TEDxWarwick - David MacKay - How the Laws of Physics Constrain Our Sustainable Energy Options

[@LuisSeijo]

Fantastic speach. Very impressive work behind it (and behind the book) and such a rational, solid, and honest approach to the problem. I can only show my deep appreciation to David MacKay.

[@antoniomartinmunoz5253]

No tienes ni puta idea, comentario inútil Luis.

[@SecondLifeDesigner]

The answer to all our energy needs is Thorium molten salt reactors. You just need 1 ton of Thorium to create 1,000 Mega Watts of electricity compared to 35 tons of high grade Uranium for conventional nuclear reactors. Molten salt reactors don't need water to cool them & are smaller than conventional nuclear reactors & far far safer. 87% of the radioactive waist become almost non-radioactive in 10 years the rest in 300 years compared to the 35 tons of Uranium reactor which takes 10,000 years.

[@incognitotorpedo42]

Thorium, the favorite of KZbin commenters. If these are so great, why are they not being built? I'm highly skeptical of conspiracy theories; my money is on thorium just not really being workable.

[@BlindMonk93]

Very true. I've been studying David MacKay's book "sustainable energy without the hot air" for my degree in sustainable energy, and he does go in to a lot of detail about the different technologies and their combinations. It's free for download from his website and definitely worth a read!

[@Zoidode]

Fine by me. But if you care, here are some numbers: (1) His back of envelope calculation is based on 1200l per ha, when 5000l are common. (2) He tells people that a energy-to-area ratio of 2,5W/m² is a physical limiation for windturbines at windspeeds of 6m/s. At the same time there are windturbines with an energy ratio of 4-6W/m² today using his approach. Those are factor 2-4 differences that distort his suggestion that it's not feasable.

[@Zoidode]

One more addition: That 270W/m² for wind turbines was for the average installed turbine in 2008 in Germany.(average capacity of 1.1MW) When you look at state of the art wind turbines that have a higher installed capacity & a significantly increased efficency, then the picture changes far more dramatically. A 7.5 MW Enercon produces about 5500 W/m² of foundation space. That's 30 GWh of annual power production per turbine. 350 Windturbines = 1 Nuclear reactor.

[@factnotfiction5915]

Because of wind turbulence, you must space the surrounding turbines farther apart than the foundations. Thus his W/m2 includes the total output of a wind farm divided by its total area. He is not stating, nor does it matter (to energy density) if the land/sea is also used for something else (like sheep farming - the presence or lack thereof of sheep does not change the output of turbines or the area of the wind farm).

[@LuisSeijo]

Thank you so much. It's a honor for me to be considered shill of such a honest and useful work for mankind.

[@egastap]

Very informative and presented the facts extremely clearly and concisely. Good job David !!

[@WJV9]

This video needs to be required viewing for anyone working on low carbon energy systems. Thanks David for your work to help save humanity from itself. Great quote: "I am not anti-renewables, but I am pro-math" David MacKay

[@somannacs]

Ha haa.... That's what my girlfriend told..." This video need more views"

[@rewtnode]

If I do the math, i come to a different result in the example with the size of the biofuel fields next to the highway. I get 1825 meters, and not 8 km. The calculation is based on: Spacing of the cars 80 meters, at 60mph makes about one car every 2.91 seconds, 10,573,000 in a year. Now assume the road length is 30 miles, then each car uses one gal, which makes in the same number of gal. Divide through the 1200 gal/hectar to get 8811.1 hectars for production for a 30 miles street, hence 1825 m.

[@74357175]

There are plenty of situations where 8 km or 25 km doesn't matter in order for a point to be valid. What matters is it's much much greater than, say, 0.01 km. It's called Seeing the Forest for the Trees, and is the essence of Science.

[@themissile3120]

I think people could really benefit from more of these tangible and comprehensible explanations. Fantastic presentation, and refreshingly straightforward. It gets so frustrating seeing a bunch of media that's trying to influence instead of simply inform. Sad to hear of the guy's death. We need a lot more people able to think so objectively like this.

[@trentbusta1]

More than adquate power is generated can be generated on the roof of the average persons house,using solar panels,countries that have less sun hours can be boosted by number of other renewable sources.this has the added benefit of putting some power back in the hands of the people which is a wonderful thing.

[@kimmer400]

I think the energy we should use after fossil fuels is complex repeating mechanisms maximizing their own repeating momentum. This way we can keep going using momentum from a certain source. Although this is probably a VERY BIG challenge for engineers,

[@birdfriday]

It’s impossible

[@rewtnode]

You're right - I think I made the mistake to use the measure 1200 gal per hectar and year, but he had used 1200 liters per hectar per year which you're used correctly. With this correction I would arrive at 6.908 km which is closer to what he said. However, seem to use a different conversion from liters to gallons: I used 1 gal = 3.78541 liters, which converts 1200 liters to 317 gallons, not as you have 264 gallons.

[@MartinHangaardHansen]

Larger wind mills are increasing the number from 2.5 to something closer to 10Wm2 and they can be placed on sea. In deserts you can place PV in between the wind mills and add another 5W/m2. The problem is mainly the current price of these techs and particularly the problem of storing the energy.

[@DAFUNK213]

Yes!Free market is exactly where it should be decided.And I'm thinking also that the efficiency of hemp oil could change a lot of this argument though I'm not sure yet.

[@Thomas-eo2fl]

I have run the numbers and his result seems right:- Our car goes 60 mi/hr and gets 30 mi/gal So we use 2 gal per hr Running our car for 1 yr needs 2 * 24 * 365 = 17520 gals From land we get : 1200 l per hec per yr 264 gal per hec per yr So the car needs 17520 / 264 hec = 66.36 hectars of biofuel to keep running 1 hec = 10 000m2 area we need 663,600 m2 We have 80m length roadway per car. So we need square with depth of 66,360/80 = 8295m = 8.29 km

[@mitchp7226]

wow FINALLY someone being realistic in regards to renewables! i can't like this enough times.

[@robinhyperlord9053]

Your infinite stupidity is noted.

[@jungtarcph]

Love to see an updated version of this with the latest increases in Wind and Solar efficiency.

[@hagechin]

Why no mention of photovoltaics in his concluding diagram? And how about tidal, air/ground/water heat source technologies?

[@SabiazothPsyche]

The "TED" show is always a great show.

[@동동동-x9b]

Paul Snookes You do realize what PV stands for right? 10:18 think for yourself, it's already a crowded diagram

[@ethansilver5892]

And also you should know that renewable aren't feasible as a large chunk of the national grid, they don't produce enough energy and aren't reliable enough (what happens when it's not windy or sunny?), plus they're being over subsidised by the government and aren't economically feasible

[@christianlibertarian5488]

Two factors I can think of which are not included here. Already available are ground loop/geothermal heat pumps. The other is fusion, which may actually start to work next year at ITER.

[@davida01]

Or maybe in another 20 to 50 years? We have been waiting a long time. Liquid thorium or fast spectrum uranium/plutonium are a much more practical and immediate solution.

[@alanky89]

The problem is they can't all be implemented simultaneously. The same area of land can't contain solar panels, wind turbines, and agriculture to produce biofuels. In a way he's being optimistic about his calculations because he's maxing out the possible production regardless of this limitation. I spent the past semester referencing his SEWTHA website and the outlook is bleak to say the least.

[@sbafa1]

from this guys data for solar parks 5w/m^2 would require 20-25% of the uk's surface, but rooftop pv produces 4 times that at 20w/m^2 (again his data) thus you'd need ~5-6% of the uk's surface. now for the fun part, 2001 data (i can only assume this figure has risen) 8.9% of the uk is developed urban areas aka, roof space for roof top pv at 20w/m^2 (leeway of ~4% for roads/non ideal roofing). BOOM problem solved, stick solar panels on all the roofs and there's already more than enough space.

[@Dariodee]

Nice talk. :) I'm hoping that since we've managed to cover every usable inch of some of these countries with farm-land, we'll soon be able to cover them with renewables... assuming their cost might eventually be low enough to compare with agriculture (or at least not be too far off from there).

[@Viper4D]

and where will we grow farmland crops

[@killokas]

You forget that 1) not everybody lives in a suburban environment with a big diagonal roof on top of his house 2) that 85% of your household energy consumption is not in the form of electricity but in the form of gas/wood/whatever you use to heat your home and your water which you have to account for 3) that household energy makes up only a rough 20% of all energy needs. So if you yourself are electricity "independent", congratz, me too, but the issue is still there...

[@JohnDlugosz]

You need to include roof areas and watt numbers with that.

[@EddieRBeer]

Very interesting study from a feasibility point of view, but due to transmission constraints and lack of economical incentives for investors, wind power is never going to be anywhere near 100% of national electrical demand anyways. Of course this was more of a theoretical study, but I think this study could have been strengthened by taking into account real-life constraints and scenarios such as this.

[@LogicalMayhem00]

Great talk helps put things into perspective When you talk about nuclear you group all types of reactors together and didn't mention mention the liquid thorium fluoride reactors, they seem to be the way of the future in green power.

[@LuisSeijo]

270 W/m2 per hour? W is power, not energy, and power is energy per time unit. I don't understand the meaning of 270 W per hour (and m2). But if we just talk about installed power per m2 of land, if you have, say, 1000 m2, how many wind turbines can you install? If you need to leave space between them, the land "occupied" by a wind turbine in order to produce energy is not just the land occcupied by the foundation, but it includes the empty land between turbines.

[@LuisSeijo]

Even if your numbers are right (and they can be) and even if they are still too conservative by another factor of, say, 2, his estimations might be wrong by a factor of 10 (just to simplify). However, a factor of 10 times more power generated per m2 of land does not change the main conclusion: For renewables to provide the human consumption of energy, they require to use a very significant part of the total territory. Do we agree on this?

[@aironeous]

What about vertical axis windmills, sapphireenergy, magnegas, blacklightpower, plasco energy?

[@ethansilver5892]

You could say exactly the same about nuclear power though, the forth generation reactors on the horizon are considerably more attractive than the current generations used in his calculations, so if anything it has a renewable bias. I don't think David is pushing "whichever power source he personally makes money off." like Jeannette says either as hes pretty respectable and is above all a physicist, a Cambridge physicist no less

[@robertweekes5783]

Great talk!

[@alanky89]

That's exactly what he's suggesting in this scenario. He's maxing out the outputs of the renewables to impossible circumstances where they're all implemented on the same area of land. The problem is simply that there's no new energy source that has a high enough EROI to satisfy our energy demands. I guess we'll just have to see what happens in Germany's attempt to switch completely to renewables. I truly do hope Mackay is wrong and we are able to make the switch.

[@TheKingdomofErnor]

He didn't even mention geothermal, which is the most abundant renewable energy source on Earth, and is also a very concentrated source of energy. Still, his talk was good, and geothermal might be similar to desert solar farms in the UK, in that they have no geothermal sources there, but I couldn't say.

[@Zoidode]

Sorry, I thought you mean his speach wasn't biased when you meant solid & honest. Because I watched it and I saw a Professor talking all sorts of nonsense about renewable energy, using outdated & purposely misrepresenting data. At the same time he called nuclear power renewable, said it's clean and used a very strange comparison to renewables to state his opinion that it's a better solution. For example windpower produced 270 W/m2 in Germany in 2008, he said: "2.5W/m²".

[@penkatadrums]

Please go to 8:45 and pause. Please explain to me how does this system produces those results. It says that those are 25 sq.m. of panels, multiplied by 20 W per sq. m. makes 500 W installation. How does a 500 W installation produces 12 kWh per day? Wouldn't that require 24 hours of sunlight? How is this 500 W installation not producing 3 kWhs per day, by getting 6 hours of light? What am I missing here?

[@berndameel5596]

+penkata drums It is 20 W/m² on average, i.e. 500W on average. The peak power is 200 W/m² (or 5kW peak power), but as you mentioned, the sun isn't shining all of the time, so on average the installation with a peak power of 5kW is only producing 500W on average.

[@penkatadrums]

+Bernd Ameel Oh, I see... that is the only thing that would make sense I guess, that 20 W is the average power for the whole day, even when the sun is down... Thanks. So when he is talking about the solar parks @ 4.2W/m2, would that mean that it is also the average for the day, that would mean 4.2 W x 24 hours equals average of 100.8 Wh (0,1 kWh) per day per sq.m.? I already did some calculations with 4.2 W of installation x 6 hours a day... So that would mean my calculations are 4 times off...

[@berndameel5596]

+penkata drums Yup.

[@penkatadrums]

Bernd Ameel Thanks :) Are you sure this information is correct, sir? I didn't hear it mentioned in the video, did you read it somewhere, or just logically deducted it?

[@pinarellolimoncello]

+Bernd Ameel I was thinking exactly the same. I have read this chaps book and generally think he's brilliant but I wasn't clear on his figures either . I have a 4kw solar system on my roof that is 25.6 sqm, it has generated 3300kwh per year for the last 4 years, that is 9kwh per day and it could perform better if it was angled. If one used his figure, maybe he would mean 9000w divided by 24hr day divided by 25.6sqm equals 14.76 w/sqm/24hr day. Doesn't sound like much and yet I happen to know 3300kwh goes a long way in a 70s built 2 bed flat. Moving on, energy is neither created nor destroyed it merely changes form. On that basis and on my reckoning we have 200 years of fossil fuels pumping out heat energy , we all need air source heat pumps to pump it back into our houses. Moving away from competitive industry to co-operational capitalism would also help as vast quantities of energy are wasted in competing against each other. A job swap app could be the first thing to be developed to stop people traipsing to and from each others towns to do similar or same job.

[@jangofet555]

i think solar panels are now 53 watts per square meter including the space between them and the trackers. ewh.ieee.org/cmte/substations/scm0/Raleigh%20Meeting/Conference%20PDFs/Technical%20tours/PE_Solar_Farm_Fact_Sheet.pdf i estimate one could use 12 kw per day including charging a 45 kw electric car each week and conversion losses, coupled with 14 kw battery. 12 kw from 4 kw solar panel system drawing 3 hours of sunlight a day. they can fit on the roofs of things. like 600,000 square kilometers(probably less). at $0.5 a watt including installation it will cost $16 trillion for 8 billion people, and $5000 for 14 kw of usable battery storage it will cost 40 trillion for 8 billion people. so 56 trillion, and it will last 10 years for batteries and 20 for panels. so 4 trillion a year for batteries, and 0.8 trillion for panels a year. the population will max at 10 billion. and like 20% percent of them will be children and 20% old people. vacuum tube transportation technology will cut energy consumption from transport sector down to like zero including personal transport by probably 80% which i didn't take into account. earth homes for passive heating and cooling or better insulation and thermal mass heating and cooliing. highest energy efficient machines and appliances with AI auto shutoff. eat a lot less meat so we don't have to spend power desalinating sea water. what else uses lots of power that we don't need? what else uses significant power? speakers, maybe growing plants,

[@Brainbuster]

To put horizon's above comment in context, I believe horizon is responding to 8:42 in the video, where the speaker asserts that solar panels deliver 20 Watts/sq meter, and then goes on to assert that solar parks deliver 5 Watts/sq meter because of the necessary gaps between each panel. I did not see "53 watts per square meter" in the linked pdf.

[@jangofet555]

i just read about a new pv panel that has reached 36% efficiency in the lab it seems like it should work out, i hope so, 30 - 35% would be virtually double output and thus half the size, cost, materials. phys.org/news/2016-09-startup-residential-solar-panels-efficient.html

[@sietuuba]

These 'figures of merit' are the averages over a year and total facility area, not just the solar cell in a solar module which comprise an installation. One must bear in mind that even a hypothetical cell with twice the conversion efficiency only doubles the production in that small area that is less than the total, and only during daylight hours. The relevant figure that is the average over the year per total area is less than doubled because there is always dead space and also the panel does not produce all the time (the capacity factor is never close to a hundred percent). Of the 8760 hours in a year a solar array far from the equator produces on the order of a thousand hours perhaps, depending on your latitude of course. Also... don't confuse kilowatts, or kW (power) with energy, or kWh (kilowatthours). Your 4 kilowatt solar array with 3 hours of sunlight produces (4 kW * 3 h) == (4*3) (kW*h) = 12 kWh of energy. Never omit the 'h' or any other units when referring to energy or doing calculations.

[@hewholistenstomusic]

or geothermal. Check out Chena hot springs for an example of how to do sustainable energy right

[@charleslong5373]

We should build millions of very reliable small gas turbines, each one capable of producing 5 kilowatts continually. You have one of these in your garage or basement, and we dispense with all the overhead wires. You pay for the methane to run the turbine. At night the turbine charges a large capacitor and during the day you use the stored energy plus what the turbine generates.

[@LuisSeijo]

By solid I mean it is based on data and transparent estimations everyone can analyze and criticize by his/her own means. By honest I mean the results are reported no matter what they are, without filtering them with political or any other sort of considerations. Start by looking at the demand is a methodological choice, but this does not mean it is intrinsically honest nor biased. I definitely cannot see what makes you think it is "the" (only) honest approach.

[@IanCocking]

Such a loss to Humanity. His work will live on

[@trentbusta1]

If he had done the research he would have come to this conclusion, here in australia many people reach there energy needs very easily,using solar infact they often make a pretty some of money buy selling the extra energy back to the power companies, the same goes for germany.20% of germany's total energy production comes from renewable energy.All we need is more education to help people to jump on board, another reason is theres an upfront cost to get started.

[@choky82kr]

I'm actually not impressed cause of the shady arithmetics at the beginning (which is probably harder to explain, and for the point being made an explanation was not necessary at all) but im more curious of what kind of plant for the biofuel they were using to calculate the area of 8km. Overall great speech.

[@chrisschene8301]

I am an engineer, I love the numbers and analysis he is doing: This guy is fantastic! My answer = Nuclear. More subsidized public transport. Electric cars are not yet economical for the typical family. Raise the cost of commuting by auto to the city and more people will choose public transit.

[@shalow2]

Firstly, the resources to make solar panels is already on the moon, what needs transporting is something to convert lunar dust into solar panels, lay them out and connect them together. Secondly converting power into a laser beam and beaming it to a receiver that converts it back to power is feasible, and will probably become the new standard, as a satellites based powergrid instead of the standard earth based powergrid. It's not feasible right this moment, but 5 years from now, 10 at the most.

[@ethansilver5892]

OK, I'll explain in chronological order. How would you get the solar panels up there? you'd need a lot and thats a lot of weight which would cost a ridiculous amount of money, the cost benefit analysis would be insanely bad. The even more serious flaw is getting this energy back to Earth, "beam(ing) the energy" would mean converting it back into light and be a hugely inefficient system, it would be more efficient to just use solar panels or even better, a viable source of energy like nuclear.

[@DameMak]

I am wondering why he omitted to mention natural hydroelectricity sources and their great potential.

[@volta2aire]

Fewer people are needed as work is automated and contraception is effective in lowering birth rates. As we reduce habitable areas, we reduce population (carrying capacity).

[@tongyunli4265]

RIP, David!

[@SeanOHanlon]

I work in the field of Renewables and I think he is being a little short sighted in his thinking. It's not a matter of which technology works best but rather one of stacking those technologies. Solar, Wind, Hydroelectric, Geothermal, Tidal, Wave, Advanced Biofuels from diversified Energy crops such as Agave, Sugar Beets, Sugarcane, Sweet Sorghum, to Algae from Waste Water Treatment Plants can meet our existing and future energy needs as long as they are combined to compliment each other.

[@factnotfiction5915]

@Sean O'Hanlon - it has been 8 years. Which country is stacking those technologies together properly? Sure, Norway, Iceland, Costa Rica are blessed with the perfect geography for hydro and geothermal - but where is Wind/Solar PV/Solar CSP a big deal? Denmark at 63% renewables (but just a tiny bit below the European average carbon dioxide per capita emissions - although better when looking at electricity only)? Germany at 37% renewables (and ABOVE the European average carbon dioxide per capita emissions - although worse when looking at electricity only)?

[@LogicalMayhem00]

Why cant i link youtube videos on youtube.....+

[@mooliki01]

The global population is widely accepted to continue to grow, potentially reaching 9 billion in 50 years. Birth rates may be declining in some countries, but it's improved living standards and longer lifespans that have been the main cause of population growth world wide. I haven't seen any studies suggesting a global decline. Where did you get your info?

[@Zoidode]

In case you are wondering: space between turbines is larger than foundation space by a factor of 100 (2,7 W/m² like a bad magical trick). That land between turbines is commonly used for farming, forestry or fish swimm around. Biofuel yield is 1600-4000l per ha and not 1200l OR 5000l worth of biogas. So on... He makes a very unscientific claim at the very start, because he states that he is about the objective truth... something that does not exists. He is about making nuclear energy look good.

[@factnotfiction5915]

And, since the space between the foundations is not full of wind turbines, the W/m2 energy density Mackay calculates is good. Wheat, trees and fish don't make the wind turbines generate more energy.

[@74357175]

What is shady about the arithmetic at the beginning? All the numbers are there, and you can do the arithmetic yourself (I did). If you think his assumptions are off by a little here or there, bear in mind that it *doesn't matter*. Whether it's 8 km, 2 km or 25 km, the point is made.

[@Aluminata]

Necessity is the mother of invention - laziness is the father: We will not produce revolutionary innovations except as we are pushed to do so; by then it will be too late. We need for instance, to completely demolish our existing houses and replace them with the highest conservation technology we can make. We need to produce electric cars recharged by solar and ocean wave power generators. The cost to us now would be enormous - the savings to our descendants massive. Ultimately these things will have to be done. Fossil fuel hydrocarbons will be no more. EVER. That is the future of this Earth.

[@Zoidode]

Renewables certainly take up space, but I wouldn't say significant. You see his 150kWh/d/capita number is based on primary energy consumption. But even he suggests that our energy consumption will be mainly based on using final energy in form of electricity by 2050. (Ch. 27 - Page 2004) He envisions an increase over todays electricity consumptioon by 3x = 1,000 TWh. About 35.000 wind turbines a 7.5 MW would be enough to produce that amount (in theory), covering 5% of the country. So bad? Dunno

[@donaldhobson8873]

Their is a lot of Sahara and its not being used for much.

[@huwjonesification]

Plenty of wildlife and nomadic tribes would suggest otherwise.

[@davida01]

@@huwjonesification Also, it's not ours.

[@thaturaniumguy]

Yep, but it's far away!

[@hotshotsunnyz]

How do you expect to transmit electricity that far without loss, genius?

[@DogCognition]

You got that right - one of David MacKay's tactics is to pick low performance for renewables and assumes they will never improve to make his argument. E.g. in his book he assumes 3 MW wind turbines - but today we already have 7 MW. Also he makes a big deal that people oppose e.g. wind turbines - but it's not true. The vast majority of people in the UK support renewables. A minority support nuclear. Almost no one wants more fossil fuels. David MacKay is a propagandist for nuclear.

[@factnotfiction5915]

Today (2020) we even have 10-15 MW turbines - but they have to be spaced further apart than 3 MW turbines - so the W/m2 is about the same. They are still intermittent, so they still need backup (storage). They haven't surpassed his 'theoretical efficiency' of about 60%. They still have an average capacity factor of 35% (although, obviously site-specific). He is not a propagandist for nuclear, it is just that you don't like to hear what he has to say. He is OK with wind, but he is saying you have to live with those shortcomings.

[@m2k16]

Lack of area well the ocean is quite big

[@robertweekes5783]

Have you heard of rust?

[@defaultUser1974]

Water + Electricity= Hydrogen Water + Electricity=HHO

[@tonycarden4989]

I know he was being very simplistic but in relation to Transport David does not give enough weight to transport. At this stage I am unaware of any technology other than Diesel Engines to run the heavy transport fleet and most heavy machinery. So the ability to reduce consumption of fossil fuels in this area is even less

[@serenityinside1]

Asda have been running a sizeable piece of their lorry fleet on recycled veg oil for years now. In the Netherlands lorries are run on propane

[@incognitotorpedo42]

Tesla is now in the process of changing this. Their new 18-wheeler looks very interesting.

[@andrewboada8130]

Hmmm, solar in the Sahara. A few thoughts come to mind. Transmission losses, night time and sandstorms, which both blot out the sun and trash solar panels. These sprawling renewables buildouts and their attendant supporting infrastructure will be enormously expensive to build and maintain as they depreciate. A big problem with renewables that people usually gloss over: it isn't good enough to install renewables with an expected annual output that matches annual demand. The power needs to be produced when it's demanded on a moment by moment basis. Power that is supplied in excess of demand is almost useless, and can be just as damaging as having demand for power exceed supply.

[@mark4asp]

Wind & solar only make sense with massive energy storage [pumped storage, synthetic fuels, compressed air, batteries, ...]. Energy storage has conversion losses so we'd need even more renewables. The same goes for nuclear power. The other problem with Sahara is that it's already inhabited, and Britain would be dependent on another country for our energy - a non-EU country.

[@robertweekes5783]

Mark Pawelek You don't need to "store" nuclear power because you can dial a reactor up and down to meet demand. Advanced reactors like molten salt reactors (LFTRs) can automatically match demand due to negative feedback loops (liquid fuel is less critical when energy demand is low and temperature rises, and vice versa).

[@heavyweather]

Robert Weekes No they can't. All those myth about gen4 are kinda boring. Try daryanenergyblog. wordpress. com

[@gasdive]

Andrew Boada I know I'm late to this, but the long distance transmission problems have been solved. High voltage direct current transmission allows very long runs with very low losses. You can get power from Australia to the UK with about 60% efficiency. That's significantly better efficiency than most storage which is around 50% round trip (lithium aside, which is about 80% but expensive). It's much much better than the commonly proposed idea of converting electricity into methane (40%) and then transporting it to the UK where it's burnt in power stations (40%) for a total efficiency of 16%. The losses from the Sahara to the UK are even less. Up around 80-90%

[@ROBwithaB]

You seem to be under the impression that coal and nuclear plants are good at following demand "on a moment-by-moment basis". They are not.

[@trentbusta1]

Our report involved 52 respected scientists. The new data, based on Belarus national cancer statistics, predicts approximately 270,000 cancers and 93,000 fatal cancer cases caused by Chernobyl. The report also concludes that on the basis of demographic data, during the last 15 years, 60,000 people have additionally died in Russia because of the Chernobyl accident, and estimates of the total death toll for the Ukraine and Belarus could reach another 140,000.

[@Mister.Psychology]

And that's only if you reduce the energy consumption from 120 to 16. Do you want to sell your car and spend a lot of less time on electronics? Wind turbines is a no go, how could you possibly get all the metal needed for them?

[@heavyweather]

Jurij Fedorov How can we possibly get all he metal for all those cars, buildings, cans,...we dig it up. you could cut material use with new wind technologies...like Kitegen. Then you get an EROEI between 300 and 1400. Todays turbines got an EROEI around 50. Let's get it done.

[@jenhulford5572]

Jurij Fedorov You are right. There are many drawbacks that renewables fans completely ignore about their pet power but the most insidious is how resource intensive they are. In the sheer numbers needed to make a dent in our HUGE power needs, and then have to REMAKE them every 10-25 years?? The hazardous waste...The processes that have been tried for recycling the rare earth elements from solar have been more toxic than even the panels are. If all factors were considered, and all facts were stated and accepted, nuclear would be our most prevalent power form on earth. But lies rule among grassroots energy groups.

[@ROBwithaB]

Bio-fuels are clearly a silly idea. No argument there. However, your starting assumptions for wind are almost certainly wrong, as the Scottish numbers are clearly starting to demonstrate. Remarkable what can happen in just three years. Might be interesting to re-run these numbers with the new capacity factors coming in for wind power. And then maybe you could do another talk...

[@scottclowe]

Sadly, he can not.

[@ROBwithaB]

Yeah. I made that comment nine months ago. Dave was a smart guy, and his approach was a sound one. His big contribution will probably turn out to be the framing of the problem is certain easy-to-understand metrics like kWh/person/day, or W/square metre of both supply and demand for a particular geographical area. But as smart as he was, he most certainly was not an economist, and (like many academics) had very little real-world business experience. His "back of the envelope" arithmetic tended to ignore the very strong drivers to technological improvement once a certain penetration threshold of new technology has been achieved. As a result, he was trapped within a paradigm of what he could see and measure, which was the existing tech of the time. This led him to vastly underestimate the potential of renewables to get the job done, and to overestimate the requirement for nuclear power. As a result, many people seem to have now adopted him as some sort of undead Messiah advocating nuclear power. Things have changed, radically, in the past few years. The revolution he spoke about at the end is already happening. And in fact was already beyond the tipping point by the time he became ill. It's a quiet revolution and is happening almost invisibly, powered by small, incremental improvements in existing technologies. For instance, an increase in average capacity factors for wind turbines of perhaps 5% (which can result from something as seemingly trivial as adding another 10m to hub heights) can change the entire calculation. For a start, that 5% improvement in capacity factor, from 25% to 30% represents an incremental improvement of 20%. So already, the area required for windmills is reduced by about 10,000 sq km. But that's not all. Higher capacity factors mean more consistent (less peaky) production. So a lot less gets wasted, meaning that you need even less land area. And there are fewer lulls, meaning less requirement for backup buffering (gas peakers, pumped hydro) etc, freeing those facilities up for balancing other loads, so less yet again. The same sort of thing applies to small incremental improvements in PV cost and efficiency, battery cost and energy/power density, demand response technologies and grid management software. Really boring stuff, but able to change the world completely in about a decade or two. Meaning that there will be a very radical redistribution of wealth within a very short timeframe, probably greater than we've ever seen in recorded economic history. Some people (those who currently have the wealth and power) are likely to be rather upset about this. Unfortunately (and ironically) many of them are citing Dr Mackay's work as a reason to DELAY the transition to renewable energy production.

[@Brainbuster]

He mentioned that they would need to cover half of UK in wind farms to provide all its energy needs. However, that seems a bit misleading, because most of the area of a wind farm is empty, usable space which can be used for anything else.

[@ROBwithaB]

Exactly. Misleading at best. Especially considering that most of the best wind areas are offshore or in very sparsely populated areas on land. And that existing technology has already halved the required area. And that the very idea of requiring a cold, wet, densely populated, economically advanced island to be entirely self-sufficient is a completely false argument for or against renewable energy. Did he require that the UK have its own sources of uranium in order to go nuclear? Or that it should supply all the steel and concrete that goes into the construction? MacKay became "famous" for this layman-friendly pseudo-scientific "Big Idea", which was that renewables would never be able to provide the energy required to sustain a modern economy. He was the affable nerdy scientist who was essentially providing "expert" validation for the emotive opinions of the uninformed conservative masses, allowing them to deride anyone who proposed a sustainable energy system. Unfortunately, his assumptions (especially as to cost and efficiency of the various technologies) were already hopelessly outdated even by the time that he became "famous". Instead of updating his talk at regular intervals to reflect the changing realities, he persisted with the same alarmist message, which led many to conclude that nuclear was a necessary (and urgent) priority. He just spouted the same packaged speech, with the same outdated data, over and over again. With conclusions that become increasingly obviously wrong, even to those with nothing more than an internet connection and a calculator. But because of his fame and his academic credentials, his obsolete "science" underpinned many energy discussions at national level. He had a young family to support, and knew that he didn't have much time left to build up a nest egg. Is it possible that he allowed his personal priorities to cloud his judgement? Is it possible that a more nuanced, less alarmist, viewpoint would not have led to the same amount of "fame"? Would he have been in as much demand as a speaker if he admitted that he'd made numerous mistakes in his famous paper? Is it possible that his "message" was music to the ears of those with a vested interest in delaying the adoption of sustainable energy? Is it possible that some of his substantial speaking fees were paid by "foundations" and other groups funded by the nuclear industry? Or even the fossil fuel industry? Was it simply easier to stick with a prepackaged, popular, dramatic, easy-to-follow narrative (even though it was flawed) than to spend dozens of hours each month following the industry, reviewing technological improvements, researching multiple new technologies, updating production numbers for multiple countries, etc etc, and then updating the speech accordingly? And would such research have diluted the underlying conclusion of the existing "show", making the entire speech less entertaining and less popular with its target audience? After all, why tamper with a winning recipe? I don't know the answers. But towards the end, his obstinate defense of his increasingly outdated views became the prominent narrative. And THAT might yet be his legacy, despite all the good intentions earlier in his career.

[@Science1314]

a combination of wind and nuclear would work

[@leonardoalcayaga6640]

Why does he bear nuclear power as a renewable?

[@jenhulford5572]

***** And what most people call "renewables" only can create power as long as the solar panel stays efficient (being generous with the word "efficient") and the wind turbine keeps spinning. When they die (10-20 years), once you have to replace it, the sheer amount of resources needed, kind of make that term a misnomer. Without them, wind and sun do not generate usable power. So their renewable moniker is 100% dependent on something that lasts less than a 1/3rd as long as a nuclear reactor. And is massively resource intensive on the level that would be needed to "replace" a nuclear reactor, which they really can't.

[@canadiannuclearman]

Leonardo Alcayaga Nuclear is renewable check fast breader

[@MrDavidBFoster]

SO... Going on three years since this talk was given.... Anything happening? Or are they still "talking"?

[@sebastianlundqvist5828]

solar power 40% efficient. 20% before

[@ROBwithaB]

Huge increases in the average capacity factors of new wind turbines. Also, he pretty much ignores PV. But if it's cheap enough (using fewer materials), it doesn't matter too much that it's not very efficient. There are also HVDC interconnect lines going up all over, especially to Norway. Norway basically has enough "battery" storage within it's hydro industry for the whole of Europe. So yeah. David was a nice guy. But he was wrong. Not egregiously, repugnantly, dishonestly wrong. Just wrong enough (by a factor of 2-5 in each of a number of different assumptions) to make his overall conclusions almost irrelevant. Especially on the "need" for nuclear. So instead of covering 1/4 of the entire UK with wind turbines, one might need only about 8% of the land area, plus a bit more in shallow offshore waters. And solar doesn't need a lot of agricultural land. There are lots of roofs in Britian, including some very big ones on shopping centres, factories, distribution hubs, etc. PV doesn't need to get much cheaper to make it worthwhile for the owners of that sort of real estate to install, and save on (retail) electricity prices. And we only need batteries to be cheap enough for peak shaving, which will probably happen within about 24-48 months. That sort of thing... It can be very difficult for anyone to imagine a complete transformation of any system. We know what we know. It is difficult to predict or foresee that which does not yet exist. Dr Mackay's analysis was predicated upon an energy system that was built around "baseload" thermal power. The energy system of the future is likely to much more responsive, more distributed, and more interconnected. It will not be driven by government policies , but by the boring dictates of free-market economics. The one thing that will change everything, and make a complete transition possible, is deregulation of the electricity market. Monopoly utilities have no incentive to change. We need a real-time open market for electricity. With proper price signals and open competition, the correct (most sensible, efficient) things will happen, and keep happening, and innovation will drive price declines and improvements in efficiency and reliability. A carbon tax would help...

[@davida01]

@@ROBwithaB TLDR. You are obviously much wiser and better at maths than him. The limiting physics of wind turbines are set by physics. the capacities per turbine might have improved, but you need to space them further apart. I sympathise greatly with those who are against going for nuclear energy to replace fossil fuels, but investment into development into safe, liquid fuelled thorium or fast spectrum uranium/plutonium reactors would reduce many of the problems with nuclear and create a much more sustainable generation, base. It would need government investment, not private.

[@hen2005]

“We need to stop shouting, and start talking”... I guess they decided not to listen.

[@shalow2]

Half the moon is constantly lit, and no one really needs the space, also, there's no rain, no wind etc to damage solar panels. Cover the sunny side of the moon in solar panels and beam the energy down to earth, it really can't be that hard. The problem is, that there really isn't a high demand for it.

[@PCMcGee1]

So, from your own numbers, 10.5m2 solar panels per person would mean you were 100% renewable. Can the gov subsidize half the costs and install on my roof tomorrow? (Solar=12kwh/d/m2 / demand=125kwh/d/p == 10.5m2/p)

[@LightInTheSky91]

Those who don't want wind farms and complain that they ruin "the views" should also have to give up their power. Or solve the fusion issue.

[@DogCognition]

No, they don't. A tiny minority of NIMBYs become hysterical but the majority of people understand the necessity of wind power and support it. That support *increases* when people are exposed to the *reality* of wind turbines.

[@KatakiUchiha]

*Conveniently forgets about Geothermal Energy, perhaps the most promising of all renewable sources...*

[@VincePhoenix]

Only few people actually think of it when talking about nuclear energy, or renewable energies. It might depend on how deep you would like to go, but as far as I know, geothermal energy is more a way to reduce our consumption than a way to generate energy. I mean, the conference was about energy in general, but it clearly covers only electricity production.

[@polka23dot]

David MacKay does not have the vaguest idea how to cope with the energy crisis.

[@LuisSeijo]

I would suggest to stick to his claim of using data rather than adjectives in the energy debate. If he is using outdated data, you have the opportunity to put it to date. Saying he's purposely misrepresenting data is a serious accusation that tends to undervalue your opinion unless you seriously support it. 270W/m2 in Germany of installed power, of produced power, per square meter of installation, per square meter of something else?

[@Zoidode]

What's solid or honest behind his approach? He doesn't have a comprehensive understanding about the possibilities of current renewable energy technologies nor does he use data in an honest way. The honest approach is to start by looking at what can be done at the demand side first. If you know what you're talking about you end up at a reduction of 50-80% energy demand. Supplying the remaining 20-50% of current energy demand is possible even with renewables 10year old renewables.

[@factnotfiction5915]

Yes! Energy conservation + nuclear power!

[@DeiwinSarjas]

They're different units. That's what you're missing

[@Spyrit2011]

How come this physicist never considered vertical farming? What about maglev wind turbines? Geothermic, wave and tidal. It is very sad to see convergent thinking coming from scientists. And it's not just a matter of using one form of renewable or another it's using many. And lastly, since 50% of energy is lost in distribution, wouldn't it make sense to correct that huge mistake?

[@killokas]

yay! that and different methods to actually produce solar panels cause the current ones use materials that are going to run out 10 x faster than the actual gas and oil reserves. But hey, with carbon nano-tubes everything seems to be possible...

[@Zoidode]

My bad. It's the installed capacity taking the actually capacity factor of the average turbine into account. As I've said, I am sure his numbers make sense in his own logic... but since the book & this talk are about the feasability of sustainable energy sources he sure tries very hard to paint a grim picture. Since he is in a political advisor position such bias is rather disturbing. Or are you suggesting that the folks at the Fraunhofer Institute who actually know about renewables are silly?

[@aerofeisst338]

Assuming we all decide that it's a great idea to stop developing these technologies.

[@hogo1]

in another 20 years there will be another billion people on earth, and they're gonna want to move to Britain, Canada, USA, Australia, good luck world.

[@jetli8703]

How depressing. But as he said, we have to grown ups and start talking.

[@trentbusta1]

Propaganda is a form of communication that is aimed towards influencing the attitude of a community toward some cause or position by presenting only one side of an argument. Propaganda is usually repeated and dispersed over a wide variety of media in order to create the chosen result in audience attitudes. The fact that the average person's power needs can easily be sourced from solar panels on there individual roofs,and barely gets a mention begins to ensue propaganda .

[@ewaf88]

Nuclear seems the way to go

[@davida01]

Liquid thorium or fast spectrum uranium/plutonium, to use up all the fuel, destroy the plutonium and reduce nuclear waste.

[@Science1314]

why not?

[@ethansilver5892]

So you think the most efficient way to produce energy is to design and build a robot capable of magically converting lunar dust into photo voltaic cells and then going on to cover half the moons surface area with them and create a power network to send the energy to a laser where the energy is affected by the inverse law, in contrast to building a nuclear power station with cheap fuel and today's technology? You need to stop watching cartoons.

[@defaultUser1974]

search magnet generator on youtube

[@Zoidode]

Wind produces 270W/m2 per hour. An assertion using anual production divided by 365d x 24h and putting it into relation to the m² used for the foundation of turbines. What he did is the very common trick of downplaying the efficency of wind turbines by considering the space between turbines as land-use. I am sure his data that is valid in his own logic. His 2.5W/m² is a theoretically valid data-game, but ridiculess considering reality. Just as 1000W/m² for nuclear power is pure charlatanism.

[@DogCognition]

Of course. MacKay is not that stupid, but like everything else he does he picks the worst figures he can find for renewables and assumes they will never improve on cost or performance beyond what they achieved c. 2005. In comparison he talks about nuke tech that does not exist as though it could be built immediately without any problem. David MacKay is just another propagandist for nuclear. He simply has a veneer of credibility due to his physics PhD which is enough to fool some people.

[@bboybasics2]

5W/m² for solar PVs? do I miss something or is he lying?

[@harmsy]

Basile Collard this is averaged out over a year, including night time!

[@hogo1]

Where are you getting your information? Because it is dead wrong, there is no evidence that the world population is declining or will even begin to decline until around the year 2050. Some countries do have declining populations (Russia, Japan) but these countries by no means offset the others that are growing. China is still growing btw.

[@terencegalland]

Right, an awful lot of common sense ted talked here, just an idea instead of lambasting Genetically Modified crops what if they could be used to make biofuel instead of using them for human consumption as they would have a greater crop output thus reducing the land area needed!

[@GieZatRedLight]

Had fun watching this video in 2018, here you can see, if you have spare time, a linear thinking man with an outdated mindset from 2012. And pretty much without matter today, fortunately!

[@TheMraptor]

The concept ifni.co/concepts/energy

[@LuisSeijo]

Too many adjectives for my test. End of discussion from my side.

[@Zoidode]

I would recommend Mr. MacKay to utilize his mind in a more objective way. From his talk it becomes VERY obvious that he is heavily biased against the science behind 100% renewable energy scenarios. His entire presentation is a showcase of ignorance by a person who believes he has discovered knowledge when he is in fact a member of a faith based cult. Simple showcase: How come his 1000 W/m² number for nuclear power doesn't consider land use from uranium mining, enrichment, spent fuel storage?

[@shalow2]

Not exactly a constructive remark.