It’s now pretty clear that renewables can replace fossil fuels in their main uses, electricity generation and land transport, at a very modest cost or, as appears to be the case for electricity, with a cost saving. But that still leaves room for doubt over whether the economy can be fully decarbonized in time to hold CO2 concentrations to 450 ppm or below. Among the big gaps are air and sea transport.
I’ve tended to argue on the basis of the idea of induced innovation that, since there are plenty of possible options, at least one will work out, given some incentives to reduce CO2 emissions. That’s proved true for electricity (solar and PV worked, while other promising contenders like geothermal and Gen III nuclear haven’t), and more recently for storage. But it doesn’t seem to satisfy everyone.
So, I was struck to realize that drones (which I’ve always thought of either as toys or as particularly nasty weapons systems) may be on the way to displacing a good deal of air and sea freight transport in the relatively near future. Initially at least, the bigger ones are likely to use conventional engines, but with greatly reduced fuel costs, as with this proposal. But it’s easy to imagine a version that carries its own solar PV system being developed in the future – possibly slower but even cheaper than the current verison.
Moreover, the size and capacity of battery-driven electric drones is increasing all the time. The current leader appears to be the Griff 300, which can (as the name indicates) lift 300kg, including its own weight of about 65 kg. Apparently there is a Griff 800 either released or in the works. At least to my understanding, there’s no fundamental scaling limit here, although there will obviously be plenty of technical challenges. On the other hand, with batteries getting lighter every year, performance can be improved over time without any significant change in design.
None of this deals with passenger air travel which looms larger in the culture wars over energy policy that its objective significance as a source of emissions justifies. But again, in the absence of fundamental limits (the kind that apply, for example, to carbon capture and storage), a sufficiently strong incentive will in all probability bring forth a solution.