Four misleading mistakes about coal vs renewables

Analysts and journalists can be easily led up the garden path about how important coal is, and how renewables will never amount to anything. Here's four ways you could be misled if you're not careful.

We’ve published an article today from Keith Orchison which, it would be fair to say, is intended as a bit of a reality check to renewable energy advocates keen to throw off coal. It certainly does this very well. But in reading it, something didn’t sound quite right with the statistics.

Orchison relied upon data cited by the University of Queensland’s Energy Initiative comparing the growth in coal use versus renewables. The text from the UQ newsletter is below. Now, the thing that sets off alarm bells for me is when people start comparing coal versus renewables and use the two words ‘primary energy’.

But an interesting back-story may be found in the next energy-driven development surge in ASEAN and South Asia. Over the last three years, coal consumption has grown by nearly 25 per cent in India and 22 per cent in ASEAN countries versus just under 20 per cent in China. Though they may be coming from a lower starting point, these countries represent a massive population base ... whose appetite for more energy is only just beginning.

Compare these figures with the combined global increase in nuclear and renewable energy (the near zero-carbon energy options) which was only 7 per cent. In fact, the growth in primary energy from all near zero-carbon energy sources over the past three years globally, was just 30 per cent of the incremental energy from coal in the Asia-Pacific region alone.

So why would alarm bells go off when I see those two words ‘primary energy’, I hear you ask?

Well, if we put aside burning dung and firewood mainly in the developing world, renewable energy use is usually measured in the amount of electricity generated from sources such as hydro, solar and wind whereas coal and other fossil fuels are usually measured in terms of primary energy, which means the raw energy released when you burn the stuff. This then needs to go through a conversion process to provide us with more useful things such as electricity. In the case of burning coal to produce electricity, about two-thirds of the raw primary energy is lost as heat to the atmosphere where it provides no useful purpose, leaving just a third as a useful product. 

Energy in the form of electricity is a vastly more useful product than raw heat. As an illustration, a typical electric motor sold in Australia will generally convert over 90 per cent of electricity into circular motion. By comparison, your average internal combustion engine in your car will convert about 30 per cent of the energy within the oil into circular motion (there are then countless other losses in translating that into movement of the car, as detailed in the picture below from the US EPA’s fuel economy website).

Source: US EPA

Uni of Queensland actually didn't manage to get primary energy comparison too badly wrong it turns out, probably overestimating coal's importance by 15% (thanks to BP's assumptions about electricity conversion efficiency). But it's not the only problem with the comparison.

The second thing that got the alarm bells ringing with this particular comparison was the inclusion of nuclear power with renewables and the time period employed for the comparison: 2010 to 2013. Now, 2010 was the year just before the Fukushima nuclear plant explosion. Since that time Japan shut down its nuclear plants and Germany also began phasing down nuclear power. According to the BP statistical review of energy, all-up nuclear generation dropped 278 TWh between 2010 and 2013. This inadvertently acts to diminish the significance of substantial growth in renewable energy over that time.

The table below gives the raw numbers. It shows that the growth of renewable energy between 2010-2013 – while falling short of coal – isn’t nearly as inconsequential as you might think based on the University of Queensland statement above. It’s actually 58 per cent of the growth in coal consumption once we correct for coal’s conversion losses to electricity. And importantly, this is on a global level across all fuels.

Which brings me to my third concern with the University of Queensland comparison. By considering coal consumption growth purely in the Asia-Pacific, it actually misses the fact that coal consumption declined across the rest of the world between 2010 and 2013. By just looking at Asia-Pacific they actually overstate the growth in coal consumption by 15 per cent.

Of course this still leaves renewables trailing coal. And given the huge existing dominance of coal in our energy supply we aren’t going to get very far in addressing global warming if renewables can’t even outstrip the growth of coal, let alone make coal consumption go down.

However, let’s look just a little bit into the future to 2018. The fourth mistake people tend to make is to fail to recognise the power of an exponential curve - significant annual growth year on year can accumulate to become a very large change a few years into the future, even if it looks small right now.  The table below details likely incremental additional energy consumption for coal and renewables in 2018 adjusting for coal’s conversion efficiency to electricity. It indicates that coal’s growth will finally be outstripped by renewables in that year.

This is based on the International Energy Agency forecast that thermal coal consumption will grow at a relatively small average annual rate of 1.7 per cent and hydro will grow at 1.9 per cent, based on current government policies. However, the IEA has been pretty hopeless at forecasting wind and solar uptake, consistently underestimating its growth. Specialist solar market analysts NPD Solarbuzz have a better track record and they expect 100 gigawatts of solar will be shipped in 2018. In terms of wind, the Global Wind Energy Council foresees 64GW installed. Using BP statistical review data on capacity factors for these two technologies, which are likely to underestimate their power generation in 2018, I’ve converted these capacity installations into power generation.

Of course, this still leaves us a very long way from making meaningful inroads on containing the level of global warming. And coal remains incredibly dominant. University of Queensland's point remains accurate that there is a massive challenge ahead of us.

But it serves to illustrate that by misinterpreting the available data you can be easily misled to underestimate the potential of renewables and overestimate the position of coal. 

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