It says the UK will need much more energy storage capacity as renewables increase on the National Grid.
It says it can add 400 megawatts (MW) of on-demand electricity by building a new dam in front of the existing dam.
But it says the £300-£400m cost is prohibitive unless it can get a guaranteed floor price for its use from the government.
In return, Scottish Power says it will accept a cap on profits.
The Cruachan plant near Oban in Scotland pumps water 400m uphill at night when energy prices from wind farms are cheap.
It
then lets the water flow downhill in daytime in order to generate
electricity when demand peaks and power prices are expensive.





