When will environment journalists learn the difference between renewables capacity and generation?

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I have too many pet peeves to list. But here is one that simply won’t lie down: environment journalists, environmentalists, Twitter based energy experts, etc. etc. who don’t know the difference between renewable capacity and actual electricity generation. Anyone paid to write about or think about the future of energy should know the difference. But do they?

Here is a report on the Guardian website today:

Europe will likely get more than half of its electricity from renewable sources by the end of the next decade if EU countries meet their climate pledges, according to a draft commission paper.

A planned overhaul of the continent’s electricity grids will now need to be sped up, says the leaked text, seen by the Guardian.

“Reaching the European Union 2030 energy and climate objectives means the share of renewables is likely to reach 50% of installed electricity capacity,” says the consultation paper, due to be published on 15 July. “This means that changes to the electricity system in favour of decarbonisation will have to come even faster.”

These numbers do not mean what the journalist thinks they mean. 50% of installed capacity being renewable does not mean that half of Europe’s electricity will be renewable. In fact, it means much less than 50% of generation will be renewable. 1 GW of solar capacity in Germany will produce less than one third of the electricity of 1 GW of offshore wind capacity in Britain. It will also produce less than one fifth of the electricity of 1 GW of fossil fuel capacity, and barely one tenth of the electricity produced by 1 GW of nuclear capacity.

Aggregate capacity numbers themselves are close to meaningless. It is like comparing the fruit sold in two shops by adding the apples, bananas, mangos, papayas, and melons together to see how many bits of fruit each shop sells, and ignoring the fact that you pay a lot more for a melon than a banana.

I like to think I can count, and I like to think I understand energy issues. But if you told me that 50% of electricity capacity in 2030 will be renewable, I would struggle to tell you what percentage of generation will be renewable. After all, the numbers would come out remarkably different if the expansion of renewables is assumed to be driven by wind or solar, or biomass for that matter.

So, here is the solution. Instead of talking about capacity we talk about generation. This will make things much clearer.


2 thoughts on “When will environment journalists learn the difference between renewables capacity and generation?

    achalhp said:
    June 27, 2015 at 4:45 am

    Without contributing substantial quantity of electricity RENEWABLES just make people FEEL and BELIEVE they are the only solution for the climate change.
    FEEL: Wind or solar farms are very occupy large area. They look large and make people feel something serious is going on.
    BELIEVE: All “green” organizations make people believe that renewables are the only solution for climate change.


    donoughshanahan said:
    July 6, 2015 at 11:57 am

    This was bugging me a bit so I did some simple maths.

    Hypothetical grid of 5GW renewables and 5GW other with capacity factors of 0.2 and 0.9 respectively.

    The important thing to do is get the GWh produced. In 1 hour the above grid will produce 5.5GWh. If we ditched the renewable portion of the grid (only other), to get the same 5.5GWh would require 6.1GW of capacity.

    Inevitably if you install lower capacity factors, you have to install more capacity than you would otherwise need. This simple problem never seems to get highlighted though. It also highlights a problem for LCOE.


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