By Tim Fray
Last summer, whilst walking in Snowdonia, I came across the Dinorwig Power Station. Known as “Electric Mountain”, it consists of a reservoir which stores water to drive six hydroelectric turbines. Water is stored at 636 metres above sea level in the Marchlyn Mawr reservoir. When power needs to be generated, water from the reservoir is sent down through the turbines into Llyn Peris, which is at approximately 100 metres. Water is pumped back from Llyn Peris to Marchlyn Mawr reservoir during off-peak times. Although it uses more energy to pump the water up than is generated on the way down, pumping is generally done when electricity is cheaper and generation when it is more expensive. This type of energy generation is almost immediate. From standstill, a single 450-tonne generator can synchronise and achieve full load in approximately 75 seconds.
So this power station serves a key role for what is aptly termed “television pickup”. These are times of acute high demand on the UK’s power grid, such as those created by the switching on of kettles during commercial television breaks on popular television shows. The Euro 2020 final held on 11 July 2021 was watched by 29.85 million people. There are approximately 67 million people in the UK. So 44.5% of the country watched the footy that day. At half time just think of the load on the national grid when everyone got up to make a cup of tea, let alone extra time and penalties!
Of course, other countries such as Norway have used hydroelectric storage for many years, and some say it could be the “green battery” for Europe. Whilst the UK perhaps doesn’t have the fjords of Norway sufficient for effective hydroelectric storage on a large scale, it does have a lot of wind turbines. It would seem that even a few more power stations like Dinorwig, linked to these wind turbines would render our power grid dramatically more rigorous and sustainable.
I would be interested to know what other forms of energy storage the UK could use. Do you know of any?
