Fishermen's fears over big green electricity machine

A green energy company set up by local people near Whitby has been awarded a loan from the North York Moors National Park to help fund the generation of hydro-electricity at Ruswarp on the River Esk.

Loans of up to 150,000 are being made available from the National Park's sustainable development fund towards the project being run by a community interest company, Esk Energy. That money is a third of what is required and Esk Energy will have to find match funding for most of the rest of the cost from the private sector.

Colin Mather, the chairman of the company, says they assessed the green options available. "There's plenty of wind up here and there's the river. We looked at the wind and thought we'd have problems finding a suitable location. It's also intermittent. But the river is flowing all the time, it's not obtrusive and also would be more acceptable to the National Park." The plan is to use an Archimedean Screw – a giant cylindrical screw, down which the water flows forcing it to turn.

Dave Mann, managing director of Mann Power Consulting which is working on about 20 schemes across Yorkshire, says this ancient technology will work as long as the river is flowing. It doesn't matter whether there has been torrential rainfall, as the screw only takes what it needs.

"What is proving to be so popular is that it is fish friendly," he says. "Fish going downstream don't need to be excluded from the turbine, they can pass though safely."

One reason for this is the large size of the thread on the screw and the fact that it only revolves at between 20rpm and 50rpm, less than

once a second, ensuring any fish passing down it remain unfilleted.

"We've carried out lots of tests which prove that is the case with live fish and demonstrated that there's no harm incurred at all as they pass through the machine." says Mr Mann.

Some anglers aren't so sure. Olly Foster from the River Esk Action Committee says there are still concerns that these hydro-electric plants could interfere with migratory fish such as salmon and trout.

"We're concerned that it is relatively new technology, obviously from ancient origins, that's unproven. It may be an obstacle to fish, that in addition to a fish-pass they may be caught in a tailrace (the water flowing out of the screw). We feel that the large volumes of fish that come into the tideway may be delayed. This may leave them vulnerable to predation."

The power-plant at Ruswarp has been approved by the Environment Agency, which is satisfied that it will not damage the ecology of the river. They says the fish will be monitored closely.

The electricity will be sold to the National Grid and is estimate to yield 40,000 a year. After expenses the cash will be spent on local community projects, in particular energy savings schemes. Supporters claim this could be the first of several small scale hydro generators along the Esk.

Unlike some of the more traditional types of hydro-electric schemes in Scotland and Wales, the Archimedes screw technology only needs a small drop in height – up to 10 metres – to work and it is driven by the natural flow of the river. In the case of the Esk at Ruswarp the drop is only about two metres.

The screws are built in Germany, each one tailored to the location where it will be fitted. Even so, the local economy still stands to benefit from them. "There's a considerable amount of work involved in the construction process," adds Mr Mann. "They're not cheap installations. They're big machines so you have to dig big holes and pour concrete in." So this means work for the local construction industry.

In areas of sensitive landscape the screws and the concrete mountings can be buried quite easily. Dave Mann's clients however often choose to leave the screws exposed as an attraction for visitors, and as a visible sign that local communities are doing their bit to reduce carbon emissions. Despite the amount of concrete, the digging, the steel of the screws and all the rest where carbon energy is expended, this can be recovered quickly.

"In terms of the carbon payback, this is an issue that gets cited with renewable energy systems – that it takes you so many years to actually repay the cost of building the system. We have done calculations and they have always shown that the embodied carbon is paid back in less than a year."

Michael Graham, who is in charge of the National Park's sustainable development fund, is particularly keen of this kind of renewable scheme. "It sits very well in the landscape there," he says. "It has a very low profile indeed. I think the key for this sort of project is that it hopes to earn money from the Government's newly introduced feed-in tariff for electricity produced from renewables and the income is going to be re-invested in community projects."

Colin Mather would love to hear from anybody who has a spare 180,000 to invest in a scheme which will help the local community, and the wider environment. "We're looking to anybody who would help us really, it would be lovely if two or three people would come along with 50,000 each.

"What is very different with this scheme is that we'd have an income coming back for the next 25 years which we can then use for more work. So it has a double whammy effect if you like. It generates an income for the community which we can use to reduce the greenhouse effect even further, which is why it's such a good project."

http://www.eskvalley energy. .uk/

CW 16/10/10