The Anonymous Widower

Repurposing The Sloy/Awe Hydro Scheme

The Sloy/Awe hydro-electric scheme was built in the 1930s and 1950s, by the North of Scotland Hydroelectric Board.

  • The scheme is now owned by SSE Renewables and has a page on their web site.
  • There are ten individual power stations; Sloy, Sron Mor, Clachan, Allt-na-Lairige, Nant, Inverawe, Inverawe, Loch Gair, Striven and Lussa.
  • There are four dams; Sloy, Allt-na-Lairige and two dams at Shira.
  • Cruachan used to be part of this scheme, but is now owned by Drax.

This map from the SSE Renewables web site shows the layout of the dams and power stations.

The sizes of the power stations in the scheme are as follows.

  • Sloy – 152.5 MW
  • Sron Mor – 5 MW
  • Clachan – 40 MW
  • Allt-na-Lairige – 6 MW
  • Nant – 15 MW
  • Inverawe – 25 MW
  • Kilmelford – 2 MW
  • Loch Gair – 6 MW
  • Striven – 8 MW
  • Lussa – 2.4 MW

This gives a total power of 261.9 MW.

It should be noted that Cruachan power station is also in this area and in Drax’s Plans For Cruachan, I talked about expanding the station from a 440 MW/7.1 GWh pumped-storage station to one of 1040 MW/7.1 GWh.

Scotland would appear to have 1.3 GW of hydro-electric power between Loch Awe and Loch Lomond.

 

This Google Map shows the same area as the SSE Renewables Map.

Note.

  1. Loch Awe, which is the sixth biggest freshwater loch in Scotland, is in the North-East corner.
  2. Loch Fyne, which is the longest sea loch in Scotland, is in the South-West corner.
  3. Loch Lomond, which is the second biggest freshwater loch in Scotland, is in the South-East corner.
  4. Loch Long reaches up from the South to the West of Loch Lomond.

These are four big lochs.

Strathclyde University And Pumped Storage Power For Scotland

This page on the Strathclyde University gives a list of the pumped storage potential for Scottish hydrogen-electric dams and power stations.

These figures are given for the dams and lochs in the Sloy/Awe scheme.

  • Sloy – 20 GWh
  • Nant – 48 GWh

It would appear that based on research from Strathclyde University, that the Sloy/Awe scheme could support over 60 GWh of pumped storage.

Water Flows In The Sloy/Awe Scheme

Looking at the SSE Renewables map of the Sloy/Awe scheme, water flows appear to be as follows.

  • Loch Awe to Loch Etive via Inverawe power station.
  • Cruachan reservoir to Loch Awe via Cruachan power station.
  • Loch Nant to  Loch Awe via Nant power station.
  • Loch Nant to Loch Etive via Inverawe power station.
  • Lochan Shira to Lochan Sron Mor via Sron Mor power station.
  • Lochan Sron Mor to Loch Fyne via Clachan power station.
  • Allt-na-Lairige reservoir to Loch Fyne via Allt-na-Lairige power station.
  • Loch Sloy to Loch Lomond via Sloy power station.

All the water eventually flows into the sea to the West from Loch Etive and Loch Fyne.

Refurbishing And Repurposing The Sloy/Awe Scheme

Perhaps as the power stations are now over fifty years old, one simple way to increase the generating capacity of the Sloy/Awe scheme, might be to selectively replace the turbines, with modern turbines, that can generate electricity more efficiently.

I suspect that SSE Renewables have an ongoing program of improvements and replacements for all of their hydro-electric stations in Scotland. Some turbines at Sloy power station have already been replaced with larger ones.

Adding Pumped Storage To The Sloy/Awe Scheme

Strathclyde University picked out two places where pumped storage could be added; Sloy and Nant.

I discussed Sloy power station in A Lower-Cost Pumped Hydro Storage System and came to these conclusions.

  • For £40 million, 14 GWh of pumped storage can be created at Sloy.
  • But it could be bigger than 14 GWh, as this page on the Strathclyde University web site, says 20.4 GWh is possible.
  • This would surely, be a project that could be first in the queue, once the environmental problems are solved.

20 GWh or even 14 GWh of pumped storage would be nice to have reasonably quickly.

As I said, this must be a high priority project.

The other project is at Loch Nant.

Note.

  1. Loch Nant is in the Western side of the map.
  2. Nant power station is marked by the red arrow.
  3. The loch to the South of the power station is Loch Awe.
  4. It appears that water can also go from Loch Nant to Inverawe power station to the North-East of the loch.
  5. Inverawe power station is on Loch Awe, which curves round Loch Nant.
  6. The 440MW/7.1 GWh Cruachan pumped-storage power station is on the other side of Loch Awe in the North East corner of the map, with the Cruachan dam and reservoir above.

Strathclyde University says that 48 MWh of pumped-storage could be possible at Loch Nant.

  • Comparing the size of Cruchan reservoir at 7.1 GWh and the larger Loch Nant, gives me hope that Loch Nant could hold upwards of 20-30 GWh.
  • From pictures on this page at Subterranea Britannica, it appears Nant power station has only a single 15 MW turbo-generator.
  • Inverawe power station is a 25 MW power station with a single turbo-generator.

I suspect that pump-turbines could be installed to fill Loch Nant from Loch Awe, just as was done at Foyers, where a 300 MW pumped storage power station was created.

Conclusion

There would appear to be up to two schemes, that could  each add around 20 GWh of pumped storage.

One advantage is that the waters of Loch Awe and Loch Lomond can be used for the lower reservoir.

 

March 1, 2022 Posted by | Energy, Energy Storage | , , , , , , , , , , , , | 1 Comment

Repurposing The Tummel Hydro-Electric Scheme

The Tummel hydro-electric scheme was built in the 1930s and 1950s, by the North of Scotland Hydroelectric Board.

  • The scheme is now owned by SSE Renewables and has a page on their web site.
  • There are nine individual power stations; Gaur, Cuaich, Loch Ericht, Rannoch, Tummel, Errochty, Trinafour, Clunie and Pitlochry.
  • There are four dams; Gaur, Errochty, Clunie and Pitlochry.

This map from the SSE Renewables web site shows the layout of the dams and power stations.

This description of the scheme is from Wikipedia.

The Tummel hydro-electric power scheme is an interconnected network of dams, power stations, aqueducts and electric power transmission in the Grampian Mountains of Scotland. Roughly bounded by Dalwhinnie in the north, Rannoch Moor in the west and Pitlochry in the east it comprises a water catchment area of around 1,800 square kilometres (690 sq mi)[1] and primary water storage at Loch Ericht, Loch Errochty, Loch Rannoch and Loch Tummel, in Perth and Kinross. Water, depending on where it originates and the path it takes, may pass through as many as five of the schemes nine power stations as it progresses from north-west to south-east. The scheme was constructed in the 1940s and 50s incorporating some earlier sites.

Note.

  1. There are no underground power stations.
  2. The scheme is what is known as a run-of-the-river hydroelectric scheme.

The sizes of the power stations in the scheme are as follows.

  • Gaur – 75 MW
  • Cuaich – 2.5 MW
  • Loch Ericht- 2.2 MW
  • Rannoch – 44 MW
  • Tummel – 34 MW
  • Errochty – 75 MW
  • Trinafour – 0.5 MW
  • Clunie – 61 MW
  • Pitlochry – 15 MW

This gives a total power of 309.2 MW.

This Google Map shows the same area as the SSE Renewables Map.

Note.

  1. Dalwhinnie is at the North of the map.
  2. Gaur is in the South-West corner of the map.
  3. Pitlochry is in the South-East corner of the map.

There are no underground power stations.

Strathclyde University And Pumped Storage Power For Scotland

This page on the Strathclyde University gives a list of the pumped storage potential for Scottish hydrogen-electric dams and power stations.

These figures are given for the dams and lochs in the Tummel scheme.

  • Errochty – 16 GWh
  • Clunie – 40 GWh
  • Rannoch – 41 GWh
  • Tummel – 38 GWh

It would appear that based on research from Strathclyde University, that the Tummel scheme could support over 120 GWh of pumped storage.

Water Flows In The Tummel Scheme

Looking at the SSE Renewables map of the Tummel scheme and reading this section in the Wikipedia entry for the Tummel scheme, which is entitled Water Route, water flows appear to be as follows.

  • Loch an t-Seilich to Loch Cuaich
  • Loch Cuaich to Loch Ericht via Cuaich power station and the Cuaich aqueduct
  • Loch Garry to Loch Ericht via Ericht power station.
  • Loch Ericht to Loch Rannoch
  • Loch Eigheach  to Loch Rannoch via Gaur power station
  • Loch Rannoch to Dunalastair Water via Kinloch Rannoch weir
  • Dunalistair Water to Loch Tummel via Tummel power station
  • River Bruar and River Garry to Loch Errochty
  • Loch Errochty to Loch Tummel via Errochty power station
  • Loch Errochty to Trinafour power station
  • Loch Tummel to Loch Faskally via Clunie power station
  • Loch Faskally to Pitlochy power station

Note.

Water from Loch an t-Seilich can take various routes to Clunie and Pitlochry power stations.

Water from Loch Eigheach goes through Loch Rannoch, Dunalistair Water and Loch Tummel to Clunie and Pitlochry power stations.

It seems a complicated scheme but it does have a capacity of 307 MW, which compares with 389 MW of Bankside power station.

Refurbishing And Repurposing The Tummel Scheme

Perhaps as the power stations are now over fifty years old, one simple way to increase the generating capacity of the Affric/Beauly scheme  might be to selectively replace the turbines, with modern turbines, that can generate electricity more efficiently.

I suspect that SSE Renewables have an ongoing program of improvements and replacements for all of their hydro-electric stations in Scotland. Some turbines at Sloy power station have already been replaced with larger ones.

In The Affric/Beauly Hydro-Electric Scheme, I wrote about the control system needs of that scheme, which I felt could be fairly challenging.

I suspect the control of the Tummel scheme is equally challenging.

Adding Pumped Storage To The Tummel Scheme

I’ll look at each possibility in turn.

Loch Errochty

Strathclyde University estimated that 16 GWh of pumped storage could be added to Loch Errochty.

This Google Map shows the Eastern end of Loch Errochty.

Note the dam at the Eastern end of the loch.

  1. The dam is 354 metres long by 49 metres high.
  2. The dam was built in 1957 and the lake is man-made.
  3. The loch stands at 330 metres above sea level.
  4. Water flows from the loch to the Errochty power station at the Western end of Loch Tummel, through a ten kilometre long tunnel.

This Google Map shows Errochty power station and Loch Tummel.

Note.

  1. Errochty power station is at the top of the map in the middle on the channel connecting it to the River Tummel.
  2. Errochty power station has two turbines and a maximum output of 75 MW.
  3. There is what appears to be a large switching station at the Western side of the map.

I obviously don’t know for sure, but I suspect this could be an easier scheme to convert, if the current turbines could be replaced with pump/turbines.

There is a section with the title; Water Supply To The Loch in the Wikipedia entry for Loch Errochty, where this is said.

Loch Errochty’s main feeder streams are the Allt Sléibh and the Allt Ruighe nan Saorach which both rise in the high ground to the west of the head of the loch. Other small streams flow directly off the 892-metre-high (2,927 ft) mountain of Beinn a’ Chuallaich which stands just to the south. Supplementary water is diverted into the loch from the east by the Errochty catchwater, a system of tunnels and surface pipelines at a height of approximately 380 metres which redirects water from five small tributary streams of the River Garry, and the Garry itself. The catchwater then goes through a tunnel in the hill which separates the Garry and Errochty valleys to join the loch. This method of re-directing water allows it to be used more often to generate electricity. Some of the water within the Tummel scheme passes through five of the power stations and thus generates electricity five times.

That strikes me as being very sophisticated for the 1950s and if the engineering and tunnels are up to a high standard, it might be that conversion of this power station to a 75 MW power station with 16 GWh pumped storage is a distinct possibility.

It might even be possible to increase the generating capacity of the power station.

Clunie

Strathclyde University estimated that 40 GWh of pumped storage could be added above Clunie power station.

This Google Map shows the River Tummel between Clunie and Pitlochry power stations.

Note.

  1. Clunie dam and power station is marked by a red arrow labelled Scottish and Southern Energy in the North-West corner of the map.
  2. Pitlochry Dam and power station are in the South-East corner of the map.
  3. River Tummel and Loch Faskally  link the two dams.

There is a large volume of water between the two dams.

In a pump-back hydro-electric water is pumped back from the lake below the dam into the reservoir above the dam. Such a system was added to the Grand Coulee Dam in the United States to increase its generating and storage capacity.

This Google Map shows how the water to the West of Clunie dam and power station stretches to the other end of Loch Tummel.

As there would be large volumes on both sides of the dam, I am fairly sure, that a pump-back system could be employed at Clunie power station.

Whether 40 GWh of storage could be added, would be one for the designers of the rebuilt dam and power station?

Tummel

Strathclyde University estimated that 38 GWh of pumped storage could be added above Tummel power station.

This Google Map shows the Eastern end of Loch Rannoch, Dunalastair Water, the River Tummel and Tummel power station.

Note.

  1. Loch Rannoch is at the Western end of the map.
  2. Dunalastair Water is the smaller lake in the middle.
  3. Tummel power station is indicated by the red arrow at the East of the map.

This Google Map shows Tummel power station.

Note.

There appears to be two branches of the River Tummel.

  1. At the bottom of the map, it appears to be in an aqueduct and above the power station.
  2. Running across the top-right corner of the map, the second branch appears to be a low-level branch of the river.
  3. The height difference will mean that power station works well and generates its full 34 MW.

As with Clunie power station, I am sure there is scope for Tummel power station to pump water from Loch Tummel to Dunalastair water, when there is a surplus of wind-generated electricity.

But could space be found above Tummel power station to store enough water to create a massive 38 GWh pumped-storage power station?

Rannoch

This description of Lord Rannoch is from Wikipedia.

It is over 15 kilometres (9.3 mi) long in a west–east direction with an average width of about 1.2 kilometres (0.75 mi), and is deepest at its eastern end, reaching a depth of 130 metres (440 ft).

The loch could hold almost a half a billion tonnes of water.

This Google Map shows Loch Rannoch and Loch Ericht

 

Note.

  1. Loch Rannoch is along the bottom of the map with Loch Dunalastair to the right.
  2. Loch Rannoch has an altitude of 205 metres.
  3. Rannoch power station is indicated by the red arrow.
  4. Rannoch power station was built in 1930 and the history of the power station is told in this page on the SSE web site, which is entitled A Real Gem In Hydro History.
  5. Loch Ericht runs to the North from above the power station.
  6. Loch Ericht has an altitude of 350 metres.

This Google Map shows Rannoch power station to a larger scale.

Rannoch power station is on the shore of Loch Rannoch and is described in this section in Wikipedia. This is said.

Rannoch Power Station, on the northern shore of the loch, is part of the Tummel hydro-electric power scheme, which is operated by SSE. The power station has a vertical head of 156 m (512 ft) and a total generating capacity of 44 MW, and uses water fed by pipeline and tunnel from Loch Ericht which is discharged into Loch Rannoch.

There are four pipes running down the hill from Loch Ericht, which deliver water to the power station.

The layout of Rannoch power station seems very similar to Sloy power station, which I described in A Lower-Cost Pumped Hydro Storage System.

  • Both power stations sit on a large deep loch.
  • Both have pipes to supply water going up the hill and then in a tunnel to a large loch over a hundred metres above the lower reservoir.
  • Rannoch power station is a 44 MW power station built in 1930.
  • Sloy power station is a 152.5 MW power station built in 1950.

SSE have been examining if a pumped-storage station could be added to Sloy power station.

Given the similarity of the layouts of the two stations, it could be that if it is possible to add pump storage to Sloy, that this could also be done at Rannoch.

Could 41 GWh be stored above Rannoch power station? I won’t say it is not possible.

Conclusion

Research at Strathclyde University gives these figures for possible storage capacity for these dams and lochs in the Tummel scheme.

  • Errochty – 16 GWh
  • Clunie – 40 GWh
  • Rannoch – 41 GWh
  • Tummel – 38 GWh

Adding these up gives a total of 135 GWh of stored energy for the Tummel scheme.

But that assumes every power station and dam is expanded to fit Strathclyde’s research.

SSE Renewables are currently calling for tenders for Coire Glas, as I wrote about in SSE Renewables Launches 1.5GW Coire Glas Construction Tender.

This was my conclusion in that post.

It looks to me, that it’s almost certain that Scotland will get a 1.5GW/30 GWh pumped-storage system at Coire Glas.

Coire Glas could supply slightly more power than Sizewell B nuclear power station for twenty hours.

Now that’s what I call backup!

But in the Tummel scheme, there could be three places, where a 30 GWh pumped-storage scheme could be developed and one where a 16 GWh scheme could be developed.

I would expect that a conservative figure of between 40-60 GWh of pumped-storage capacity could be added to the Tummel scheme.

 

 

 

February 25, 2022 Posted by | Energy, Energy Storage | , , , , , , | 1 Comment

Up To 24GW Of Long Duration Storage Needed For 2035 Net Zero Electricity System – Aurora

The title of this post, is the same as that of this article on Current News.

This the first three paragraphs.

Deploying large quantities of long duration electricity storage (LDES) could reduce system costs and reliance on gas, but greater policy support is needed to enable this, Aurora Energy Research has found.

In a new report, Aurora detailed how up to 24GW of LDES – defined as that with a duration of four hours or above – could be needed to effectively manage the intermittency of renewable generation in line with goals of operating a net zero electricity system by 2035. This is equivalent to eight times the current installed capacity.

Additionally, introducing large quantities of LDES in the UK could reduce system costs by £1.13 billion a year in 2035, cutting household bills by £26 – a hot topic with energy bills on the rise as a result of high wholesale power prices.

The report also says that long duration storage could cut carbon emissions by ten million tonnes of carbon dioxide per year.

I feel strongly, that this is a target we will achieve, given that there are at least four schemes under development or proposed in Scotland.

It certainly looks like the Scots will be OK, especially as there are other sites that could be developed according to SSE and Strathclyde University.

We probably need more interconnectors as I wrote about in New Electricity ‘Superhighways’ Needed To Cope With Surge In Wind Power.

There are also smaller long duration storage systems under development, that will help the situation in the generally flatter lands of England.

One of them; ReEnergise, even managed to sneak their advert into the article.

Their high density hydro could be a good way to store 100 MWh or so in the hills of England. As they could be designed to fit into and under the landscape, I doubt their schemes would cause the controversy of other schemes.

Conclusion

I think we’ll meet the energy storage target by a wide margin.

February 18, 2022 Posted by | Energy, Energy Storage | , , , , , , , , , | 1 Comment

A Lower-Cost Pumped Hydro Storage System

Whilst writing some of the posts recently about pumped storage I came across the Loch Sloy Hydro-Electric Scheme.

This is the introductory sentence in Wikipedia.

The Sloy/Awe Hydro-Electric Scheme is a hydro-electric facility situated between Loch Sloy and Inveruglas on the west bank of Loch Lomond in Scotland.

This page on the Greenage web site gives comprehensive details of the power station and is well worth a read.

This Google Map shows the Lochs Sloy and Lomond.

Note.

  1. Loch Sloy is in the North-West corner of the map.
  2. The page on Greenage says that Loch Sloy can store 14 GWh of electricity
  3. Loch Lomond is the body of water towards the Eastern side of the map.
  4. Inverglas is on the West bank of Loch Lomond to the North of the Loch Lomond Holiday Park, which is indicated by the green arrow with a tent.

This second Google Map shows the power station and Inverglas.

Note.

  1. It is a classic layout for a hydro-electric power station.
  2. In the North West corner of the map is the valve house, which is connected to Loch Sloy by a three kilometre tunnel.
  3. The valve house controls the water flows to the power station by Loch Lomond.
  4. There are four two-metre pipes running down the hill, one for each of the four turbines.
  5. According to the page on Greenage, the power station has three 40 MW turbines and one 32 MW turbine, which gives a total output of 152 MW.
  6. The water discharges into Loch Lomond after doing its work in the power station.

Loch Sloy is the largest conventional hydroelectric power plant in the UK.

Extending The Loch Sloy Hydro-Electric Scheme

This page on Hydro Review, which is dated the 10th of November 2010, is entitled SSE Gets Government Consent For Sloy Pumped-Storage Hydropower Project.

These are the first paragraph.

SSE Generation Ltd., the wholly owned generation business of Scottish and Southern Energy, has received consent from the Scottish Government to develop a 60-MW pumped-storage hydro project at its existing Sloy hydropower station at Loch Lomond, SSE reported.

Note.

  1. Two 30 MW pumps will be added to the power station to pump water up the hill from Loch Lomond to Loch Sloy.
  2. According to the page on Greenage, if the two pumps worked together for six hours, they would transfer 432,000 m3 of water. Note that a cubic metre of water weighs a tonne.
  3. Water would be transferred, when there was a surplus of energy being generated over the demand.

It would appear to be a simple scheme, as it is just adding two pumps to pump the water up the hill.

  • As pumps rather than pump/turbines as at Foyers are used, there is no corresponding increase in generating capacity.
  • Water also appears to be pumped up to the valve house in the existing pipes.
  • Loch Sloy and Loch Lomond would not need major works to enable the scheme..

The page on Greenage gives the cost at just £40 million.

Originally, the project was supposed to have started in 2012, but as there are environmental problems with the fish, the work has not started.

These problems are detailed on the page on Greenage.

Conclusion

For £40 million, 14 GWh of pumped storage can be created at Sloy.

  • But it could be bigger than 14 GWh, as this page on the Strathclyde University web site, says 20.4 GWh is possible.
  • This would surely, be a project that could be first in the queue, once the environmental problems are solved.

20 GWh of pumped storage would be nice to have reasonably quickly.

 

February 16, 2022 Posted by | Energy, Energy Storage | , , , , , | 6 Comments