Posts Tagged ‘hydro’

Harris’ young scientists investigate

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Earlier this month, we hosted a visit to the Bunavoneader Hydro-electric scheme. The Science Club at Sir E Scott primary school has been working on a hydro-electric project and wanted to see a full-sized scheme in operation. The pupils hiked up to the intake and then back down to look around the turbine house. The visit took place in an unusually dry spell, so the turbine was not working on the day, however everyone did go home clean and dry!

The Trust is part owner of a windfarm and a hydro-electric scheme. These are proving to be great educational resources for the local school.

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Another 100 homes with green energy

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Bunavoneader hydro-electric scheme is finally operational!

Back in July, Ross-shire Engineering handed the scheme over to River Generation Limited (RGL). RGL is the developer and the joint venture company formed by the Trust and Sustainable Technology Investors Limited. The main works were complete and the scheme entered a phase of close monitoring. Despite three weeks in October with no rain, we have now emerged from this phase, and all systems are go, as we enter the rainy season.

shed

Nestling amongst the houses in Bunavoneader, you’ll see a new building , the size of a double garage, with a red roof. This is the turbine house located at the bottom of 250m of 630mm pipe. The pipe brings water form a new intake up the river behind the old dam. The turbine is located inside, along with the electricity grid connection point. Water is returned to the river at the side of the building.

turbineInside the building is a 100kW Francis turbine. You’ll just see in the picture above, the intake pipe entering the buiding, under all the dials on the wall. The pipe or penstock feeds water around the outside of the turbine, through the blades and out from the middle of the casing, down into the ground. The big blue box with the black wires is the generator which is attached to the spinning blades to make electricity.

The scheme is now exporting electricity to the Harris grid. It is forecast to generate  371,000 units of electricity each year -enough to power over 100 homes. The crofter and the Bunavoneader-Meavaig North grazings committee will benefit directly from a share of the rent paid by RGL. The wider North Harris & Scalpay residents will benefit indirectly through the Trust’s share. The scheme is a good example of how the Trust aims to make best use of the 25,000ha North Harris estate for the benefit of the whole community.

 

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Bunavoneader update

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intake2

New intake, located behind old dam

The last update on the Bunavoneader Hydro-electric Scheme was in September when the sun was still shining and the intake was being cast. Since then, much water has flowed down the river. The intake was completed and over the winter, the surrounding area was landscaped. When the weather improved, work started at the bottom of the scheme, constructing the turbine house.

At the end of April, amongst snow showers, the external works are complete. Technicians are huddled together inside installing cabling and control equipment in the turbine house. The key milestone will be reached in mid-May when the electricity grid will be connected to the site. Provided we have enough rain, the scheme will be commissioned soon after. What are the chances of a June drought in Harris?

 

Generator in foreground, turbine behind

Generator in foreground, turbine behind

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Bunavoneader hydro scheme gets under way

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This week sees the contractors starting the civil works at Bunavoneader. The project reached financial closure last week. A joint venture company has now been established for the Trust and its partner, Sustainable Technology Investors Limited to take the project forward.

The 100kW hydro-electric scheme is being built by Duncan MacKay&Sons. The mechanical and electrical works are contracted to Ross-shire Engineering who we started talking to in 2010.

access track week1

The first task is to get an access track in, below the road. This will give access for temporary welfare facilities and the site of the new turbine house. The project will take 9 months to complete due to the long lead time on the mechanical components. We will however be able to complete the civil works in the “dry season” -when it arrives.

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Maraig Hydro update

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Early last year, we started exploring the possibility of building a small-scale hydro-electric scheme on the Maraig river. Since Maraig and Rhenigedale were connected to the Carragraich Treatment Works, the small water treatment works at Maraig stopped extracting from the river. This gave the Trust the opportunity to take water for hydro-electricity.
In April, the Trust was awarded Community and Renewable Energy Scheme funding to progress the project through the permissions stage. Highland Ecodesign was the company that carried out the feasibility work. They were engaged once more to come up with a scheme that fits the constraints imposed by the grid company and meets planning and SEPA water extraction requirements.

map
The scheme comprises a small weir and intake next to the Rhenigedale turn below the old water treatment works. A turbine house will be constructed down near the shore on the Eilean Anabaich side of the footbridge. The two sites will be linked by a buried 350m length of 560mm plastic pipe.
intake
During the summer, the prescribed environmental surveys were carried out. Firstly a fish habitat survey with electro-fishing; then a protected mammal survey, looking for otters and fresh-water mussels. Then a full topological survey and a peat management plan. Finally a sediment plan allowed us to submit our application for planning permission in September. In December we secured planning permission and a SEPA licence. With a £12,000 deposit already paid to SSE for the grid connection, all the permissions are now in place.

The next stage is to decide how the project will be funded.

maraig

 

 

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Bunavoneader Hydro Scheme update

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dam4

It’s getting on for 18 months since we last reported on this project. Things have been progressing slowly – but just not very visibly. We have had a number of set-backs with grid connections and finance deals, but now things are looking more hopeful.

Last year in May, we received a new grid connection offer. This is a very rare item in the Western Isles. All proposed large turbine schemes are on hold until the new undersea cable is installed to the mainland. You’ll have seen from the local press that this is still not confirmed. The latest estimate is 2019. Anyway, we received the offer for a 150kW turbine and immediately accepted it and paid the deposit. With planning already in the bag, all that was remaining was the finance.

In December 2013 we were introduced to Sustainable Technology Investors Limited by a community group on Mull. They are keen to help develop small scale hydro schemes. Since the start of the year, STIL has reviewed the design and have signed a Heads of Terms agreement with the Trust to start the wheels moving. Engineering Consultancy AECOM has been engaged. They have started the detailed design works and are liaising with Ross-shire Engineering and their civil engineering partner to firm up pricing for the turbine and the civil works. At the moment, the team is aiming to get all the in-river work complete before the wet season starts in 2014. The Turbine itself is on a 35 week lead time – so commissioning of the scheme will not be before summer 2015.

Now that the detailed design work is nearly complete, the critical thing is for SEPA to approve the designs. We await final approval from the crofters in the area, but once this has been done, we can get on and build something. We’re now in the sixth year of this project; let’s hope no more spanners get thrown in the works.

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Micro-hydro is feasible on the Maraig river

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Following a number of months work by Highland Eco Design, we finally have confirmation that a micro hydro-electric scheme on the river at Maraig is feasible. Since Maraig and Rhenigedale were connected to mains water, the local treatment works at Maraig has stopped extracting water from the river. This gives the Trust the opportunity to take water for hydro-electricity.

The Highland Eco team have come up with a scheme that fits a number of constraints – the biggest being the national grid. As most people will be aware, there is a freeze on all large-scale renewable energy projects in the Western Isles. All such projects hinge on the undersea cable being installed to Ullapool. Whilst there is no firm date for this, we have to limit ourselves to micro-generation schemes that are under the 50kW limit. Despite the Maraig river being capable of powering a much larger turbine, we now have details of a 50kW scheme that could be extended when the under-sea cable is commissioned. This comprises a small weir and intake next to the Rhenigedale turn below the old water treatment works and a turbine house down near the shore on the Eilean Anabaich side of the footbridge.

We submitted a screening request to the council (13/00615) in December. This will give us an idea of what environmental survey work we have to carry out before we can submit a full planning application. As at Bunavoneader, we think we will have to carry out a fish survey and an otter survey. These can’t be completed until early summer when the water levels drop.

In the mean time we have an application pending to help fund the remaining feasibility work required to confirm viability and allow us to submit applications for Planning, Grid Connection and SEPA Licence.

Details of the feasibility work to date is available HERE and artists’s impressions of the building and intake  HERE (1.4Mb)

The work to date has been funded by the Outer Hebrides Community Energy Fund and its managers:

 

 

 

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Maraig in the mist

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The Feasibility Study for a hydro scheme on the river at Maraig is underway. It’s taken over six months since the original enquiry, but after pulling together three other community groups and sourcing funding from Community Energy Scotland and Leader – we are finally on our way.

On a misty Friday morning, three engineers braved the midges and headed out to walk the river. Highland Eco Design won a tender to review four potential community hydro schemes. After visiting Swordale, Galson and Gress, they “saved the best to last”. We haven’t had any serious rain for weeks. I thought this would be a bad thing – they said no -it’s exactly what we need to see. The level of the river they saw was the level that SEPA will insist is retained as a minimum throughout the year.

We walked from the Scottish Water weir down to the shore then back up to walk another tributary. It’s clear that there are a number of options for a scheme. There is one big constraint though -SSE will only allow a 50kW generator onto the grid. Until the interconnector goes under the sea to Ullapool – which will be a few years away yet – 50kW is where it’s at. So the dilemma is whether to design a 50kW scheme now or to build a bigger scheme and constrain it to 50kW until the new cable is in place. If we build a 50kW scheme, do we build it on a smaller tributary, keeping the bigger stream clear for future or do we use the best stream and get the best output now? So many questions – and three engineers to think about it – one already has his thinking cap on!

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Another hydro opportunity pops up

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Just when you’re really not getting anywhere with a project, another one comes along.

Scottish Water has spent a fortune upgrading the Water Treatment Works at Carragreich. This is now supplying purified water to the majority of North Harris and Scalpay. Last year a pipe was installed over the hill to Maraig; connecting the village to the new water main. In doing so, another of the remote, village-scale treatment works becomes redundant. And there’s the opportunity. Plenty of water tumbles down from behind the Clisham, now with no-one to use it. Maybe we can design a 50kW scheme that will get around the grid constraint that is holding up the bigger Bunavoneader project. All projects >50kW are on hold until the undersea cable and interconnector are in place… and who knows when that will be?

Community Energy Scotland has offered to put together a tender for a feasibility study for this river as well as two other potential community schemes on Lewis. Hopefully in a few months time we’ll have a better idea of the costs involved, and how productive the river could be.

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Hydro scheme update – November

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A short video giving an update on progress this year.

Hydro update Nov11 from North Harris Trust on Vimeo.

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