New Green Jack New Green Jack

39 responses to “ROCs, REGOs and wind-powering GB”

    • Dave Howey

      Dale (hallo again by the way!), you said “I don’t disagree with Prof McKay on the need for us to reduce energy use, but I do disagree with his apparent fixation on that to the exclusion of actually building renewable forms of power. The two things are not opposing forces – they are reinforcing – we need to use less and make what we have to use, from renewables.”

      I don’t quite follow what you are saying here… and I don’t think MacKay says this in his book ( From my reading of his book, he seems to be saying, basically:
      1. How much do we need to live on now, today, without reducing any demands.
      2. Can renewable energy supply this need?
      3. How can we reduce our needs (efficiency etc)?
      4. How can renewable energy supply our reduced needs?

      Therefore I think you and MacKay are basically on the same page…

    • Jeffrey Lam

      Ok, so you get both ROCs and REGOs for your renewable energy. You sell all your ROCs, except for the ~10% that you are obliged to keep.
      I’m not too clear about what you do with your REGOs, if anything. Is it your REGOs that allow you (legally) to claim that 50% of your energy is renewable? And for your “plus” tariff, you buy a REGO with every unit of electricity you purchase, which allows you to claim that 100% is renewable?
      Presumably, GE have *no* energy production capacity of their own, they purchase the equivalent amount of energy to their customers’ demand from other (green?) suppliers. Then they buy the ~10% ROC obligation, plus 5% (allegedly) extra to retire? And they also buy 100% REGOs, allowing them to claim it is 100% renewable?
      Have I understood correctly?

      I’m fairly chuffed that my arithmetic using google/wikipedia figures combined with Dale’s rule of thumb chimes with the ETSU study!

    • Anthony Manning

      Thanks for the post Dale, it helps, particularly with reference to ROCs.

      I too have the same question as Jeffrey about what happens to the REGOs attached to what you produce.

    • Vicky Portwain

      ROCs or no ROCs we have to accept that green energy comes with a (relatively small) increase in cost to the consumer. However I agree that a completely market “consumer chooses to pay approach” will not work as unfortunately Jeremy Clarkson needs to be forced into paying for it (and the ROC system does this).

      I disagree with Dave Howey’s comment – that Dale and McCay are on the same page. We already know the answer to 1 and 2 (lots of energy required and not enough renewable energy to supply). 3 and 4 suggest an ordered approach along a time line. Global warming is going to happen so fast and the job of reducing carbon emissions so huge that we cannot afford to take such an approach – 3 and 4 need to be combined and both happen now.

    • David MacKay

      Just to confirm, I (David MacKay) advocate simultaneously doing the following things:
      1) implement efficiency measures as fast as possible (Eg electric vehicles, heat pumps, insulation); AND 2) get lots and lots of green electricity supply built up as fast as possible; AND 3) make appropriate demand-balancing/storage systems to cope with demand/supply fluctuations.
      I find it strange to be told that I advocate “only efficiency”. Please read my book. It is free online! Incidentally, other people seem to propagate the other (equally incorrect) view that “MacKay ignores efficiency options”. Sigh. Please read the book. If equal numbers of people propagate both these incorrect statements, does it mean I roughly got the balance of the book right? 🙂

    • Dave Howey

      well- there you have it from David MacKay himself. I agree– if you haven’t read the book, read it first before commenting!!!

    • Chris

      Dale, when will the latest figures for 2008 be published on ?

    • Alan Tayler

      Dear Dale,

      I admire what you have achieved and your green approach in general and wish you and your company well. I have emailed your company with questions on two occasions and have had absolutely no response so I thought that an approach to the man at the top might be interesting.

      I read on your site that you are developing a domestic wind generator model and I simply wanted to know if this was the case still and how things are going? This does have a slight bearing on your ROCs explanations and contrasts interestingly with the situation in Germany where I believe the subsidy for micro-generation is greater than here – leading obviously to a greater take up. With the general fall in investment returns a slight tweaking of subsidies would make home generation look relatively attractive – particularly when you consider how UK energy prices are so ‘world – beating’ in the negative sense…

      All the best

      Alan Tayler

    • Vicky Portwain

      In relation to comments from Dave Mackay/ Dave Howey I had read some of the book when I commented. I confess I did originally skim read it and came to an early judgement as some of the initial content did not seem revolutionary and in some parts contained incomplete information e.g wind speeds generally being below 6m/s in the UK (without referring to a height above ground level or lack of context e.g. the fact that even in lower wind speed areas energy can be maximised by bigger wind turbine rotors effectively giving a similar energy output to turbines in windier areas). The references to bigger wind turbines not greatly increasing the total power output per unit land area does not reflect the “real life picture” as although wind turbines need to be spaced further apart the relative output from fewer turbines with larger blades is greater even using the same land area (given higher capture of energy through greater overall blade swept area). Other constraints such as noise (fewer larger turbines may be quieter than a larger number of smaller turbines) allow you to fit more turbines onto a site) and there are many other constraints on wind farm sites aside from the technical e.g. ecology land use, etc. Furthermore many smaller (in term of overall turbine numbers) wind farms could contain turbines closer together whilst still generating at a high capacity factor as the wake effect behind the turbine is reduced. OK – detailed points but this is a detailed book.

      The scary numbers are already out there – on climate change, the scientists at the Hadley Centre have been on the case for some time and in terms of energy demand sources such as the UK digest for energy statistics have good workable figures. Responses from energy companies to government consultations have contained the clear message about the energy gap (including the numbers) and the need to do everything we possibly can (in a big way) to deal with this. These numbers have informed renewable energy targets and ultimately the tough decisions the government has to make on issues such as coal fired power stations and nuclear.

      What is good about your book (having re-read the book in further detail) is the overarching agreement – we need to do everything in a “big” way. However this does not stop the need at least get the public doing the little things in terms of energy saving and renewables – it all contributes and I think this is where the message sent out by the book is being perceived differently. We do have to find a simple and effective way of getting the efficiency/ green generation message across to the public quickly and effectively. Rather than being “codswallop” for example comparisons of energy production with the number of homes equivalent at least lets people put into context what a wind farm might generate. They are not going to read a 300 page plus book about the numbers.

    • David MacKay

      Vicky, thank you for reading my book, and for your positive overall reaction. You complain that the book is too long, and you also complain that when I mentioned wind speeds, I didn’t say what height the wind speed data was gathered, nor discuss the dependence of wind speed on height. Well, please make your mind up – do you want the book to be longer or shorter?! Yes, I omitted discussion of height in the three-page-long chapter on Wind
      because I wanted to keep the length down to three pages! But please don’t misrepresent what is in the book. I _do_ say what height the data is measured at (namely 10m, page 265) in the Chapter “Wind II” (pages 263-268). And I _do_ discuss (on page 266) the variation of wind speed with height. Finally, you assert that turbines can be packed closer together without losing power? Please provide data. (That idea would seem to contradict the Danish Wind Energy Association, who say that you get significant shadowing if the spacing is closer than 5 diameters.) I’m always keen to see new data. All the best, David MacKay.

    • Alexandra Deegan

      A couple of points worth noting!

      China is rapidly emerging as the next global wind power. During 2008 it doubled wind energy capacity – for the fourth straight year – adding 6,300 megawatts of new electricity generation for a total capacity of 12,210 megawatts….

      And in the rush to build the next gen’ hybrid cars or EV’s, a sobering fact confronts both automakers and govts seeking to lower their reliance on foreign oil: almost half of the world’s lithium, the mineral needed to power the vehicles, is found in Bolivia — a country that may not be willing to allow much access to the mineral!

    • Vicky Portwain


      I am not saying your book is too long. I am saying that different methods of spreading the word are needed for different audiences and the short messages are not necessarily as you describe in your book “codswallop”.

      Thanks for your clarification on wind speed height – my key point is that there is huge potential for wind energy in the UK from a technical and commercial perspective and the success of modern turbines coupled with the ROC are to thank for this. Wind speed (and therefore viability) is not the key constraint. Neither is physical space.

      It is correct that if you reduce spacing to under 5 by 3/4 rotor diameters you may reduce energy but this depends on a huge number of factors including topography and forestry and the size of the wind farm (I test this by using energy estimates from wind farm design software and actual measured anemometry data fed in – developers use this to maximise the potential of a proposed wind farm site). My point is that other factors are hindering the potential of renewables and wind energy – mainly politics at a local level. It is here that you often hear – “efficiency first”, or “we agree with renewable energy but this is not the right place” (hence my misplaced reaction to Dave Howey’s comment).

      A quick question for Dale – in light of the recent Warwick Wind trials by Encraft are you continuing your domestic turbine development or are you going to target it for a specific “niche” market?

    • Bob


      You mention the concept of “intelligent demand” (yet another phrase aka demand-side management, demand response, demand-side participation). This is very encouraging.

      Given that Ecotricity has presumably the most variability in supply of any generator, it stands to benefit most from getting flexible demand from its customers. So are you doing anything in this area?

      I’d say the key issues are:
      – Metering
      – Settlement
      – Consumer perception

      In addition to the technology/integration, to make it work we may need to completely re-write the way that smaller customers are handled. Smart Metering can provide much of the data (1/2 hourly reads), but unless we significantly alter the way that electricity is settled through the BSC and get rid of profile settlement, there will be no way to realise the value of customers using power at different times – no way for suppliers to capture value and share it with customers.

      Also,have a look at the recent Daily Mail coverage of the RWE/RLtec trial (especially website comments) and you’ll see that there’s a mountain to climb there in terms of public opinion.

      The evolution of the energy system to a demand-led “predict & provide” to your nirvana of a supply-led wind-powered world (a good vision) is something that will take active engagement and *collaboration* between all participants in the market- DECC, OFGEM, Big6, NatGrid, DNOs and consumers. I would be an extremely disappointed Ecotricity customer if you continued to wax lyrical about this opportunity and didn’t contribute.

      It may not feel like it, but have it on good authority that many organisations listed above are taking it demand-side flexibility very seriously.

    • David


      Good work on what you are doing.
      I just have one question and it relates to your numbers:
      you say “100,000MW of wind to power the whole UK”
      “That’s 50,000 of our 2MW machines”

      Is that not a bit misleading given that you need to take into account the capacity factor, given that for Wind this is about 30% then we would need 3-4 times as many Wind turbines as you estimate.
      If I am right then these things need to be clear so we on the pro wind side can not be seen to be misleading.


    • David MacKay

      To David, from David MacKay: I expect Dale already factored in the load factor in his “roughly 100 GW”. UK electricity consumption today is about 45 GW on average; so (at a load factor of 30%) you need 150 GW of wind to cover it (plus appropriate energy storage systems to cope with supply and demand fluctuations). I think that if we talk about “powering the UK”, it’s good to speak about how much power is needed to provide all power, not just today’s electricity. In particular, there’s heating power and transport power (both currently fuelled by fossil fuels). If we want to defossilize both these power sources then it increases the number of windmills required by quite a bit. In my free book ( I estimate how much power would be required by zero-carbon Britain. To cover not only today’s electricity but also (efficient electrified) transport and (efficient electrified) heating (using heat pumps), we would need something like 125 GW of electricity on average (more in the winters of course). This plan, I must emphasize, involves very significant energy efficiency measures compared with today. Now, If we delivered this power mainly with wind, we would need about 420 GW of wind capacity (and lots of storage). The land or sea area required for the windfarms is roughly 62,000 square kilometres. Which is roughly one quarter of the area of the UK and roughly three times the area of Wales. So yes, technically we can power the whole UK from wind alone – as long as it’s acknowledged that one quarter of the UK would be occupied with wind-farms. I’m fine with that idea. I’m not anti-wind. Just pro-arithmetic! If people don’t like having so many wind-farms they can always choose to buy **kes instead. Other options, other mixes, are sketched in the book. They all involve big building projects – there’s no way of getting away from it.

    • Damon Hart-Davis

      UK unrestricted peak demand is only ~65GW anyway AFAIK, so by some measures that’s too much (that peak peak demand comes in winter and correlates with more wind) and by some too little.

      Given that 100% pure wind supply is unlikely to be practical, 100GW of wind is probably a reasonable stab at enough capacity ignoring balancing/backup.



    • David

      David MacKay – I’ve brought and read the book cover to cover and was very impressed, it was party why I wanted Dale to be clear in his arithmetic i.e. what the numbers ment and where did they come from.

      The book has increased my ambition to change career into renewable energy. I am currently studing via distance learning at Loughborough University for an MSc in Renewable Energy, I just need to find an employer and leave IT Contracting behind.

      Thanks for the clarification.
      Anyone got any jobs?
      Interested in Wind and Biomass.

    • Alan Tayler

      Interesting to see that the ROCs changes have already caused BT to abandon their wind power initiative.

    • Dave Howey

      Dear David “The book has increased my ambition to change career into renewable energy” (there are a lot of Dave/Davids on this page – me included!).. I know someone who has done just what you want to do, his blog is here: – I suggest you get in touch with him perhaps. I think he did an MSc in renewable energy.
      Dave Howey

    • Vicky Portwain

      BT pulling out because they have been double accounting – I wondered how they were offering such great deals to landowners for wind farms on their land. You will notice the more established wind farm developers not being affected.

    • Jonathan Rowles

      Hello Dale

      Ecotricity is an exciting company and reading your website caused me immediately to apply to switch from my current supplier, Southern Electric (which I understand to be part of Scottish & Southern).

      I think your sales pitch needs tidying up a smidge though (bear with me, this ends up positive :)). Your Jan 2008 Progress Report says “1 in 6 of the wind projects in England today have been planned and built by Ecotricity.” Well ok, but England is a relatively small part of what’s happening as yet and it is the quantity of generated wind power that matters to me, not particularly where in the UK it comes from. Do you disagree? I wanted to check out what you were saying and found the British Wind Energy Association UKWED database [], which tells me that when your report came out there were a total of 419 active wind projects (in planning, consented, in construction or operational), of which Ecotricity had 16 (57.9MW) and Scottish & Southern had 12 (724.25MW) – a factor of 12.5 in favour of Scottish & Southern in terms of power. And yet you quote Scottish & Southern as spending zero per customer on wind. That is, at the very best, disingenuous and it doesn’t become you – you should either find a fair estimate to quote or not quote anything at all.

      At this point, having applied to switch to Ecotricity, I had a very uncomfortable feeling that I had been conned.

      I wanted a fairer picture of the amount of energy being generated per customer from wind, to allow a rational comparison and check my decision. Dividing the power output of the wind projects that a company is carrying out by how many customers it has gives the number of Wind Project Watts per Customer (WPWC, prounounced “WiPWaCs”). Ecotricity had 33,000 customers at the time of your report and Scottish & Southern around 5M (excluding its gas customers). This gives 1,755 WPWC for Ecotricity and 145 WPWC for Scottish & Southern – a factor of 12.1 in favour of Ecotricity.

      So I’m going ahead with the switch to Ecotricity.

      If you want to get the real facts over to people without danger of insulting their intelligence, this is the number you should be headlining. It shows simply and fairly the difference in companies’ commitment to wind, normalised with respect to the number of customers. Quoting absolute pounds spend per customer reminds me of the sort of thing a government might say to skate over the size of a problem:).

      It’s really striking that 75% of planning applications for major developments are decided in 13 weeks but only 7% of applications for onshore wind! [] What would you say are the main problems? As a Psychology graduate doing Project Management, I’m well used to working on multi-stakeholder projects constrained by regulation and standards, enforced whimsically at times. I’d like to get involved. I can think of almost nothing more satisfying than taking a wind project through from application to planning consent. An insightful article by Prof Susan Opotow on the subject of managing conflicts in environmental projects talks about how to recognise when stakeholders are not responding positively to eachother and what to do about it []. But looking at the planning decisions for various refused wind energy projects reveals a more complicated picture that would be very interesting to work on.

      Which stage do you find hardest – planning, funding or building?


    • Adam

      A Question…

      If you were to leave 30 million electric cars (with their battery packs) parked and hooked up to the grid most of the time, to what extent could that provide demand balancing for wind energy distribution? What percentage of wind penetration would be fesable assuming normal driving and charging patterns for the cars?

      i.e. Can electric cars balance a wind-powered grid?

    • Damon Hart-Davis


      So far as I know, basically ‘yes’, the amount of storage would be enough to deal with short-term balancing and long-term lulls pretty well.