Per the IEA numbers, Final Investment Decisions on new coal plants were ~22GW in 2018. Retirements, by contrast, were about 31GW.
It takes ~4 years to build a plant so we're still seeing 2015-level FIDs coming online. But the peak should arrive by 2021 or 2022.
The resources industry is notoriously cyclical. So it's possible, even likely, that we're just seeing a low-point in the investment cycle. Mining and energy companies wasted a fortune on capex over the past decade.
But at some point, the investment drought should lead to supply shortages, which should in turn lift prices, which should spark investments in new capacity.
And at some point, betting that an ongoing fall in investment is just a temporary phenomenon and not a permanent change becomes a version of praying for the second coming.
That would mean the energy companies who produce fossil fuels are markedly less optimistic about their prospects than policymakers.
Investments in renewables are only running at about 50% of what the IEA reckons they need to be hitting -- so it's not like all the smart money is being placed on the energy transition.
The one thing we can forecast with some certainty from this investment data is that energy markets are going to be *undersupplied*, assuming the IEA's demand projections are correct.
Your view of that depends on your opinion of the cyclical/structural issue, but to me both paths seem plausible.