What a change since my last blog! As most people will be all too well aware, after a wet winter, with lots of generation, we are now experiencing what may well turn out to be the driest spring for many years, and as a result we haven’t generated anything at all for weeks. At least anyone with solar panels should be doing well.

UK weather is so variable anyway that we budget for long dry periods, so it’s not a financial disaster if we don’t run for a while. We also recently paid off the last instalment of our loan from the National Park – we are very pleased to have reached this landmark –  so we are in a strong position with our finances., even if we have a poor year for generation. We do like to keep funds in reserve in case of a major breakdown needing costly repairs – particularly as we have struggled recently to get breakdown insurance cover. It’s a good time to have finished paying back the Park.

I mentioned the dam in the last blog. The dam at Ruswarp was of course built to provide a head of water to drive the mill on the other side of the river; now the mill is no longer operating and has been converted into housing, the same head of water is what drives the turbine. A mill has been in place for many years, and as a result so has the dam which is starting to show its age. It’s an interesting construction: the upstream face is made of vertical timbers (we think aspen is the wood) with a stone cap; behind this is rubble infill covered by a sloping stone facing leading down to the lower river. In places the stone facing has become dislodged, or the rubble infill has shifted, resulting in holes in the downstream dam face; there’s also one area where the stone cap looks unstable. One advantage of the dry weather is that it’s now relatively safe to walk along the dam for a more detailed inspection, and we will be doing this. Watch this space as to what repairs might be needed.

Meanwhile enjoy the sunshine while it lasts!

Rory Newman, Chair of Esk Energy

I’ll start with some good news, as we all need a bit of cheering up when the weather is as cold and gloomy as it has been recently: we had another excellent year for generation: after a record year in 2023 we did even better in 2024, generating just under 160 MWh. As I write we are generating flat out again, and things are looking good at least for the next couple of weeks.

As I’ve said before, what we need is steady bur not torrential rain; it can be seen from the plot below (which shows rainfall in Westerdale, at the head of the Esk catchment) that last year was wet but not exceptionally so. Torrential rain, as we got with storm Darragh, will raise the lower river level too much and by reducing the “head” – the drop from upper to lower river which drives the turbine – will reduce or even stop generation (by the way, Darragh was so wet that the water level JUST got into the turbine kiosk – only the second time this has happened since we started).

I promised in the last blog to talk a bit about maintenance. Winter is usually a busy time for the turbine to be running – it’s usually wetter than the Summer – and of course we want to run while the river is high and we can generate lots of power. However, like any complex machinery, the turbine needs some care and attention, and some of this has to be done while we are stopped, so we try to schedule the major predictable maintenance for the quieter Summer period. Some of the regular jobs, like greasing, happen all year round, but there’s a big annual service (a bit like the one a car gets) when a number of checks are done, and this is an opportunity to (for example) replace worn hydraulic hoses. Last year – because it was 10 years old – we also had to replace the high-pressure cylinder which drives the hydraulics (there’s a good explanation on the website of how the hydraulics operate the penstock which regulates flow through the turbine). Strictly speaking we didn’t have to replace it, but it needed pressure-testing, which can’t be done on-site, and the time (weeks) and cost of re-using our existing cylinder far exceeded just replacing it….frustrating.

As you may have gathered, Winter is the time to plan things which are better done in warmer drier conditions which we at least hope to get in the Summer. We are currently discussing possible repairs to the dam, and wondering how to deal with some river bank erosion. I may write more about the dam in a later blog.

We have been submitting evidence to the House of Commons Energy Security and Net Zero Select Committee for their Unlocking Community Energy at Scale inquiry Debbie and Mark made our points so well that we appear third in the list of 147 submissions – we hope that government is listening.

To finish on another happy note, we will pay off the last instalment of our loan from the North York Moors National Park Authority in March. This is a significant moment and we are planning a little celebration – maybe more about this next time.

Rory Newman, Chair of Esk Energy