1930s Tummel Bridge hydro station life extended by 40 years after £50M refurb

The plant, which is in the centre of the Tummel Valley Hydro Scheme cascade, is now generating renewable electricity following the successful installation and energisation of two new hydro-electric power turbines. 

The project, which started in April 2022, involved the replacement of the station’s two original “Camel Back” twin-runner, horizontal Francis hydro turbines, which were installed in 1933, with new modern runner technology. 

This new technology increases water flow, enabling the increase in generation output at the plant and extending the hydro power plant’s working life by at least 40 years.  

Undertaking its largest ever investment in its hydro fleet, SSE Renewables has repowered the station to increase its potential generation output from 34 to 40MW during optimum conditions. 

The first of the new Tummel units started generating in March this year with the second energised during testing in May 2024. The overall project took two yeras to complete. 

All the large components for the turbines were delivered to site in July and September 2023.

Inverness-headquartered Global Infrastructure operated as principal contractor while Stantec led on civil design as well as supporting the engineering team for the project. 

Voith Hydro, a leading manufacturer of hydropower turbines and generators, conducted the mechanical and electrical elements of the project. Other Scottish based supply chains firms working on behalf of SSE Renewables included Global Energy Group at Port of Nigg in Cromarty Firth which was responsible for forebay stoplog fabrication and tailrace gate modifications, while Kaefer oversaw corrosion protection works on the water intake structures and the team at Konecranes Demag UK modernised and upgraded the 90 year old 120t station crane. 

Commissioned in 1933, Tummel Bridge power station is one of the oldest hydro power plants in Scotland. The power station, which is housed within an iconic Category A listed structure, currently delivers around 140GWh of renewable generation output each year. 

As well as generating its own power output, it plays an important role in efficiently moving water onwards in the overall Tummel Valley hydro-electric scheme to the Clunie and Pitlochry power stations. 

First Minister of Scotland John Swinney said: “The reopening of Tummel Bridge Power Station marks a significant moment in Scotland’s renewable energy journey. 

“This £50M investment ensures that one of our country’s iconic hydro stations will continue to play a crucial role in generating clean, sustainable energy.  

“The modernisation of this historic site demonstrates how Scotland’s natural resources can be harnessed to support our transition to net zero, while also preserving an important part of our industrial heritage. 

“I congratulate everyone involved in successfully bringing this project to fruition and look forward to the long-term benefits it will deliver over the coming decades.” 

SSE chief commercial officer Martin Pibworth said: “It’s a very proud moment for SSE and the Hydro team to host Scotland’s First Minister, John Swinney MSP, at Tummel Bridge today. 

“This marks an important milestone for SSE Renewables and our supply chain partners. 

“The Tummel Bridge refurbishment programme is one of the largest single investments we’ve made in our existing hydro fleet, and clearly supports hydro’s vital role in the path to achieving UK and Scottish net zero carbon emissions targets. 

“Tummel Bridge has been a part of the energy landscape for generations and this investment will ensure this iconic and historic site continues to play a crucial role in Scotland’s energy mix for decades to come.” 

Stantec director of hydropower Craig Scott said: “Refurbishment schemes like Tummel Bridge are an integral piece of our low carbon future.  

“Retrofitting existing energy assets with modern, highly efficient equipment, rather than rebuilding them, brings added value for our clients as well as the communities they serve. 

“Both in terms of project costs and carbon reduction.  

“This plant is an important part of local history, culture, and Scottish innovation, and we’re proud our staff have been deeply involved in helping secure its future alongside SSE.” 

Global Infrastructure managing director David MacDonald said: “This is a good day for all concerned with this interesting project. I am proud Global Infrastructure played a key role in the delivery of this complex project and look forward to further to assisting with similar works in the future. 

“The project was a great example of teamwork and collaborative working as a project team. We look forward to working together with both Voith and SSE in the future.” 

Like what you've read? To receive New Civil Engineer's daily and weekly newsletters click here.