Ingenious Blog - Coal Vs Gas Vs Renewables

Thursday, 28 January 2021

As part of our Ingenious Engineering, Kids field project funded by the Royal Academy of Engineering the team have been hard at work developing blog posts to share ideas from the project with young people. This blog post is written by Josh one of our volunteer engineers and looks into coal, gas and renewable means of energy production and how we use these different types of energy. 

The UK runs for 67 days without coal!” was a big headline floating around in the summer of 2020. But for most people the positive association with the headline could have missed the mark. So what? Why should we care? Is that really a good thing?

The UK has historically lit homes and heated living rooms using coal fired power plants. These coal burning furnaces turned enough water into energy generating steam to produce 40% of the UK’s energy needs just a decade ago. But now all coal fired power plants are set to be closed by 2025. Why this change of heart?

UK coal consumption has dropped dramatically in recent history.

www.gov.uk/government/statistics/uk-energy-in-breif-2020 

Burning fossil fuels creates a large amount of heat but also a large amount of carbon dioxide and other emissions. If this carbon dioxide is released into the atmosphere it traps heat and through the greenhouse effect, causes an increased overall temperature here on Earth. There are many effects of climate change but for the most part they are negative and we want to avoid them. The government has committed to net zero emissions by 2050, meaning we have to stop pumping carbon dioxide into the atmosphere. 

So the answer is to stop burning coal! Great, but we still want to be able to run our fridges and cook dinner. What new method are we using to generate all this power? If you want to see where your energy is coming from at any time in the day then check out Gridwatch. On most days there will be a few percentage points of coal, but a third of our energy is supplied by something called “CCGT”. 

Combined cycle gas turbine power plants (CCGT) burn natural gas to generate electricity. Natural gas is a fossil fuel and so this begs the question, why are we burning it at all? Burning natural gas does emit greenhouse gases but up to 60% less than burning coal. This is a big reduction and, just like coal, we can turn these power plants on and off whenever we want. 

However, we are still burning fossil fuel which means that our emissions are not zero. What if there was a way to generate electricity without emitting any greenhouse gasses at all? Fortunately, there are many ways. These methods usually fall under a broad category named “renewables”. If you drive around the UK you might see large fields of wind turbines twirling away or dark reflective seas of solar panels stretching into the distance. These are two examples of power generation that emit nothing at all!

 

So why aren’t we using 100% renewables? It seems like the obvious choice, all that power and no emissions. The reality is that, unlike coal and gas, we are not able to turn wind and solar on and off as we please. If it’s not a windy, sunny day then there is no energy available.  This is a problem! Imagine waking up in the middle of the night, looking out of the window and seeing the trees standing still and reaching to turn on your bedroom light. Nothing, no power. It's dark and there isn’t any wind. Maybe if we could store some energy when we have too much we could use it when we are not generating enough. 

This is one of the many problems that engineers are trying to tackle as we seek to drive our emissions down to zero. How do we store energy when we don’t need it, so that we can use it when we can’t generate enough? Examples of this are springing up all over the country. The largest liquid air battery in the world is being constructed in Manchester. We have pumped storage facilities for our hydroelectric power, and a tidal lagoon is being proposed in Swansea. Gas turbines could even make a comeback! We can use the excess energy created on sunny windy days to create hydrogen to burn in gas turbines. 

The UK needs engineers now and in the future to work on these projects and make them a success. All different disciplines of engineering will be required and the design, construction and maintenance of these facilities will stretch into the decades. This is a real opportunity for anyone looking to contribute to a low-carbon sustainable future to utilise their energy skills and get involved with any of these exciting projects. 

Written by Josh Maynard. 


Find more about the Ingenious project here. - if you have a question for any of our engineers or would like to find out more about the project please do get in touch to askanengineer@woodcraft.org.uk