Renewable progress globally

Solar PV is doing very well globally, with over 1TW now in the pipeline and a 20% annual growth rate.  Its success is clear from the IEA’s recent global assessment of manufacturing capacity, which also shows that wind is behind target: projected throughput from existing wind capacity and announced new projects equates to just under 30% of planned Net Zero Scenario deployment levels. Hydrogen electrolysers are doing a bit better at just over 60% and heat pumps just over 40%. 

The IEA survey also shows that China leads in most areas, with 80% of current and projected (‘in pipeline’) global PV capacity and over 60% of existing and projected global wind capacity. It also does well on battery storage (around 75% and 70%) and quite well on electrolysis (40% and 35%) and heat pumps (35% and 25%). Only the EU beats it in the projected pipeline for heat pumps (40%).  So is that how the global energy future is going to look? China in the lead with PV, followed by wind? With hydrogen coming on strong too there? And heat pumps maybe following up, but not as fast? 

There are some global and local  issues. Crucially, is there enough room for this huge solar expansion? In crowded countries like the UK for example? Well maybe. A UCL study for the Campaign for the Protection of Rural England found that all the PV needed for a zero carbon scenario could be located in the built environment, some at similar cost to rural solar farms, although some costing more. The land-take would be about the same as for onshore wind farms (1.3%). Biomass would need a lot more (8%).  

There are certainly ways in which land use can be avoided or limited, in the UK as elsewhere - most obviously by using roof tops for PV. But large rural solar farms are the cheapest. They can be sited to reduce impacts: vertical ones take up less room, but they can then have lower efficiency.  Mounting them on sun shades over fields or over car parks/parking lots is also possible.  

In the end though, in terms of solar, it may mostly come down to who has got the most land, and China may do well on that, although so may countries with even more desert areas. But it also matters where exactly the resource is. Power can be transmitted long distances to loads with relatively low energy losses, so can hydrogen gas, but it does add costs and risks.  It may be easier to generate power, or hydrogen, on the spot and store it until it is needed- e.g. via photo-catalytic solar.  

The last year or so has seen an interesting debate on the right mix of options, partly focussed on the role that hydrogen might play- see my recent posts on this. Just about everyone now has major hydrogen projects, with the G7 summit saying its use should be prioritised. Some projects are for fossil derived ‘blue’ hydrogen, with CCS to reduce its emissions, but there will increasingly be a shift to zero carbon green hydrogen from renewables. China is in the lead with hydrogen electrolyser manufacture, although that may change. Some green hydrogen may be fed/admixed into the gas grid replacing fossil gas, or used in dedicated new green gas networks, as Germany is doing. 

There are disagreements about the way ahead, for example over the value of hydrogen blending, but it does seem clear that, hydrogen may have many industrial and some transport uses, and could be used in grid backup power systems. However, it’s not very suited to home heating: heat pumps are far more efficient. Of course, although they may need less of it than hydrogen electrolysers, heat pumps still do need green power to run.  So we can’t escape the issue of where that is going to come from. 

So what will power heat pumps and also electrolysis? Presumably, in addition to PV, to replace fossil gas, in many places in the world, it’s going to be from wind, onshore, and, if relevant, offshore, increasingly using floating devices, with of course no direct land take then being involved.  A bit of tidal and wave perhaps too in some locations, and with no direct land take being involved. Some small to medium scale run-of-the-river hydro possibly, with lower eco-impacts than large reservoir-based hydro. And geothermal in some locations. Plus solar heating in many places, backed up in some locations by community heat stores. It’s not all just about power supply. Though there are environmental uncertainties about role of biomass in heat supply and biofuels in transport, as well as energy crops for power generation. Biowastes, including biogas from farm and food waste, are generally less of a problem.    

Although there may be debates over each item, the overall renewable menu is by now very familiar. Will it be enough? The global scenarios differ on that. Some say renewables can do it all, everywhere, given proper attention to energy saving and efficient use of energy. Others are more cautious, with the transport sector often seen as being problematic: given the resource limits we can’t all have electric cars and aviation may have to be constrained. So, at the very least, there may have to be some social/lifestyle changes. Or other technical fixes. Carbon capture/removal technology has its fans, though, as the UNFCC has pointed out, it’s as yet unproven at scale. Nuclear power is another favourite for renewable contrarians, though not for many environmentalists, not least given its safety and security risks and costs.  Others again are even more bleak, or if you like, more radical. Technical fixes and lifestyle changes will not be enough, they say: we will have to abandon economic growth, since we can’t keep expanding resource use on a finite planet. Indeed, some say frugality may be forced on us at some point.  

Will it come to that? Or will it be possible to get social commitments for cutting consumption of key resources dramatically?  Hard to say, although there have been some brave efforts to map out a way ahead. However there are many often major uncertainties. Can population growth get tamed?  Will AI take over from humanities often puny efforts at sustainable system management?  We don’t know. However, what can be said with some solidity is that renewables are doing quite well, although they could do even better.