power, meaning combative, energy storage measures would need to be put in place to balance output in light-less hours. This is an added cost almost as much as the panelling, which again, is off-putting to many companies and residential homeowners.
Especially in the UK, where sunlight is sometimes at a premium, production would not be perhaps as reliable and constant as it would be in many other countries. That said, however, even on cloudy days, solar panels will pick up a considerable, yet reduced, amount of energy.
Even with the advancement in solar panel technology, today’s panels still only convert roughly 20% of the sunlight they take in, which on a large scale would need to have more impressive numbers to attract the big players in the production business.
Solar panels present an extremely beneficial and exciting prospect to those homeowners who have the money to spend on the initial investment. Not only can you create your own electricity free of charge, reducing or eliminating electricity bills, but if you’re creating energy in excess of your usage, you’re able to sell your leftovers back to the electricity companies for a nice little fee. However, considering the average household consumes around 3,100 kWh per year, you’d need a 4kW solar panel system, requiring an approximate roof space of 28 square metres. This is going to cost you between £6,000 - 8,000, which is huge! As mentioned before, this is an investment that requires considerable amounts of time to see any return. For example, on a 4 kW system, you can expect to see around £2,100 profit over 20 years. Not to mention the 40 tonnes of C02 emissions you’d save over 25 years.
In the UK, despite being a little sun-deprived from time to time, we have managed to take advantage of what we do have. The largest solar farm currently in operation in the UK is in Bournemouth in southern England. It’s called Chapel Lane Solar Farm and covers around 310 acres, roughly 175 football pitches. At full capacity, it is able to generate 51.3 megawatts (51,300 kW), which is enough to power around 60,000 households.
Geothermal energy refers to electricity generated by the heating up of areas of water deep beneath the surface of the earth. You may have seen hot springs or geysers; this is caused by the water being heated up by the earth’s crust, causing it to project through the surface. Geothermal energy uses this action to generate electricity in a variety of methods, such as powering small turbines with the steam collected.
Geothermal energy contributes very little to the UK electricity mix; however, the United States of America is a relatively large producer of geothermal, producing over 6 times the amount that we do. According to the US Department of Energy, geothermal energy already powers around 60% of the northern Californian coast. That said, it still only accounts for less than 1% of the electricity mix in the United States as a whole. A report in The Guardian made in 2012 said that geothermal energy had the potential to fuel around a fifth of the UK’s electricity demands; however, as of yet we have not seen any great advances on this claim.
Currently, in the UK, we don't have much of an infrastructure for geothermal energy. As such, much of the geothermal potential in the country is not yet accessible. However, there are a few sites scattered around the country that have been heavily invested in throughout recent years. One of the most notable is the Eden Project in Cornwall. Compared to more advanced renewables here, such as wind energy, the output of geothermal is very low. The Eden Project plant has a capacity of 3-4 megawatts (3,000 - 4,000 kW), which, working to its full capacity, could power a maximum of around 5,650 houses in real-time per hour.
Hydroelectric refers to the conversion of natural water current into electricity. This uses large areas of water in a variety of methods to power underwater turbines and generators. Like wind energy, this is a completely renewable and reliable source of electricity generation; however, hydroelectric could perhaps be said to be even more reliable. Due to the water cycle, this form of generation is extremely sustainable and can be controlled in a way that proves most efficient. New technology has also made hydroelectric generation even more environmentally friendly by creating fish-friendly stations, preventing local wildlife from feeling the potential negative effects of the generation process.
Like wind energy, hydroelectric generation relies heavily on geographical circumstances. In the UK we are blessed with a rich variety of terrain; however, many countries are not so lucky. Hydroelectric energy represents around 2% of the UK’s electricity mix, which is still relatively low given its potential and popularity worldwide. Countries that are extremely invested in hydroelectric generation include the United States, Canada, Brazil and China, each of which use this form of production for a large percentage of their renewable efforts.
By quite some distance, the largest capacity hydroelectric power station in the UK is Dinorwig in Gwynedd, Wales. However, despite it's 1.8 gigawatt (1,800,000 kW) capacity that has the potential to power over 2,540,000 households at full capacity, it is used for pump-storage. This means that energy is stored to be released in high-demand periods in order to balance the grid. The largest traditional hydroelectric plant in the UK is Sloy in Argyll, Scotland. This has a potential output of 160 megawatts (160,000 kW), which in relation, is much lower; however, still very large.
Biomethane is a great step towards a solution for the depleting natural gas resources worldwide. It is a form of gas, used in the same manner as the gas we use every day, created using the breakdown of organic matter. In the UK, around 15 million tonnes of food are thrown away each year, 2 million of which are made up of organic elements such as potato skins and fruit peelings. This, along with other organic matter, such as cowpat, decomposes naturally and produces large amounts of methane, a greenhouse gas that is 25 times more potent than CO2. This is taken by biomethane plants, cleaned, and turned into useable gas that can be pumped into the grid.
The Veolia biogas plant in Northallerton, North Yorkshire has been generating biomethane gas now for a number of years and is estimated to be able to fuel around 3,000 local homes and businesses using solely renewable energy, showing that it does have the potential to progress and have a large effect. This concept, however, is still relatively primary and as such, has not made a considerable impact as of yet; however, according to Dr Kiara Zennaro, the head of biogas at the Renewable Energy Association, biomethane has the potential to meet around 20% of the UK’s gas demands by 2020.
Reducing the effects of fossil fuels
Obviously generating energy through fossil fuels is not a sustainable solution and is in addition contributing largely to the destruction of our environment, but unfortunately for the time being, it is an integral part of our energy mix. As such, we should try to do everything that we can to reduce the damaging effects this is having on the earth. One of the ways which this is currently being achieved is the removal of some of the CO2 emissions from power stations by taking the waste produced by the burning of coal and storing it deep underground. Once it has been obtained, it can then be compressed and pumped around two miles down into the earth and released into the rock grains to be absorbed. There are risks within this method, such as gradual leakage to the surface, or in natural events such as earthquakes, more dramatic leakage; however, it is constantly monitored by scientists and engineers and up to now has seen much more positivity than negativity.