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  • For a few hours in May 2016, for the first time in more than a century,

  • Britain was burning zero coal to generate electricity.

  • None at all.

  • All the coal-fired power plants were turned off.

  • And this here is one of the reasons why.

  • Welcome to the Griffin Wind Farm in Scotland.

  • 68 turbines, more than 150 megawatts of capacity.

  • And the turbines rotate and trim the blades to track the wind in real time.

  • At full output, this can power entire cities just from the wind.

  • But as the world moves to renewable energy,

  • we've got a little bit of a problem.

  • Because coal, oil, gas, and nuclear stations are basically just giant boilers.

  • They take water, they heat it up, that turns to steam,

  • the steam gets forced through a massive turbine which rotates and generates power.

  • When I say turbine, I don't mean like the blades here,

  • I mean hundreds of tonnes of steel rotating thousands of times a minute.

  • And all those turbines, all around the grid,

  • rotate in sync with each other.

  • After gearing, they all move at 50 cycles a second.

  • 60 in America.

  • All perfectly in time: one slows down, they all slow down.

  • One speeds up, they all speed up.

  • And that is what stops your lights from constantly flickering.

  • Because electricity supply has to always match demand, pretty much exactly.

  • There isn't a battery in the world big enough to store power on a national scale.

  • So if a power station suddenly falls off the grid for some reason,

  • then where's that supply going to come from?

  • And the answer is the kinetic energy that's already in those turbines,

  • in that spinning thousands of tonnes of steel around the country.

  • Homes and factories will literally suck the kinetic energy out of that turbine

  • to cover the gap, starting to slow it down.

  • But that won't cause a problem for 60 seconds or so,

  • and in that time the National Grid Control Centre will, I don't know,

  • throw another nuclear rod on the barbie

  • and up the power output from other stations. They'll cover the demand.

  • But, well, that relies on having enough rotational mass,

  • enough system inertia, as it's called.

  • And here, in this turbine?

  • Well, you can see.

  • There's no hundreds of tonnes of spinning steel,

  • just some blades, a bit of metal,

  • and some circuitry that feeds the power into the grid at the right frequency.

  • If the whole grid were running on just wind and solar,

  • there's no rotational mass. There's no grid stability.

  • The minute that supply and demand mismatch, breakers would trip,

  • and the whole thing would fall apart.

  • Now there are some possible solutions to this.

  • Pumped hydro storage has been around for a while,

  • which is where you have two lakes at different heights.

  • When you've got too much power, you pump water up,

  • and when you've got not enough, you drop it back down again through generators.

  • But that takes seconds or minutes to kick in.

  • There's also some experiments going on with things like molten glass storage,

  • compressed air storage, and flywheels,

  • but they're all experimental at the minute and not particularly efficient.

  • The actual solution may come from somewhere a little unexpected.

  • Because yes, wind is replacing coal and oil,

  • but it's also replacing petrol, the gasoline that you put in your car.

  • And as more and more and electric cars get connected to the grid, well,

  • you've got a load of quite large batteries with computers.

  • Your car could sell power back to the grid in real-time,

  • second by second, as it's needed.

  • Combine that with smart appliances and meters that can watch the grid

  • and work out when would be the best time to turn on your air-conditioning and fridge is,

  • and you have a grid that does a lot of the balancing itself.

  • Yes, we will probably always need a turbine somewhere,

  • some big spinning mass of steel to cover the little glitches second to second,

  • but the solution to balancing a power grid is not what we thought it was 20 years ago.

  • It's not big, monolithic batteries.

  • It's millions of small ones up and down the country.

  • Thank you very much to all the team from SSE

  • who have helped get me, and my team, up on top of this wind turbine.

  • I am incredibly grateful.

  • They have gone above and beyond to help out, so please,

  • have a look at the links in the description for more about them,

  • and about the Griffin Wind Farm.

  • [Translating these subtitles? Add your name here!]

For a few hours in May 2016, for the first time in more than a century,


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再生可能エネルギーの問題点(どうやって直しているのか (The Problem With Renewable Energy (and how we're fixing it))

  • 4 1
    林宜悉 に公開 2021 年 01 月 14 日