Dinorwig Power Station

Located in the heart of Snowdonia, in one of the most beautiful landscapes in Great Britain, Dinorwig power station is quite an oddity. The location was carefully chosen out of hundreds of different areas surveyed, and consequently the power station was built near Llanberis, North Wales. Except this was an area of such astounding natural beauty that the entire powerstation had to be built underground, inside the mountain.

Construction

The station became operational in 1984, but construction work had started ten years previously. It was a huge process, 12,000,000 tonnes of earth had to be removed and thousands of jobs were created in an area much in need of employment after the collapse of Wales' slate and coal industries. In total 6,000 man years of labour were used.

Why go to Such Lengths?

In England and Wales power is distributed throughout the country by a network of criss-crossing power lines owned and controlled by The National Grid. It is their job to make sure that if there is a need for electricity, then there is enough of it in the right place at the righ time to meet the demand.

Unfortunately The National Grid had a problem, as new technology became widely available, and prices fell, the number of household electrical goods rocketed. This in itself was not a problem, new powerstations were built to cope with this across the country, but another, more difficult problem arose. The cause was advert breaks in television programmes. During prime time TV slots millions of people would all be watching the same programme, then all at almost exactly the same time would switch on their kettle when the adverts started.

This created a massive surge in the demand for electricity, a spike that the National Grid was struggling to handle. This very rapid demand for large quantities of electricity could not be met by standard power stations, for them to significantly increase their output often took hours, sometimes even days. The solution was Dinorwig - A power station that within seconds of being turned on could produce enough electricity to Power the whole of wales, and sustain that power for up to six hours.

How Does it Work?

The basic idea behind Dinorwig is quite simple, the power station consists of two lakes, Marchlyn Mawr and Llyn Peris each one and a half kilometred from the other, with a height drop of 500metres separating them. The two are interconnected by a series of pipelines. Inside the mountain between the two lakes is the largest man made cave in Europe, and inside looks remarkably like the set for a James Bond movie. Inside this cavern are the turbines, when there is a sudden need for power water is allowed to flow out of the first lake, down through the pipes into the turbines, at immense pressures, the force of gravity acting on the water forces the turbines round and once the water has passed through, it drains down into the lower lake. This in itself is an excellent system, but can only be used once, if the top lake is empty then no more power can be produced, so the solution is simple. During the night when there is an excess of power in the National Grid, the turbines are reversed, and used to pump water from the lower lake back to the top lake, ready for the next time their is a sudden surge in demand.

Take a Tour!

The power station has an accompanying museum in Llanberis, the museum is excellent and from there for a small fee (£2 at time of writing) a minibus will take you inside the power station and you will be given a guided tour through the insides of the mountain. The tour is well worth it, the main cavern where the turbines are is quite spectacular, but be warned - take a jumper, you will go a long way underground and it gets quite cold down there, even in summer.