Farewell King Coal ?
Why did we not Party? I bet Sir David Attenborough at least smiled and raised a cup of tea, or possibly something stronger, to his lips. The 21st April 2018 was the first day since the 1880s, in the UK, that no coal was used for electricity generation. In fact, since the Holborn Viaduct coal-fired generator, or Edison Electric Light Station as it was known, opened in 1882. Within 2018 there have been several coal-free days.
Ah, now I remember, we didn’t party because the air we were breathing was still polluted. Even here in the UK many lives were being shortened as a result.
Some reports claimed it was the first day no coal was burned in the UK. This was rather sloppy as no doubt some was burned in a few private homes and by enterprises such as heritage railways.
It has always been my intention to occasionally cover issues other than cycling and walking on this site. My other interests that have already made appearances are sustainable food production, rare breeds of livestock and green energy production.
If you read my blog, “Wow – I was 25 Years Ahead of my Time”, you will know my interest in alternatives to carbon-based power generation goes back a long way. I still have my first reference book on the subject ‘Energy Primer – Solar, Water, Wind and BioFuels’ – which I bought in 1974.
The use of coal for power generation is declining in the UK, in line with the government’s plans to phase it out completely by 2025. This is part of a programme to cut carbon emissions. A reduction in electricity use has also contributed toward this being achievable. The rest of the shortfall is to be made up by power generated from; wind and solar, biodigesters and biomass, tidal and hydro, and imports.
The UK Government’s Department for Business, Energy and Industrial Strategy provide official statistics that show the proportion of electricity generated from each fuel source.
While gas may be better than coal it still gives off CO2 and other pollutants and, like imported electricity, is subject to the volatility of the international supply market. Biomass, despite industry claims to the contrary, is certainly not carbon neutral. The government’s preferred solution is to introduce further nuclear generation capacity.
A different approach is to harness tide power either by creating tidal lagoons, or by placing turbines on the ocean floor to harness tidal flows. Located off the North coast of Scotland, power generation from the world’s first commercial-scale tidal flow plant commenced earlier this year.
Looking to the Past can Provide a Map to the Future
The demand for electricity is not a constant. The graph above shows that traditionally the winter peaks in demand have been catered for by increasing the amount of power generated from coal.
In the coldest darkest nights of winter, the air can be very still. Wind turbines don’t turn and it is deadtime for solar panels. This is also a time when the energy demand for domestic heating increases. If carbon emissions are to be reduced at these times, then another source of green energy is required.
Fortunately, this is also the time of year when the water flow in some of our rivers, canals and inland navigations are at their highest. If the energy in these waterflows is captured, then it can be used to help meet that increased energy demand with electricity generated from this renewable resource.
Developments in materials and technology mean that turbines to generate hydro-electric power no longer need to be at the foot of a high mountain or massive dam creating a huge head of water. Much smaller flows can be utilised and exploited. What is even better, is that many potential sites are easily identifiable. Throughout the country there are watercourses that were once lined with mills to grind grain, make paper or lace, process and weave cotton, or power a range of other industrial processes.
These mills had the weirs, leats and ponds necessary to manage the water and maintain a supply sufficient to power the machinery within it. These are usually suitable for at least micro hydropower installation, if not a small hydropower. To give an idea of what this means: the company Renewables First gives these definitions “…‘small hydropower’ actually means less than 1 MW power output, while ‘micro hydropower’ is less than 100 kW. Typically a small hydro system could power 1,000 ‘average’ homes, and a micro hydro system could power 100 homes, which by most peoples’ standards is actually quite big!” Now there are even smaller schemes referred to as ‘pica hydropower’.
Aside from the mills, the major rivers and navigations in this country are littered with weirs that during the course of a year have massive amounts of water pouring over them. If these were to all have hydropower schemes incorporated, then a significant part of the energy currently generated from gas could be replaced with this green option.
According to the British Hydropower Association, which represents the industry, recent resource studies have indicated that there is a practical potential for a further 2GW of capacity in the UK. If my calculations are right, this is equivalent to six nuclear power stations the size of Hinkley C. Hydro installations also have a lifespan three times that of a nuclear power plant.
Simple Question – Does it Work?
Lest you think this is all pie-in-the-sky stuff, small and micro-hydro generation schemes are being installed across the country. Sometimes these are the initiative of a land or property owner, whether an individual, an organisation or a company. Others are community-based projects
During the course of a walking trip on Bodmin Moor, I spent time exploring the area around the De Lank granite quarry and the course of the old tramway, and also the De Lank river and gorge.
I came across a building which I knew had been a hydro plant to provide compressed air for the quarry. I was delighted to find that it had been resurrected and was now generating electricity. This short video tells the story.
Twice the Tonic in Buckfast
On the way back from Cornwall I stopped off at Buckfast Abbey in South Devon, and was able to admire the waterwheel at the abbey’s Upper Mill site. This was originally a woollen mill and, in the mid 20th Century, was used as an electro-plating works. The abbey acquired the run-down site in the 1990s and renovations included the installation of a new waterwheel.
In recent years the plant has been modernised and now generates electricity whenever there is sufficient water supply. As these pictures show, it is also a popular spot for visitors to pause for a moment.
At the lower end of the Buckfast Abbey site, on the River Dart itself, there is a relatively new hydroelectric plant that was installed as part of the redevelopment of an historic industrial site. I am grateful to Renewables First, a company with which I have no links, for allowing me to use some of the following photographs.
The plant was shoehorned into a space between old and new buildings which cannot have been an easy task. If you stop at the Abbey Inn, a quarter of a mile along the road, and perhaps have a meal on their terrace overlooking the Dart, you will see the river running by unaffected by having shed some of its energy to create electrical power. At full output it is capable of generating sufficient power to run 160 average households.
Every New Waterside Development Needs One
The weir in the pictures below is on the river Roch in Rochdale, and originally constructed to provide water to power a mill. The photographs are from late 1960s, 1984 and 2010. A multi-modal transport hub has now been built on the site and is part powered by a hydropower scheme that can supply up to 21kW of electricity, which is equivalent to that used by about 40 average houses.
The design by Renewables First incorporates the weir infrastructure left from the original mill. An Archimedes screw was installed next to it and is rotated by the water passing through it. This rotational energy is transferred through a gearbox in the powerhouse to drive the generator that produces the electricity.
Preserving the Past whilst Securing the Future
As I mentioned earlier, there are many old water-driven mills in this country that are now redundant. Some of these are listed buildings, or in historically or environmentally sensitive settings.
Mapledurham Mill is the last operational mill on the River Thames and produces high-quality stone-ground flour. It has a long history. The following illustration and accompanying text is from: “The book of the Thames: from its rise to its fall” by Mr and Mrs S. C. Hall, first published in 1859.
MAPLE-DURHAM CHURCH AND MILL
A little further, and we arrive at an assemblage of choice picturesque objects, such as are not often met with even singly, and are very rarely encountered grouped together into one rich picture as we here find them. At one view we have Maple-Durham ferry, lock, and weir — the mossy old mill embosomed in rich foliage, from which again rises the grey church tower, behind which, though almost hidden by lofty trees, we see the turreted outline of Maple-Durham House, forming altogether a painter’s paradise. *
The river here becomes broad and studded with numerous islets, between which extends a series of weirs, over which the water tumbles and foams, adding life and variety to the general calmness of the scene.
* It was built in 1581 by Sir Michael Blount, then Lieutenant of the Tower of London. In the church are many interesting memorials of the Blount family. Maple-Durham is a corruption of Mapulder-ham, literally meaning, the residence or manor among the maple-trees. Mapulder was the Saxon and early English name for a maple-tree, Apulder for an apple-tree, &c.
The Mapledurham Estate owns much of the village and parish including the Mapledurham Watermill.
Kenneth Grahame, author of Wind in the Willows, lived in Pangbourne, a couple of miles upstream from Mapledurham, and it is believed that Mapledurham House and Mill provided the inspiration for the Wind in the Willows’ ‘Toad Hall’, as well as featuring in E. H. Shepard’s illustrations for the book.
The pictures above show that the mill has changed little in the last 160 years since it appeared in the book by Mr and Mrs Hall. In 1970 it gained fame when a picture of it was used on the eponymously named Black Sabbath album cover.
There was (for the geeks) a 90-year-old vertical shaft Francis turbine that had originally provided electricity for Mapledurham House. This was to be replaced with a modern Archimedes Screw type turbine.
The Renewables First case study states “The project involved dismantling the existing turbine building and removing the old turbine. It also involved draining the mill pond of its water to enable structural work to be undertaken beneath the mill. A temporary bridge was also constructed to enable access onto the mill island for machinery and equipment. Planning stipulations required that the turbine building be reconstructed in a manner consistent with the existing mill building.”
Specialists builders were employed to rebuild the turbine building in the style of the original including “…the curved and gnarly roof line”. Comparing the picture of the finished project below, with the one with the horses in above, surely shows just how successful this project was in terms of respecting the environment into which it was installed.
And it’s Good for the Fish too.
There have been objections to these small hydropower schemes particularly from some of the anglers. This despite all the evidence to the contrary. There are strict rules regarding fish screening and maintaining migratory routes. The Environment Agency require, in many cases, the incorporation of fish and eel bypasses to maintain or enhance the biodiversity of the river or other watercourse. In most cases the fish pass will be a secondary route to be used by any fish that have missed a main route and therefore may become stuck in what would otherwise be a cul-de-sac for them.
Many weirs were built before or during the industrial revolution. Scant regard was given for the impact on the environment. As industry grew, many rivers and canals became heavily polluted to the point that all life within them became extinct.
As rivers have become cleaner and re-stocked, those physical obstacles have had more impact on some species than others. Careful choice of the right kind of fish bypass can benefit a wider range of species and, therefore, the biodiversity within that environment; as well as helping to boost fish stocks.
The right design can also result in less energy needing to be expended by the fish, than would be required to overcome some traditional weirs. Longer fish bypasses can incorporate a resting pool, or pools, to assist weaker individuals.
“The picture (above) is looking down into the fish pass. (at Buckfast) The fish will ascend up the middle of the shute. The fish pass is designed to be as efficient as possible at creating white water. The fins down each side create lots of re-circulation of the water, creating an up-current up the middle part of the fish pass enabling easy passage for fish.” From case study by Renewables First.
Water passing through a hydro plant or a fish bypass will be disturbed and aerated. At times when the oxygen levels are depleted, this provides immense benefit in terms of the sustainability of that environment.
Stories regularly appear in the media claiming that there have been state-sponsored cyber-attacks on UK organisations and establishments. Rather like solar panels on the rooves of individual homes, these smaller widely distributed power generation schemes add to the security of supply. One piece of rogue software in a major powerstation can result in its shutdown and the loss of the entire output. To attack 500 or a thousand individual plants, with individual control systems not necessarily permanently connected to a network, is an entirely different proposition. They will mostly each have their own operator who can isolate the plant from any central control network, and manually press a reset button to restart production should they have to.
Like all small power generations schemes, if the use of hydropower is to prosper and grow, then government and regulators have to ensure that there is an equitable feed-in tariff in place. If the UK is to have security in its energy supply, then more of these sustainable, ‘green’ sources of electricity are required. The feed-in tariff should give a fair return to those who invest in meeting that need.