I realize I have been doing a lot of archaeology posts recently, so I have been trying to come up with something a little different this time and an idea came to me while I was watching “Jurassic Park” the other day (I’ll explain later), so here goes.
I’ve been asked a few times what my favorite thing about Wales was, and people are surprised when I always mention a hydro-electric power plant. I’d say that’s completely understandable, sounds pretty boring to me too. But Dinorwig Power Station really is worthy of the list (I believe it is pronounced day-nor-wig, but Welsh pronunciation is some of the most confusing collection of rules I’ve ever encountered, so all bets are off).
It is located in Northern Wales, in Snowdonia National Park, inside a mountain named Elidir Fawr. It is also sometimes also called Electric Mountain for obvious reasons. At a glance, this is why its really really cool:
- Except for the water reservoirs, it was built completely underground in order to preserve the natural beauty of the National Park. The cables that transmit power from the plant were also buried for 4 miles leaving the plant in order to prevent unsightly transmission towers. Score 1 for the environment!
- It is a hydro-electric plant meant to take the burden off nuclear and fossil-fuel burning plants by providing a renewable energy source. Score 2 for the environment!
- It is built from an abandoned quarry that was expanded with over 10 miles of underground, two-lane roads. It features the largest man-made cavern in Europe and was the largest civil engineering project by the UK government at the time.
The people of Wales are certainly proud of Dinorwig, so much in fact that it is a tourist attraction. It is accessible from the Electric Mountain Centre, which also has a coffee shop with some of the worst coffee I have ever had the pleasure of drinking. Though I was dissatisfied with the level of commercialism involved in the site – the Dinorwig Electric Gift Shop seemed excessive – it was pretty cool to see something so nerdily scientific receiving such positive public interest.
Visitors can don a hard-hat and ride a minibus through the caverns and expansive underground tunnels, feeling as though they are actually on their way to see a secret base of a James Bond villain. I visited as part of an environmental class and it was truly an awe-inspiring sight – I wish I had some amazing photos to include, but out of a necessity to protect certain technology, visitors must check everything in a locker before departing on the tour. So here’s a Bond villain base.
The tour begins with a video that gives you a basic overview of the plant, which also takes place in a dark cavern with rows of seats with metal railing – I was quite certain I would soon learn I was actually in Jurassic park and that the bars were going to snap in place and the ride would head toward the mountain (which is actually full of dinosaurs). My daydream about this had just ended when our tour guide made a Jurassic Park reference – the water reservoirs for the plant were built to be absent of fish, but somehow now they are both full of fish… life finds a way.
The main function of Dinorwig is to aid in the supply of power to the national power grid by stabilizing the amount of energy at any given time and also to provide extra energy when needed. The balance of power in a national grid is extremely important – let it go too high or too low and rolling blackouts occur, much to the dismay of the general populous. Dinorwig can respond to fluctuations in the power grid and go from completely off to fully functioning in 12 seconds – fastest in the world. (Similar hydro-electric plants in the US have reaction times of over 4 minutes). Once on, it can run full power for 6 hours and if needed, could supply power to all of Wales.
It generates power by using gravitational potential energy of a water reservoir to spin its 6 turbines, each of which weigh 450 tons and are capable of 500rpm. When powered, the water in Marchyn Mawr is drained down into the mountain, through the turbines and into the lower Llyn Peris reservoir. In 5 hours of a fully-operational state, the amount of water that will run through the turbines is equal to the amount of water that is consumed by all 8 million of the inhabits of London in one day.
The downside to a pump-storage power plant is this: it cannot generate any power if all of the water is in Llyn Peris – the water must be above the turbines, in the Marchyn Mawr reservoir, otherwise there is no gravitational energy to power the turbines.
So one might ask, how exactly does it continue to produce power if it uses all the water in 5 hours? Well, here’s where it gets tricky. And a little controversial. The plant must pump all of the water back into the higher reservoir, reversing the turbines to act as pumps. And working against gravity means this actually takes more energy than it gained from the potential energy of the water falling. How then does the plant operate?
Opponents of hydro-electric plants (who usually happen to be proponents of nuclear or fossil-fueled plants) argue that they are more power-costly to use due to this energy imbalance. And technically they would be, except the power that they use is power that is generated but would be wasted anyway.
Nuclear power plants must run at the same power-output 24/7, whether or not the power is needed. So at night, when the demand for power is much less, the same amount of power is being produced. This creates a demand for a place to get rid of this excess, lest it overload the power grid. But during the day it still needs help when everyone is watching television or playing countless hours of video games. So Dinorwig steps in a provides the additional power needed in the day by draining the water reservoirs and generating electricity. Then, it uses the unwanted electricity that is produced at night, that needs to be consumed somehow anyway, to perform the energy-intensive re-pumping of the water back into the reservoir so it is ready for the next day’s use.
So yes, admittedly the hydro-electric plant is not perfect. It only operates at 75% efficiency, consuming more energy than it can produce – BUT if it did not exist, another type of plant would have to operate during the day anyway to aid in the stabilization of the national power grid and somehow the excess power produced at night would still have to be consumed. So overall, though it is technically inefficient, its inefficiency comes at a time of day when power suppliers are looking to get rid of excess energy and it is the best option available when considering its less-polluting impact on the environment and its long-term potential (the water will always be there, but we all know the coal won’t be).
And on that note, I would like to leave you with a photo I took the day I toured Dinorwig, of Snowdonia National Park. Natural beauty indeed.
If you would like to learn more about the specifics, here is their website: First Hydro Company, Dinorwig Power Station