A reality check on renewables - David MacKay

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  • Published on Jun 25, 2013
  • How much land mass would renewables need to power a nation like the UK? An entire country's worth. In this pragmatic talk, David MacKay tours the basic mathematics that show worrying limitations on our sustainable energy options and explains why we should pursue them anyway. (Filmed at TEDxWarwick.)
    Lesson by David MacKay.

Comments • 3 671

  • Wayward Geologist
    Wayward Geologist 3 years ago +131

    Finally a discussion about renewables production and not their capacity. The talk was an honest look at the nature of the technology. Renewables do have their place but too many people are selling a myth behind them when they use the word capacity to describe their installation.

    • oystla
      oystla Year ago

      Erik Lakeland technology advanses and cost reductions will make solar and energy storage the cheapest option within a decade.

    • oystla
      oystla Year ago

      Jakob Schulze you can also combine solar and agriculture. ITS called agrivoltaics 😎. This presentation is no longer relevant caused by technology advances.

    • Erik Lakeland
      Erik Lakeland Year ago

      @Jakob Schulze Storage + wind and solar is not cheaper when it is included in a decent amount - you know, an amount that would prevent lots of natural gas being burned. The largest battery in the world, Gateway in California, lasts for 1 hour. That's simply not close to adequate when wind and solar regularly have 24 hour droughts. In my US state, solar's capacity factor is better than Germany's but only 18% total, which requires even more storage than Gateway in its optimal location. Continued natural gas use unacceptable and should really dampen the enthusiasm for renewables.

    • fact not fiction
      fact not fiction Year ago

      @Jakob Schulze He wasn't counting the space as lost to other development; he was counting the space as lost to more energy production - thus the catchment is the correct measure, not the footprint.
      In other words, a wind farm has X W/m2 energy density, but a wind-sheep farm _also_ has X W/m2 energy density!
      I.e. you can cover 100 km2 with wind farm _catchment area_, but you can only put 1 wind farm there. Yes, you could put a solar farm or biofuel farm on top of, but you can't put -both- a solar and biofuel farm on top of. Such a wind/solar-farm or wind/biofuel-farm would have slightly better W/m2, but not much.
      It is easier to imagine with hydro - a hydro plant has maybe 10,000km2 catchment area. If you reduce it to 9,000km2, then 1000km2 worth of rain went somewhere else (perhaps to another hydro plant), thus you have a smaller hydro plant.
      With nuclear, the footprint s the correct measure because an additional plant doesn't change the catchment much.
      If we use your figures (1km² footprint of the facilities, 8km², exclusion zone, 314km² population exclusion zone) you can immediately see that adding in a 2nd, 3rd, 4th plant changes the facility footprint (1->2,3... - 200%/300%) a lot, it doesn't really change the exclusion zone (8->10 - 10%) or low population zone much (0.1%?).
      (actually, multiple reactors on the same site use about the same area as a single reactor).

    • fact not fiction
      fact not fiction Year ago

      @Abhik Kumar De 3rd misleading question, 3rd proper answer:
      current 2020 numbers:
      www.cleanenergyreviews.info/blog/most-powerful-solar-panels
      the Jumbo 800W panel from JA solar at 2.2m high and to 1.75m
      800 W per 3.85m^2 = 208 W/m2 ( _NOT 1000 W/m2_)
      @ 25% capacity factor in the UK = 52 W/m2, which taking into account 7 years of progress, shows his back-of-the-envelope is still the correct order of magnitude

  • Paul G
    Paul G 3 years ago +325

    Amazing. A man who is both a fan of the environment *and* math+common sense.

    • Richard Monroe
      Richard Monroe 2 years ago

      @Ground Control increased rainfall. When did it rain substantially in a desert.

    • Alexander LegisNonScriptae
      Alexander LegisNonScriptae 2 years ago +1

      " why is the Sahara shrinking?" I don't know. Did he take a cold shower?

    • Alexander LegisNonScriptae
      Alexander LegisNonScriptae 2 years ago +1

      Also, methane burns to form C02 and water so: plant growth and human water shortage solved!
      Sure, one might have to move a bit of beach front property around

    • Alexander LegisNonScriptae
      Alexander LegisNonScriptae 2 years ago +1

      Africa had 227 million people in 1950, 1200 million in 2014, and is set to have 4100-4400 million by end of this century.
      Will there be a lion, elephant or a tree left? Who knows.
      However.
      That's a LOT of poop!
      Use that methane to power the World!
      Someone please do the calc on that, if they can find an envelope that hasn't been used as loo paper

    • Bertdog
      Bertdog 2 years ago +5

      @Ground Control Don't ask hard questions. It might hurt someone's feelings.

  • Dominic Barber
    Dominic Barber 3 years ago +203

    Wow - a sane person, talking sense without an agenda. Amazing.

    • Stefan Starkov
      Stefan Starkov 6 months ago

      ​@Abhik Kumar De Hi Abhik, as others seem to have posted in this same overall thread, MacKay's numbers for renewable energy density are accounting for seasonal fluctuations in solar and wind output, in addition to the intermittent nature of these natural fuel sources. Across seasons, wind and sun output differ, and within a single day, the sun does not shine at night and wind is not always blowing. When accounting for this, the total average power output for solar panels as of 2020 is still roughly 5 to 20 W/sq-m, and for a Wind turbine it is roughly 0.5 to 1 W/sq-m.

    • Troy LaDoux
      Troy LaDoux 10 months ago +1

      @fact not fiction clouds, dust and rain/snow may have been factor in his calculations. All reducing the efficiency of solar.

    • fact not fiction
      fact not fiction Year ago +2

      @Gaz Masonik The late Dr. David Mackay was an upstanding guy. Please don't cast aspersions on him or his motives. Learn more:
      en.wikipedia.org/wiki/David_J._C._MacKay

    • Gerold Firl
      Gerold Firl Year ago +1

      @Abhik Kumar De Maybe he's doing a 24-hour average for the panel.

  • jahenders
    jahenders 4 years ago +21

    A great presentation -- discussing a real issue like grown-ups

    • shandcunt
      shandcunt 3 years ago +1

      Except he isn't, we literally ran his experiment and let the free market decide and hinkley point C is expensive, over budget and delayed whilst renewables continue to drop in price - he was 100% wrong

  • DaztheDuke
    DaztheDuke 6 years ago +444

    A great loss for humanity. So sad to discover Sir David MacKay passed away recently. I think Davids book 'without hot air' is a truly inspirational piece of work and such an important read. The work of a true 'Hero'.

    • Derrick Stableford
      Derrick Stableford 2 years ago

      DaztheDuke His book is very good. One of the big things really, is that no one solution will work on its own. Isn’t the uk offshore wind farm capacity layout actually looking like the map in the video now.

    • Brad Davies
      Brad Davies 2 years ago

      Yes I am heartbroken, who was he?

    • MindSight
      MindSight 2 years ago +1

      First time I heard of him and seen anything of his work. Very clear and interesting. Sorry he passed away. A loss for our society.

    • John Baugh
      John Baugh 2 years ago +2

      Just came across this clip. So sad to hear he passed

    • fly bobbie
      fly bobbie 3 years ago

      @Lee McBroom I had a school friend in 1976 when he was 17 die from stomach cancer.

  • Henrik J
    Henrik J 4 months ago

    This is still one of the best TED talks I have ever watched. Thank you kindly, Sir David McKay. May you rest in peace

  • Rafael Gomez
    Rafael Gomez 4 years ago +104

    I've seen a lot of videos on the subject this by far is the clearest projection of ideas by a humble human being. May he rest in peace

    • NeverSettleForMediocrity
      NeverSettleForMediocrity 2 years ago +1

      @shandcunt If you consider the limitations in depths and distance from the shore, I would say, we have almost exhausted a lot of space already. How much space would the storage power plants for that much energy consumption need?

    • shandcunt
      shandcunt 3 years ago

      @Will Baker Logically, thats how I worked it out - how on earth do you work things out? Illogically? that seems like a silly idea

    • shandcunt
      shandcunt 3 years ago +1

      @Best Bits He's wrong about how much space you would need for solar and wind - how much land does an offshore wind farm use (You know, the places where there are lots of wind like in the north sea in england) - he act's like "Ohhh noes, the precious land, leave brittany/the land alone..."

    • Best Bits
      Best Bits 3 years ago

      @shandcunt Go on then, what exactly is he wrong about?

  • This Guy
    This Guy 3 years ago +31

    honestly my money's on nuclear power, it just seems far more practical than everything else, especially the newer types being developed, but we're too scared to really try them because of all the fear-mongering.

    • Gary Sacriponte
      Gary Sacriponte 6 months ago +1

      @Jackson Reasoner Much safer, cleaner and practical than all renewables combined.

    • Jackson Reasoner
      Jackson Reasoner 7 months ago

      Yeah! I’ve applied to study nuclear engineering in college, but don’t get word until December at the earliest. I’ve spent hours satisfying my fascination via research though

  • Charlton Jones
    Charlton Jones 2 years ago +2

    It is refreshing to hear from a scientist who appears more interested in facts and possible solutions than pushing a particular flavor of the month environmental agenda.

    • Vincent L.
      Vincent L. 3 months ago

      Should we now scrap Net Zero?

  • Cor Graveland
    Cor Graveland Year ago

    Well, excellent Ted-talk back in 2013 already! So rich in knowledge, compact and understanding. Look forward to an update of the talk, to see what has changed since 2013. Well done and thanks!

  • Jason B
    Jason B 3 years ago +3

    Really sad to hear about his passing. It'd be very interesting to see a revision/update to this talk with the acceleration of EV adoption -- courtesy of cars such as _any_ Tesla, the Leaf, e-Tron (I think they're shipping those now), i-Pace, and the larger array of PHEVs and their functionality as EVs for some commuters. It's been a short while since this talk and things are already looking far brighter.

    • Tommy Vercetti
      Tommy Vercetti 2 years ago

      E-tron and I-pace don't seem to be doing that well, but ya Tesla seems to be doing pretty well

  • JigneshKumar Limbachiya

    Marvelous talk on "A reality check on renewables". Thank you sir.

  • Dr. Vrushali Wagh

    Marvelous talk on "A reality check on renewables". Thank you sir.

  • Hart Fischer
    Hart Fischer 3 years ago +2

    Wow, great explanation of what the reality with renewables is. I am going with solar roofs, electric cars, and energy efficiency and CNG or Nuclear for the rest. Great video.

    • Jakob Schulze
      Jakob Schulze 2 years ago

      He did an error with nuclear.
      The exclusion zone around a nuclear power plant is a radius of 1.6km or 8km² and nuclear power plants normally have a run time of 80%.
      So nuclear isn't producing 1000W /m² but closer to 100W/m².

  • Glen W
    Glen W 3 years ago +1

    Would love to see an updated version of this analysis. Technology has made great strides. :)

  • inventsc
    inventsc 3 years ago

    Great Work from David Mackay . It would be great if we could now re calculate all this by taking methane release from meat into account. Cutting co2 is critical but cutting methane from meat reduction would get the planet cooler quicker and cheaper

  • ʀɪᴛʜɪᴋᴀ ᴀᴘ

    Thank you Sir, for the relevant facts on renewables.

  • David Ramsay
    David Ramsay 7 months ago

    A very good video and lecture on the context of energy supply. This provides perspective. Planning laws should have been changed to make it law to have all new house builds with a south facing roof and installed solar plus a battery. While not supplying all needs it would be a significant contribution. Sooner this is legislated the better.

  • Jacobus DeRottmann
    Jacobus DeRottmann 2 years ago +4

    One big undiscussed issue with the "other people's backyards" approach:
    Transmission losses. X kilowatts produced does not magically appear as X kilowatts where it is used. When you transmit power from point of generation to consumers 10 miles away, transformer substations are used to raise the voltage to thousands of volts with proportionately lower amps to reduce losses in the wires. There will still be SOME LOSSES even in that short distance. It will then be stepped down by local distribution transformers close to the building, the voltage goes to typically 240, and you get most of the amps back.
    If the distance increases to 100 miles away, the transformers must raise the voltage to perhaps 128,000 volts or more and drop the amps further to get MOST of the power to the big substation which steps it down to maybe 10% of the voltage for distribution to the streetside transformer that makes it 240 volts of usually a single phase of the power and your breaker box handles typically 200 amps and the electrical installer splits the circuits to be either 240 or 120. And every step-up and step-down and every mile of transmission wire uses up part of the power.
    Increase that to a thousand miles, and the hundred-mile losses increase 10 times, or you will have to raise the voltage to a horrifically dangerous 1,280,000 volts radiating electromagnetic energy the whole way, which will help efficiency and make it possible to get it there, but it absolutely WILL LOSE POWER IN TRANSMISSION OVER DISTANCE.
    Remember this whenever someone says, "Oh, we can just produce it over there." That is the LEAST efficient way to get power to the user.

    • Nachannachle
      Nachannachle 2 years ago

      True.
      The talk about UK getting energy from Oz or Canada is just theoretical. Transporting the energy from one end of the planet to the other DOES have its costs...in energy. Clearly, not a sensible/pragmatic option.

  • SevenRiderAirForce
    SevenRiderAirForce 3 years ago +7

    This was really cool. He put practical numbers and ideas out there rather than just whinging about stuff everyone already knows is bad.

    • shandcunt
      shandcunt 3 years ago

      His numbers were out of date even for 2012 and they are even more wrong now - he literally was just whinging about stuff

  • Erik Ecoologic
    Erik Ecoologic 3 years ago +4

    very informative about what is realistically achievable with renewable energy

  • Bayesian Factory
    Bayesian Factory 3 years ago +21

    Brilliant Scientist. Thank you for everything, Sir MacKay.

  • Mark Giblin
    Mark Giblin 3 years ago

    A few years back, the average household consumed 14 KwH a day.
    Back then I made an effort to change over to other ways of saving power like LED's and turning things off and it worked for a short while until the energy companies switched over to apparent power over actual because some electronics can appear on the meters as less of a load and cause some inconsistencies but under a mosde of what they think you are using, accounts for this difference.
    I noticed that my bills have doubled, so I am slowly going back to incandescent bulbs because they are loads not electronic... So power companies can shove their apparent power usage up their backsides.

  • Stuffed Chicken
    Stuffed Chicken 3 years ago

    For the last 4 months I've been reading my meter every morning. Mainly to save money, but also to check if the energy companies are for real. Most days it varies quite a lot even when using identical power day to day. My meter racks up what it wants, it seems. (within reason)
    On the bills - before i was up to £135 pcm (although i was suspicious). Now I'm down to average £70 pcm but with Bulb instead of SSE. And i have 3 kids under 6.

  • khushbeer Dhaliwal

    Amazing ideas, talking about some very important issues.

  • stef
    stef 6 years ago +281

    What a man, a great loss for humanity. If our politicians would reason like he did, we would actually be making efficient change.

    • Meg Martel
      Meg Martel 2 years ago

      Jonny - no it actually hasn't "moved forward a lot" R.E means wind & solar. Both of these produce about 1% of global energy. That's because they are grossly inefficient & expensive (need baseload power). UN climate talk 2019 - they want $US2.5 trillion EVERY year from the West to give to poor countries. If they really believed in the CO2 myth they would be advocating nuclear. And how is "wealth redistribution" supposed to alter the climate? It's communism on a grand scale. Resist

    • Newtonian time
      Newtonian time 2 years ago

      @hzuiel This is so true!

    • Ffuukk Yootoob Ffuukk Yootoob
      Ffuukk Yootoob Ffuukk Yootoob 3 years ago

      @sam guapo
      Yeah, a modern industrial giant. :-/

    • Johanness Willery
      Johanness Willery 3 years ago

      @sam guapo I think a little research will reveal that plenty of Costa Ricans have no air conditioning. It is also worth noting that it takes way less energy to cool a living space in Costa Rica than it does to heat a living space in North Dakota.

    • sam guapo
      sam guapo 3 years ago

      @Johanness Willery yeS they dont, they have cooling needs.

  • Nachannachle
    Nachannachle 2 years ago +1

    This lecture is the best demonstration of the fact that renewables, weather and Climate change go hand-in-hand.

  • K K Hinson
    K K Hinson 2 years ago +8

    Honest, scientific, practical, wide range, fearless, fail safe, problem solving, realistic, commonsense, and trustworthy approach to necessary energy consumption.
    After all, plants, trees, food etc. rely on Carbon Dioxide and give off Oxygen which we need. Oxygen to Carbon Dioxide back to Oxygen is PURPOSEFUL and unbreakable Cycle of Life!!!

  • Derrick Stableford
    Derrick Stableford 2 years ago

    When you consider how the solar industry has changed with 200W per ^m, now, allowing a 1:1 spacing would give you 100W per ^m. A great improvement.
    Plus all the energy efficiency possibilities.

    • redo348
      redo348 2 years ago

      The highest power density solar farm I have been able to find averages 14W/m^2.
      You have to bear in mind that there are different power outputs depending on what you are talking about. I suspect you have "peak power". So in direct sunlight what is the maximum power output. Here it is average power, including that it is night half the day so solar produces nothing then.

  • Rick Maynard
    Rick Maynard 2 years ago

    Very interesting, technology has been improved and Offshore Wind Power was in it's infancy. I would think these numbers have improved but still requiring a mix for both power stability and dependability.

    • Jakob Schulze
      Jakob Schulze 2 years ago +1

      There are some issues with his numbers.
      For example in his car example those cars drive 24/7.
      Oh and nuclear is closer to 100W/m² and not 1000. (The exclusion zone of a nuclear power plant is around 8km² and not 1 and nuclear power has an off time of 20%)

  • Irani Chatterjee
    Irani Chatterjee Year ago

    a very alarming truth about the present environment spoken. very smart and to the point talk. thank you so much sir. we need more of such awareness talk

  • Diedert Spijkerboer
    Diedert Spijkerboer 4 years ago

    That was a brilliant presentation, which actually made me change my views.
    I thought solar was the way forward, but now I hesitate. I do still think thougj that efficiency of solar panels can increase, which means less space.
    Also, putting solar farms in the Sahara sounds like a good idea, maybe ones that produce Hydrogen for concentrated fuel and cheap transport.
    It also seems obvious that we need a global solution with a global energy market not unlike the fossil fuel market of today.
    The Middle East have many deserts, so they could still be big energy exporters.

    • Doug Mcdonell
      Doug Mcdonell 4 years ago

      Diedert Spijkerboer - A solar farm in the Sahara to transmit electricity to the UK might not be the best idea, the cost of the line and the percentage losses would be horrendous. Hydrogen gas is neither a concentrated fuel nor is it cheap to transport, but it can travel a very log way, unlike electricity.
      Wind has a much better capacity factor and worldwide is growing at about four times the rate of solar, so perhaps the Sahara isn't all that necessary.

    • Doug Mcdonell
      Doug Mcdonell 4 years ago

      John Kechagais - Not correct for what? Are you counting energy or just electricity? If you are counting energy are you also including industry and public transportation, those people use energy at work and at home.

    • John Kechagais
      John Kechagais 4 years ago

      His numbers on consumption are wrong. 150kwh/day/person in the UK is not correct.

  • Dr. Jayita Saha
    Dr. Jayita Saha Year ago

    Excellent speech on "A reality check on renewables".

  • Graham W Griffiths
    Graham W Griffiths 2 years ago

    Excellent talk.
    Read Dr McKay's book: "Sustainable Energy" 2009, for very much more detailed information on this subject.

  • GonePlaces
    GonePlaces 6 years ago +64

    I was thinking about David's biofuels "verge" calculation at the beginning of the video, and thought I would finish his thought. If each car required a verge 80 meters by 8000 meters, that's 64 hectares per vehicle. So how many vehicles would this biofuel system support even if everyone lived underground and the entire land area of the UK were turned over to biofuel production (a complete physical impossibility, but a useful point of perspective)?
    Google says the UK is comprised of 94,058 sq miles which my conversion calculator transforms into 24,360,910 hectares of land area. Divide by 64 hectares per car, and you end up at 380,639 cars in total for all of the UK. Except the UK has over 34 million at present.
    There is a two orders of magnitude disconnect between the two.
    We have to move away from the off the cuff wishful thinking about energy transitions and move towards sensible plans built on real math and plausible expectations.

    • Vito Tuxedo
      Vito Tuxedo 2 years ago +1

      @Richard Monroe - I'm not sure what your point is, but I'd like to know how you did your calculations. Surely, you had to make an assumption about the *output capacity* of each of the estimated 5,000 nuclear plants. What figure did you use?
      In any case, it's probably not realistic to assume that future nuclear power plants will be monolithic. One of the advantages of Generation 4 nuclear technologies is that they can be purpose-built, and some of the designs are scalable. Hence, I would expect plant sizes to vary greatly.
      Meanwhile, it's turning out that some of the capital-poor (so-called "undeveloped") nations - who can't afford the luxury of the costly, inefficient toys promulgated by the green religion - are quietly moving ahead with their own development of Generation 4 nuclear power infrastructure to provide clean, cheap, safe nuclear power.
      In other words, they're using technologies *_we_* developed here in the western world to better their own prosperity, while we run around in sanctimonious circles, patting ourselves on the back about how many greenie points we can rack up with horribly inefficient and cost-ineffective non-solutions.
      Such "green" technologies admirably fulfill the purpose of making their proponents feel good about themselves at the expense of actual progress. Alas, they can never provide more than a small fraction of our energy needs.

    • bashful228
      bashful228 2 years ago

      @Patrick Proctor biomass consumption is on the rise, and the forests to supply it are being decimated in Australia and USA. The thing is when you cut a 100-500 year old tree down, it takes 100-500 years to recapture that carbon, so it's a total farce in carbon accounting terms and many people otters than me are working within UNFCCC processes to get a proper scientific understanding of the negative impacts of biomass harvesting.

    • Patrick Proctor
      Patrick Proctor 2 years ago

      @bashful228 Global usage of green fuels has fallen since 2010, not risen. Do try again.
      And induction is no safer once a pan is on top of it and hot. The residual heat is still more than enough to sear your little ones.

    • Patrick Proctor
      Patrick Proctor 2 years ago

      @bashful228 Both United and Delta among the American carriers actively disagree with you. And Qantas does as well.

    • bashful228
      bashful228 2 years ago

      @Patrick Proctor many chefs prefer induction to gas, it's faster, the surface is factors of ten faster and easier to clean and it's safer with kids. Oh and more energy efficient and no GHG emissions if you are using green power, which increasingly the UK grid and most other countries are.

  • AVIJIT DAS
    AVIJIT DAS Year ago

    Thank you sir, very interesting discussions.

  • Henry Acosta
    Henry Acosta 3 years ago +1

    What a great talker. Thank you!

    • King Brilliant
      King Brilliant 2 years ago

      true, except for the constant lip smacking

  • Dr.NavnIT Jadav
    Dr.NavnIT Jadav Year ago

    Amazing talks sir. Thank you.

  • hbarudi
    hbarudi 3 years ago

    This video shows the energy situation "in a nutshell". To reduce dependence on fossil fuels, you need to use all the suggestions in this video from going for all the different kinds of alternative energy sources to also reducing consumption such as changing energy hungry lights (all non LED kinds) to LED and building electric trains and public transportation as well as developing energy efficient ways to heat and cool buildings.

  • Daniel Vivarelli
    Daniel Vivarelli 3 years ago

    Good talk, if a bit dated now. 5 years is a long time when it comes to technology these days. Maybe I missed it but the thing I didn't see is factoring in rates of improvement and lowering of costs. Most of these technologies become more effective, efficient and cheaper over time. Simultaneously, energy improvements are happening all over the place (TVs, computers, light bulbs etc.) saving us an incredible amount of energy needed. Another awesome talk is from the legendary Avery Lovins' "Disruptive Oil Futures" (search on TheXvid) A super solid must-watch talk if you're into this kind of stuff.

  • JK
    JK Year ago

    Insightful presentation on reality check on renewables !

  • Amira Lozse
    Amira Lozse 3 years ago +182

    11:15 "People are Anti-everything!" 100% true. i dont want to comment about the consequences - every person capable of doing is encouraged to try

    • Rice Cake
      Rice Cake 2 years ago

      @Alex aoeu256 how long do you shower?

    • Big Al
      Big Al 2 years ago

      @George Samaras lol 👌👍

    • Alexander LegisNonScriptae
      Alexander LegisNonScriptae 2 years ago

      @CanadaCommunity Org , did you get your lobotomy free on the CHS?

  • sam guapo
    sam guapo 4 years ago +64

    Watching this video is good because it will teach you to audit data presented and be more prudent when you hear other presentors whichever side of the fence they are. That way, fake news spreads less.

    • shandcunt
      shandcunt 3 years ago +4

      ​@Xyz Same Also his numbers act as if A) Wind Turbines aren't better out at sea and B) Solar on rooftops and covering car parks make sense as it's closet to the source of use.....all this fear about the land area needed is misleading

    • Xyz Same
      Xyz Same 3 years ago +3

      he should have talked to a specialist in the field. His numbers for solar are not even correct for 2012. And no one in their right mind (so not the EU) that is working in the field thinks that bio fuels are the solution. He is setting up a straw man. - he conveniently neglects that heat pumps using large bodies of water (ocean, lakes) could be well used in the U.K. he correctly says that heating uses a lot of energy. - the situation is not ideal for solar (not sure though if it is better in Germany).
      A densely populated country can have well insulated houses and can have excellent public transportation. (See Switzerland, and they have these expensive tunnels through the mountains). That would mean people can easily make do w/o car, so they save on the costs.
      If the kites ever get some traction (small decentral wind harvesting) that would be splendid - an ideal solution for foggy, windy, rainy U.K.

  • DefCon1Shooter
    DefCon1Shooter 4 years ago +3

    Interesting and honest video. The truth is, we need way to much energy in the developed world and if massive countries like China, India, Indonesia, Brasil etc. move up to our level of consumption that might be just too much to handle.
    People often forget that its not only about the CO². If energy sources become scarce around the world there is great potential for big future wars over the ressources left (this also is the case with nuclear energy).
    He mentioned many important ways to reduce power, the most important ones in my opinion are reducing heating power (e.g. look up Passive-House concept) and good public transport. I assume these two alone could, in some countries, reduce the energy consumption by at least a third.

    • John Johno
      John Johno 3 years ago

      There are still large amounts of coal, gas and oil. Enough for many decades for the world to ramp up production faster. They will all be used up by the end of this century and by that time wind, solar nuclear fusion will be in place. But at that time it's too late for climate change.

    • John Kechagais
      John Kechagais 3 years ago

      Its per person not as a nation. 1.3 billion as opposed to 65 Million, each person in China now produces more CO2 than each person in the UK on average, I think China is at 7.4 Tonnes per person per year and the UK is 6.5 Tones per person per year. France is about 5.3 tonnes per person and Germany is at 9.8 tonnes per person.

    • John Kechagais
      John Kechagais 3 years ago

      The answer is about reducing energy while increasing production. there is a concept called Factor 4 see link below. One example is the energy consumption of electric cars as compared to petroleum cars. I don't think a tesla or an I pace is a compromise in terms of mobility and they use about a quarter the energy than comparable cars.www.gdrc.org/sustdev/concepts/12-f4.html

    • John Kechagais
      John Kechagais 3 years ago

      They don't produce more per capita

  • Just_Chris
    Just_Chris 4 years ago

    Such an incredible man, between him and stern the whole debate was changed

  • SloopJohn B
    SloopJohn B 2 years ago +8

    Thank you David MacKay! for your relevant Facts!

  • Goutam Pahari
    Goutam Pahari Year ago

    Awesome talk on A reality check on renewables.

  • very nice Meghana

    Amazing. A man who is both a fan of the environment and math+common sense.

  • Abid Ali Luton
    Abid Ali Luton 3 years ago +1

    Phenomenal eye opener! sad to read below Sir David MacKay is no longer around to contribute; a great loss indeed.

  • Stefan Heid
    Stefan Heid 3 years ago

    What he says about saving energy is very true. if you measure and really try to figure out, you can make a large inpact on your own consumption, because you start using the ressources, that have value for your live and you save the stuff that is actually useless, but you never thought of it.

  • rupan baro
    rupan baro Year ago

    Outstanding presentation on consumption of per head energy. Quite Interesting

  • Dr. Sushil Charpe

    Very informative. Renewables energy is must need.

  • Smoovie119
    Smoovie119 3 years ago +5

    It'd be nice to see some updated information showing the improvement of renewable tech over the last 5 years.

    • Dominic Adams
      Dominic Adams 2 years ago +1

      Cost per kwh will be significantly reduced and energy density will be fractionally higher due to efficiency increases but fundamentally it is what it is... there have been no breakthroughs in energy storage. A solar panel is still a solar panel. We've been getting a bit better at putting wind turbines out at sea. Nuclear power always was and always will be the most energy dense option and far more progress has been made there

  • Kevin Deck
    Kevin Deck 2 years ago +21

    Lets say we don't want to give up an immense amount of farm land to an inefficient form of creating energy.... or we use nuclear energy.

  • LaughingInfidel
    LaughingInfidel 3 years ago +1

    It should be mentioned that wind can be combined with solar or agriculture on the same land.

  • Panchali Bhattacharya

    Wonderful analysis of alternative sources of energy

  • Virtual Media
    Virtual Media 2 years ago +5

    Vehicles cover a huge part of our land mass, and consume much of our energy and often sit outside in the sun baking all day.
    Houses have walls, windows and roofs which do the same.
    Oceans cover most of our planet and do the same..
    Not arguing with his math however he's left a lot of possibilities out of the equation.

    • Nafiul Shelim
      Nafiul Shelim Year ago

      @Virtual Media because they dont work. Especially in areas where its not sunny all year round, and batteries create high pollution and toxic waste

    • Virtual Media
      Virtual Media Year ago

      @Nafiul Shelim I would be content powering my home with them. Why are you so against them?

    • Nafiul Shelim
      Nafiul Shelim Year ago

      @Virtual Media ok I hope you are able to power a city and industry with your solar power..

    • Nafiul Shelim
      Nafiul Shelim Year ago

      @Virtual Media well solar panels do not scale like micro-processor nodes, and we already have superior alternatives with lower carbon emissions. so your example doesnt fit.

    • Virtual Media
      Virtual Media Year ago

      @Nafiul Shelim Not long ago a Pentium 75 MHz PC went for $2,000. Imagine if they said forget this no one will ever buy a computer let alone a smartphone.
      Consider as well most people never make or save money from them.

  • MrMarsman
    MrMarsman 3 years ago

    Modern windmills can deliver around 3 MW, average throughout the year (here in the Netherlands). If you assume that wind power generates 2.5 W/m2 (like stated in this video), then this translate to roughly 10^6 m2 used per windmill. This is one square kilometer. That sounds a lot less intense than building 20% of the country full of windmills.

    • redo348
      redo348 3 years ago

      A megawatt turbine per km^2 over 20% of britain doesn't sound intense?

  • Nigel Ritson
    Nigel Ritson 3 years ago

    Excellent information and presentation.

  • ufewl
    ufewl 3 years ago

    Sorry to hear the guy died RIP, this is a great video and provide me with a lot of useful info. One point I need to mention though, he talks about climate change as if it is a problem when it is the solution, that is the maddness of current climate politics.
    Climate change increase energy porduction per square metre (warmth + CO2 fertilisation) and also reduces the energy consumption per square metre (warmer planet needs less heating).

  • Aarti Pradhan
    Aarti Pradhan Year ago

    Delightful and fascinating talk on renewables.

  • Richard Mosimann
    Richard Mosimann Year ago

    There is an additional issue: Renewables such as Wind and Solar have to be flatted by massive storages. A useful technology is not yet available.

  • Stephen Verchinski
    Stephen Verchinski 3 years ago

    28 years ago I showed up at a talk where I was the guest speaker along with 6 Phd's. On my transparencies I showed a home proximate 50% reductions in power consumption done by exercising personal responsibility. He did the same and then did not note the offsets then possible in the supply side. We have a choice actually choices. To be responsible and clean up our mess, including decarbonizing.

  • zytigon
    zytigon 9 years ago +6

    Thanks for video. David JC MacKay's book, " Sustainable energy without the hot air " is can be read for free from his website withouthotair. Really interesting.

  • Washington Digital
    Washington Digital 3 years ago +2

    The efficiency of Solar PV systems has definitely improved since this video was made. However his no nonsense thinking is a good way to start pondering the problem of which technologies to use.
    Clearly we can use less and more efficient house design (passive solar and sustainable building materials and methods) really add up to some fantastic solutions which tell a different story from his estimates. I suggest anyone wanting a more up to date understanding of renewables read Mark Diesendorf book "Sustainable Energy Solutions for Climate Change" which certainly gives a more recent understanding of the problems and looks at the Australian context.

    • redo348
      redo348 3 years ago

      @Patrick Proctor
      You seem to be verging on the "every little helps" mentality. The problem with this is discussed here:
      www.withouthotair.com/c19/page_114.shtml
      I just do not believe that efficiencies here and there will cut it, and I haven't seen numbers that convince me otherwise. Likewise solar on roofs is nice, but 10m^2 for everyone works out at 5kwh/person/day, vs 125 which is UK consumption (that's 20% efficient panels).
      www.withouthotair.com/c6/page_39.shtml
      If we want to go solar then we need to talk something like country-sized solar farms in deserts. Then we'd be making progress.

    • Patrick Proctor
      Patrick Proctor 3 years ago

      @redo348 Considering that opens up both complimentary and supplementary applications, I'd say it has huge impacts, which is demonstrated by Boeing and Airbus looking to integrate panels into their next-generation long haul craft planned for 2030. Even if the panels and batteries can't drive the engines, they can take the powerplant requirements off of the engines and leave behind only the bare essentials for cockpit instrumentation as a backup should the main cells fail mid-flight. Another 2-3% gain in engine efficiency for a less than 1% increase in aircraft empty weight is a bargain.
      Our household electronics get more and more efficient every year thanks to innovations from Intel, AMD, Nvidia, Samsung, TSMC, and others. That does have a hard limit like everything else, but it helps enable population growth. Getting solar panels into the upper 20s on efficiency can make your average household self-sustaining on its individual pure electrical footprint for at least half the year. The math bears that out pretty easily as shown in this talk. Applying the same to corporate buildings, depending on scale and ratios of surface area to volume, can cut their foot print anywhere from 15-50%. The Burj Khalifa can be made entirely self sustaining if you get 31% efficient panels for the walls and 10% efficient panels for the windows, so clearly this can be done. So while we pull the pressure off of our old power plants, we make room for their replacement. Newer plants = cheaper electricity = cheaper total cost of ownership for electric vehicles, which means gasoline and natural gas also get cheaper since the demand pressure decreases (or slows in growth relative to growth in supply). Then as oil companies start losing out economically, they pour their billions into R&D on better renewables.
      Every bit counts, and your home is no small part. Honestly I'd love a house with Swedish building standards built on the coast in Virginia. It would be so easy to keep cozy or cool. That's honestly the biggest problem with my parents' colonial home. It leaks like a sieve. It needs to be knocked down and redone, much as it would kill my Mom inside to do that.

    • redo348
      redo348 3 years ago

      @Patrick Proctor
      Good, so we agree on the ballpark numbers.
      From an engineering context, you are right, an improvement from 17% to 22% is a big deal. How about from an energy planning context though- what do you think that changes about the country scale energy picture?

    • Patrick Proctor
      Patrick Proctor 3 years ago

      @redo348 5 percentage points, or a ~31% improvement vs. the 17% efficient panels at the time of his recording. If a jet engine was 30% more efficient over the one it replaced the world would be up in arms about it. Even 10% leaps are considered huge.

    • redo348
      redo348 3 years ago

      @Patrick Proctor
      I didn't say nanowire research was silly. I said talking about it in this context was silly. The goal here is to make a plan that adds up to reduce country-scale fossil fuel use over the next few decades. TLR 7-9, rather than TRL 1-4.
      en.wikipedia.org/wiki/Technology_readiness_level
      I'm happy to talk about grid efficiency, but first we should finish what we are talking about. You are saying that solar efficiency has significantly increased since this video was made. That is not the impression I have, I'd guess commercial panels that you can put on your roof today have increased in efficiency maybe 5%. Correct me if I am wrong. It is my impression that cost is where the real progress has been made rather than efficiency.

  • Thomas Carden
    Thomas Carden 3 years ago +1

    Great video, everyone needs to see it.

  • Dr. Sandeep Roy Sarkar

    Wonderful lecture.

  • shailja
    shailja Year ago

    Informative lecture on A reality check on renewables.

  • orion stanbro
    orion stanbro 3 years ago

    yes, if you base calculations on our current levels of energy consumption these facts are correct. Sadly the fact that most cars only get 1.5 to 2x kilometers per liter than they did in 1955. Couple that with everything is disposable and so heavily based on it being redundant in 10 years... we are in trouble... Any old timer who knows how little they used to consume could tell you that.

  • GoVegan!
    GoVegan! 2 years ago +6

    What is always, deliberately, missing out of these "national conversations" we have on future fuel generation is how renewables can be installed small scale to the direct financial benefit of the individual house hold, either at a household, local or regional scale, win win. Meanwhile we pay subsidies to power companies and landowners for large scale projects. Why is this? Because big business will not profit from energy self sufficient people.

    • D E Lee
      D E Lee 2 years ago

      Also intentional in this case is a) beginning with biofuel...the most inefficient of the renewables, and b) the perpetual, ubiquitous pretense of the limited-source mechanism.
      Wind and solar and tidal generation do NOT have to cover land area. Tidal, of course, doesn't even work on land, but wind and solar also work, and work BETTER, offshore.
      This presentation is biased in favor of fossil-fuel industries. It's a for-profit bias.

  • enoch1680
    enoch1680 2 years ago

    Of course the final best solution will be some combination of the different approaches. Your graph is brilliant and a great way to think about the different approaches with some caveats. Solar on homes is symbiotic in that the area's initial use is not undermined, IOW the person can still use their house, so no downside. Land based wind is also symbiotic. The footprint of the towers is small so that most of the space attributed to wind is usable for industry or agriculture. Finally, I was glad to see that in your final image you showed large scale use of offshore wind which has no detrimental impact on the land. Their should have been another line for wind that showed land aerial density for wind when you are also using offshore sites. It would have been much more favorable.

  • Jay Patel
    Jay Patel Year ago

    Thank you for informative session.

  • ༒Gorm Auslander༒
    ༒Gorm Auslander༒ 2 years ago +4

    The problem is that renewables and taking action at all has popularity issues.
    It's not about what's popular. It's about what's right.

  • Brett Hansen
    Brett Hansen 3 years ago +64

    This isn't that difficult- nuclear is and always has been the solution. Conservation and lifestyle changes will just mitigate the amount of nuclear necessary- but that's the long and short of it- moralizing about the solution only delays its implementation - we wait long enough waiting for unicorns to solve the problem and it won't matter.

    • Gary Lewis
      Gary Lewis Year ago

      Check the cost of electricity in California compared to France and Ontario Canada.

    • fact not fiction
      fact not fiction Year ago

      @Gerold Firl current 2020 numbers:
      www.cleanenergyreviews.info/blog/most-powerful-solar-panels
      the Jumbo 800W panel from JA solar at 2.2m high and to 1.75m
      800 W per 3.85m^2 = 208 W/m2 ( _NOT 1000 W/m2_)
      @ 25% capacity factor in the UK = 52 W/m2, which taking into account 7 years of progress, shows his back-of-the-envelope is still the correct order of magnitude

    • qwertzundefined Apfel
      qwertzundefined Apfel Year ago +1

      @Abhik Kumar De
      "it should come to more like 150-200 watts per sq.m and not 20 watts per sq.m"
      I guess his figure is the power per square meter if averaged for a whole year. So, yes, you get some 190 W/m² at noon, but thats only on a sunny day and only a few hours per day.
      Sounds reasonable, I just calculated a yearly average of some 15 W/m² for my setup - but with a rather large error margin for the area.

    • Gerold Firl
      Gerold Firl Year ago

      @Abhik Kumar De Your calculations look right to me. Unfortunately these pro-nuclear types don't mind twisting the truth to get the result they're looking for. Solar and wind have made nuclear unnecessary, and they just can't stand it.

    • Abhik Kumar De
      Abhik Kumar De Year ago

      @Gerold Firl
      I was a little confused on his back of the envelope calculations regarding the solar ...
      I mean may be the info out there on the internet websites is wrong or i am missing something...
      But a standard panel has around max input of around 1000 watts per m2
      (say for peak 4 hrs in sahara).
      With 15-20% efficiency rates
      it should come to more like 150-200 watts per sq.m and not 20 watts per sq.m
      Well there might be spacing issues in solar farms ..But is it inevitable..
      Would appreciate a reply..😌😌😌😌

  • Mike Stevens
    Mike Stevens 3 years ago

    Never mentioned harnessing the plasma energy from lighting. But this could be unrealistic. Due to the fact that thunderstorms are just to unpredictable. But the plasma energy created in one bolt of lightning could be harnessed and stored for months for usage.

  • Ziva Fister
    Ziva Fister 3 years ago

    There are plenty of places outside our view, that we could produce large amounts of electricity. The problem is how to transmit them over large distances. here are some of them:
    - Solar above the cloud levels
    - wind in high altitudes
    - constant catabatic winds on the rim of Antarctica
    - constant sea current around Antarctica

    • redo348
      redo348 3 years ago

      "Large amounts"
      Well we use large amounts of energy. So which large is bigger?

  • A.G Abbey
    A.G Abbey 2 years ago +2

    I'm an advocate of having grown up conversations that are based on numbers and facts!

  • ChinaFactors
    ChinaFactors 4 years ago

    Excellent teacher

  • willy reeves
    willy reeves 3 years ago +11

    I reduced my heating/AC bill by over 60% by moving from Illinois to Florida. not why I moved but it was a nice side effect. so where people live matters greatly in this equation.

    • Ethan Ekstrand
      Ethan Ekstrand Year ago

      @Hope Young Warmer climates and more sun actually correlates with increased risk of poor cardiovascular health.

    • Jacobus DeRottmann
      Jacobus DeRottmann 2 years ago

      @dan at canyon lake - both.

    • dan at canyon lake
      dan at canyon lake 2 years ago

      Is it a reduction in consumption or a reduction in per kWh cost? Florida has low electricity cost.

    • Hope Young
      Hope Young 2 years ago

      This is why most migrate to warmer climates. Warm good for life, cold, not so much.

  • Elie The Prof
    Elie The Prof 3 years ago +113

    Also imagine the quantity of *rare metals* we'd have to dig out of the earth, to cover most of a desert in solar panels 😕

    • David Davison
      David Davison 2 years ago

      @I'll let you finish but first Tell that to the people in one town of China where the solar panel manufacturing plant so polluted their river that the people rioted and got the plant shut down. When your pollution is too great even for the Chinese, it's bad.

    • Dost Thou Even Logic Brethren?
      Dost Thou Even Logic Brethren? 2 years ago +1

      Also how much power lines would need to be spread across the world. Solar uses DC, which diminishes rapidly over distance, unlike AC. To move power from a desert to the UK would require insanely more power than is actually consumed, to make up for the massive loss of power from the process of moving it.

    • Gaz Masonik
      Gaz Masonik 2 years ago +1

      @Embalmer Trick And bat and Bird Shredders that take more carbon to(carbons not the problem) make!..than they save! No surprise.. Bloody Wind mills.

    • Gaz Masonik
      Gaz Masonik 2 years ago

      @A.G Abbey nik Tesla. Musk is a fraud. Don't know his motives but actual rocket scientists said they're keen to find out why the space X video were frauds. Does it mean the rockets weren't real or just film of them. After alerted by it having no reverse thrust to slow down but made maneuvers that reversed and slowed before almost right angle turn in violation of newtons law of thermodynamics! ?? Odd. It's been suggested by Richard Hall (the best journalist left)he is distracting from the mini cold fusion+anti gravitic, of the navy's new patent? No one says much about it.Has definatly been granted! The"air and under water craft". AUC that's been successfully trialed. Ending speculation that the TRB 3 whistle blowers described. Or "flying triangle" will be disclosed. Debunkers silent or complicit.Oh the shame!!

  • Tom Z.
    Tom Z. 2 years ago +66

    I'd like to see someone making a similar speech today, seeing that this presentation is very old

    • Stefan Starkov
      Stefan Starkov 6 months ago

      ​@Jakob Schulze You propose some interesting talking points here and it's great that you're critically thinking about this presenter's energy analysis (especially how converting rooftop solar technically does not require any additional space as it is simply repurposing an existing space). I will add though that energy density is not a red herring; it is one of the single most important factors when measuring electrical power output. Fossil fuels, which are damaging to the environment from an emissions perspective, provide far more energy per unit of volume (or in this case land mass) than renewables, which require far more scale to replicate the same amount of energy per unit volume.
      As far as cost, renewables are far and away more expensive than virtually any other form of generation, due primarily to their lower energy density factors (this is why they require huge government subsidies as well as higher utility rate increases per kWh, as seen by the higher prices for electricity in both France and Germany as compared to the US). Germany's emissions have decreased, but their cost for electricity has increased. Naturally, like with many things, there is a tradeoff decision as to how clean they want to be compared to how much that would cost ratepayers/consumers.
      Nuclear is expensive, yes, but relative to how much power it can produce, it is far less expensive than solar and wind. The presenter in this video is simply articulating that the current world consumption of electricity cannot be feasibly provided solely by renewable energy without significant compromise in terms of land use required. As Robert Bryce mentioned in his book on electrical power, the main components that make renewable energy prohibitive are primarily cost, storage (and by extension technological advancement such as battery technologies), scale and of course land use. These components are what physically make renewables much harder to implement as compared to the more energy dense fossil fuel or nuclear generation. David MacKay is correct by stating that there are many advocates for each group and they often loudly exclaim, without any numbers or analysis, that their proposal is the better solution, but I praise this video because I cannot find any bias or agenda in his analysis. He is approaching this entirely from a mathematical perspective to paint a clearer picture.
      The only part in this TED talk that I can see might draw some controversy is where he mentions having a grown-up conversation. That might come off as condescending because it implies that other people are acting childish in their views by either promoting alternative solutions with little to no analytical support or that they are not allowing for any scrutiny of their proposals, both of which are not professional in my opinion. Otherwise, I respectfully disagree with your assertion that his information is a mix of half-truths/facts. He has presented very clearly and has provided empirical evidence to back his assertions.

    • Jakob Schulze
      Jakob Schulze 11 months ago

      @thetravdawg
      "Is he wrong about nuclear?"
      Mostly yes.
      "Is he wrong about solar/wind not being dense enough?"
      Yes.
      It is dense enough to run all of humanity on it.
      Also the denseness is a red herring.
      Solar on a roof takes up zero additional space. Same with Agrovoltaik.
      A wind turbine in a field uses less space per kWh than a nuclear power plant.
      He ignores nuclear exclusion zones and than acts as if a wind turbine uses the space between 2 wind turbines.
      "What specific is he lying about?"
      About the emissions in Germany.
      He claimed emissions rose while in reality they fell.
      About the cost of energy production in Germany and France. (When he did the ted talk Germany had actually cheaper production cost than France. He compared consumer price, which is subsidiesed in France and heavily taxed in Germany. So he didn't compare equal thinks.)
      He uses a lot of half trues or facts out of context to paint a picture which isn't real.
      New nuclear is around 2 to 6 times the cost of wind/solar and that gap will most likely increase in the future.

    • thetravdawg
      thetravdawg 11 months ago

      @Jakob Schulze Is he wrong about Nuclear? Wrong about solar/wind not being dense enough? What specifically is he lying about?

    • Jakob Schulze
      Jakob Schulze 11 months ago

      @thetravdawg
      I would watch out with him.
      He is lying a lot and is cherry picking a lot of his data. Like looking at total emissions, while saying he is talking about emissions from power production or by picking data from certain years to show an increase in emissions (like 2009 where there was a global recession and therefore less emissions than usual).

  • Julian Alcock
    Julian Alcock 3 years ago

    Yes, people are anti everything, except turning their lights on and jumping into their cars to drive somewhere. I suggest that those who protest should be the first get the power cuts which will come through not providing generating capacity. I am also pro Mathematics and pro renewables.

  • Robert Mizek
    Robert Mizek 3 years ago +3

    Brilliant. The authors of “The Green New Deal” need to understand these numbers.

  • KUMAR GAMIT
    KUMAR GAMIT Year ago +1

    thank you for wonderfull talk on A reality check on renewables.

  • Jor S
    Jor S 3 years ago

    Understanding that graphene is ridiculously expensive (currently), to manufacturer, in large quantities, I would like to see an analysis of a geothermal graphene power plant, when we do get graphene production costs to their theoretically lowest limit. Supposedly it takes less land area than nuclear to produce the same density of energy.

  • Husky Dogg
    Husky Dogg 3 years ago

    Speaking of demand. I travel 30 miles a day to get to and from a job which I can easily do from home, in order to satisfy the "face time" requirements of my company. Most of my driving each year is for this purpose. Why can't there be incentives for companies to drastically change this face time necessity? I feel this would be a huge savings, especially here in the US.

    • DJ Force
      DJ Force 3 years ago

      Unfortunately, companies have tried this and it fails. Boeing tried this in Seattle, and had to revert to traditional offices. Workers are less efficient, when they are actually working.

  • Bram Declercq
    Bram Declercq 3 years ago +8

    Maybe one of us could start putting the current data together and make an updated video? The way sir MacKay did it isn't too bad: not too much bias in his way of speech. Just entering the data of 2017-2018 would help to restart the discussion. Pretty sure our volunteer would make it to TED as well...

    • John Johno
      John Johno 3 years ago

      We can probably expect solar and wind to power 30% of our needs without storage. Much higher if we have storage. Fossil fuels will always have a place in modern society.

    • redo348
      redo348 3 years ago +4

      I've been looking at this a while now, my summary is the numbers don't really need updating (yet). E.g. he assumed 20% efficient solar panels and that is still roughly the best on the market.

  • Noto Sure
    Noto Sure 3 years ago +2

    Wow, it's amazing how far we've come in just 6 years!

  • Chris Richardson
    Chris Richardson 3 years ago

    We definitely need more efficiency in the utilization side. Solar farms on the moon can be even more efficient. Moving most of our manufacturing there makes a lot of sense in that there are plenty of resources already there in the form of asteroids that have impacted the moon over the millions of years. The energy potential is huge so the process of mining and manufacturing and delivery is cheap as well. Launching from the moon to any square kilometer on earth is easy, lower gravity well, to a deeper energy well is easy to accomplish with a mass driver built on the moon. Reentry vehicles can be made with basaltic thread weaved into reentry one use lifting bodies that can be filled with product manufactured up on the moon.

  • RELAXAVOUS68
    RELAXAVOUS68 2 years ago +2

    Now here’s something that actually makes sense and puts a real perspective on all the fluff!!!!

  • Andy Owens
    Andy Owens 3 years ago +4

    Thanks, good arithmetic. Needs wider understanding. And dont forget, covering 20% of the country with any option will introduce massive transmission losses. Roll on ITER.

  • Andrew Nel
    Andrew Nel 2 years ago

    Substitute servos on the vehicle's wheels and a diesel electric generator instead of the transmission and engine to optimize the motor car and reduce the need for fossil fuels. If the power grid goes down the car can serve as a generator on site, eliminating another problem.

  • Dr. Anandi Kurmi
    Dr. Anandi Kurmi Year ago

    Thanks for lecturer on "A reality check n renewables."

  • Travis Harger
    Travis Harger 4 years ago

    One of my fav ted talks to date. Sad to hear he’s passed away.

  • Rohit Sharma
    Rohit Sharma Year ago

    Relevant information , engaging session.

  • yoloswagmaster 9000
    yoloswagmaster 9000 3 years ago +1

    I did a rough estimation on how much known and and estimated accessible nuclear fuel not including thorium and even with relatively inefficient reactors we have enough for about 250,000 years at current power usage levels but that was in 2015.

  • Jeff Galef
    Jeff Galef 3 years ago

    You still need a great deal of fossil fuels to make renewables work. The mining, transportation, construction, and disposal isn't done with other renewables. Plus, solar and wind need fossil fuel backups running at all times to keep the electricity flow constant. You could construct massive battery banks, but they need massive amounts of fossil fuels to build them, as well.

    • redo348
      redo348 3 years ago +1

      'A great deal of fossil fuels to make renewables work'
      I think that's a myth. You get 80 times more renewable energy out of a turbine than it takes to manufacture it. Solar is less good, but still 4 times the manufacturing energy.
      www.withouthotair.com/c6/page_41.shtml

  • Dr. Dinesh Patel
    Dr. Dinesh Patel Year ago

    Thank you so much for very useful session

  • Singingway
    Singingway 3 years ago

    We know a radical shift in our energy consumption habits will be needed. Nobody believes we can continue the extractive expoitative practices which would take five Earth's worth of resources if everyone lived so wastefully. So one-to-one replacement is not really the goal. Being able to continue essential services such as medical and emergency services, are the goal. Continue as we are and everything collapses and we won't even have those essential services. Make a change for the better, ahead of climate breakdown, and everyone benefits.

  • Jason Turner
    Jason Turner 2 years ago

    The math here is based on the technology in 2013. Reporting from 2020, we can see that in 2019 the UK produced over 35% of its energy from renewables. My UK-based colleagues confirm that 35% of the UK land mass is *not* being used to produce renewable power. We can now officially move on from this.