A reality check on renewables
-
0:00 - 0:03When the Industrial Revolution started,
-
0:03 - 0:05the amount of carbon sitting underneath
-
0:05 - 0:09Britain in the form of coal was as big as the amount
-
0:09 - 0:13of carbon sitting under Saudi Arabia in the form of oil,
-
0:13 - 0:16and this carbon powered the Industrial Revolution,
-
0:16 - 0:18it put the "Great" in Great Britain,
-
0:18 - 0:22and led to Britain's temporary world domination.
-
0:22 - 0:26And then, in 1918, coal production in Britain peaked,
-
0:26 - 0:28and has declined ever since.
-
0:28 - 0:31In due course, Britain started using oil and gas
-
0:31 - 0:35from the North Sea, and in the year 2000,
-
0:35 - 0:37oil and gas production from the North Sea
-
0:37 - 0:42also peaked, and they're now on the decline.
-
0:42 - 0:45These observations about the finiteness of
-
0:45 - 0:48easily accessible, local, secure fossil fuels,
-
0:48 - 0:52this is a motivation for saying, "Well, what's next?
-
0:52 - 0:55What is life after fossil fuels going to be like?
-
0:55 - 0:57Shouldn't we be thinking hard about
-
0:57 - 0:59how to get off fossil fuels?"
-
0:59 - 1:02Another motivation, of course, is climate change.
-
1:02 - 1:05And when people talk about life after fossil fuels
-
1:05 - 1:08and climate change action, I think there's a lot of
-
1:08 - 1:12fluff, a lot of greenwash, a lot of misleading advertising,
-
1:12 - 1:15and I feel a duty as a physicist to try to
-
1:15 - 1:17guide people around the claptrap and help people
-
1:17 - 1:20understand the actions that really make a difference
-
1:20 - 1:25and to focus on ideas that do add up.
-
1:25 - 1:28Let me illustrate this with what physicists call
-
1:28 - 1:30a back-of-envelope calculation.
-
1:30 - 1:32We love back-of-envelope calculations.
-
1:32 - 1:34You ask a question, you write down some numbers,
-
1:34 - 1:35and you get yourself an answer.
-
1:35 - 1:38It may not be very accurate, but it may make you say,
-
1:38 - 1:38"Hmm."
-
1:38 - 1:41So here's a question: Imagine if
-
1:41 - 1:43we said, "Oh yes, we can get off fossil fuels.
-
1:43 - 1:45We'll use biofuels. Problem solved.
-
1:45 - 1:47Transport, we don't need oil anymore."
-
1:47 - 1:53Well, what if we grew the biofuels for a road
-
1:53 - 1:57on the grass verge at the edge of the road?
-
1:57 - 2:01How wide would the verge have to be for that to work out?
-
2:01 - 2:03Okay, so let's put in some numbers.
-
2:03 - 2:06Let's have our cars go at 60 miles per hour.
-
2:06 - 2:08Let's say they do 30 miles per gallon.
-
2:08 - 2:11That's the European average for new cars.
-
2:11 - 2:13Let's say the productivity of biofuel plantations
-
2:13 - 2:16is 1,200 litres of biofuel per hectare per year.
-
2:16 - 2:19That's true of European biofuels.
-
2:19 - 2:22And let's imagine the cars are spaced 80 meters
-
2:22 - 2:24apart from each other, and they're just perpetually going
-
2:24 - 2:25along this road.
-
2:25 - 2:27The length of the road doesn't matter, because the longer
-
2:27 - 2:30the road, the more biofuel plantation we've got.
-
2:30 - 2:31What do we do with these numbers?
-
2:31 - 2:33Well, you take the first number, and you divide by
-
2:33 - 2:35the other three, and you get eight kilometers.
-
2:35 - 2:36And that's the answer.
-
2:36 - 2:39That's how wide the plantation would have to be,
-
2:39 - 2:41given these assumptions.
-
2:41 - 2:44And maybe that makes you say, "Hmm.
-
2:44 - 2:48Maybe this isn't going to be quite so easy."
-
2:48 - 2:51And it might make you think, perhaps there's an issue
-
2:51 - 2:54to do with areas, and in this talk,
-
2:54 - 2:57I'd like to talk about land areas, and ask,
-
2:57 - 3:00is there an issue about areas? The answer is going to be
-
3:00 - 3:03yes but it depends which country you are in.
-
3:03 - 3:05So let's start in the United Kingdom,
-
3:05 - 3:07since that's where we are today.
-
3:07 - 3:10The energy consumption of the United Kingdom,
-
3:10 - 3:14the total energy consumption, not just transport, but everything,
-
3:14 - 3:16I like to quantify it in light bulbs.
-
3:16 - 3:20It's as if we've all got 125 light bulbs on all the time,
-
3:20 - 3:23125 kilowatt-hours per day per person
-
3:23 - 3:27is the energy consumption of the U.K.
-
3:27 - 3:29So there's 40 light bulbs' worth for transport,
-
3:29 - 3:3140 light bulbs' worth for heating,
-
3:31 - 3:34and 40 light bulbs' worth for making electricity,
-
3:34 - 3:35and other things are relatively small
-
3:35 - 3:38compared to those three big fish.
-
3:38 - 3:41It's actually a bigger footprint if we take into account
-
3:41 - 3:43the embodied energy in the stuff we import
-
3:43 - 3:47into our country as well, and 90 percent of this energy today
-
3:47 - 3:51still comes from fossil fuels, and 10 percent only
-
3:51 - 3:53from other, greener -- possibly greener -- sources
-
3:53 - 3:56like nuclear power and renewables.
-
3:56 - 3:57So,
-
3:57 - 4:01that's the U.K., and the population density of the U.K.
-
4:01 - 4:04is 250 people per square kilometer,
-
4:04 - 4:06and I'm now going to show you other countries
-
4:06 - 4:07by these same two measures.
-
4:07 - 4:09On the vertical axis, I'm going to show you
-
4:09 - 4:12how much light bulbs -- what our energy consumption
-
4:12 - 4:15per person is, and we're at 125 light bulbs per person,
-
4:15 - 4:18and that little blue dot there is showing you the land area
-
4:18 - 4:20of the United Kingdom,
-
4:20 - 4:23and the population density is on the horizontal axis,
-
4:23 - 4:26and we're 250 people per square kilometer.
-
4:26 - 4:28Let's add European countries in blue,
-
4:28 - 4:31and you can see there's quite a variety.
-
4:31 - 4:33I should emphasize, both of these axes
-
4:33 - 4:35are logarithmic. As you go from one gray bar
-
4:35 - 4:39to the next gray bar you're going up a factor of 10.
-
4:39 - 4:42Next, let's add Asia in red,
-
4:42 - 4:45the Middle East and North Africa in green,
-
4:45 - 4:49sub-Saharan Africa in blue,
-
4:49 - 4:52black is South America,
-
4:52 - 4:55purple is Central America,
-
4:55 - 4:58and then in pukey-yellow, we have North America,
-
4:58 - 5:00Australia and New Zealand.
-
5:00 - 5:03And you can see the great diversity of population densities
-
5:03 - 5:06and of per capita consumptions.
-
5:06 - 5:08Countries are different from each other.
-
5:08 - 5:11Top left, we have Canada and Australia, with enormous
-
5:11 - 5:14land areas, very high per capita consumption,
-
5:14 - 5:16200 or 300 light bulbs per person,
-
5:16 - 5:20and very low population densities.
-
5:20 - 5:23Top right, Bahrain has the same energy consumption
-
5:23 - 5:25per person, roughly, as Canada,
-
5:25 - 5:28over 300 light bulbs per person,
-
5:28 - 5:31but their population density is a factor of 300 times greater,
-
5:31 - 5:321,000 people per square kilometer.
-
5:32 - 5:36Bottom right, Bangladesh has the same population density
-
5:36 - 5:41as Bahrain but consumes 100 times less per person.
-
5:41 - 5:44Bottom left, well, there's no one.
-
5:44 - 5:46But there used to be a whole load of people.
-
5:46 - 5:47Here's another message from this diagram.
-
5:47 - 5:51I've added on little blue tails behind Sudan, Libya,
-
5:51 - 5:52China, India, Bangladesh.
-
5:52 - 5:55That's 15 years of progress.
-
5:55 - 5:57Where were they 15 years ago, and where are they now?
-
5:57 - 6:00And the message is, most countries are going to the right,
-
6:00 - 6:01and they're going up,
-
6:01 - 6:03up and to the right -- bigger population density
-
6:03 - 6:05and higher per capita consumption.
-
6:05 - 6:08So, we may be off in the top right-hand corner,
-
6:08 - 6:11slightly unusual, the United Kingdom accompanied by
-
6:11 - 6:14Germany, Japan, South Korea, the Netherlands,
-
6:14 - 6:16and a bunch of other slightly odd countries,
-
6:16 - 6:18but many other countries are coming up
-
6:18 - 6:20and to the right to come and join us,
-
6:20 - 6:24so we're a picture, if you like, of what the future energy
-
6:24 - 6:28consumption might be looking like in other countries too.
-
6:28 - 6:32And I've also added in this diagram now some pink lines
-
6:32 - 6:34that go down and to the right.
-
6:34 - 6:36Those are lines of equal power consumption
-
6:36 - 6:40per unit area, which I measure in watts per square meter.
-
6:40 - 6:41So, for example, the middle line there,
-
6:41 - 6:450.1 watts per square meter, is the energy consumption
-
6:45 - 6:49per unit area of Saudi Arabia, Norway, Mexico in purple,
-
6:49 - 6:53and Bangladesh 15 years ago,
-
6:53 - 6:56and half of the world's population lives in countries
-
6:56 - 7:00that are already above that line.
-
7:00 - 7:03The United Kingdom is consuming 1.25
-
7:03 - 7:05watts per square meter.
-
7:05 - 7:09So's Germany, and Japan is consuming a bit more.
-
7:09 - 7:12So, let's now
-
7:12 - 7:14say why this is relevant. Why is it relevant?
-
7:14 - 7:18Well, we can measure renewables in the same units
-
7:18 - 7:20and other forms of power production in the same units,
-
7:20 - 7:23and renewables is one of the leading ideas for
-
7:23 - 7:28how we could get off our 90 percent fossil fuel habit.
-
7:28 - 7:29So here come some renewables.
-
7:29 - 7:32Energy crops deliver half a watt per square meter
-
7:32 - 7:34in European climates.
-
7:34 - 7:37What does that mean? And you might have anticipated
-
7:37 - 7:39that result, given what I told you about the biofuel plantation
-
7:39 - 7:41a moment ago.
-
7:41 - 7:44Well, we consume 1.25 watts per square meter.
-
7:44 - 7:45What this means is, even if you covered
-
7:45 - 7:48the whole of the United Kingdom with energy crops,
-
7:48 - 7:52you couldn't match today's energy consumption.
-
7:52 - 7:54Wind power produces a bit more,
-
7:54 - 7:572.5 watts per square meter, but that's only twice as big
-
7:57 - 8:01as 1.25 watts per square meter,
-
8:01 - 8:04so that means if you wanted literally to produce total
-
8:04 - 8:06energy consumption in all forms on average from
-
8:06 - 8:11wind farms, you need wind farms half the area of the U.K.
-
8:11 - 8:15I've got data to back up all these assertions, by the way.
-
8:15 - 8:18Next, let's look at solar power.
-
8:18 - 8:20Solar panels, when you put them on a roof,
-
8:20 - 8:26deliver about 20 watts per square meter in England.
-
8:26 - 8:28If you really want to get a lot from solar panels,
-
8:28 - 8:31you need to adopt the traditional Bavarian farming method
-
8:31 - 8:33where you leap off the roof and coat the countryside
-
8:33 - 8:35with solar panels too.
-
8:35 - 8:37Solar parks, because of the gaps between the panels,
-
8:37 - 8:39deliver less. They deliver about 5 watts
-
8:39 - 8:42per square meter of land area.
-
8:42 - 8:44And here's a solar park in Vermont with real data
-
8:44 - 8:48delivering 4.2 watts per square meter.
-
8:48 - 8:51Remember where we are, 1.25 watts per square meter,
-
8:51 - 8:55wind farms 2.5, solar parks about five.
-
8:55 - 8:58So, whatever, whichever of those renewables you pick,
-
8:58 - 9:01the message is, whatever mix of those renewables
-
9:01 - 9:04you're using, if you want to power the U.K. on them,
-
9:04 - 9:06you're going to need to cover something like
-
9:06 - 9:0920 percent or 25 percent of the country
-
9:09 - 9:11with those renewables.
-
9:11 - 9:12And I'm not saying that's a bad idea.
-
9:12 - 9:14We just need to understand the numbers.
-
9:14 - 9:16I'm absolutely not anti-renewables. I love renewables.
-
9:16 - 9:21But I'm also pro-arithmetic. (Laughter)
-
9:21 - 9:23Concentrating solar power in deserts delivers
-
9:23 - 9:25larger powers per unit area, because you don't have
-
9:25 - 9:27the problem of clouds,
-
9:27 - 9:30and so this facility delivers 14 watts per square meter,
-
9:30 - 9:32this one 10 watts per square meter,
-
9:32 - 9:35and this one in Spain 5 watts per square meter.
-
9:35 - 9:37Being generous to concentrating solar power,
-
9:37 - 9:40I think it's perfect credible it could deliver 20 watts
-
9:40 - 9:42per square meter. So that's nice.
-
9:42 - 9:45Of course, Britain doesn't have any deserts.
-
9:45 - 9:48Yet. (Laughter)
-
9:48 - 9:51So here's a summary so far.
-
9:51 - 9:54All renewables, much as I love them, are diffuse.
-
9:54 - 9:56They all have a small power per unit area,
-
9:56 - 9:58and we have to live with that fact.
-
9:58 - 10:02And that means, if you do want renewables
-
10:02 - 10:04to make a substantial difference for a country like
-
10:04 - 10:07the United Kingdom on the scale of today's consumption,
-
10:07 - 10:10you need to be imagining renewable facilities
-
10:10 - 10:13that are country-sized, not the entire country
-
10:13 - 10:17but a fraction of the country, a substantial fraction.
-
10:17 - 10:20There are other options for generating power as well
-
10:20 - 10:22which don't involve fossil fuels.
-
10:22 - 10:25So there's nuclear power, and on this Ordnance
-
10:25 - 10:26Survey map, you can see there's a Sizewell B
-
10:26 - 10:29inside a blue square kilometer.
-
10:29 - 10:31That's one gigawatt in a square kilometer,
-
10:31 - 10:33which works out to 1,000 watts per square meter.
-
10:33 - 10:36So by this particular metric, nuclear power
-
10:36 - 10:41isn't as intrusive as renewables.
-
10:41 - 10:44Of course, other metrics matter too, and nuclear power
-
10:44 - 10:46has all sorts of popularity problems.
-
10:46 - 10:48But the same goes for renewables as well.
-
10:48 - 10:51Here's a photograph of a consultation exercise in full swing
-
10:51 - 10:54in the little town of Penicuik just outside Edinburgh,
-
10:54 - 10:56and you can see the children of Penicuik celebrating
-
10:56 - 10:59the burning of the effigy of the windmill.
-
10:59 - 11:04So people are anti-everything, and we've got to keep
-
11:04 - 11:06all the options on the table.
-
11:06 - 11:10What can a country like the U.K. do on the supply side?
-
11:10 - 11:13Well, the options are, I'd say, these three:
-
11:13 - 11:16power renewables, and recognizing that they need to be
-
11:16 - 11:19close to country-sized; other people's renewables,
-
11:19 - 11:22so we could go back and talk very politely to the people
-
11:22 - 11:24in the top left-hand side of the diagram and say,
-
11:24 - 11:26"Uh, we don't want renewables in our backyard,
-
11:26 - 11:29but, um, please could we put them in yours instead?"
-
11:29 - 11:31And that's a serious option.
-
11:31 - 11:34It's a way for the world to handle this issue.
-
11:34 - 11:39So countries like Australia, Russia, Libya, Kazakhstan,
-
11:39 - 11:43could be our best friends for renewable production.
-
11:43 - 11:45And a third option is nuclear power.
-
11:45 - 11:48So that's some supply side options.
-
11:48 - 11:51In addition to the supply levers that we can push,
-
11:51 - 11:53and remember, we need large amounts,
-
11:53 - 11:54because at the moment,
-
11:54 - 11:56we get 90 percent of our energy from fossil fuels.
-
11:56 - 11:59In addition to those levers, we could talk about other ways
-
11:59 - 12:02of solving this issue, namely, we could reduce demand,
-
12:02 - 12:04and that means reducing population
-
12:04 - 12:06— I'm not sure how to do that —
-
12:06 - 12:09or reducing per capita consumption.
-
12:09 - 12:12So let's talk about three more big levers
-
12:12 - 12:14that could really help on the consumption side.
-
12:14 - 12:16First, transport. Here are the physics principles that tell you
-
12:16 - 12:19how to reduce the energy consumption of transport,
-
12:19 - 12:22and people often say, "Oh, yes, technology can answer everything.
-
12:22 - 12:24We can make vehicles that are a hundred times more
-
12:24 - 12:26efficient." And that's almost true. Let me show you.
-
12:26 - 12:29The energy consumption of this typical tank here
-
12:29 - 12:33is 80 kilowatt-hours per hundred person kilometers.
-
12:33 - 12:37That's the average European car.
-
12:37 - 12:39Eighty kilowatt-hours. Can we make something a hundred times
-
12:39 - 12:42better by applying those physics principles I just listed?
-
12:42 - 12:47Yes. Here it is. It's the bicycle. It's 80 times better in energy
-
12:47 - 12:50consumption, and it's powered by biofuel, by Weetabix.
-
12:50 - 12:52(Laughter)
-
12:52 - 12:54And there are other options in between, because maybe
-
12:54 - 12:55the lady in the tank would say, "No, no, no,
-
12:55 - 12:58that's a lifestyle change. Don't change my lifestyle, please."
-
12:58 - 13:01So, well, we could persuade her to get into a train,
-
13:01 - 13:03and that's still a lot more efficient than a car,
-
13:03 - 13:04but that might be a lifestyle change,
-
13:04 - 13:05or there's the eco-car, top-left.
-
13:05 - 13:07It comfortably accommodates one teenager
-
13:07 - 13:09and it's shorter than a traffic cone,
-
13:09 - 13:11and it's almost as efficient as a bicycle
-
13:11 - 13:15as long as you drive it at 15 miles per hour.
-
13:15 - 13:17In between, perhaps some more realistic options
-
13:17 - 13:20on this lever, transport lever, are electric vehicles,
-
13:20 - 13:23so electric bikes and electric cars in the middle,
-
13:23 - 13:25perhaps four times as energy efficient
-
13:25 - 13:29as the standard petrol-powered tank.
-
13:29 - 13:31Next, there's the heating lever.
-
13:31 - 13:34Heating is a third of our energy consumption in Britain,
-
13:34 - 13:36and quite a lot of that is going into homes
-
13:36 - 13:39and other buildings doing space heating and water heating.
-
13:39 - 13:42So here's a typical crappy British house.
-
13:42 - 13:46It's my house, with the Ferrari out front.
-
13:46 - 13:47What can we do to it?
-
13:47 - 13:50Well, the laws of physics are written up there,
-
13:50 - 13:55which describe what -- how the power consumption
-
13:55 - 13:58for heating is driven by the things you can control.
-
13:58 - 14:00The things you can control are the temperature difference
-
14:00 - 14:02between the inside and the outside, and there's this
-
14:02 - 14:04remarkable technology called a thermostat.
-
14:04 - 14:06You grasp it, you rotate it to the left,
-
14:06 - 14:09and your energy consumption in the home will decrease.
-
14:09 - 14:13I've tried it. It works. Some people call it a lifestyle change.
-
14:13 - 14:17You can also get the fluff men in to reduce the leakiness
-
14:17 - 14:19of your building -- put fluff in the walls, fluff in the roof,
-
14:19 - 14:22and a new front door and so forth,
-
14:22 - 14:26and the sad truth is, this will save you money.
-
14:26 - 14:28That's not sad, that's good, but the sad truth is, it'll only
-
14:28 - 14:32get about 25 percent of the leakiness of your building,
-
14:32 - 14:34if you do these things, which are good ideas.
-
14:34 - 14:37If you really want to get a bit closer to Swedish
-
14:37 - 14:39building standards with a crappy house like this,
-
14:39 - 14:43you need to be putting external insulation on the building
-
14:43 - 14:47as shown by this block of flats in London.
-
14:47 - 14:50You can also deliver heat more efficiently using heat pumps
-
14:50 - 14:53which use a smaller bit of high grade energy like electricity
-
14:53 - 14:56to move heat from your garden into your house.
-
14:56 - 14:59The third demand side option I want to talk about,
-
14:59 - 15:00the third way to reduce energy consumption is,
-
15:00 - 15:02read your meters.
-
15:02 - 15:04And people talk a lot about smart meters,
-
15:04 - 15:05but you can do it yourself.
-
15:05 - 15:08Use your own eyes and be smart, read your meter,
-
15:08 - 15:11and if you're anything like me, it'll change your life.
-
15:11 - 15:12Here's a graph I made.
-
15:12 - 15:15I was writing a book about sustainable energy,
-
15:15 - 15:17and a friend asked me, "Well how much energy do you use
-
15:17 - 15:19at home?" And I was embarrassed. I didn't actually know.
-
15:19 - 15:22And so I started reading the meter every week,
-
15:22 - 15:24and the old meter readings are shown
-
15:24 - 15:26in the top half of the graph, and then 2007
-
15:26 - 15:28is shown in green at the bottom, and that was when
-
15:28 - 15:31I was reading the meter every week, and my life changed,
-
15:31 - 15:34because I started doing experiments and seeing
-
15:34 - 15:36what made a difference, and my gas consumption
-
15:36 - 15:37plummeted because I started tinkering
-
15:37 - 15:39with the thermostat and the timing on the heating system,
-
15:39 - 15:42and I knocked more than a half off my gas bills.
-
15:42 - 15:45There's a similar story for my electricity consumption,
-
15:45 - 15:49where switching off the DVD players, the stereos,
-
15:49 - 15:52the computer peripherals that were on all the time,
-
15:52 - 15:54and just switching them on when I needed them,
-
15:54 - 15:58knocked another third off my electricity bills too.
-
15:58 - 16:01So we need a plan that adds up, and I've described for you
-
16:01 - 16:04six big levers, and we need big action because we get
-
16:04 - 16:0690 percent of our energy from fossil fuels,
-
16:06 - 16:11and so you need to push hard on most if not all of these levers.
-
16:11 - 16:14And most of these levers have popularity problems,
-
16:14 - 16:17and if there is a lever you don't like the use of,
-
16:17 - 16:19well please do bear in mind that means you need
-
16:19 - 16:23even stronger effort on the other levers.
-
16:23 - 16:26So I'm a strong advocate of having grown-up conversations
-
16:26 - 16:30that are based on numbers and facts, and I want to close
-
16:30 - 16:32with this map that just visualizes for you
-
16:32 - 16:37the requirement of land and so forth in order to get
-
16:37 - 16:39just 16 light bulbs per person
-
16:39 - 16:42from four of the big possible sources.
-
16:42 - 16:46So, if you wanted to get 16 light bulbs, remember,
-
16:46 - 16:50today our total energy consumption is 125 light bulbs' worth.
-
16:50 - 16:54If you wanted 16 from wind, this map visualizes a solution
-
16:54 - 16:56for the U.K. It's got 160 wind farms,
-
16:56 - 16:59each 100 square kilometers in size,
-
16:59 - 17:01and that would be a twentyfold increase
-
17:01 - 17:03over today's amount of wind.
-
17:03 - 17:06Nuclear power, to get 16 light bulbs per person, you'd need
-
17:06 - 17:09two gigawatts at each of the purple dots on the map.
-
17:09 - 17:11That's a fourfold increase
-
17:11 - 17:14over today's levels of nuclear power.
-
17:14 - 17:17Biomass, to get 16 light bulbs per person, you'd need
-
17:17 - 17:21a land area something like three and a half Wales' worth,
-
17:21 - 17:24either in our country, or in someone else's country,
-
17:24 - 17:27possibly Ireland, possibly somewhere else. (Laughter)
-
17:27 - 17:30And a fourth supply side option, concentrating solar power
-
17:30 - 17:32in other people's deserts,
-
17:32 - 17:35if you wanted to get 16 light bulbs' worth,
-
17:35 - 17:38then we're talking about these eight hexagons
-
17:38 - 17:39down at the bottom right.
-
17:39 - 17:41The total area of those hexagons
-
17:41 - 17:46is two Greater London's worth of someone else's Sahara,
-
17:46 - 17:47and you'll need power lines all the way across Spain
-
17:47 - 17:53and France to bring the power from the Sahara to Surrey.
-
17:53 - 17:56We need a plan that adds up.
-
17:56 - 18:00We need to stop shouting and start talking,
-
18:00 - 18:04and if we can have a grown-up conversation,
-
18:04 - 18:07make a plan that adds up and get building,
-
18:07 - 18:08maybe this low-carbon revolution
-
18:08 - 18:11will actually be fun. Thank you very much for listening.
-
18:11 - 18:14(Applause)
- Title:
- A reality check on renewables
- Speaker:
- David MacKay
- Description:
-
How much land mass would renewables need to power a nation like the UK? An entire country's worth. In this pragmatic talk, David MacKay tours the basic mathematics that show worrying limitations on our sustainable energy options and explains why we should pursue them anyway. (Filmed at TEDxWarwick.)
- Video Language:
- English
- Team:
- closed TED
- Project:
- TEDTalks
- Duration:
- 18:35
Krystian Aparta commented on English subtitles for A reality check on renewables | ||
Krystian Aparta edited English subtitles for A reality check on renewables | ||
Krystian Aparta edited English subtitles for A reality check on renewables | ||
Thu-Huong Ha edited English subtitles for A reality check on renewables | ||
Thu-Huong Ha approved English subtitles for A reality check on renewables | ||
Thu-Huong Ha edited English subtitles for A reality check on renewables | ||
Morton Bast accepted English subtitles for A reality check on renewables | ||
Morton Bast edited English subtitles for A reality check on renewables |
Krystian Aparta
The English transcript was updated on 12/16/2016.