A tunnel at the Glendoe hydro scheme at Fort Augustus
A dam which is crucial to the generation of electricity at a £140m hydro power scheme has begun filling with water.
First Minister Alex Salmond was invited to close a sluice gate on the reservoir at Glendoe, near Fort Augustus, in the Highlands.
Work on the plant was started in 2006 when the then prime minister, Tony Blair, triggered a tunnel blast.
The project is to begin generating electricity by early 2009.
Scottish and Southern Energy (SSE) said that once it is operational, the scheme will provide power for 250,000 homes.
It is the first large-scale hydro-electric project since 1957.
Ahead of the reservoir ceremony, Mr Salmond said: "I am delighted to be involved in marking this major milestone in this ambitious project, which will utilise Scotland's natural resources for the creation of clean renewable energy.
"The Scottish Government has set an ambitious target to generate 50% of our electricity demand from renewable sources by 2020."
He added: "Today hydro energy continues to be an important source of power, but if we are to achieve our ambition of making Scotland the green energy capital of Europe we must realise the potential of our huge untapped water resources."