0:00:02 > 0:00:12This programme contains some strong language.
0:00:12 > 0:00:15The sun is 93 million miles away.
0:00:15 > 0:00:19And yet it can illuminate the surface of the Earth.
0:00:19 > 0:00:22You can fit a million Earths inside.
0:00:22 > 0:00:26The surface temperature is 6,000 degrees.
0:00:26 > 0:00:29At its core, it's 15 million degrees.
0:00:29 > 0:00:34It loses 4 million tons of mass every second.
0:00:34 > 0:00:37That mass is turned into energy and we feel it as heat.
0:00:39 > 0:00:43The sun is powered by the strongest force in the universe.
0:00:44 > 0:00:48And, as a physicist, I believe that our long term future depends on us
0:00:48 > 0:00:50learning to do the same.
0:00:57 > 0:01:00That's why, across the world, teams of engineers and scientists
0:01:00 > 0:01:03are stepping into the unknown.
0:01:03 > 0:01:06You are looking inside the Star Chamber.
0:01:06 > 0:01:09We're gonna discharge about 26 million amps.
0:01:09 > 0:01:15That little ball starts collapsing at a million miles an hour.
0:01:15 > 0:01:19They're all united in a single quest.
0:01:19 > 0:01:22So, it's about to get dangerous, so we'd better take off.
0:01:22 > 0:01:26It's the greatest engineering challenge that we have yet faced -
0:01:26 > 0:01:30to build a machine that will make a star on Earth.
0:01:53 > 0:01:58Sunrise, dawn. That moment when night becomes day that had
0:01:58 > 0:02:01an immense significance for our ancestors.
0:02:04 > 0:02:07The sun sets the rhythm for life on Earth.
0:02:07 > 0:02:11Each day it returns and the world awakens.
0:02:13 > 0:02:16I think in one way we lost that sense of
0:02:16 > 0:02:21significance of the sunrise in our modern, electrically-lit world.
0:02:21 > 0:02:24But, in another way, that's been replaced
0:02:24 > 0:02:26by modern science's understanding
0:02:26 > 0:02:31of the sun as a violent, majestic and massive object.
0:02:31 > 0:02:36And...as is often the way when you understand the true nature
0:02:36 > 0:02:41of something, then that's all the more reason to revere it.
0:02:44 > 0:02:47The sun bathes our planet in energy.
0:02:47 > 0:02:51It's so powerful that in just one second its light
0:02:51 > 0:02:56could supply the United States with energy for a million years.
0:02:56 > 0:02:59And hidden at its heart is the power source -
0:02:59 > 0:03:05all 385 million, million, million, million watts of it.
0:03:11 > 0:03:13It's a power source that lights up
0:03:13 > 0:03:17every one of the 100 billion stars in our galaxy.
0:03:20 > 0:03:22So the universe is awash
0:03:22 > 0:03:28with effectively limitless amounts of energy.
0:03:28 > 0:03:31Then you have to ask the question, is there a way of producing
0:03:31 > 0:03:36the energy that you need to run all this for everyone in the world,
0:03:36 > 0:03:39in a way that doesn't damage the planet?
0:03:39 > 0:03:43As a physicist, there is a way. In principle, there's a way.
0:03:43 > 0:03:46It's the same way that stars produce energy. It's nuclear fusion.
0:03:49 > 0:03:54Nuclear fusion is nature's power source, a process that has
0:03:54 > 0:04:00kept our sun burning without fail for five billion years and counting.
0:04:00 > 0:04:04The question I want to ask in this film is, is it possible that fusion
0:04:04 > 0:04:06is a power source for the future?
0:04:06 > 0:04:10Can a nuclear fusion power station be constructed? And can we do it
0:04:10 > 0:04:13sufficiently quickly that we can use it to address
0:04:13 > 0:04:17the pressing and serious energy crisis that we've got today?
0:04:23 > 0:04:24It sounds like science fiction.
0:04:24 > 0:04:28But in the heart of Oxfordshire, they've been busy lighting
0:04:28 > 0:04:32little stars for over 30 years.
0:04:32 > 0:04:36- So, what's the advantage of fusion? - Well, the chief advantage of fusion
0:04:36 > 0:04:40is probably it doesn't produce carbon dioxide, so no global warming gasses.
0:04:40 > 0:04:43'The Joint European Taurus, or JET,
0:04:43 > 0:04:48'is the world's largest experimental fusion reactor where each day
0:04:48 > 0:04:53'they initiate this beautifully simple nuclear reaction.'
0:04:53 > 0:04:55So it seems to me that, in principle,
0:04:55 > 0:04:58we have the ideal energy source.
0:04:58 > 0:04:59It couldn't be better, could it?
0:04:59 > 0:05:03It had one downside, that it's very hard to do.
0:05:03 > 0:05:06You had to create the conditions that are 10 times hotter than
0:05:06 > 0:05:10- the centre of the sun to initiate these reactions.- HAD, you said?
0:05:10 > 0:05:12But, right, we've done it -
0:05:12 > 0:05:15in the machine that you're about to look at.
0:05:18 > 0:05:25Seven, six, five, four, three, two, one.
0:05:25 > 0:05:28There it goes.
0:05:28 > 0:05:32'Scientists have learned how to create and hold star matter,
0:05:32 > 0:05:37'a cocktail of gasses heated to 100 million degrees.
0:05:37 > 0:05:42'For a moment, a little piece of the sun springs into life on earth.'
0:05:44 > 0:05:47It's amazing. So we're looking at the conditions,
0:05:47 > 0:05:50ten times the conditions that are present in the centre of the sun?
0:05:50 > 0:05:52They're ten times the temperature of the sun?
0:05:52 > 0:05:54- Absolutely.- In that reactor? - It's incredible
0:05:54 > 0:05:57and it goes on for all those seconds, you know, it's impressive.
0:05:57 > 0:06:00The remarkable thing is it seems routine.
0:06:00 > 0:06:03I'm sure there's a lot of work gone into making it routine.
0:06:03 > 0:06:06- Yeah.- That's my sense of this. - As people have got used to it.
0:06:06 > 0:06:09Of course, there are times when we actually put the real fuel in there
0:06:09 > 0:06:12and a shot like that will be producing lots of fusion power.
0:06:12 > 0:06:14Very exciting, when that happened.
0:06:15 > 0:06:19To this day, JET holds the world record for fusion power.
0:06:21 > 0:06:26Yet, despite decades of research and this fleeting glimpse of fusion,
0:06:26 > 0:06:29no electricity will ever make it from here to the grid.
0:06:33 > 0:06:36Learning how to produce useful power from fusion
0:06:36 > 0:06:39remains beyond our capabilities.
0:06:44 > 0:06:47One thing we do know is that, in nature,
0:06:47 > 0:06:51fusion only occurs in one place -
0:06:51 > 0:06:53right in the centre of stars.
0:06:53 > 0:06:57Vast celestial power houses, like our sun.
0:07:15 > 0:07:18The road to understanding the sun has been long.
0:07:19 > 0:07:23And it all began with a remarkable piece of deduction.
0:07:25 > 0:07:28So, how could you begin to find out what the sun's made of?
0:07:28 > 0:07:31I mean, you can't go there.
0:07:31 > 0:07:34It's a long long way away and it'd be a bit hot when you arrived.
0:07:34 > 0:07:39Well, actually, the story began back in the 1660s
0:07:39 > 0:07:41with the British physicist Isaac Newton.
0:07:41 > 0:07:45He used one of these, a prism, to look at the light from the sun.
0:07:45 > 0:07:50What Newton found is that if you look at light through a prism
0:07:50 > 0:07:56then it splits up into its component colours. It makes a rainbow.
0:07:56 > 0:08:00Now, at the time, Newton didn't appreciate the full significance
0:08:00 > 0:08:03of his discovery, or at least the usefulness of it.
0:08:03 > 0:08:06Through the 18th and 19th centuries, chemists and physicists
0:08:06 > 0:08:10looked at the light in real detail.
0:08:10 > 0:08:15And what they noticed was that the spectrum isn't continuous.
0:08:15 > 0:08:18It has pieces missing, it has black lines through it.
0:08:19 > 0:08:24This was a puzzle. Why was some of the sun's light missing?
0:08:26 > 0:08:29The answer is beautifully simple.
0:08:31 > 0:08:35Each chemical element in the sun absorbs light
0:08:35 > 0:08:38to produce its own unique pattern of black lines,
0:08:38 > 0:08:41known as absorption lines, in the solar spectrum.
0:08:41 > 0:08:46A kind of fingerprint for every element in the universe.
0:08:49 > 0:08:52That leaves you with an interesting possibility.
0:08:52 > 0:08:57If you look at the light from the sun and you look
0:08:57 > 0:08:59where the black lines are,
0:08:59 > 0:09:04then you can deduce exactly what elements are present in the sun.
0:09:06 > 0:09:10And today, from many precision observations of the light
0:09:10 > 0:09:12from the sun, using just this technique,
0:09:12 > 0:09:17we know that the sun is 75% hydrogen,
0:09:17 > 0:09:2324% helium and about 1% the heavier elements that make up the universe.
0:09:29 > 0:09:34Scientists had discovered what the sun and stars were made of.
0:09:34 > 0:09:38But they were no closer to figuring out how something
0:09:38 > 0:09:41made of the two lightest elements in the universe -
0:09:41 > 0:09:46hydrogen and helium - could emit such vast quantities of energy.
0:09:46 > 0:09:48Progress came with the discovery of one of
0:09:48 > 0:09:52the most famous equations in science.
0:09:54 > 0:09:57Now, it took until 1905 and Einstein
0:09:57 > 0:10:02for the key to the sun's energy source to be revealed.
0:10:02 > 0:10:04The equation E=MC2.
0:10:04 > 0:10:08Energy equals mass times the speed of light squared.
0:10:08 > 0:10:10Speed of light squared, immense number.
0:10:10 > 0:10:13It's got 16 noughts after it.
0:10:18 > 0:10:21This huge number means
0:10:21 > 0:10:26that only a small amount of mass contains vast amounts of energy.
0:10:26 > 0:10:30Einstein had uncovered a remarkable facet of nature.
0:10:30 > 0:10:34Mass is just an incredibly condensed form of energy.
0:10:38 > 0:10:42Imagine I took a dollar bill,
0:10:42 > 0:10:46that's about a gram, and converted that into pure energy.
0:10:46 > 0:10:49That is the mass lost in a hydrogen bomb.
0:10:49 > 0:10:56So there's one hydrogen bomb's worth of energy in every dollar bill.
0:10:58 > 0:11:04When Einstein first wrote down his famous equation, E=MC2,
0:11:04 > 0:11:08it wasn't realised at first that that was the key
0:11:08 > 0:11:11to understanding the power of the sun.
0:11:14 > 0:11:16It took another 15 years or so
0:11:16 > 0:11:19for the British scientist, Arthur Eddington, to...
0:11:19 > 0:11:22well, what seems like put two and two together.
0:11:22 > 0:11:24But that would be disrespectful to Eddington.
0:11:24 > 0:11:28He noticed a result that had again been known for many years.
0:11:28 > 0:11:31That if you take four hydrogen nuclei,
0:11:31 > 0:11:34like these rocks,
0:11:34 > 0:11:39and you can stick them together to make one thing, to make helium.
0:11:39 > 0:11:41And it was known that the helium weighed less.
0:11:41 > 0:11:47It was less massive than the four hydrogen nuclei on their own.
0:11:47 > 0:11:52Eddington suggested that the sun shines by combining hydrogen
0:11:52 > 0:11:57into helium, releasing the missing mass as energy.
0:11:59 > 0:12:02And in fact we now know that the sun loses
0:12:02 > 0:12:08about 4 million tons of mass every second as energy.
0:12:10 > 0:12:14Now, of course it wasn't clear at the time that Eddington was correct.
0:12:14 > 0:12:16But correct he turned out to be.
0:12:16 > 0:12:20What he'd actually discovered was the process that came to be known
0:12:20 > 0:12:22as nuclear fusion.
0:12:25 > 0:12:30When Eddington had suggested that fusion might be the process
0:12:30 > 0:12:33that powers the sun, it was pointed out to him that actually
0:12:33 > 0:12:37the centre of the sun was not hot enough for fusion to happen,
0:12:37 > 0:12:39as physicists understood the process at that time.
0:12:39 > 0:12:43What you actually need is an understanding of quantum mechanics
0:12:43 > 0:12:45and that didn't come until later.
0:12:45 > 0:12:46But Eddington was so sure of himself
0:12:46 > 0:12:51that he said, "To those who suggest that the centre of a star is not hot
0:12:51 > 0:12:57"enough for fusion to take place, I say go and find a hotter place."
0:12:57 > 0:13:00Which is a very polite, British way of saying, "Go to hell."
0:13:05 > 0:13:09Of course, no hotter place was found
0:13:09 > 0:13:14and Eddington's model for solar fusion was adopted and refined.
0:13:14 > 0:13:17But it left a big question -
0:13:17 > 0:13:21how on earth do you light a star in the first place?
0:13:26 > 0:13:27A drive-in movie theatre.
0:13:27 > 0:13:31Last time I saw one of these was in Grease
0:13:31 > 0:13:34with John Travolta and Olivia Newton-John.
0:13:38 > 0:13:42To find an answer, I've arranged to meet a Californian astronomer
0:13:42 > 0:13:47called Alex Filippenko who's going to take me back 13.5 billion years
0:13:47 > 0:13:51to a time before the stars ever existed.
0:13:54 > 0:13:57Remarkably, astronomers have been able to collect light from
0:13:57 > 0:14:03this time, just 380,000 years after the universe began at the Big Bang.
0:14:05 > 0:14:08Oh, wow. Here we're seeing the launch of WMAP.
0:14:08 > 0:14:10'A satellite called WMAP
0:14:10 > 0:14:15'was able to take a snapshot of the universe in its infancy.'
0:14:15 > 0:14:17The different colours, what do they represent?
0:14:17 > 0:14:19Yeah. The reds and blues
0:14:19 > 0:14:23signify slightly hotter than average and cooler than average regions.
0:14:23 > 0:14:27And those correspond with slight differences in density.
0:14:27 > 0:14:32'In the denser regions, the primeval constituents of the universe were
0:14:32 > 0:14:34'drawn together by gravity.'
0:14:35 > 0:14:39So the universe was, at the time of the WMAP image,
0:14:39 > 0:14:42- was hydrogen, helium? - Hydrogen and helium, that's it.
0:14:42 > 0:14:45Because during the Big Bang temperatures and pressures
0:14:45 > 0:14:49weren't high enough for very long to produce the heavier elements.
0:14:51 > 0:14:57'Over time the regions of hot, dense hydrogen and helium clumped together
0:14:57 > 0:15:03'to create huge stellar nurseries - ideal places for stars to form.'
0:15:03 > 0:15:06These slight little variations in the density
0:15:06 > 0:15:09led to regions that started collapsing, clouds of gas
0:15:09 > 0:15:13that started collapsing to form clusters of galaxies and galaxies.
0:15:13 > 0:15:17And then, within them, stars could form as well.
0:15:17 > 0:15:21'The first generation of stars lit up,
0:15:21 > 0:15:26'initiating fusion and bringing an end to the universe's Dark Age.'
0:15:26 > 0:15:29That would be a star there, would it, beginning to form?
0:15:29 > 0:15:32Yeah, that's right. You're seeing clumps of hydrogen and helium
0:15:32 > 0:15:36and then gravity, the great sculptor of the universe,
0:15:36 > 0:15:40causes these things to collapse, forming stars like this one.
0:15:53 > 0:15:57'Many of these first stars were giants,
0:15:57 > 0:16:00'hundreds of times more massive than the sun.'
0:16:02 > 0:16:04'They burnt their hydrogen fuel quickly
0:16:04 > 0:16:08'and died in supernova explosions.
0:16:08 > 0:16:12'They were the early chemical factories of the universe.
0:16:13 > 0:16:18'From just hydrogen and helium in the beginning, generations of stars
0:16:18 > 0:16:22'have created every element we're familiar with today.'
0:16:22 > 0:16:24The stars are the fusion reactors
0:16:24 > 0:16:28that produced the heavy elements of which we are made.
0:16:28 > 0:16:32I think it's a wonderful thought, because I look at my hand and
0:16:32 > 0:16:37that is... Well, it's red because there is iron in it and it's made
0:16:37 > 0:16:41- of carbon and oxygen and that stuff. - You're made of star stuff.
0:16:41 > 0:16:44Quite literally the heavy elements in your body -
0:16:44 > 0:16:46anything other than hydrogen and helium
0:16:46 > 0:16:51was produced inside of stars billions of years ago.
0:17:02 > 0:17:05We really are children of the stars,
0:17:05 > 0:17:10created by the simplest of nuclear reactions - fusion.
0:17:10 > 0:17:13And now that we understand this remarkable process
0:17:13 > 0:17:17it offers us a tantalizing prospect.
0:17:17 > 0:17:21If we could reproduce the energy generating process
0:17:21 > 0:17:26at the heart of the sun, if we could build a star on Earth,
0:17:26 > 0:17:31then our energy generation problems would be over for ever.
0:17:39 > 0:17:46For now, though, we continue to rely almost entirely on our sun.
0:17:54 > 0:18:01I suppose in a way our civilization runs off batteries.
0:18:01 > 0:18:06Over billions of years the sunlight has been captured
0:18:06 > 0:18:09by stuff like this. Then it's decayed away.
0:18:09 > 0:18:12And in places like this, on the San Andreas Fault,
0:18:12 > 0:18:17the geological conditions are just right to cook this
0:18:17 > 0:18:22into oil that we can then pump out of the ground and burn
0:18:22 > 0:18:27and take that condensed sunlight and use it to power our civilization.
0:18:30 > 0:18:35The energy from fossil fuels like coal, gas and the oil here
0:18:35 > 0:18:40in California have provided the power that built the modern world.
0:18:40 > 0:18:41All of it the result of biology and
0:18:41 > 0:18:47chemistry made possible thanks to the great fusion reactor in the sky.
0:18:50 > 0:18:52We thought we'd got lucky.
0:18:52 > 0:18:56We'd found a seemingly endless supply of energy.
0:19:01 > 0:19:06Here in the heart of oil country, I hooked up with physicist
0:19:06 > 0:19:09Rich Muller to chew over our dependence on the black stuff.
0:19:11 > 0:19:13I love this.
0:19:14 > 0:19:18What is our love affair with this substance, oil?
0:19:18 > 0:19:20Well, you know, I don't think of it
0:19:20 > 0:19:23so much as a love affair as a marriage.
0:19:23 > 0:19:25And a somewhat unhappy marriage.
0:19:25 > 0:19:29And we seek a divorce but the divorce is going to be expensive.
0:19:31 > 0:19:35It really is a very remarkable substance.
0:19:35 > 0:19:38It has enormous energy, enormous energy.
0:19:38 > 0:19:41So much more than even TNT or dynamite.
0:19:41 > 0:19:43It doesn't leave behind any residue.
0:19:43 > 0:19:47Unlike coal, you don't have to clear the ashes out of your car.
0:19:47 > 0:19:52All it does it is spew off this, what we used to call harmless gas,
0:19:52 > 0:19:54carbon dioxide, into the atmosphere.
0:19:55 > 0:20:00In terms of energy, it's got more energy than TNT and natural gas.
0:20:00 > 0:20:03More energy than these shotgun shells
0:20:03 > 0:20:05by a factor of almost a thousand.
0:20:09 > 0:20:13The incredible energy density of oil is part of the reason
0:20:13 > 0:20:15why fusion is not yet here.
0:20:17 > 0:20:20It's not simply that making the star is too difficult.
0:20:20 > 0:20:22It's also that we haven't had to
0:20:22 > 0:20:26because the sun has given us the black gold.
0:20:26 > 0:20:29It's such a wonderful thing.
0:20:29 > 0:20:33Only problem is... one, we're short of it.
0:20:33 > 0:20:36And so it leads to war in the Mid-East.
0:20:36 > 0:20:40And the second problem is, it does put out carbon dioxide
0:20:40 > 0:20:43and that very likely leads to global warming.
0:20:43 > 0:20:45GUNSHOT
0:20:45 > 0:20:48This is my new sport, man. I like this.
0:20:57 > 0:21:01Most of us on this planet, as we sit in our air-conditioned hotel rooms
0:21:01 > 0:21:05or at home watching TV, are still burning fossil fuels.
0:21:05 > 0:21:09As a result, the carbon dioxide we are releasing
0:21:09 > 0:21:12continues to warm the planet.
0:21:12 > 0:21:14Quite how this will change our world,
0:21:14 > 0:21:18and what this means for our civilisation, no one yet knows.
0:21:20 > 0:21:24But what's strange is even though we do know our demand for energy
0:21:24 > 0:21:27is unbalancing the climate, the world cannot agree
0:21:27 > 0:21:30on how our species should power the homes,
0:21:30 > 0:21:33factories and farms of the future.
0:21:35 > 0:21:39In search of an answer I've come to San Francisco,
0:21:39 > 0:21:42to the headquarters of a wind power research company,
0:21:42 > 0:21:43to meet its chief engineer.
0:21:45 > 0:21:49I met Saul Griffith about a year ago, and I wanted to talk to him
0:21:49 > 0:21:52in this film because he's one of the few people I've met
0:21:52 > 0:21:55that takes the emotion out of the energy debate.
0:21:55 > 0:21:59He just speaks in raw facts and figures.
0:21:59 > 0:22:03And he's got an office in a control tower on a disused military base
0:22:03 > 0:22:04which is...
0:22:06 > 0:22:08Here we are on this finite
0:22:08 > 0:22:11little bowl that's spinning through the universe.
0:22:11 > 0:22:16There is a limit to how much power per square metre we can get.
0:22:16 > 0:22:18We shouldn't be afraid of that limit,
0:22:18 > 0:22:20but we should certainly try to operate within it.
0:22:20 > 0:22:22Let's as quickly as possible
0:22:22 > 0:22:28get the debate about energy away from emotional and qualitative and polar bear issues,
0:22:28 > 0:22:30and to a very rational,
0:22:30 > 0:22:32"what do we have to do, how do we get this done?"
0:22:32 > 0:22:35Saul's response was to begin at home.
0:22:35 > 0:22:40He wanted to understand exactly how much energy he uses.
0:22:40 > 0:22:42I'm a bicycle commuter,
0:22:42 > 0:22:44I use public transport, I run a wind energy company.
0:22:44 > 0:22:46I should be a good human, right?
0:22:46 > 0:22:49But I didn't actually know, numerically, if I was good.
0:22:49 > 0:22:52So I counted up all the energy my lifestyle uses.
0:22:52 > 0:22:54I can tell you the amount of power it takes
0:22:54 > 0:22:56to have the New York Times delivered,
0:22:56 > 0:22:59how much power it takes to have a hot shower.
0:22:59 > 0:23:02I know how much power I use flying around the place
0:23:02 > 0:23:04to talk to people like you.
0:23:04 > 0:23:08I know how much power I use driving. And I was a little shocked.
0:23:08 > 0:23:11I actually use more than the average American.
0:23:11 > 0:23:15I'm one of the planet fuckers. So I am right now a hypocrite.
0:23:15 > 0:23:18Here I am talking to you about all of this,
0:23:18 > 0:23:21but I'm using way more than the average US person.
0:23:21 > 0:23:24That means that this halo of light behind me you see
0:23:24 > 0:23:26is not actually genius.
0:23:26 > 0:23:29That's the 300 light bulbs that are burning constantly
0:23:29 > 0:23:3124 hours a day, seven days a week.
0:23:31 > 0:23:35That's how much power my lifestyle uses.
0:23:36 > 0:23:41The average American uses 11.4 kilowatts.
0:23:41 > 0:23:45The global average is 2.2 kilowatts.
0:23:45 > 0:23:47Which means the world's total energy consumption
0:23:47 > 0:23:54is currently around 13 terawatts, or 13 million million watts.
0:23:59 > 0:24:03To understand the scale of the problem, I posed a question to Saul.
0:24:03 > 0:24:07What would it take to share the world's energy equally,
0:24:07 > 0:24:10and give all six billion of us five kilowatts each?
0:24:13 > 0:24:16A global total of 30 terawatts.
0:24:16 > 0:24:23And let's see if we can achieve this, without fossil fuels, by 2035.
0:24:23 > 0:24:25Let's shoot for this morally pleasing level.
0:24:25 > 0:24:27This one.
0:24:27 > 0:24:29We'll call this the Brian Agenda.
0:24:29 > 0:24:34Well, yeah, because the Brian Agenda is to allow everybody on the Earth
0:24:34 > 0:24:38to live a lifestyle approximately like mine.
0:24:40 > 0:24:43'In the west, we'd have to get used to using a lot less.
0:24:43 > 0:24:44'But in the developing world,
0:24:44 > 0:24:48'this extra energy could provide roads and schools and hospitals,
0:24:48 > 0:24:51'everything we take for granted.'
0:24:51 > 0:24:54So let's go with that. It's hugely optimistic, but let's do it.
0:24:54 > 0:24:56Let's go to five kilowatts.
0:24:56 > 0:24:59'The next step is to figure out just how much clean energy
0:24:59 > 0:25:01'that is for the entire world.'
0:25:01 > 0:25:04Thirty terawatts of energy
0:25:04 > 0:25:08has to come from some new clean source or sources.
0:25:08 > 0:25:11OK, 30 terawatts, 25 years.
0:25:11 > 0:25:13I'm totally behind the Brian Agenda.
0:25:15 > 0:25:18So, what are the implications of my eponymous plan
0:25:18 > 0:25:21to make the world a more equitable place?
0:25:25 > 0:25:28How about generating a sixth of our power, five terawatts,
0:25:28 > 0:25:30from conventional nuclear?
0:25:30 > 0:25:34So we need 5,000 nuclear reactors in 25 years.
0:25:34 > 0:25:39That's two and a half full size nuclear reactors every week
0:25:39 > 0:25:41for the next 25 years.
0:25:41 > 0:25:43Every three minutes you need to install
0:25:43 > 0:25:45a full size three megawatt wind turbine.
0:25:45 > 0:25:48That's gonna be a couple of percent of the land area of the world
0:25:48 > 0:25:49that has wind turbines on it.
0:25:49 > 0:25:56Solar at 10 terawatts, 250 square metres of solar cell every second -
0:25:56 > 0:25:59second after second after second after second for the next 25 years.
0:25:59 > 0:26:03Biofuels, two terawatts. This one looks a little scary.
0:26:03 > 0:26:06That's something like four Olympic swimming pools
0:26:06 > 0:26:08full of genetically engineered bacteria,
0:26:08 > 0:26:10every second for the next 25 years.
0:26:10 > 0:26:12And so on.
0:26:12 > 0:26:16It's becoming clear that freeing ourselves of our fossil fuel addiction,
0:26:16 > 0:26:19let alone creating a more equitable world,
0:26:19 > 0:26:22is gonna require a massive global effort.
0:26:22 > 0:26:25And we haven't even factored in the inevitable population growth.
0:26:28 > 0:26:32So, look, this is possible to realise the Brian Agenda.
0:26:32 > 0:26:35But it's a pretty radical programme.
0:26:35 > 0:26:39This is like the re-tooling of manufacture for World War II,
0:26:39 > 0:26:42except Britain, Germany, Japan and America
0:26:42 > 0:26:43are playing on the same team.
0:26:43 > 0:26:49And every week that passes by, when the world fails to build these alternative sources,
0:26:49 > 0:26:53means Saul's numbers just keep on getting bigger.
0:26:53 > 0:26:55Could fusion power help?
0:26:55 > 0:26:59Unfortunately, right now for nuclear fusion, it's a question mark.
0:26:59 > 0:27:01We don't know whether it works.
0:27:01 > 0:27:03But the sensible thing would be to increase investment?
0:27:03 > 0:27:05Certainly if we nail fusion,
0:27:05 > 0:27:08that looks like the Get Out Of Jail Free card for humanity.
0:27:13 > 0:27:19The aspiration to raise everybody up to a minimum standard of energy use,
0:27:19 > 0:27:24that is comparable with the energy use in the west,
0:27:24 > 0:27:26is not beyond the realms of possibility.
0:27:28 > 0:27:30But a global consensus
0:27:30 > 0:27:34that we have to stop our destructive use of fossil fuels, is emerging.
0:27:36 > 0:27:42What I'm not clear about is whether fusion is probably so far away
0:27:42 > 0:27:45that it won't have an impact on the first phase of the energy crisis,
0:27:45 > 0:27:47the phase we're in now.
0:27:47 > 0:27:50So do we need to focus our investment efforts
0:27:50 > 0:27:55on building more efficient power stations, building solar and wind?
0:27:55 > 0:27:58Or, if we are convinced that fusion will work
0:27:58 > 0:28:02and the technological difficulties can be overcome
0:28:02 > 0:28:04on a very short timescale, then do we really go for it?
0:28:04 > 0:28:10Do we say we're gonna spend 10 or 100 times more R&D money,
0:28:10 > 0:28:12worldwide, on fusion now?
0:28:13 > 0:28:17I believe we must at least try as hard as we possibly can.
0:28:17 > 0:28:23After all, we have already built a star, but for wholly different ends.
0:28:33 > 0:28:34During World War II,
0:28:34 > 0:28:39a generation of the finest scientific and engineering minds
0:28:39 > 0:28:42were brought together in the New Mexico desert
0:28:42 > 0:28:45to work on the top secret Manhattan Project.
0:28:56 > 0:29:04This is it, the place where the nuclear age began, the Trinity site,
0:29:04 > 0:29:09where the world's first nuclear bomb was exploded, July 16th 1945.
0:29:09 > 0:29:12It's where the power of the nucleus was unlocked.
0:29:19 > 0:29:21In just five years,
0:29:21 > 0:29:23they'd learned how to access the power of the nucleus
0:29:23 > 0:29:26by splitting nuclei apart.
0:29:26 > 0:29:29They created a fission bomb.
0:29:31 > 0:29:34They soon realised that they could release even more energy
0:29:34 > 0:29:38if they could fuse the nuclei and the fuel together.
0:29:39 > 0:29:42Thing is, the fuel is positively charged.
0:29:42 > 0:29:47And that means that as it comes closer together, it repels away.
0:29:47 > 0:29:49What you're fighting is electro-magnetism.
0:29:49 > 0:29:52But if the nuclei can be brought close enough together,
0:29:52 > 0:29:55against the repulsive electro-magnetic force,
0:29:55 > 0:30:00another force of nature, the strong nuclear force,
0:30:00 > 0:30:03will take over and bind the nuclei together.
0:30:03 > 0:30:06Fusion.
0:30:06 > 0:30:09So what you need to do is get these things moving fast enough
0:30:09 > 0:30:12that they get close enough for the strong nuclear force to kick in,
0:30:12 > 0:30:14short range, to lock them together.
0:30:14 > 0:30:17Now, getting things moving fast is another way of saying
0:30:17 > 0:30:19you need to make them hot.
0:30:19 > 0:30:22That's what temperature is, the measure of the speed of the fuel.
0:30:24 > 0:30:27And the bomb builders had just the tool.
0:30:27 > 0:30:31They would use the incredible temperatures and densities of a fission bomb
0:30:31 > 0:30:36to overcome the electromagnetic force and achieve fusion.
0:30:39 > 0:30:41NEWSREEL MUSIC
0:30:43 > 0:30:46ORIGINAL ANNOUNCER: This is the first full scale test
0:30:46 > 0:30:48of a hydrogen device.
0:30:48 > 0:30:51If the reaction goes, we're in the thermo-nuclear era!
0:30:55 > 0:30:58Just eight years after entering the nuclear age at Trinity,
0:30:58 > 0:31:03they were at the brink of lighting the first ever star on Earth.'
0:31:04 > 0:31:07SITE PA: Now 30 seconds to zero time.
0:31:07 > 0:31:10Ivy Mike, as the test was known,
0:31:10 > 0:31:16was the first full-scale attempt to detonate a fusion or hydrogen bomb.
0:31:16 > 0:31:20One of the scientists who witnessed the birth of the nuclear age
0:31:20 > 0:31:22is Sterling Colgate.
0:31:22 > 0:31:27We can simulate what goes on in a star.
0:31:27 > 0:31:31In... It isn't quite the laboratory, but at the test range,
0:31:31 > 0:31:37or some exquisitely beautiful atoll that we blow all to shit,
0:31:37 > 0:31:39if you don't mind the word.
0:31:39 > 0:31:42Cos it's just ghastly what all of that did!
0:31:42 > 0:31:44And it's a lesson for the whole world.
0:31:44 > 0:31:47Never, never, never let that happen again.
0:31:47 > 0:31:52Five, four, three, two, one, zero!
0:31:57 > 0:32:01They had unleashed the most powerful force in nature.
0:32:01 > 0:32:05This happens in the stars, it happens in our sun.
0:32:05 > 0:32:07If it didn't, we wouldn't be here.
0:32:07 > 0:32:09And so you can't turn the clock back.
0:32:09 > 0:32:11You can't deny the physics.
0:32:11 > 0:32:17It's there. What we have to do is deny the use of a fusion bomb,
0:32:17 > 0:32:20a hydrogen bomb as it's called,
0:32:20 > 0:32:25in any anger whatsoever.
0:32:25 > 0:32:29We absolutely have to make a massive commitment as a culture
0:32:29 > 0:32:32that this can never, never happen.
0:32:32 > 0:32:36However we also need to take that knowledge
0:32:36 > 0:32:38and use it to generate power.
0:32:38 > 0:32:40And make the power that we need to go on.
0:32:41 > 0:32:44Future lab is completely gone.
0:32:44 > 0:32:49Nothing there but water and what appears to be a deep crater.
0:32:49 > 0:32:54Whatever you think about the power you can extract from the atomic nucleus,
0:32:54 > 0:32:57the simple fact, the scientific fact is,
0:32:57 > 0:33:00there is no greater power source in the universe.
0:33:00 > 0:33:03It's the power source that powers the sun,
0:33:03 > 0:33:06it's the power source that powers the stars
0:33:06 > 0:33:11and it can be the power source that powers our civilisation.
0:33:11 > 0:33:17What's needed is a Manhattan Project type effort
0:33:17 > 0:33:24to unlock the immense energy store of the atomic nucleus.
0:33:24 > 0:33:26But this time for peaceful purposes.
0:33:26 > 0:33:32Today, fusion scientists continue to face the same challenge.
0:33:32 > 0:33:35They must overcome the electromagnetic force
0:33:35 > 0:33:39by creating incredibly high temperatures and pressures,
0:33:39 > 0:33:42but in a much more controlled way.
0:33:44 > 0:33:50Currently, the world spends only £1 billion a year on the problem.
0:33:50 > 0:33:54In the UK, we spent more money on ringtones last year
0:33:54 > 0:33:58than we contributed to the global fusion efforts.
0:33:58 > 0:34:01You've got to ask yourself whether our civilization
0:34:01 > 0:34:03has got its priorities right.
0:34:06 > 0:34:10Much of fusion funding still goes into bomb research.
0:34:10 > 0:34:14But these days, the demolition of South Pacific islands
0:34:14 > 0:34:16is out of fashion.
0:34:16 > 0:34:21Instead, the generals hire the world's most powerful bomb simulator.
0:34:22 > 0:34:25Well, welcome, Brian. This is the Z Machine.
0:34:25 > 0:34:29Located on a high security base just outside Albuquerque,
0:34:29 > 0:34:34the Z Machine, as it's known, is run by John Porter.
0:34:34 > 0:34:38So, this is the largest pulse power device in the world.
0:34:38 > 0:34:41It's also the largest X-ray generator in the world.
0:34:41 > 0:34:46So in about an hour we're going to discharge about 26 million amps
0:34:46 > 0:34:51through a little thimble-sized cylinder of wires.
0:34:51 > 0:34:52This is, you know, 100 times bigger
0:34:52 > 0:34:55than the instantaneous power consumption of the United States,
0:34:55 > 0:34:57at least.
0:34:57 > 0:34:59So, again, just phenomenal amounts.
0:34:59 > 0:35:01But for very short periods of time.
0:35:01 > 0:35:04With all this power at its disposal,
0:35:04 > 0:35:08the Z Machine is able to recreate the conditions inside an H bomb.
0:35:08 > 0:35:12And so at this point, the conductors are inside a vacuum.
0:35:12 > 0:35:16And then they're converging all to the axis and about, I dunno, 10 feet down there
0:35:16 > 0:35:19is where all the current gets concentrated in the thin wires.
0:35:19 > 0:35:23Nearby, John shows me a target
0:35:23 > 0:35:25that will sit at the centre of the machine.
0:35:25 > 0:35:28So the 26 million amps is flowing right along there.
0:35:28 > 0:35:31And then you can barely see the array of wires.
0:35:31 > 0:35:35There's probably like 300 wires here.
0:35:35 > 0:35:37- They look like a spider's web. - Exactly.- Absolutely tiny.
0:35:39 > 0:35:43When it fires, these wires are rapidly vaporised.
0:35:43 > 0:35:48And the strong magnetic field generated by the enormous electric currents
0:35:48 > 0:35:51force the wire remnants to implode.
0:35:51 > 0:35:53This is known as a Z-pinch.
0:35:54 > 0:35:57And it's this that creates the conditions
0:35:57 > 0:35:59for nuclear fusion to occur.
0:35:59 > 0:36:01The diagnosticians are back down from re-arming
0:36:01 > 0:36:03and we're gonna continue with our check list.
0:36:03 > 0:36:07The radiation generated by this machine is extreme,
0:36:07 > 0:36:10and it can, in certain places, create lethal doses of radiation.
0:36:10 > 0:36:15- So it's not a good idea to be stood here when you do that?- That's right!
0:36:17 > 0:36:20- So it's about to get dangerous, so we'd better take off!- Right.
0:36:20 > 0:36:22And we've got red flashing lights,
0:36:22 > 0:36:26- all the signs that it's better to leave.- Yeah. Very exciting.
0:36:26 > 0:36:28So we do about one shot a day.
0:36:28 > 0:36:32So this has already been locked up. I'll take you to the control room.
0:36:34 > 0:36:38The X-rays are so intense that people and video cameras
0:36:38 > 0:36:42are only safe inside the specially-shielded control room.
0:36:42 > 0:36:45- You guys ready?- We're ready for you to arm.- OK, we're still armed.
0:36:45 > 0:36:49Attention building 983, Z is preparing to fire.
0:36:49 > 0:36:51We are starting ZBL countdown.
0:36:51 > 0:36:53We are counting, T-minus 135.
0:36:53 > 0:36:55We are charging.
0:36:55 > 0:36:58They're gonna take it up to 82,000 volts.
0:36:58 > 0:37:00We are charging the MTGs.
0:37:00 > 0:37:04When it fires, this vast brute of a machine is powerful enough
0:37:04 > 0:37:09to create a minor Earthquake that's felt across the entire site.
0:37:09 > 0:37:11Charge complete, arming to fire.
0:37:11 > 0:37:13T-zero...
0:37:16 > 0:37:18- DISTANT BOOM - Trigger!- Whoa!
0:37:19 > 0:37:23Only one image of the blast has ever been captured.
0:37:23 > 0:37:26This is that image.
0:37:26 > 0:37:28It's called a flash-over,
0:37:28 > 0:37:31the result of the ferocious electromagnetic pulse
0:37:31 > 0:37:35as lightning dances around the metals in the room.
0:37:35 > 0:37:37Thanks, John.
0:37:37 > 0:37:39Did you guys trigger? Cool.
0:37:39 > 0:37:41That was it, it's a success.
0:37:41 > 0:37:44I felt the ground move.
0:37:44 > 0:37:46I think you did too, Brian?
0:37:46 > 0:37:48Yeah. And heard it out there, actually!
0:37:54 > 0:37:57All right, let's go look and see what's left after the shot.
0:37:59 > 0:38:04So this was all fairly pristine, at one point, stainless steel.
0:38:04 > 0:38:06It's quite remarkable. It's almost like the...
0:38:06 > 0:38:09Well, it is the conditions in an atomic bomb, isn't it?
0:38:09 > 0:38:13Well, that's the reason these facilities were first created.
0:38:13 > 0:38:16- So, that's why it looks like it's been in a nuclear war?- Exactly!
0:38:16 > 0:38:18- Cos it has!- Right.
0:38:18 > 0:38:23A relic of the Cold War, the Z Machine is being re-invented.
0:38:23 > 0:38:26It turns out that this bomb simulator
0:38:26 > 0:38:31could perhaps be turned into a peaceful source of fusion energy.
0:38:31 > 0:38:36It costs a few tens of thousands of dollars to machine.
0:38:36 > 0:38:40All the parts we just blew up in a few billionths of a second.
0:38:40 > 0:38:44The big hurdle is doing it a few times a second
0:38:44 > 0:38:48or a few times a minute, depending on the yields,
0:38:48 > 0:38:51to get enough power to be useful.
0:38:51 > 0:38:54- Then you've got a power station. - Exactly. It's the last few feet,
0:38:54 > 0:38:56the stuff that gets blown up.
0:38:56 > 0:38:59Coming up with new ideas on how to rapidly replace that.
0:39:01 > 0:39:04Currently it takes at least a full working day
0:39:04 > 0:39:07to prepare the Z Machine for another shot.
0:39:07 > 0:39:12But if they can learn how to replace all the hardware that gets destroyed quickly enough,
0:39:12 > 0:39:14in less than a minute,
0:39:14 > 0:39:17then it's possible that a machine similar to this
0:39:17 > 0:39:21could one day produce a steady stream of energy.
0:39:21 > 0:39:23But it's a tall order.
0:39:23 > 0:39:27We believe this technology that you're seeing here is the simplest,
0:39:27 > 0:39:29most elegant and efficient technology
0:39:29 > 0:39:32that one could imagine to create fusion.
0:39:32 > 0:39:35But no one knows, you know, what's really possible. Right?
0:39:38 > 0:39:41The Z Machine proves it is experimentally possible
0:39:41 > 0:39:46to light a star on Earth by initiating a controlled explosion
0:39:46 > 0:39:48around a fusion fuel.
0:39:48 > 0:39:52So it does recreate the conditions that are present
0:39:52 > 0:39:55at the heart of a star.
0:39:55 > 0:39:58It's also produced fusion.
0:39:58 > 0:40:00But most of all it's simple.
0:40:00 > 0:40:05That is the most impressive thing to me. It was, or it is,
0:40:05 > 0:40:07in a way, 19th century technology.
0:40:07 > 0:40:10And that's not to denigrate the machine at all.
0:40:10 > 0:40:12It's a very simple idea.
0:40:12 > 0:40:16And I suppose if you want to build a power station,
0:40:16 > 0:40:19if you really want technology you can produce on an industrial scale,
0:40:19 > 0:40:23then you want to do it in as simple a way as possible.
0:40:25 > 0:40:28And that's because the scientists are facing
0:40:28 > 0:40:33perhaps the most difficult engineering challenge in history.
0:40:33 > 0:40:37To produce a viable power plant, they must engineer machines
0:40:37 > 0:40:42that can not only create and withstand the violent conditions found in stars,
0:40:42 > 0:40:47but that are capable of creating hundreds of these exploding stars,
0:40:47 > 0:40:49every minute.
0:40:49 > 0:40:53Only then will they be able to extract a steady supply of energy
0:40:53 > 0:40:57and create significant amounts of electricity for the grid.
0:41:00 > 0:41:04No wonder fusion power is taking so long to come online,
0:41:04 > 0:41:07even though we've understood this process at the sub-atomic level
0:41:07 > 0:41:09for well over half a century.
0:41:12 > 0:41:14This is how fusion works in the sun.
0:41:14 > 0:41:16You start off with protons.
0:41:18 > 0:41:20Nuclei of hydrogen.
0:41:20 > 0:41:23And if those protons can get close enough together,
0:41:23 > 0:41:28so the strong nuclear force, short range force can lock them together,
0:41:28 > 0:41:31then one of those protons can turn into a neutron.
0:41:31 > 0:41:35And two particles called the positron and neutrino
0:41:35 > 0:41:36come flying out.
0:41:36 > 0:41:41And that makes an isotope of hydrogen,
0:41:41 > 0:41:43something called deuterium.
0:41:43 > 0:41:47And about a 7,000th of the hydrogen in your water
0:41:47 > 0:41:49is actually deuterium.
0:41:49 > 0:41:50So it's pretty common on Earth.
0:41:50 > 0:41:54That process takes a long, long time.
0:41:54 > 0:41:56In fact, for a single proton in the sun,
0:41:56 > 0:41:59then it would have to wait billions of years
0:41:59 > 0:42:02to get close enough to undergo that process.
0:42:02 > 0:42:05So that's the blockage in fusion in the sun, if you like.
0:42:05 > 0:42:08Once that's happened and the deuterium's formed,
0:42:08 > 0:42:10then everything goes very quickly.
0:42:10 > 0:42:13Another proton can come and meet the deuterium
0:42:13 > 0:42:17and that turns the deuterium into helium-3.
0:42:17 > 0:42:20And actually a photon particle of light comes flying out.
0:42:20 > 0:42:26And then two of these helium-3s can stick together into helium-4,
0:42:26 > 0:42:28and a couple of protons come flying out.
0:42:28 > 0:42:33So that's the process by which energy is released in the sun.
0:42:33 > 0:42:36It's the process that allows the sun to shine.
0:42:38 > 0:42:42On Earth though, we have an advantage.
0:42:42 > 0:42:46We don't have to go through the lengthy process of making deuterium
0:42:46 > 0:42:48because the oceans are full of it.
0:42:48 > 0:42:52A rich seam of energy that could supply the entire world
0:42:52 > 0:42:54for millions of years.
0:42:55 > 0:43:00It's this tantalising promise of effectively unlimited energy
0:43:00 > 0:43:04that has inspired another approach designed to initiate fusion.
0:43:10 > 0:43:14At the Lawrence Livermore National Laboratory in California,
0:43:14 > 0:43:17they're attempting to create a stream of exploding stars
0:43:17 > 0:43:20using nothing more than a light beam.
0:43:21 > 0:43:22Wow!
0:43:24 > 0:43:26The governor yesterday, and me today!
0:43:32 > 0:43:34VIDEO NARRATOR: The National Ignition Facility
0:43:34 > 0:43:37will do what has never before been accomplished.
0:43:39 > 0:43:43To create a self-sustained nuclear fusion reaction
0:43:43 > 0:43:45in a safe, controlled setting.
0:43:48 > 0:43:51At the National Ignition Facility, or NIF,
0:43:51 > 0:43:56they've built the world's largest and most powerful laser.
0:43:56 > 0:44:02Showing me around this enormous site is fusion scientist Eric Storm.
0:44:02 > 0:44:06- Is that the laser?- Yeah, stop a second. It looks like a factory.
0:44:11 > 0:44:16The 500 trillion watt laser beam travels half a kilometre,
0:44:16 > 0:44:19guided by a series of lenses and mirrors,
0:44:19 > 0:44:24a pulse of light with a thousand times the instantaneous amount of energy
0:44:24 > 0:44:27in America's national grid.
0:44:29 > 0:44:32This shows the actual size of one of these laser beams.
0:44:32 > 0:44:34They all come from one single source
0:44:34 > 0:44:37and at the end get focused onto this fusion target.
0:44:37 > 0:44:40TWO-WAY RADIO: We're trying to get hold of Sopado or Seranowski.
0:44:40 > 0:44:43Copy.
0:44:43 > 0:44:44OK.
0:44:44 > 0:44:47- You can see it is somewhat more impressive.- It's incredible.
0:44:47 > 0:44:51You know, this looks like a facility that creates stars.
0:44:51 > 0:44:56It does, doesn't it? It looks like it does what it says it does.
0:44:56 > 0:45:01These aluminium square tubes here,
0:45:01 > 0:45:04that's where the laser beams come in.
0:45:04 > 0:45:08There are 96 beams on the top and 96 on the bottom.
0:45:08 > 0:45:11There are focusing lenses that take these beams
0:45:11 > 0:45:14and focus them down to a human hair.
0:45:14 > 0:45:17That would give you quite a suntan, wouldn't it?
0:45:17 > 0:45:19Yeah, you would?!
0:45:19 > 0:45:21I do not recommend it.
0:45:24 > 0:45:28Let's go and look inside the chamber.
0:45:31 > 0:45:35INDISTINCT VOICE ON RADIO
0:45:35 > 0:45:39- Right, you're looking inside the star chamber.- Look at that.
0:45:39 > 0:45:43INDISTINCT VOICE ON RADIO
0:45:43 > 0:45:47- The target will be sitting... You can see the...- It's moving in.
0:45:47 > 0:45:52That's the one that will hold the target in the centre of the chamber.
0:45:52 > 0:45:56- Which is the seed of the star. - The seed of the star, absolutely.
0:45:57 > 0:45:59BELL RINGS
0:46:00 > 0:46:04'The man in charge of the most powerful laser on Earth
0:46:04 > 0:46:07'is Ed Moses.'
0:46:07 > 0:46:10I want to talk about the target because this is the...
0:46:10 > 0:46:14First, how much energy do you get out of one of those targets?
0:46:14 > 0:46:17It's an interesting question. This target is pretty small.
0:46:17 > 0:46:20That little ball is where the fuel for this target is.
0:46:20 > 0:46:23Cos this is where the challenge is, right?
0:46:23 > 0:46:24The design of this thing.
0:46:24 > 0:46:28There's a lot of challenges. You have to put the laser together,
0:46:28 > 0:46:32- you have to get all those lasers... - You've done that, though.- Yeah.
0:46:32 > 0:46:36We have to get those 192 beams steered very precisely into this target.
0:46:36 > 0:46:39The laser light is coming down and up on it
0:46:39 > 0:46:44in a very symmetrical fashion so we make a very uniform oven.
0:46:44 > 0:46:50That little ball starts collapsing at a million miles an hour.
0:46:50 > 0:46:52When it starts moving,
0:46:52 > 0:46:55the hydrodynamic forces on it are such that
0:46:55 > 0:46:57it could start ripping itself apart.
0:46:57 > 0:47:01So you have to make it come together really nicely and smoothly
0:47:01 > 0:47:04till it's about the diameter of your hair.
0:47:04 > 0:47:06When you do, you'll have temperatures
0:47:06 > 0:47:07of around 100 million degrees
0:47:07 > 0:47:10and pressures of around 100 billion atmospheres.
0:47:10 > 0:47:13It'll be about a hundred times as dense as lead
0:47:13 > 0:47:16and that's when it will light up and this is not chemical burn.
0:47:16 > 0:47:19This is nuclear burn, that's what's so interesting.
0:47:19 > 0:47:22You get around 30 million times more energy per mass
0:47:22 > 0:47:25out of a nuclear burning device than a chemical burning device.
0:47:25 > 0:47:31But no laser-powered fusion device has yet to achieve this.
0:47:31 > 0:47:35So far, it's proved difficult to focus all the power
0:47:35 > 0:47:38onto the target at precisely the same time.
0:47:38 > 0:47:43Only if this can be overcome will the fuel target be heated
0:47:43 > 0:47:45and condensed enough for fusion to occur.
0:47:45 > 0:47:51This is the Holy Grail - the quest for ignition.
0:47:53 > 0:47:56So you had this star that's about the diameter of a human hair
0:47:56 > 0:47:58for a billionth of a second.
0:47:58 > 0:48:02Yeah, it's star power on Earth. That's what we say.
0:48:02 > 0:48:04If we can do it a few times a second
0:48:04 > 0:48:08then you get the kind of energy that comes out of a power plant.
0:48:08 > 0:48:11NIF is not a power plant,
0:48:11 > 0:48:17but this vast experiment may be on the brink of igniting a star.
0:48:17 > 0:48:19It is our future.
0:48:19 > 0:48:22When is that future going to arrive?
0:48:22 > 0:48:25What would you say? I know it's difficult to speculate,
0:48:25 > 0:48:27but 10 years, 20 years, 50 years?
0:48:27 > 0:48:35I think from the point of view of proving fusion in this laboratory,
0:48:35 > 0:48:38our goal is to do that in the next two or three years.
0:48:38 > 0:48:41Sometimes, people talk about fusion as being 50 years away.
0:48:41 > 0:48:44Right now, I look at it as two or three years away.
0:48:46 > 0:48:52By 2011, the world should know whether laser-powered fusion will achieve ignition.
0:48:54 > 0:48:58Should they fail, then all humanity's hopes for fusion
0:48:58 > 0:49:01will shift to another group of scientists.
0:49:02 > 0:49:06These researchers believe our future energy will come,
0:49:06 > 0:49:10not from a stream of short-lived mini stars,
0:49:10 > 0:49:16but from learning how to create and hold the very matter
0:49:16 > 0:49:19of the sun for days and months on end.
0:49:19 > 0:49:22They too face a tremendous challenge
0:49:22 > 0:49:27for they seek to control the least well understood state of matter -
0:49:27 > 0:49:29plasma.
0:49:31 > 0:49:35If you heat up any atoms or molecules,
0:49:35 > 0:49:39what happens very quickly is that the electrons around the nucleus
0:49:39 > 0:49:41start to boil off.
0:49:41 > 0:49:46The temperature's too high for them to stick in orbit around the nucleus
0:49:46 > 0:49:50and that is the state of most of the universe,
0:49:50 > 0:49:53including the state of our nearby star,
0:49:53 > 0:49:58that incredibly hot ball of plasma - the sun.
0:50:05 > 0:50:08Producing long-lived plasmas
0:50:08 > 0:50:11is the oldest line of fusion power research.
0:50:13 > 0:50:18For 50 years, a small group of countries have run prototype fusion reactors
0:50:18 > 0:50:22in an attempt to extract energy from stable plasma.
0:50:22 > 0:50:25The very latest country to join this club
0:50:25 > 0:50:27is South Korea.
0:50:29 > 0:50:32Here we are - the National Fusion Research Centre.
0:50:32 > 0:50:36Strange thing as well, it's in the middle of an industrial estate.
0:50:36 > 0:50:41When you think of a nuclear reactor facility, you tend to think of it out in a field somewhere,
0:50:41 > 0:50:44but it's right in the middle of the city.
0:50:53 > 0:50:56- Good morning, how are you? - Good to see you.
0:50:59 > 0:51:01- OK, I'll show you the KSTAR. - Thank you.
0:51:02 > 0:51:05'KSTAR, like the jet reactor in Oxfordshire,
0:51:05 > 0:51:09'is a type of fusion reactor called a tokamak.'
0:51:09 > 0:51:12- It's a beautiful device.- Ah-ha. - It's clean.
0:51:12 > 0:51:15'It was completed in late 2007
0:51:15 > 0:51:21'and I've been invited to see the device before it begins operation later this year
0:51:21 > 0:51:24'by its chief creator, Dr Lee.'
0:51:24 > 0:51:26He used to be a vacuum engineer.
0:51:26 > 0:51:28- Thank you.- You can go.
0:51:28 > 0:51:30Bye.
0:51:30 > 0:51:32Thanks.
0:51:36 > 0:51:41'What makes KSTAR unique are the advanced super-conducting magnets
0:51:41 > 0:51:43'that hold the plasma in place.
0:51:45 > 0:51:49'They cool to minus 269 degrees.
0:51:49 > 0:51:51'At this temperature,
0:51:51 > 0:51:56'the magnets have no electrical resistance,
0:51:56 > 0:52:01'which means KSTAR needs a lot less power to run than its predecessors.'
0:52:01 > 0:52:06What's the thing you hope to learn with this machine?
0:52:06 > 0:52:09So far, all the tokamak fusion reactor
0:52:09 > 0:52:11runs for a very short period of time.
0:52:11 > 0:52:13A few seconds.
0:52:13 > 0:52:19So we, scientifically, we have proven fusion can be realisable.
0:52:19 > 0:52:24- Yeah.- But on the other hand, we have to make energy
0:52:24 > 0:52:27- so this machine has to run a long way, you know?- Mmm.
0:52:27 > 0:52:30Eventually, nine months and ten months continuously.
0:52:30 > 0:52:32So, you would contain the plasma?
0:52:32 > 0:52:34- Yeah.- What, months at a time?
0:52:34 > 0:52:36Yes.
0:52:36 > 0:52:42'KSTAR aims to show that plasma can be routinely created and held
0:52:42 > 0:52:46'for long periods deep within the heart of the machine
0:52:46 > 0:52:50'in the way needed for a commercial fusion power station.'
0:52:50 > 0:52:53This is a very exciting moment, actually.
0:52:53 > 0:52:58I never imagined I'd get to climb inside the reactor, which is...
0:52:58 > 0:53:00unbelievable.
0:53:01 > 0:53:04It's not easy access!
0:53:04 > 0:53:06How did he do that?
0:53:06 > 0:53:07HE LAUGHS
0:53:07 > 0:53:09Oof!
0:53:11 > 0:53:13This is brilliant, I've got to say.
0:53:14 > 0:53:17Well, this is the inside of KSTAR.
0:53:17 > 0:53:21When this is operating, where my head is, there will be a plasma,
0:53:21 > 0:53:2510, 20 times hotter than the core of the sun.
0:53:25 > 0:53:29And it works, basically, like a home microwave oven,
0:53:29 > 0:53:32except that six megawatts is the power consumption of
0:53:32 > 0:53:362,000 domestic houses. So...
0:53:36 > 0:53:38it's a remarkable place.
0:53:38 > 0:53:41The temperature here, 20 times hotter than the centre of the sun.
0:53:41 > 0:53:46Below my feet, where the magnets are, minus 269 degrees,
0:53:46 > 0:53:51which is something like the temperature, if you go outside the Earth's atmosphere,
0:53:51 > 0:53:55and outside, actually, to the most distant planets, incredibly cold.
0:53:56 > 0:53:59And this is one of the best bits, in a way,
0:53:59 > 0:54:02it's the television camera.
0:54:04 > 0:54:07And they've already had some success.
0:54:07 > 0:54:09Just before my visit,
0:54:09 > 0:54:12they ran the machine for the first time.
0:54:12 > 0:54:13It's not fusion yet,
0:54:13 > 0:54:17but an important step towards KSTAR's goal
0:54:17 > 0:54:22of holding 100,000 degree plasma for five minutes.
0:54:22 > 0:54:24If they can achieve this,
0:54:24 > 0:54:28it will be a significant landmark on the road to fusion power.
0:54:29 > 0:54:33Will you get net energy out of KSTAR?
0:54:33 > 0:54:35KSTAR will be...
0:54:35 > 0:54:38kind of break even machine.
0:54:38 > 0:54:41So, energy consumption to really support the whole system,
0:54:41 > 0:54:46and the energy out is almost, you know, one to one, like.
0:54:46 > 0:54:49But an economical power plant,
0:54:49 > 0:54:55we are now considering, is about 30 to 50 times of this is necessary.
0:54:55 > 0:54:57Means one watt comes in,
0:54:57 > 0:54:59and 30 to 50 comes out.
0:54:59 > 0:55:01Then, we can really make it in
0:55:01 > 0:55:05the reasonable cost of electricity from the fusion device.
0:55:07 > 0:55:09The South Koreans have built KSTAR
0:55:09 > 0:55:12as their contribution to an international project
0:55:12 > 0:55:18to build the biggest fusion reactor ever attempted, called ITER,
0:55:18 > 0:55:23which is about to begin construction in Southern France.
0:55:23 > 0:55:29- Really, this is the start of the final phase of R&D towards fusion.- I think so. Yes.
0:55:29 > 0:55:31We have done 50 years of R&D in fusion,
0:55:31 > 0:55:33fusing lots of machines, many places.
0:55:33 > 0:55:36- Now, this is endgame.- Yes.
0:55:36 > 0:55:41So, now, put together all the knowledge of these 50 years
0:55:41 > 0:55:47and now, merging into this, KSTAR, ITER, and finally, commercialisation.
0:55:52 > 0:55:56This machine, having seen it, means more to me than I thought it would
0:55:56 > 0:55:59because I really get the sense that if this doesn't work,
0:55:59 > 0:56:04then, we're in, literally, real trouble.
0:56:04 > 0:56:09Hopefully, it's all engineering, and it's all practice.
0:56:09 > 0:56:11It's not simple because it will take decades.
0:56:11 > 0:56:14But it's not a fundamental issue,
0:56:14 > 0:56:17because if it were a fundamental issue,
0:56:17 > 0:56:20then this kind of fusion would drop out of the race,
0:56:20 > 0:56:22and we'd be left with one, with laser fusion.
0:56:22 > 0:56:26And for me, if you think that fusion is the future of our civilisation,
0:56:26 > 0:56:28that's a big risk.
0:56:28 > 0:56:31So, good luck, KSTAR.
0:56:46 > 0:56:48If you'd asked me before I made this film -
0:56:48 > 0:56:52what are the greatest achievements in the history of humanity?,
0:56:52 > 0:56:54I would say, the moments when we overreach,
0:56:54 > 0:56:57the moments when we set foot on the moon,
0:56:57 > 0:57:01or took photographs of Saturn and Jupiter and distant planets.
0:57:02 > 0:57:05Building a fusion power station that works
0:57:05 > 0:57:09and delivers electrons into the power grid of a city
0:57:09 > 0:57:11will be the next step
0:57:11 > 0:57:13in the evolution of our civilisation.
0:57:13 > 0:57:17It's just about beyond our capabilities,
0:57:17 > 0:57:20technologically and scientifically, at the moment.
0:57:20 > 0:57:23And that's surely the best place to be.
0:57:23 > 0:57:27That's the place you want to stand, as a human being.
0:57:27 > 0:57:30So, I would celebrate the fusion power station builders
0:57:30 > 0:57:33in a way that I wouldn't have done before we made this film.
0:57:40 > 0:57:47So, when can we expect fusion power from the mains?
0:57:47 > 0:57:50All right. My prediction. I hate being a futurist.
0:57:50 > 0:57:56# This time tomorrow, where will we be?... #
0:57:56 > 0:57:592036, June.
0:58:01 > 0:58:03That's when it COULD be done
0:58:03 > 0:58:04with an exerted effort.
0:58:04 > 0:58:062027.
0:58:06 > 0:58:09I don't think it will happen until then.
0:58:09 > 0:58:12# This time tomorrow
0:58:12 > 0:58:14# What will we know...? #
0:58:17 > 0:58:19There's a 50% chance of it working,
0:58:19 > 0:58:2420 years after you seriously fund the science.
0:58:24 > 0:58:26So, it's time for a commitment.
0:58:26 > 0:58:29# I'll leave the sun behind me
0:58:29 > 0:58:35# And I'll watch the clouds as they sadly pass me by
0:58:35 > 0:58:39# Seven miles below me
0:58:39 > 0:58:45# I can see the world and it ain't so big at all
0:58:47 > 0:58:50# This time tomorrow
0:58:50 > 0:58:53# What will we see...? #
0:58:53 > 0:58:55Subtitles by Red Bee Media Ltd
0:58:55 > 0:58:56E-mail subtitling@bbc.co.uk