Ozzie renewables boom

Last year, one of the largest coal power stations in Australia, Hazelwood in Victoria, closed down.  It was old and its owners, Engie, decided that it would cost too much to fix, plus there was reputational damage because Hazelwood burned brown coal (lignite) which is by far the highest emitter of CO2 per MW of any large-scale generation.  When it closed, the Right had an orgy of ill-informed recrimination, blaming Labor and forecasting that the loss of Hazelwood's output would lead to blackouts this summer (even in Victoria, in the south of the country, demand is highest in summer because of air conditioners)

In fact, there were no blackouts because of insufficient supply this summer.  (Several coal power stations however had units which went off line because of the heat, and some substations tripped because of excessive demand during heat waves.)  As it happened, the output of solar this summer from 8 am to 4 pm exceeded the maximum output of Hazelwood  last summer.  (What happens after 5 p.m.?  Wind and hydro take up the slack, though when the whole grid goes renewable, storage via batteries or pumped hydro will be necessary.  In any event, 60+% of electricity demand is during the day.)

Source: PV Magazine

This is part of a renewables boom in Oz.  5 GW (gigawatts, = 1000 MW) of wind and large scale solar is under construction now, the largest ever--and that ignores rooftop solar which is also at a record.  Total generation capacity in the NEM (national electricity market, which covers all of Australia except for the Northern Territory and WA) is about 45 GW.   Effective capacity of renewables is about 40% compared with fossil fuels of 60% (varies a lot, though).  So a quick calculation suggests that we would need about 65 to 70 GW of renewables capacity.  At this rate it would take 30 years or so to replace Oz's current coal generation with 100% renewables. 

But the rate of retirement of coal generators will accelerate as solar and wind costs continue to decline.  We're close to the point in Australia (and in many other countries round the world) where new wind and solar will be cheaper to run than old coal, and when that happens, coal power stations will be rapidly retired.  Which means we're likely to have a 100% green grid here in Australia and in other developed countries well within 20 years.  In China and India, they're still building new coal power stations, so their transition is likely to take 30 years, but even there, the construction  rate of new coal power stations is slowing fast.  It seems entirely plausible that for the developed world, there will be no coal-fired power stations within 20 years, and for China, India, Vietnam, Bangladesh, etc, there will be none within 30 years or soon thereafter.