The Germans in the unusual role of impractical dreamers

We Brits haven’t properly understood the scale of the German Energiewende, or energy transition. A recent seminar at Germany’s Environment Agency (Umwelt Bundesamt or UBA) assessed whether the country could stop using fossil fuels entirely by 2050 and concluded it is technically feasible to produce all the country’s energy (and not just electricity) from renewable sources without using biomass, nuclear or carbon capture. This would mean generating about 3,000 terawatt hours (TWh) of renewable electricity and converting most of this into methane (Power to Gas) or methanol/butanol (Power to Liquid).  This is six times current electricity generation from all sources. And it assumes a 50% reduction in Germany’s total energy use.

Are they mad? I think they probably are. But Germany society is strongly behind the Energiewende and we shouldn’t underestimate the ability of a determined, resourceful and technologically sophisticated country to achieve almost unimaginable growth in renewable energy. What looks to us like impractical dreaming may eventually work. 

Looked at as a multiple of existing low carbon generation, the target numbers are even more startling. In 2013, German wind produced 47 TWh and solar 30 TWh. Hydro added a further 15 TWh. In total, these renewable sources provided 92 TWh, or about 3% of what the Agency says will be needed to decarbonise the economy in 2050. Large scale expansion of hydro power is not an option. So wind and solar will have to be expanded about 40 fold to cover all the country’s energy needs.

It should be said that the UBA seminar papers avoided any detailed discussion of how the country will grow PV and wind to meet the huge need for electricity at mid-century. A 40 fold expansion of PV would mean that over half of German grassland would carry photovoltaic panels but nobody mentioned this. Of course some energy can be imported, but since most other countries in Europe will attempting their own form of Energiewende there won’t be much surplus to go around.

The nature of the ambition.

The UBA seems to have decided that a low-carbon future critically depends on using electricity to completely replace gas and motor fuels. Whereas the UK talks of converting to electric cars and using electric heat pumps to provide home heating, Germany is committing to using power as the raw material for renewable methane and for renewable liquid fuels. (Older articles on this web site have looked at the reasons why the natural gas grid is the only conceivable way of storing surplus electricity generated on very windy days).

One paper at the symposium examined the relative storage capacities of the existing electricity system in Germany (this is almost entirely hydro-electric power schemes that pump water uphill when the grid is in surplus and then let it flow down again at times of shortage) and compared it with gas and oil storage networks.

German primary and final consumption

The argument is compelling: large scale seasonal storage of electricity can only be achieved by converting power into gas, through electrolysis and methanation, or into methanol/butanol using similar processes. Whatever advances we can possibly expect in batteries or other conventional technologies won’t provide more than a tiny fraction of the energy storage we will need. Complete decarbonisation, the UBA seems to be saying, will need huge investment in today’s nascent power to gas and power to liquids technologies.

The graphic below makes repeated appearance in the symposium papers.

specht graphic

To replace all carbon fuels with renewable electricity, much of it converted to other energy carriers, necessarily involves large conversion losses. Turning surplus power into methane, and then burning it a gas-fired power station to regenerate electricity, recreates less than a third of the original energy. But if an advanced society, such as Germany or the UK, really wants to decarbonise, there really is very little choice. We have to accept the wastage of energy entailed because intermittent renewables will otherwise need huge backup from fossil fuels.

The scale of what is envisaged

The seminar saw estimates of the amount of primary energy needed to create the fuels a modern economy requires. The table below gives the figures.


Primary energy needed Final energy created from this
Electricity 550 TWh 460 TWh (1)
Gas 1110 TWh 300 TWh
Liquid fuels 1280 TWh 520 TWh

 (1)      For electricity, the difference between primary and final energy arises from grid losses and from the losses in pumped hydro and in using some electricity for making methane, prior to conversion back to electricity.

The Germans are saying no to nuclear, but also to CCS and biomass. In one paper from a UBA employee, CCS is called ‘unsustainable’, an attitude remarkably at variance with the UK position. Biofuels of all forms are rejected for similar reasons. So all energy (not just electricity) comes from renewables in 2050 and the UBA sees PV and wind as being the dominant source. The need is for almost 3,000 Terawatt hours of electricity to provide this.

Today Germany has 36 GW of PV, compared to around 3 in the UK. This technology 5.3% of total electricity production in 2013. Wind power supplied about 8% of all electricity need from 33 GW of turbines, about four times the UK’s capacity.

To supply just Germany’s current electricity demand, not the total energy need that the UBA suggests, would need a sevenfold increase in turbines and solar panels. This is not impossible, particularly if Germany successfully moves into offshore wind, which is currently a negligible fraction of its wind capacity. But can Germany reasonably aim to then increase renewable electricity a further six fold to produce the power for methane and butanol production as well? I’m sceptical.

There’s one other important point. Whether or not Germany achieves the ambition of 100% renewable energy, avoiding biofuels and other questionable sources, it is now very focused on developing conversion technologies that turn large volumes of electricity into gas and liquid energy carriers. There is no discussion whatsoever of this in the UK. Time to start learning from the German focus on this critically important issue?




  1. Mike Lloyd’s avatar


    You write in the penultimate paragraph:

    “This is not impossible, particularly if Germany successfully moves into onshore wind, which is currently a negligible fraction of its wind capacity.”

    Do you mean offshore wind?


  2. Samuel’s avatar

    The politicians and Grunen are effectively mad, but the German people won’t follow when their energy bill & taxes will triple.
    Given that the puny contribution of PV (less than 5%) to the energy mix will cost them 130B€ thanks to idiotic FiT, this madness will stop sooner than later.
    And this seminar is telling: There’s not a single mention of costs in their summary paper !

  3. wookey’s avatar

    Full marks for ambition, and I think it’s right that electricty->gas is a really important technology. The UK discussion often ignores the huge fraction of our total energy usage coming from gas for space heating as well as power generation. Despite the losses it’s one of the most useful storage technologies. I’ve not seen any numbers on costs at a large scale. Did this seminar say something about efficiencies?

    Has anyone done a study (like WithoutHotAir or more rigorous/up-to-date) for the German situation on what the actual practical limits for renewables are. Can you get 2000+ TWh from covering the whole country and however much of the North sea they are allowed in turbines? It’s a huge number… Or will it only work with a Desertec-type scheme?

    It does seem to me that putting in some nuclear makes this whole transition a lot easier and probably a lot cheaper, but if they can make it work, especially by 2050, then good for them.

    On what basis are CCS and biomass deemed unsustainable? Is it that large-scale biomass involves taking useful elements out of the soil and putting them into the atmosphere, thus impverishing soils over the long term? It should be a reasonably circular system over time (getting the trace elements back into the soil), but that timescale may be too long to be helpful. I must admit to some ignorance of the details here.

  4. Chris Goodall’s avatar

    oops. Thanks, Mike.

  5. Roger Anthony’s avatar

    As usual, this is all a bit strange. The off shore windmills are all to the north of Germany. Their industry and major population are in the south. The existing national grid cannot transmit all the power that is produced at the moment from the north to the south. (like us)
    I would expect, that they will continue with locally produced electricity and ignore this grand illogical proposal.

  6. Robert Wilson’s avatar


    The most obvious question that needs to be asked here is where they are getting the carbon from that is going into the methane. CCS is out apparently. As is biomass. Unless I am missing something this leaves us with sucking it out of the sky.

    So, based on the numbers in the report Germany will have to suck over 100 million tonnes of CO2 out of the air each year to feed the methanation process. Strangely the authors of the report don’t mention that this might be a problem. And if we can figure out a way to economically suck carbon dioxide out of the air at this scale have we not solved the climate problem? Just stick it underground at that point.

    The whole thing is quite absurd. We must live without nuclear and CCS, but rely entirely on technologies that have not gone beyond the trial stage, are incredibly unlikely scale and have blatantly dubious economics.

    Germany is a country with a high level of engineering expertise. It is a shame this is not reflected in this silly scenario.


  7. Chris Goodall’s avatar


    I looked very hard through the conference papers to see where the carbon atoms were going to come from. No clear idea there . Waste biomass might provide c 5%. But otherwise they can only come from a) the air, running into the issue you identify or b) a closed loop gas turbine/CO2 separation/methanation/gas turbine cycle (ie carbon capture).

    I have to say that I don’t think our friends in Germany have really thought this issue through.

  8. Robert Wilson’s avatar


    Based on their table 2 the overwhelming majority of emissions from renewable fuels aren’t capturable, either being non-stationary sources (such as a transport) or processes that are too small scale to be capturable. This leaves us with sucking carbon dioxide out of the air. Transport alone seems to require at least 100 million tonnes of CO2 as a feed stock. And this quite simply has to be sucked from the air.

    Yes, our friends in Germany seem to have what looks like the energy equivalent of a perpetual motion machine.

  9. Chris Goodall’s avatar


    I agree. Like you, I was struck by the lack of any form of background analysis of exactly how so much electricity might be generated and how the carbon would be captured from – for example – home heating. The UBA stresses that that its work isn’t a ‘forecast’ or a ‘plan’ but I still expected much more rigour in its work. It is much less detailed than, for example, the work of the UK Committee on Climate Change.


  10. michael knowles CEng’s avatar

    Cost, cost and cost? But then Germany with its huge technology base probably makes up for that by exporting to us with our puny base.’Twas ever thus. Germany drives the EU’s environmental legiislation and then reaps the rewards – dash for gas, SO2, NOx, Low Carbon etc.,

    UK’s answer ‘Muddle on regardless!’, then do something different when it gets too costly!

    sent from warm (20 degC) and sunny Cyprus!

  11. Mark Brinkley’s avatar

    Fascinating post, Chris, and fascinating comments too. I too struggle with methanisation(sp?) as a process. If you can add hydrogen to carbon to produce methane, you’ve arguably solved the carbon conundrum at the heart of our energy future. Converting it back to CO2 during combustion seems a backwards step. It’s rather like industrialising the biofuel cycle. On the other hand, if you didn’t burn it, you would simply have come up with another version of CCS, which they eschew too. So quite how the Germans rule out biofuels and CCS whilst endorsing methanisation makes no sense to me. I guess I too had hoped that the clever Germans might have thought this all through and have compelling answers to these questions, but your post seems to confirm my worry that they haven’t.

  12. John Newlands’s avatar

    As a backyard experimenter I’ve been thinking about rich CO2 sources. I’m currently using acid on powdered chalk but another possible source is oxyfired charcoal.
    The 30 bar 300C catalysed Sabatier reaction is CO2 + 4H2 = CH4 + 2H2O
    Water electrolysis is 2H2O = 2H2 + O2
    Perhaps we could use the oxygen to burn carbon C + O2 = CO2 using scorched weeds or garbage for charcoal, that CO2 being hopefully free of sulphur and nitrogen compounds. Then we use the hydrogen and the pure CO2 in the Sabatier reaction. Combining we have
    CO2 + 4H2O = CH4 + 2H20 + 2O2 showing there is more than enough oxygen to burn the charcoal.

    As the article says all energy storage options are unsatisfactory. The main costs in this approach seem to be water splitting then charcoal gathering. Can those costs be reduced enough? I haven’t quite achieved repeatable results yet.

  13. Mike Lloyd’s avatar


    Where is the butanol coming from? I’d also like to know how a 50% reduction in total energy use is to be achieved. Did the seminar cover that?

  14. Robert Wilson’s avatar


    A key point here is that this document does not really reflect what “the Germans” are thinking. It is most likely just a scenario that has been put together to suit certain green pressure groups. Quite obviously a no-nuclear, no-CCS, and no-biomass scenario is preferred by many. Thus these scenarios.

    The same is true of DECC and the CCC. Look through those scenarios and you can see that many exist purely to please certain interest groups. The difference however appears to be one of judgement. The treatment of “technological feasibility” is naive to the extreme. The CCC for example rarely indulges in this type of wishful thinking. (Of course it does indulge in spin, on occasion).

    This also puts the quality of CCC reports in stark relief. I have a lot of problems with recent CCC reports, but none of them are as dreadful as this. Essentially the German environment agency has tossed together a scenario with zero regard for its technological or economic feasibility and labelled it “technologically feasible.” I have hard of other such scenarios from them. Apparently there is one where they proposed building 30 GW of interconnectors to Norway that would run at full tilt when there was no wind in Germany. Where Norway would get its electricity from on these occasions had apparently not been thought about.

  15. Robert Wilson’s avatar


    The 50% reduction in final energy consumption is used because this is Germany’s official target for 2050. No doubt if you hoke around the German Environment Agency’s website you can find scenarios for how they think this can be done.

    But this raises an obvious problem. They use *final* energy consumption. Conversion of renewable electricity into methane entails significant losses. They to assume about 40%. In fact (page 12 of their report) they find that losses within the energy system will go from 27% today to 44% in 2050 largely because of this “power-2-gas” business.

    So here then are the headline numbers. Total electricity production: 2,800 TWh. This is either consumed as electricity, or converted to methane etc. About 44% of it is lost.

    Now, if we look at land requirements for wind and solar things get rather sobering. 2, 800 TWh averages out at about 350 GW on average. German onshore wind farms average about 2 W/m2, offshore 3 W/m2 (to be on the optimistic side). So to get all of this electricity from wind farms you would need about 170, 000 km2 of onshore wind farms.

    That is approximately 50% of Germany covered in wind turbines. Solar panels in Germany are around 4-5 W/m2. So you could cover about a quarter of Germany in solar panels to get this result. We can argue over whether this is “technologically feasible”, but I find it impossible to believe it is politically feasible.

  16. Coling’s avatar

    If I am not mistaken their energy diagram omits the losses from burning the motor fuel to produce kinetic energy. There is another 60% loss there if they stick to internal combustion engines (less if they go for fuel cells).

    It would still be far more efficient to take the original electricity and charge a battery EV.

    I cannot help feeling that this grand proposal is an excuse to perpetuate the use of gas infrastructure and internal combustion engines indefinitely: and if the transition to synthetic fuels fails to happen as quickly as they imagine (which seems inevitable) they just keep burning natural gas and fossil liquid fuels.

    It seems like a plan to keep the fossil fuel and auto industry comfortable for the foreseeable future.

  17. Mike Lloyd’s avatar


    Thank you. I seem to recall that Professor Mackay uses a 50% reduction for his scenarios in SEWTHA. However, he also assumes that heating and transport will be electrified and both of these will have energy efficiency gains.

    I have a lot of respect for the technical capabilities of the German chemical industry but I’m inclined to view 44% losses as optimistic.

    From my experience with technological changes, the first step is to use technology to reproduce the current situation and only later does the technology get used in a different way. I suspect we will do the same with renewable energy technologies in due course.

  18. Robert Wilson’s avatar


    Reducing energy consumption is a lot easier in Germany, mostly because of population issues. Britain’s population is expected to go up 18% between now and 2050 (according to central UN projections), while Germany’s is expected to decline 12%. The difficulty however with this “50%” reduction is that it’s rather misleading.

    In final energy consumption things are going down 50%. However primary energy consumption is essentially going from about 3,900 TWh to about 2,800 TWh, a 28% decline. So in per capita terms we are looking at something like a 15% reduction in primary energy consumption.

    I would agree that 44% losses are optimistic. This sounds like dubious accounting. The obvious problem here is how dreadfully inefficient the power-2-gas process will be. Consider that global steel production capacity is something like 1.8 billion tonnes currently. 1.5 billion tonnes is produced each year. This is considered to be over-capacity. Now think about these power-2-gas plants. If you hooked one of them up to a nuclear power plant they could run 24-7, except when the nuke is out of action. But power them with wind and solar and you will only be able to run them at no more than 20% of capacity. This then raises the totally obvious question of how this can be economical. The power-2-gas facilities will have to be incredibly cheap to build and run.

    Overall the economics seem to make it a complete non-starter. Simplifying things. 1 TWh of gas gives you about 0.5 TWh of electricity. Therefore 1 TWh of electricity is at least two times more expensive than electricity (in raw terms). Let’s be generous and assume 1 TWh of electricity from renewables is as cheap as that from gas. We then convert that 1 TWh of renewable electricity into methane. The cost per TWh of this methane will be at least two times higher than the cost per TWh of renewable electricity (based on losses converting electricity to methane). Therefore the cost of this “renewable” methane will be at least four times that of old fashioned natural gas taken out of the ground. This seems to end the conversation as far as large scale power-2-gas goes.

  19. Michael Knowles’s avatar

    BP’s Chief Economist & VP has written an interesting review of fracking gas & oil worldwide. US now using gas in abundance & exporting cheap coal like there is no tomorrow! Result – US chemical & pharmaceutical. Industries will dominate world markets & US growth will outstrip all unless we get real. Dream on and we are lost?

  20. Michael Knowles’s avatar

    BP’s Chief Economist & VP has written an interesting review of fracking gas & oil worldwide. US now using gas in abundance & exporting cheap coal like there is no tomorrow! Result – US chemical & pharmaceutical. Industries will dominate world markets & US growth will outstrip all unless we get real. Dream on and we are lost?

  21. Michael Knowles’s avatar

    Apologies for double posting on BP shale oil/gas comment. I only meant give the link as a p.s.

  22. Dan’s avatar

    Robert says: “And if we can figure out a way to economically suck carbon dioxide out of the air at this scale have we not solved the climate problem? Just stick it underground at that point.”

    I’m not arguing it’s a good idea one way or the other, but this isn’t quite right, is it? The economics of just pulling out of the air and storing vs using to create another saleable product are quite different. Compare to current CCS projects where the carbon is being used to retrieve more oil or gas: just storing carbon is expensive; using it to gain access to saleable oil and gas is, economically, completely different (which is why I’m highly suspicious of the hoopla surrounding CCS, since successful projects appear to be based on enhanced oil recovery, not purely storage).

  23. Roger Anthony’s avatar

    This is spot on!
    My worry is that the ongoing Free Trade Area talks between the USA, Europe and GB, will be a disaster for us.
    At the obvious level, the USA with lower power costs will blow us out of the water, then the Eastern Europeans, Chinese etc will do the same with their lower employment costs.
    Germany has done well for years with no minimum pay, but their new coalition is working to change this. While we will always do well with the high tech stuff, other manufacturers will suffer.

  24. Mike Lloyd’s avatar

    The German military are not nearly as optimistic as BP about oil.


  25. Paul D’s avatar

    Blue-sky thinking is valid, in its place; it may point the way to something interesting. To believe that it represents the future, full stop, is considerably less than credible.

    Technology advances by small increments but the cumulative effect can be revolutionary. For example: Put a boiler on wheels and you get a railway. Now, you can have a railway powered by electricity. If we had waited for electrified engines before putting vehicles on rails, then how would we have advanced from the horse and cart or the canals, also powered by horses? When thinking about this question, another question is, where would the electricity come from in the era of horses and carts?

    What technological advance, that is known today, can advance the ‘green’ programme economically? I emphasise economically. Where is the engineering support to underpin 100% of energy supply as electricity, generated by just wind and solar? We do not know how to store the stuff in quantity yet; experiment scale electricity-to-hydrogen and a few chemical processes that may or may not be right and each with its own inefficiency.

    All this ‘green’ investment is just one enormous experiment, that may or may NOT be right. Engineers and scientists will deliver the future, not ‘greens’ or politicians, and they will do it incrementally. The cultural divide is palpable; engineers and scientists live in the real world and design and calculate. What the ‘greens’ and politicians do is demand ever greater budgets with no financial return on them. Sometime soon this has to stop. It is becoming unaffordable. It is everybody’s taxes.

    I have a small, but telling, example of what happens when politicians take over. Every house in the country is supposed to get a big heat pump to electrify home heating. To drive these things, the national electricity grid needs to increase in size by a factor of four or five, and so does the generation.

    The generation is to consist of wind turbines and solar. As debated in a previous blog, the last ten years onshore wind turbine generation had a load factor of less than 20%. This needs full backup for the coldest days with no wind. 100% capacity backup and 80% generation backup? Come on, stop pulling my leg! This is a gas turbine with an expensive economiser (expensive economiser – sound a bit contradictory?). The economiser is so expensive that it would not be built at all without massive subsidies. If you gave(price £0) a wind turbine to a gas turbine operator, then the operator would probably run it; if you charged him/her full capital price and only paid market price for the electricity, then he would not buy it in the first place – too expensive, no return.

    Because this overall scheme has not been considered by real engineers and scientists, it has not been cost-engineered; include the heat pumps, cables, transformers, wires, gas and wind turbines in the analysis. If you think that wind turbines are expensive, then think again; add up the capital cost of that lot and see a real horror story. At £1k for each 1kW of pump, grid, gas and wind turbine capacity and a 10kW pump per house, the capital cost becomes £40k per house. 27 million houses, cost 40,000×27,000,000=£1080×10^9=£1.08 trillion of capital and you still need 80% fossil-fired generation until you can store electricity when the capital rises by a factor of five again: £5.4 trillion plus losses for storage, say £7 trillion and this is just home heating. Just remind me again how big the total government debt is at the moment.

    Even a cursory examination shows me how to reduce the number of gas turbines and their uneconomic wind powered economisers by a factor of ten whilst doing 90% of the job. Any ‘greens’ and politicians interested? Not likely, in my view. It would involve a nought off the end of their budgets(your taxes and mine).

    All ‘green’ projects and engineering should be economic. Economic is a tough discipline and I can fully understand why ‘greens’ and politicians do not like it. If British politicians want to come up with uneconomic projects, then they should use their own money and not mine. Did German taxpayers really vote for this Umwelt Bundes Amt stuff?

  26. Robert Wilson’s avatar

    Paul D

    Your comment seems rather off topic, plus your numbers (while impressive) lack credibility. You seem to just be plucking capital costs out of thin air. UK electricity capacity is around 70 GW. Yet you seem to imagine future capital costs work out at £5.4 trillion. This is £70 billion per GW. This is more than ten times higher than current capital costs of nuclear power plants, which have very high capital costs. I’m curious how you have got to such an inflated figure.

  27. wookey’s avatar

    Yes economics matter, but ultimately climate change matters more and will overrule economic choices that don’t sufficiently take it into account in the long term.

    Insulate houses properly and you need a 2kW heat pump, not a 10kW one, which would have a dramatic effect on Paul’s numbers. Still needs a lot of capital, but dramatically less.

  28. Paddy’s avatar

    The problem with all the calculations as to why power to gas won’t work is that they fail to take into account the instantaneous nature of electricity. Electricity not required is not just “lost”, it also creates a surplus of supply over demand, which as any economist will tell you, leads to lower and lower prices. Where that electricity cannot be stored, then these prices become negative. The Danish electricity grid has already seen negative 2000euros per MWh (the maximum allowable) as a result of Germany’s over supply of electricity during windy conditions. Power to gas economics are not about running all the time but about taking advantage of excess electricity which would otherwise have no value. This then creates a feedback loop, meaning that power to gas regulates the electricity market to a level where it is economic to run. Don’t suppose that power to gas is a waste of time – the Germans made PV work for them when people were saying similar things. The cost may be high but so is the cost of doing nothing…

  29. Paul D’s avatar

    Robert Wilson on Tuesday 14 January 2014 at 10.29am writes :-
    Your comment seems rather off topic, plus your numbers (while impressive) lack credibility. You seem to just be plucking capital costs out of thin air. UK electricity capacity is around 70 GW. Yet you seem to imagine future capital costs work out at £5.4 trillion. This is £70 billion per GW. This is more than ten times higher than current capital costs of nuclear power plants, which have very high capital costs. I’m curious how you have got to such an inflated figure.
    Engineering capital in the field of heat pumps and generation could, at a first, very crude estimate, be estimated at £1000/kW installed.

    For example,
    1: I was quoted £16,000 for a 10kW air-to-water heat pump to heat my house. That would be £1,600/kW installed. Similar amounts seem to apply to generation capacity.

    2: In the case of a nuclear power station that supplies 1200MW and cost about £2.4 billion the cost per kilowatt capacity installed would be 2,400,000,000/1200,000=2,400/1.2=£2,000/kW installed.

    3: A wind turbine in Islay that is currently seeking financial support and has issued a prospectus states the the turbine will cost £1.25M and has a capacity of 330kW. 1,250,000/330=£3800/kW installed.

    So, taking heat pumps, wind turbines, gas turbine backup plant and grid reinforcement at £1,000/kW installed, for a 10kW pump in each of 27 million houses in the UK, you get :-
    (10+10+10+10)x1000x27,000,000=40x27x10^9=1080×10^9=£1.08 trillion.
    This is the current target for the year 2050, so 35 years to install it, so 1,080 billion /35=£31 billion per year capital spend to install full sized air-to-water heat pumps in 27 million houses.

    The load factor of all onshore wind turbines in the UK for all years is below 20%. Offshore load factors are higher. Taking the 20% as a starting point, 5 wind turbines would be needed to be built to produce the 5×20=100% load factor of one wind turbine. That is what the German ‘Qualitative representation of the energy flow in the UBA THGND 2050 Scenario’ shows, 100% renewable power (I am ignoring the solar panels here).

    So based on wind turbines and allowing nothing for conversion losses, you need five times as much capital for the wind turbines and their grid reinforcement, if you are going to 100% wind generation. At the start of the process of creating this 100% wind generation, you need to have gas turbine backup generation to match it and that costs.

    It is important to remember that you are creating a new, much bigger grid system to do all this. The direct ‘renewable power’ to ‘power’ on the German graph, if applied in this country would initially increase the grid capacity by about a factor of four or five. The ‘renewable power’ to ‘electrolysis’ path would load the grid if the electrolysis plant was not kept close to the wind farms and the grid would get bigger again. If the electrolysis plant is close to the wind farms, then the hydrogen grid pipes would also cost large sums and the cost and efficiency of the ‘hydrogen synthesis’ also gets into the calculation. I see this 100% renewable capital cost scaling from the £1.08 trillion for the turbine/gas generator scenario to the 100% wind scenario as some first crude estimate of where all this is taking us in terms of cost.

    The £1.08 trillion I suggest is just for electrifying domestic heating in the UK. Equally, the 5x£1.08 trillion=£5.4 trillion is just for 100% renewable supply for electrified domestic heat. I offer no calculation for industrial heat or production of liquid fuels for transport, as shown on the German graph. On the German diagram, the direct electric power looks like about 20% of the ‘renewable power’. If that were right, then the capital cost of this diagram in the UK would be about 5×5.4=£27 trillion.

    In the case of the UK, DECC are actually trying to construct this electrified heat scenario. They do not have a clue whether it is right or not. I offer my view that I can get the costs down by a factor of ten and if I can do that, then there are other engineers who will be able to do better again. That is the reason I have addressed the risk factor in all this. I do not believe that the UBA have got a clue either. Have the German UBA put any numbers to the cost of their proposed 100% renewable power by 2050?

  30. Paul D’s avatar

    wookey on Tuesday 14 January 2014 at 11.45am
    Insulate houses properly and you need a 2kW heat pump, not a 10kW one, which would have a dramatic effect on Paul’s numbers. Still needs a lot of capital, but dramatically less.
    Really good to see someone else trying to figure out how to get these incredible numbers down.

    My house has a 0.45kW A2A(air-to-air) heat pump fitted in the hall of a 5-bed detached modern estate house, in order to run the experiment that wookey suggests. It has consumed about 450kWh to half-way through winter for a cost of £64. By running 24/7, this pump has saved something like 5,000kWh of mains gas. The backup gas-fired boiler has not run at all this winter for whole house heating (the pump average daily load since 1/12/2013 has been 6.1kW/day against a 10.8kW/day capacity but that is down to the mild weather; really cold weather will need the boiler.). Payback looks like five winters.

    So a 10kW(that was the quote) A2W pump, cost £20,000, is replaced by a 0.45kW A2A, cost £2,000, in my house but this is the retrofit situation and I retain the gas-fired boiler. That is a reduction by a factor of 10/0.45=22 in electrical peak demand, a reduction of ten in capital cost and the A2A runs at half the price in electricity as well. Put one of these into every house in the country and redo the sums: divide previous sums by 22.

    I am sure that other engineers would be able to further improve this number. For example, fit a 1kW(electrical) / 5kW(heat), methane fuel cell, one per house with a 0.5kW heat pump and you get electricity, hot water and space heating from two sources, cell and pump. This setup actually exports(or at least reduces imports) electricity during the coldest part of the year. 0.5×27,000,000 =13.5GW of electricity for the grid(grid max demand 56GW). Number of wind turbines needed for domestic heating: zero. Of course the gas has to come from somewhere.


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