Wind growth rate slowing

These data are from GWEC (Global Wind Energy Council).  You can see just how much capacity in wind has grown over the last 20 years.  It's risen 80 fold since 1996.  Because it is a log scale, a constant growth rate should produce a straight line, with a fixed slope.  And you can see that the slope of the line is falling.  This slowdown is shown more clearly in the lower chart, which shows the year-on-year percentage increase in cumulative capacity.

This slowdown is partly due to a slowdown in the switch to renewables in Europe--the Energiewende in Germany has stagnated--and partly to an increased preference for solar, which has fallen even faster in cost than wind has.  Whereas wind capacity was doubling every 3 years, the growth rate has slipped to a doubling every 5 years.

Wind makes up just 4.2% of total electricity produced globally (2017).  Wind and solar together are about 6% of total global electricity production.  The growth rate in solar (a doubling every 2 years) is very likely to continue because of the rapid decline in costs.  So even though wind's growth is slowing, I estimate that it still seems likely that wind and solar together will provide about 20% of total world electricity production in 5 years time, while wind, solar and hydro will be just under 40%.

These numbers may be too low: what constrains the renewables percentage of electricity in the grid above 20 or 30% is the need for storage.  As storage costs decline, this constraint will disappear.  For example, in Australia, rooftop solar plus behind the meter storage (e.g, the Tesla Powerwall) is already cheaper than retail electricity, and while the costs of solar and of batteries are falling fast, the costs of retail electricity continue to rise.  Households make up 25% of electricity demand in Australia, and at least half of these will install solar and storage.  A 6 kW solar panel rooftop installation plus a Tesla Powerwall will provide for 80+% of the average household's electricity demand.

My projections suggest that 66% of world electricity demands will be provided by wind and solar in 10 years time (2028), and the projections include slower growth in wind (14% per annum) but continued growth in solar (40+% a year until 2025, slowing thereafter).  I have not included CSP in the forecasts, but I suspect it will play a big part in time, given its ability to produce both baseload and dispatchable power.