Emissions: Step on the natural gas for German cars

Journal name:
Nature
Volume:
541,
Page:
157
Date published:
DOI:
doi:10.1038/541157b
Published online

The decision by Germany's Federal Council to phase out petrol and diesel vehicles by 2030 is at odds with the government's investment in renewable energy, which is not enough to produce the extra power that electric cars will need. We show how natural gas could plug the gap.

Replacing internal-combustion vehicles with electric cars would reduce Germany's primary energy needs by 60%, from about 570 terawatt-hours (TWh) to about 230 TWh (detailed calculations available from the authors). However, the government's brake on renewables, mainly to protect stability of the electricity grid, means that only 63 TWh will come online by 2030 (see also Nature 534, 152; 2016). Making up the deficit with electricity generated by burning natural gas would create 131 million tonnes of carbon dioxide, which would still save 30 million tonnes on 2014 road-transport emissions.

To decarbonize its transport sector entirely — and to meet the shortfall under its plan to phase out nuclear energy by 2030 — Germany will need to step up production of renewable energy and develop smart storage grids.

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Affiliations

  1. Lancaster University, UK.

    • Dénes Csala &
    • Harry Hoster

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Comments

  1. Report this comment #69253

    James Biscoe said:

    Good. That can be natural gas produced by Anaerobic digestion of putrescible wastes or hydrogen produced by electrolysis using off peak electric and used in fuel cells. Just need to check which gives the best return per euro invested.

  2. Report this comment #69451

    Tam Hunt said:

    Interesting analysis, but it seems to me that the authors state their conclusions far too conclusorily, failing to acknowledge a great many uncertainties, and leaving out a number of key elements, including: 1) increased efficiency and run-time of existing power plants that can charge EVs at night with far less than a one to one increase in emissions; 2) a strong trend toward EV owners charging EVs with their own panels at home; and, most importantly 3) a likely shift toward self-driving cars before 2030, sufficient to lead to a substantial increase in efficiency in transportation for a variety of reasons. Moreover, it's not remotely realistic to expect that Germany would actually achieve a full EV turnover of its ICE fleet by 2030. Maybe all new car sales could be EVs by 2030, but not the entire fleet itself. So, it seems that while there may well have to be some new coal and gas plants to reach the 2030 100% EV goal a) that goal isn?t remotely realistic; and b) the authors leave out some key aspects of the analysis. My fear is that such gaps in this kind of research may have a negative real-world impact on Germany's laudable goals with its ongoing Energiewende and I'd urge Nature to be more demanding of this kind of writing and research.

  3. Report this comment #69457

    Dénes Csala said:

    Hi all – let me clarify a few points which are obviously not possible to convey in such a short correspondence format: This is positioned as a thought-experiment rather than number hairsplitting, since all of the quantities have uncertainty bands attached to them. We wanted to highlight the importance of policy synchronization in a "what-if scenario" of replacing al cars in 2030 with EVs overnight. The Germany's Federal Council (Bundesrat) calls for all new vehicles electric in 2030, but of course, there would be a lifetime involved until the car stock turns over. If any directive mandating electric cars would become binding, there would be serious issues with its enforceability from a legal aspect – and there is also the vast existing fossil infrastructure creating a lock-in effect. So currently, the average age of German cars is 7-8 years and it would take that long let's say for the fleet to turn, but maybe longer because of convenience/resistance to change/campaign by fossil companies/etc. At the same time, the nuclear phase-out might be delayed too. In any case, in the end, maybe a decade later, we will be still facing the problem of new electricity supply and a limiting high renewable share. Even letting renewables grow at the restricted pace, would not cover 20% of the supply gap. And you cant have a 100% renewable grid, unless it's an intercontinental one – unless: storage. Therefore energy storage policies should (and probably will) be deployed and synchronized in parallel with lifting the renewable energy deployment cap.

  4. Report this comment #70271

    Tim Fischer said:

    You mentioned, that that only 63TWh renewables will come online by 2030. Could you give a bit more details about the source / calculation of this value?
    Based on the estimates from development plans for the suppy network (Netzwerkentwicklungsplan), the gross electricity consumption 2030 might be about 560..620TWh. The goal of the EEG for 2030 is about 50% renewables of the gross electricity consumption. This numbers result in about 290TWh renewables in 2030 or a plus of about 100TWh, given 188TWh in 2016.

  5. Report this comment #70473

    Dénes Csala said:

    Hi Tim! This report announces a limit of 2.8GW annually for wind and 0.6GW annually for solar. We assume that small installations are nearing their capacity limits in terms of deployment and therefore most of the significant future growth will come in the form of power-plant-sized installations. It must also be mentioned that off-shore wind was not explicitly part of this particular ban, although some sties reported as if it were. However, since the ban calls for limiting all wind energy to 40 to 45% of all total capacity, no major expansion of off-shore wind is allowed, particularly when we think about the current strains of the north-south electricity corridor, with most off-shore wind generation in the north and most consumption in the south. So we took the then latest numbers from EUROSTAT Electrical capacity [GW in 2014] Wind:39.2, Solar PV: 38.2. We then calculated the full-load hours from the generation values. Wind FLH: 57.2TWh/39.2GW=1459; capacity factor: 1459/8760=16.7% and PV FLH 36TWh/38.2GW=942; capacity factor: 942/8760=10.8%. Then, the capacity additions mandated by the cap equal: Wind 2.8 GW for 14 years=39.2GW. This yields 39.2x1459=57.2TWh; PV 0.6 GW for 14 years=8.4GW. This yields 8.4x942=7.9TWh. Total: 65TWh. Since these are generation values if we assume an additional 3% loss on transmission, about half of today?s typical values, this gives us 63TWh for consumption. Sorry about having to clarify this here in a comment, but we couldn't of course fit everything into this short correspondence format. Having taken a look at this new Netzwerkentwicklungsplan I can see that there is very significant growth in off-shore wind (responsible for about 15 TWh difference, but in reality even more, since the off-shore capacity factor will be at least double that of onshore). And there is also massive growth in PV. This is about 3 times higher than the announced cap though.. In any case, thank you very much for driving our attention to this new plan – I hope I could clarify at least some of the points.

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