Achieving a 50% cut in emissions

Toyota RAV4 plug-in hybrid, with 60 k's of electric range

This is from a comment I wrote about a piece in Melbourne's The Age newspaper.  It's specifically about Australia, but the same forces are operating everywhere.  A 50% cut in emissions by 2035 is easy.  The next 50% (to be achieved by 2050) might be a little harder.

In 2009, new-build solar cost 3.1 times as much as new-build coal (US data, Lazard). Now it costs 1/3rd. The ratio has completely inverted. In fact, in several countries, new-build wind and/or solar are cheaper than the *operating* cost of coal power stations. In other words. it costs more to dig up, transport and burn the coal than it does to build a new wind/solar farm from scratch. The implication is that for *economic* reasons, coal power stations are going to be closed down over the next decade. The government could, were it not a wholly-owned subsidiary of coal companies, make a virtue of the inevitability of this. "See, we're cutting emissions by a third! Aren't we green! We really care!"  Not that they do, of course.

What about the variability of wind/solar? Three points:

1. Wind and solar are complementary, in fact negatively correlated. The wind often blows when the sun doesn't shine, for example during winter in southern states. So a 50/50 wind+solar powered grid has an output profile much closer to baseload than either by itself.
2. A continent-wide grid produce much less variable output than a local one. When the wind isn't blowing in western Victoria, it is in east Gippsland. When it's raining in Sydney, it's sunny in Broken Hill or Port Augusta.
3. Battery cost are plunging. Over the last 30 months, they've fallen 60%, even after the cost impact of the fall in the A$. Storage costs are falling fast, which means the costs of "firming" the grid are too. It is now normal in the US for new solar farms to come with 4 hours of storage. As battery costs continue to slide--they should halve again over the next 3 years--solar farms will add even more storage to allow them to provide power overnight (o/n demand is 2/3rds of day demand, so in principle, 8 hours of storage will be enough)

One final point. Already simple hybrids cost only $1500-$2000 more than their (automatic/CVT) petrol equivalents (for example, the 2020 Toyota Corolla sedan), but they use 40-50% less petrol in urban driving. If your fuel bill is $100 per month, the higher cost of the hybrid engine will pay for itself within 3 years. And transitioning our vehicle fleet to simple hybrids will cut total emissions by another 10% (transport emissions are ~20% of the total.)  Plug-in hybrids are even more fuel efficient, cutting tailpipe emissions by 80% plus.  They cost just a couple of thousand dollars more than an ordinary hybrid.  A small tweak to the tax system could cut emissions from transport by 75%.

By 2030 or 2035, we could cut emissions by 50%, at no extra cost to ourselves. And look good while doing it.  But our conservative government is so beholden to fossil fuel interests that it cannot bring itself to acknowledge this.