Coal power is dirty – but abandoned mines could help create a clean energy future

Pushing on into a bright future: the Old Meadows Coal Mine, Bacup, Lancashire, 1936. Image: Hulton Archive/Getty.

Energy from coal is now being linked to global warming and pollution on a global level. In fact, it has been estimated that coal contributes to 25 per cent of green house gases.

Coal use has caused severe negative environmental impacts, from its mining and processing, to its transportation and combustion, leading to high levels of pollution. In October 2017, a United Nations weather agency report indicated that levels of carbon dioxide surged at “record-breaking speed” compared to 2016.

Around the world, coal mining contributed historically to the industrial revolution and played an important part in the development of modern society. But many mines have since been closed in the UK and Europe. In the UK, this led to hard financial times and unemployment in many communities, including the miners’ strikes of the 1970s and 1980s, an impact recorded in the 1996 movie Brassed Off.

But what happens inside the coalmines after their closure? Surprisingly, most disused coalmines start producing methane – known as Coal Mine Methane (CMM) – which can be a clean source of energy. It can be used to generate electricity via gas engines or, with some technical processing, be fed into the gas grid. Over time, however, the mines will begin to fill with water and the methane will almost entirely disappear.

Water, water everywhere

But this will create yet another opportunity. The UK’s historic coal mines have an approximate residual void space of a billion cubic metres. When flooded, that’s the equivalent of 400,000 Olympic swimming pools of water at a stable temperature. This vast volume of water can be used for efficient heating and cooling applications and reduce carbon emissions.

But how? A recent publication by the team at Nottingham Trent University explains. The water in the coalmines is generally at a stable temperature – normally between 12C and 20C depending on the location – which makes it perfect for warming, or cooling, buildings or industrial processes.

We developed and tested a new technology for several years using two systems, one at Markham Vale and one at the National Coal Mining Museum for England, and found it can use this water to provide green, sustainable energy to homes and businesses in the UK.


Opportunities and challenges

The technology, which is based on using water source heat pumps, is simple and straightforward and works along similar lines to a refrigerator or air-conditioning system. It produces no noise or local air pollution and is also three or four times more efficient than a standard electric heater or gas boiler.

To understand how heat pumps in general work, consider the refrigerator in your kitchen. This extracts the heat from the food and drinks inside it, and diverts it into the surrounding environment via a condenser (which is simply a radiator) on the fridge’s exterior. Our technology employs a similar system. In this case, we extract the heat from the coalmine water and use it to warm buildings.

In the UK, coal mining technology programmes already pump nearly 112m megalitres of water for environmental reasons, such as avoiding the pollution of drinking water, springs and rivers. The new technology could use this water, which is being pumped anyway, potentially generating 63 megawatts of heat per year.

But the technology has its own challenges, specifically a lack of investment and “champion” organisations to lead the process. In part, this is because it remains a little-known or understood technology by many investors.

There is also a lack of a clear model to follow in the UK when implementing new technologies such as this, not just commercially, but contractually and legally as well. Most housing developers in the UK and Europe, for example, prefer to rely on well-established technologies such as gas boilers or electric heaters, even in areas where coalmines are available. If such new, green technologies are to succeed, comprehensive strategies are needed to get developers – and the general public – on board.

Hot topic

On the positive side, the technology can be integrated with other heating technologies, and in many cases existing building infrastructure can be used to implement it. The technology can also reduce carbon emissions and energy use and support compliance with the EU Energy Efficiency Directive and UK ESOS regulations.

We also have excellent, large-scale case studies, showing how effective it can be. In Asturias, north-west Spain, for example, a hospital and a university building are already being heated using coalmine water.

The ConversationOur research shows this technology could give the world’s disused coal mines a new, green, lease of life. What a fitting legacy for the industry that would be.

Amin Al-Habaibeh, Professor of Intelligent Engineering Systems, Nottingham Trent University.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

London’s rail and tube map is out of control

Aaaaaargh. Image: Getty.

The geographical limits of London’s official rail maps have always been slightly arbitrary. Far-flung commuter towns like Amersham, Chesham and Epping are all on there, because they have tube stations. Meanwhile, places like Esher or Walton-on-Thames – much closer to the city proper, inside the M25, and a contiguous part of the built up area – aren’t, because they fall outside the Greater London and aren’t served by Transport for London (TfL) services. This is pretty aggravating, but we are where we are.

But then a few years ago, TfL decided to show more non-London services on its combined Tube & Rail Map. It started with a few stations slightly outside the city limits, but where you could you use your Oyster card. Then said card started being accepted at Gatwick Airport station – and so, since how to get to a major airport is a fairly useful piece of information to impart to passengers, TfL’s cartographers added that line too, even though it meant including stations bloody miles away.

And now the latest version seems to have cast all logic to the wind. Look at this:

Oh, no. Click to expand. Image: TfL.

The logic for including the line to Reading is that it’s now served by TfL Rail, a route which will be part of the Elizabeth Line/Crossrail, when they eventually, finally happen. But you can tell something’s gone wrong here from the fact that showing the route, to a town which is well known for being directly west of London, requires an awkward right-angle which makes it look like the line turns north, presumably because otherwise there’d be no way of showing it on the map.

What’s more, this means that a station 36 miles from central London gets to be on the map, while Esher – barely a third of that distance out – doesn’t. Nor does Windsor & Eton Central, because it’s served by a branchline from Slough rather than TfL Rail trains, even though as a fairly major tourist destination it’d probably be the sort of place that at least some users of this map might want to know how to get to.

There’s more. Luton Airport Parkway is now on the map, presumably on the basis that Gatwick is. But that station doesn’t accept Oyster cards yet, so you get this:

Gah. Click to expand. Image: TfL.

There’s a line, incidentally, between Watford Junction and St Albans Abbey, which is just down the road from St Albans City. Is that line shown on the map? No it is not.

Also not shown on the map: either Luton itself, just one stop up the line from Luton Airport Parkway, or Stansted Airport, even though it’s an airport and not much further out than places which are on the map. Somewhere that is, however, is Welwyn Garden City, which doesn’t accept Oyster, isn’t served by TfL trains and also – this feels important – isn’t an airport.

And meanwhile a large chunk of Surrey suburbia inside the M25 isn’t shown, even though it must have a greater claim to be a part of London’s rail network than bloody Reading.

The result of all these decisions is that the map covers an entirely baffling area whose shape makes no sense whatsoever. Here’s an extremely rough map:

Just, what? Image: Google Maps/CityMetric.

I mean that’s just ridiculous isn’t it.

While we’re at it: the latest version shows the piers from which you can get boats on the Thames. Except for when it doesn’t because they’re not near a station – for example, Greenland Pier, just across the Thames to the west of the Isle of Dogs, shown here with CityMetric’s usual artistic flair.

Spot the missing pier. You can’t, because it’s missing. Image: TfL/CityMetric.

I’m sure there must be a logic to all of this. It’s just that I fear the logic is “what makes life easier for the TfL cartography team” rather than “what is actually valuable information for London’s rail passengers”.

And don’t even get me started on this monstrosity.

Jonn Elledge is the editor of CityMetric. He is on Twitter as @jonnelledge and on Facebook as JonnElledgeWrites.