PowerSwitch

During a particularly tedious night shift at the power station project I got looking at small scale hydro power in England.

Scotland has nearly all the UK's hydro potential and most of the large projects have been developed that are not pumped storage capable. However some projects have been considered in Nottinghamshire and Yorkshire on relatively high flow and low head sites where there are existing wiers.

Check out this site which shows one such project in Yorkshire on the Calder. The same company is also planning one on the Trent River at the notoriously dangerous Cromwell Lock and wier.

Quite how much potential is there is debatable. From the estimated 3 MW on the Trent project you may get at total of maybe 20 MW from all weirs between Newark and Nottingham for a cost per MWh that is higher than Hinckley Point C. On the plus side it will be run of river, not produce much more CO2 after construction and have black start capability, output is fairly predictable a few weeks ahead at least and be a good source of power to local communities. Could these projects be used to provide evening peak power at the expense of stopping water going over the weir temporarily?

The following website seems to think that another 800 to 1500 MW of hydro potential is available throughout the UK with the majority in Scotland.

What do you think? Worth it to save one nuclear plant being built or not?

Depends on how much environmental damage it does on top doesn't it?

If it's low then I see no reason not to do it. Surely the per MWH cost will increase at a much slower rate than, say Hinkley C over time?

I think I have spelled weir wrongly. Nevermind.

Maybe shutting off the weirs, or at least reducing the flows a lot, will damage the oxygenation of the river. However one of the reports I linked to for the river Trent project says that only 2 cumecs (metres cubed per second) out of the average 88 cumecs for the Trent are required for oxygenation. Therefore the rest could go to power production. Maybe there are less power hungry ways of oxygenating rivers such as blowing compressed air in there I don't know.

From various websites the levelised cost per MWh for pico (1kW scale) is about 200 pounds and for small hydro (1MW scale) is 100 pounds per MWh. I understand the government will pay something around 95 pounds per MWh for Hickley Point C.

So these type of hydro will never be financially only viable but may be better than the environment. Furthermore I think they may be more localised, sustainable and resilient. It may be more difficult to hack several thousand small hydro stations than one large nuclear and the ramifications may be less severe. I am sure some fish will suffer - such is life.

I found this link which gives some detail on the potential generation and location for small hydro in England and Wales.

These installations are very popular with Community Energy Projects although getting planing permission and river authority permission is sometimes difficult. Local angling clubs get up in arms about them because they "eat fish" apparently. Sounds to me a bit like the well known problem of wind turbines chasing birds and killing them.

There is a project running on the Thames in Oxford and another in Abingdon, I think, which are giving positive paybacks to the community groups that had them built. There has been a bigger one at Henley which hasn't been built yet but has been in the planning and design stage for a good ten years I would think. The Queen also proposed one on the weir at Windsor to supply the castle but I'm not sure what stage that one is at.

A local group that I belonged to looked at installing a pair of turbines between the Kennet and Avon Canal and the river Kennet at a lock in Newbury but it never got going. You really need someone working on it almost full time to get through all the hoops and jumps in the regulation of these things. It was always going to be financially viable.

I don't think that there are any environmental problem with them as the river authority only allows a proportion of the flow at any one point to be diverted through the turbine. You would never have 100% of the flow through the turbine even if flow was very low because the river authority would insist on the turbine being shut down before then.