Environmental Engineering Reference
In-Depth Information
Storing electricity
So far there is only one type of storage - that of hydroelectricity - that
works well as a back-up to intermittent wind or solar. Denmark depends
on wind power for as much as twenty percent, on average, of its total
energy consumption, and it can do so because in the event of a shortfall,
it can draw on Norwegian and Swedish hydropower. In many other coun-
tries, pumped storage is very common. This requires two bodies of water:
a higher and a lower lake (the lower one could, in fact, be the sea). The
process involves pumping water from the lower to the upper lake at times
when electricity is cheap (usually at night) and then releasing it from the
top lake top in times of need to turn turbines and generate power.
The UK has one unusual pumped storage facility, the Dinorwig power
station in Snowdonia in Wales. It is unusual in that the top part is a hol-
lowed-out mountain, a process that took ten years (1974-84) to complete.
It was initially designed, before the days of commercial wind power,
purely to provide a store for cheap night-time power from the UK nuclear
power plants. But now there is an extra rationale for Dinorwig as a back-
up for wind power. Dinorwig also has the capability of re-starting the UK
national grid after a complete power failure, were that ever to happen.
