Solar power, specifically PV, has grown rapidly since the turn of the century. That growth shows little sign of slowing down on a global basis. The initial driver of growth was subsidy, in particular the introduction of feed-in-tariffs (FiTs) in Europe, along with other policy mechanisms like tax credits in the US. Now though, continued growth is being driven by the competitiveness of solar energy: even without subsidy, solar in many markets is already the cheapest way to generate a kWh of electricity. Subsidy has largely done its job and is, quite rightly, being reduced or removed. Both at the product level and between project developers, through auctions, a combination of technological progress and market competition are and will continue to drive costs down.
Of course there are plenty of criticisms of solar, in particular the potential limits of its value to electricity systems once “full costs” are taken into account: those required to balance the supply and demand of electricity in the face of variability (which is an factor for both supply and demand). My response to those criticisms is that we’ll increasingly live in a “solar +” world. Solar will be the preferred way to produce a kWh of energy, because nothing will be able to compete on cost. The “+” will refer to a variety of integrations that add ‘dispatchability’ (flexibility and predictability – and hence value) to that energy.