Britain's Largest Battery Is Actually A Lake

  • Published on Nov 5, 2018
  • Dinorwig Power Station, otherwise known as Electric Mountain, is a pumped-storage hydro station in Llanberis, Wales. And yes: it's Britain's largest battery. Here's how it works, and why some of the things you think you know about TV pickups might not be so true any more.
    Thanks to all the Engie team! More about them:
    Public tours of Electric Mountain are closed until mid-2019, but you can find details here:
    Camera op: Ryan Priestnall
    Editor: Michelle Martin (@mrsmmartin)
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    and on Instagram as tomscottgo

Comments • 1 493

  • rjc0234
    rjc0234 2 days ago

    so where does it get its power at night to pump the water back up? seems a bit backwards. why not just build a new power station to meed that extra daytime demand, and turn it off at night. defeats the purpose of not having enough capacity in the national grid if at night time that limited capacity is being used "recharge" a giant battery whose purpose is to take up the slack when it is needed.

  • John Dooley
    John Dooley 7 days ago

    Turlough Hill in Co. Wicklow, Ireland runs a similar system, known as a pumped storage system.

  • Matthew Tolentino
    Matthew Tolentino 14 days ago


  • Damp de Lux
    Damp de Lux 15 days ago

    We have a similar mountain in Luxembourg: The Niklosbierg (Nicholas Mountain).
    But I guess the Welsh one is bigger.

  • LALLAREN#1 !
    LALLAREN#1 ! 15 days ago

    very nice

  • d0nk0
    d0nk0 19 days ago

    Stupid prick in his health and safety gear while sitting in his office giving an interview.

  • Brian Cox
    Brian Cox 20 days ago +1

    Another excellent video... i'd never heard of power stations like this before (well, i'd heard of hydroelectric, but never where it pumps it back up at night)

  • Pav Litt
    Pav Litt 20 days ago

    Things like this used to be on TV.

  • max nye
    max nye 26 days ago

    Iceland's battery is Iceland

  • BenjaminSimsVids
    BenjaminSimsVids 26 days ago

    Do you work at Nottingham University?

  • Wendel Bolide
    Wendel Bolide 27 days ago

    3:25 NO DANCING

  • Omar Omar
    Omar Omar 27 days ago

    One of my favourite channel on TVclip. Thank you

  • Steven McGuinness
    Steven McGuinness 28 days ago

    Went there on a school trip in the 90’s!

  • James Samways
    James Samways 28 days ago


  • GMT {FS}
    GMT {FS} 29 days ago

    So they create energy then use more energy than they made to get it back up the mountain? So they lose energy every time it turns on

  • Clarence Trumble-Lovegod

    It must be very energy intensive to pump the water back to the top again. Cheaper, sure, but the amount of energy needed must surpass by some margin the energy produced.

  • Javier Reyna
    Javier Reyna 29 days ago

    Really? So can be this considered a perpetual energy machine? Because it supllies itself again with pumpig up the water

  • Vince mckaine
    Vince mckaine Month ago

    The Mark Rober of UK

  • Hagelslag
    Hagelslag Month ago

    What's the efficiency? Surely you'd be wasting huge amounts between the dumps and pumps.
    Are the only benefits to ease demands on the grid?

  • Unequal
    Unequal Month ago

    0:38 Who else thought this looked like a Bungie hat

  • BrutalTurtle
    BrutalTurtle Month ago

    what happens to the fish in the reservoir? they're just passed back and forth?

  • Ryan Priestnall
    Ryan Priestnall Month ago

    Was a fun day working with you Tom! Great edit too.

  • Pawcket
    Pawcket Month ago

    Whoa, really cool stuff. Thanks for your work, Tom!!

  • Janita G
    Janita G Month ago

    This makes my little engineering heart explode. So cool. I've been at a water treatment plant when a valve shut too fast - water hammer is intense!

  • Tyee Cambrón
    Tyee Cambrón Month ago

    In Seattle we just call it a dam. We have a good one in Washington state that powers Seattle.

  • InvadersDie
    InvadersDie Month ago


  • Roc Aràjol
    Roc Aràjol Month ago

    that's bonkers

  • that-nerdy-hufflepuff

    I went there with my family a few years ago. It was very interesting, but I felt quite sick because the roads to get there are very twisty.

  • Nighthawk
    Nighthawk Month ago

    the setup of exposed piping and heavy machinery, and crude mountain rock, reminds me a bit of TF2 and it's level design.
    you know, circa 1970's technology, underground bunkers, missile silos, turbines and control rooms..... hell, you even have Engies

  • Dk Filchev
    Dk Filchev Month ago

    It's scary knowing that whole nations sit in front of TVs for decades now, getting brainwashed together, being fed censored and moderated content.

  • ChancelorPalpetine
    ChancelorPalpetine Month ago

    I actually went here a while back during a storm and the mountain got struck by lightning. It broke all the electrics, including the theatre they show movies about the mountain in. Basically everyone in the room had to try and cover their ears whilst the speakers blared out a high pitch tone on full volume.

  • Matt Helton
    Matt Helton Month ago

    Your videos are by far some of the best on TVclip. I'm so happy to see your views and subscriptions continue to increase. Keep making videos, please!

  • KlankOntwerp
    KlankOntwerp Month ago

    Didn’t you make a video about a weight inside of a deep well that would be lifted by solar and wind energy via an electric motor and then dropped controllably to give off power again? That’s one of my favorite ‘simple ideas’ for a sustainable future ever!

  • Ferble-kun Sakrrislin
    Ferble-kun Sakrrislin Month ago +1

    Very impressive.

  • Cj Iscool
    Cj Iscool Month ago

    I thought the salt in the water could make a battery or something

  • Cj Iscool
    Cj Iscool Month ago

    Looks very expensive

  • The Ethicist Philosophy Show

    10-30 seconds?!?!

  • Kaleb Bruwer
    Kaleb Bruwer Month ago

    This is really cool, but you would need a lot more to balance a fully renewable grid. It's easier to go nuclear, that shouldn't be much harder to balance than coal. Take Germany and France as examples of both approaches.

  • James Mead
    James Mead Month ago

    How efficient is it?

  • wolfedog99
    wolfedog99 Month ago

    Grand Coulee dam in Washington does some of this with Banks lake. Though there are three levels plus some irrigation going on, the Columbia river at the foot of the dam, Roosevelt Lake behind the dam(about 400 feet), and Banks Lake on the plateau above(add another 280 feet). The maximum height of Lake Roosevelt is the elevation of the river at the Canadian USA border 151miles upstream. Some years after Grand Coulee was originally built two dams were built upstream in Canada to help regulate the seasonal flow variations, under a bargain that provides British Columbia electricity as payment for the dams.
    Anyway, when the spring-summer flows are high and electricity demand is relatively low excess power is used to pump water up to Banks lake from Roosevelt Lake, and a large fraction of the water in Banks lake is used for irrigation so there are 6 pumps plus 6 pump-generators about 50Mw each(600Mw for pumping and 300Mw generating), pumping capacity is 600cubic meters per second(45-55per unit).
    The main dam has a total capacity of 6.8Gw and the 3 largest turbines are 805Mw each, 3 more at 600Mw, the original 18 at 125Mw each and the 10Mw service generator. The total power capability from the dams in this river basin is 29Gw.

  • Karl Black
    Karl Black Month ago

    I have been on one of the public tours at this power station. There is two railways in the town beside it, and National Slate Museum is beside it as well. The ticket office for the public tours is in the town of Llanberis

  • mumiemonstret
    mumiemonstret Month ago

    Nice to have a battery that trickle charges itself in the typical Welsh weather!

  • Pseudo Nym
    Pseudo Nym Month ago

    Ba Dum tss
    😩I feel the groans 😦

  • Dr Moriarty
    Dr Moriarty Month ago

    You call THAT large? I think not...

  • Amani Hamis
    Amani Hamis Month ago

    I really thought it was gonna be a lake with enormous quantities of an electrolytes dissolved in and separated by a semipermeable membrane.

  • Miles Davenport
    Miles Davenport Month ago

    Excellent and informative. Thank you.

  • haiironezumi
    haiironezumi Month ago

    I can see a great potential for this as storage for solar, with the solar power feeding the grid as required, but also powering the pumps to store the gravitational energy.

  • James Berend
    James Berend Month ago

    Isn't this just a hydroelectric dam then?

  • Jon
    Jon Month ago

    hell yeah ive been there

  • mellowfish316
    mellowfish316 Month ago

    So would so say the rain is a trickle charger?

  • ericcartmansh
    ericcartmansh Month ago

    Would love to see a james burke style connections for how water in this lake gets turned into youtube cat videos being consumed at home by kids!!

  • nobody
    nobody Month ago +1

    I thought that the title meant that Britains largest battery has the same name as a lake

  • Dryw Bach
    Dryw Bach Month ago

    Bit disappointed I didn't get to hear Tom say Llanberis

  • Alan Sproul
    Alan Sproul Month ago

    Should have went to Cruachan

  • Fahim Ebrahim
    Fahim Ebrahim Month ago

    I have a question, doesn't the energy used to pump it back up = the energy created coming back down?

  • Draven Rainrix
    Draven Rainrix Month ago

    That is truly amazing. Thanks Tom and all involved, I'd never heard of that place.

  • BC Joshiee
    BC Joshiee Month ago

    Another good reason wales would flourish in independence.

  • Corn Kopp
    Corn Kopp Month ago

    I heard about one of these lake batteries in Virginia, but heard that it’s completely pointless and takes more energy than it uses. It only stays up through essentially financial trickery to make it turn a profit

  • Lobster Patrick Stewart

    Is it just me or would this place make a really good Shining-esque horror setting

  • samthepoor
    samthepoor Month ago

    Huh, does the potential energy increase then when it rains?

  • Andrew Peterson
    Andrew Peterson Month ago

    Not a new idea but a brilliant one. We need to implement this worldwide with solar powered pumps. We can harness the Sun, time to stop killing our only spaceship for the sake of tradition.

  • penguins forall
    penguins forall Month ago

    No. Its not a battery its a type of hydroelectricity. Batteries are a set of electrochemical cells that store energy in redox reactions.
    Further the potential energy distinction is just misleading. Its technically correct because all electric charges are potential energy. But redox reactions are a specific chemical process.

  • Kenny Grenier
    Kenny Grenier Month ago


  • Rocky712 - Let´s Plays

    Kinda funny that I got a math task last week with this context a water resovir like this. :D

  • Gus.
    Gus. Month ago

    Mad ting, that battery could just about power a modern smartphone for 2 days, or 200 homes... ;)

  • Sukacita Yeremia
    Sukacita Yeremia Month ago

    You know you're British when you can make a living out of moving water up and down the mountain using market prices.

  • Brian Cooper
    Brian Cooper Month ago

    A lot of road improvements where required to take the machinery from suppliers in England to the power stations in Wales and Scotland. This is why when travelling in these areas the road widths are disproportionate to the amount of normal traffic. There is also a similar power storage system by Ffestiniog.

  • Brian Cooper
    Brian Cooper Month ago

    I have seen the large valves being refurbished in Sheffield ,

  • Brian Cooper
    Brian Cooper Month ago

    Loch Awe in Scotland does/did the same thing.

  • Terran Nobody
    Terran Nobody Month ago

    I wonder what sort of power generation Africa has invented!

  • Lycerion
    Lycerion Month ago

    I've always wondered what the efficiency of this would be! How much power do they get back out compared to what is put in?

  • Hugo Bouquard
    Hugo Bouquard Month ago

    Relations have been spoted between dams and earthquakes, may these huge perpetual swing of tons of water weaken the geology of the ground ? (These sound too miraculous for me, every techniques have advantages and disadvantages, despite what Engie can say)

  • neo geo
    neo geo Month ago

    99% of all electricity in my country comes from water powerstations like this

  • Melchior Hof
    Melchior Hof Month ago

    What is the efficiency of pumping up and generating down?

    • Melchior Hof
      Melchior Hof Month ago

      We plan for our land to dig a lake up the hill of our land to store the solar energy of our intentional community in Spain.

    ORACLE'S CAVE Month ago +1

    Wow that's cool, I didn't even know this place existed,
    You said it was called Wales.. I'm gonna look it up to see if it's real.
    I'm from Scotland and I have never heard of a place called Wales in the UK

    • rfarevalo
      rfarevalo Month ago +2

      If you have yet to take your geography courses , here is my recommendation: Start by reading about the United Kingdom or U.K. You'll learn what countries make up the U.K. including one named Wales. If you are from Scotland you should probably know this information by the age of 12 years.

  • Augusto Amorim
    Augusto Amorim Month ago

    This concept is actually widely used in Brazil, as we have 90% of our electricity coming from hydroelectric powerplants. We also have 98.3% of electrical capacity in the country interconnected by a single grid. Dude, this is a lot when you take into consideration the dimentions of Brazil. This grid is controlled by the Natonal Systems Operator (ONS) and they have protocols for almost every problem of supply and demand possible. I've already been there in Brasília. They control hydroelectric capacity at the many powerplants of the coutry to ensure equilibrium, from the Amazon rainforest, Northern region, to the South Pampas.

  • David Learmonth
    David Learmonth Month ago +1

    Just curious in these systems what efficiency do they realize? For 1 MWh of electricity used to pump water, how much can be later recovered?

  • Max Bustos
    Max Bustos Month ago

    oops I mistook you for Tom Ska

  • UXXV
    UXXV Month ago

    I reckon if this had a better title it would get more views. I watch everything anyway and was pleasantly surprised about a crazy power station pump station hiding in an Austin Powers lair

  • Sneaky Gweilo!
    Sneaky Gweilo! Month ago

    Very well filmed, on par with a TV show/or better than a news segment

  • Raider
    Raider Month ago

    Does it take less energy to pump the water back up than it makes?

    • woodfur00
      woodfur00 Month ago

      Raider No, but it's less expensive at a different time of day.

  • Joshua Carnes
    Joshua Carnes Month ago

    That's awesome. We have one of these here in Massachusetts too, at Northfield Mountain.

  • Mackk
    Mackk Month ago

    That's really cool. Thanks for the vid!

  • Jens Jensen
    Jens Jensen Month ago

    practical engineering channel has done a lot of cool videos on water hammer

  • Alessandro Damario
    Alessandro Damario Month ago

    Isnt a battery chemical energy?

  • Anudeep R
    Anudeep R Month ago

    Woah the quality just had a massive increase

  • Brandon Neely
    Brandon Neely Month ago

    How the hell are these videos so entertaining. Literally always happy to watch one.

  • Dominic Savage
    Dominic Savage Month ago

    Thank you Tom for making the techdif intro so load and prominent that when I fall asleep watching some science stuff and youtube autoplay, as it somehow always does, gets me to techdif after 20mins- half an hour it wakes me up to tell me to turn my pc off, or more likely watch another hour of techdif repeats

  • Draconicrose Gaming

    How the hell did they build that?!

  • jehugarcia
    jehugarcia Month ago

    Hell yeah, huge battery, and kind of never degrades as long as you maintain the mechanicals and the water level.

  • richard Walker
    richard Walker Month ago

    Bout time u covered this topic

  • MrVTNsalo
    MrVTNsalo Month ago

    this actually could help a lot with the swan curve and move use closer to green energy

  • Peter Jensen
    Peter Jensen Month ago

    Check our Practical Engineering's video about water hammer. His small version is just like this scenario.

  • tanklord99 da boss
    tanklord99 da boss Month ago

    2:43 Jurassic park be like...

  • Ashley Blackwater
    Ashley Blackwater Month ago

    Isn't pumping that water back up just wasting more energy than it creates?

  • Prayank Lalan
    Prayank Lalan Month ago

    This comment is an 'ad' for another comment I made on this video. Please 'like' it to help it serve its purpose! ;P :)

  • MadTeeJay
    MadTeeJay Month ago

    I went through here on a tour. Its actually really huge inside.

  • Reclusive Eagle
    Reclusive Eagle Month ago +1

    Why don't they just add a pipe from the bottom to the top so when the water pressure increases from the flow the added pressure helps push water back up refilling its self to a point? Will probably add 15-25% more power generation that way.

    • rfarevalo
      rfarevalo Month ago

      NO. The solution doesn't work that way.

  • Jon Harris
    Jon Harris Month ago

    I'd love to know more about the pump design for refilling the upper reservoir and what the difference in electricity produced / energy consumed to refill the upper reservoir. I wondered if it incorporated anything like a siphon that would reduce the power required.
    Cool video!