| Small hydro
and controlled through our Supervisory Control and Data Acquisition system,” Moorcroft says. The integration of modern digital systems into a 120-year-old hydropower asset reflects the wider evolution of the sector. While the core civil structures at Cwm Dyli have remained largely unchanged, operational practices have adapted significantly in recent decades, particularly around monitoring, control and maintenance planning. Remote operation allows the station to be integrated into a wider fleet strategy while reducing the need for permanent staffing at isolated locations.
Maintaining infrastructure
in difficult terrain While the station itself has proven highly reliable, the recent refurbishment programme focused on one of the project’s most challenging physical elements: the steep mountainside pipeline installed in 1988. The maintenance work centred on the concrete plinths supporting the penstock. Over time, the sliding surfaces between the pipeline and supports had begun to stick, requiring intervention to restore movement and reduce stress on the structure.
Access was a major challenge. In places, the pipeline
crosses gradients as steep as one in four, creating difficult conditions for workers and equipment. “The pipeline runs down a steep mountainside and the plinths which support it are difficult to reach,” Moorcroft
explains. “To refurbish them, materials were delivered by helicopter and welfare facilities for the craftsmen were installed on the slopes.” The work was phased over two years. Five supports
were initially repaired as a pilot project to validate the repair method before the full programme was rolled out. Of the remaining supports, 98 were completed during the first summer campaign, with the balance completed the following year. The logistical complexity maintenance work requires
extensive planning. Maintenance teams operate from Dolgarrog, approximately an hour away from the site, meaning work preparation and material management were critical to avoid delays and unnecessary journeys. “For heavier maintenance, we establish welfare facilities and offices near the powerhouse for the contractors, and materials are delivered directly to where they are needed on the mountainside by helicopter,” says Moorcroft. The site’s remote location also influences how outages and maintenance windows are scheduled. Work must account not only for weather conditions in Snowdonia but also for the practical limitations of moving personnel, lifting equipment and materials onto steep terrain. Detailed planning therefore becomes central to both project efficiency and workforce safety. Despite the challenges, the refurbishment programme was completed without significant technical issues. The
Above: Llyn Llydaw, the natural reservoir supplying water to the Cwm Dyli hydropower station
Below left: The turbine hall at Cwm Dyli
www.waterpowermagazine.com | June 2026 | 31
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45
