February update on Nethermills Hydro Scheme

 

Since the corn mill at Nethermills was demolished in the 1950s at least 20 Gigawatt hours of useable energy have passed over the weirs in the centre of Ayr.  The Energy Agency commissioned a hydrological study in 2015 followed by a feasibility and design study by Mann Power Hydro Ltd. The result is the current construction project by Energy Agency Renewables Ltd, with TLS Renewable Consulting Ltd as project manager and Bailey Contracts Ltd as civils contractor.

The fish-friendly, 4-metre-diameter Archimedes screw will generate up to 85 kilowatts and a total of 320 megawatt hours in a typical year. Revenue from feed-in tariff and electricity sales will be used to maintain the system, the surplus supporting the fuel-poverty-and-carbon-reducing activities of the non-profit Energy Agency. 

Features of the scheme:

❖ A hydro scheme providing 100% green electricity is in keeping with South Ayrshire Council’s long-term development plan to regenerate the riverside area in a sustainable way and contribute towards the Council’s Carbon Management Plan

❖ Local benefits include a source of carbon-free electricity and funds for local projects by the Energy Agency

❖ The turbine will be a local attraction on the River Ayr Way, displaying information on renewable energy generation to passers by

❖ The scheme design, including new smolt chutes and eel passes, will assist the passage of migratory salmon and eels and the installation of a fish counter in the existing fish pass will benefit the management of the River Ayr catchment fishery

❖ The scheme will prevent the emission of an estimated 147 tonnes of CO2-equivalent greenhouse gas annually and continue to generate green energy for many decades, just as the watermills did from the 13th to 20th centuries

Where are we now - 15 February 2022

The hydro scheme passed its grid connection testing today and video shows the turbine turning and generating electricity.

Work has continued onsite throughout December, January and into February 2022.  The civil construction contract was extended to 11^th February 2022 to allow remaining works to complete following high water events throughout the autumn and winter months.

The powerhouse and concrete construction along with the turbine are all in place. The site currently has:

Reinforced concrete construction fully complete

·       All grouting and concreting works in and around the turbine base and by-wash gate complete

·       The Archimedes screw, connected to its gearbox and generator

·       The bywash gate and its hydraulic ram

·       The sluice gate

·       Some of the eel and lamprey ladders

·       Cabling connection from College building to powerhouse complete

·       The electronic control equipment installed

·       Fully installed roof including substructure and sedum roof

·       The security fencing, complete with 1 additional section to be fitted

·       All final adjustments to the turbine and by-wash gate by Vandezande engineers – mostly complete

·       Reinstatement of river bank and walkway – mostly complete

·       Successful withdrawal of all cofferdams

·       All scaffolds removed

·       All powerhouse decking and steps installed

 Work Planned for February 2022:

·       Installation of smolt chutes and remaining eel and lamprey ladders

·      Final visit by Vandezande engineers.

·       Extra section of security fence installed.

·       CCTV security system installed on the powerhouse.

·       The fish counter installation by Fishtek on behalf of Marine Scotland Science

·       Display boards are being designed/prepared by Ayrshire College

·       Official opening taking place 28^th February 2022.

 After benefiting earlier in the project from an unusually dry summer, the contractors encountered significant difficulties caused by high water levels during Autumn and Winter 2021. This situation only occurred because of a delay of a month in the delivery of the turbine equipment from Belgium due to the steel supply chain problems linked to COVID-19-related fluctuations in global demand.

This has resulted in the final installation phases being delayed into the autumn and winter.  High levels of rainfall over this time resulted in river levels rising rapidly affecting the progress of works. It had been our earlier intention through careful project planning to avoid this period, but with the delays encountered with steel shortages we inevitably ran into this difficult weather season.

Ultimately this has resulted in the civil construction completion date being extended initially to the end of January then further into mid-February 2022.

The contractors have worked tirelessly throughout to meet challenging demands and weekly progress meetings have been held to ensure we remain on-track for our official ‘opening’ at the end of February and electricity generation by March 2022.  The civil contractors, Bailey Construction Ltd, have been working their way through finishing touches and are progressing through a comprehensive ‘snag-list’. Their sub-contracted roof specialists Skygarden installed the sedum roof over two days in late January.

The smolt/eel/lamprey works that were scheduled for this week have again been delayed until the water levels recede, likely w/c 14^th February.

The Vandezande engineers have completed most of their commissioning works on the screw and by-wash gate, with a final visit expected w/c 14^th February. 

The electrical contractor TLS Renewable Consulting Ltd and their sub-contractors have completed most of the installation of the control system. Testing of this began on 3^rd February and is ongoing in readiness for the G99 grid-connection test with SPEN on 15^th February.  A short test allowing water to flow through and turn the turbine for the first time took place successfully on 7^th February. 

We remain confident that we will achieve successful completion well in advance of the final commissioning deadline of 18^th March 2022.