📋 Project Overview
Foyers is a 300 MW pumped storage hydroelectric station on the eastern shore of Loch Ness. Its two 150 MW Francis pump-turbines use Loch Mhor as the upper reservoir and Loch Ness as the lower reservoir — both of which are natural lochs, not artificial impoundments. Opened in 1975, Foyers was one of the second generation of Scottish pumped storage facilities after Cruachan (1965). SSE Renewables operates it as part of their pumped storage portfolio alongside Coire Glas (consented).
Site Schematic
Schematic diagram — not to scale. Illustrative layout based on project specifications.
⚡ Key Facts
300 MW — two 150 MW Francis pump-turbines
Uses Loch Mhor (upper) and Loch Ness (lower) as natural reservoirs
Operational since 1975 — nearly 50 years of flexible generation
SSE Renewables owner — same developer as consented Coire Glas
6.3 GWh storage capacity
🔧 Technical Specifications
| Capacity (MW) | 300 MW |
| No. of turbines/units | 2 |
| Turbine / unit model | Two 150 MW Francis pump-turbines |
| Unit capacity | 150 MW each |
| Upper reservoir | Loch Mhor (elevated above Loch Ness) |
| Lower reservoir | Loch Ness (discharge point) |
| Annual output | 750 GWh/year |
| Homes powered | 150,000 homes |
🔌 Grid Connection & Infrastructure
| Grid connection point | Beauly substation, Inverness |
| Voltage | 275 kV |
| CfD held | No (merchant / PPA) |
🏢 Development & Ownership
| Developer | SSE Renewables |
| Owner / operator | SSE Renewables |
| Year consented | 1972 |
| Construction started | 1972 |
| Commissioned / target | 1975 |
| Location | Above Loch Ness at Foyers, Inverness-shire — upper reservoir Loch Mhor |
| Region | Scottish Highlands |
| Coordinates | 57.26°N, 4.52°W |
📅 Project Timeline
🌿 Environmental & Planning
Uses natural lochs — no dam construction required. Ecological monitoring of Loch Ness and Loch Mhor water quality and fish populations maintained.