Why can’t ground PV match the StratoSolar deployment scenario?

A simple question is why can’t ground PV do the same thing as the StratoSolar scenario? The simple answer is it is too expensive and  it won’t get cheap enough anytime soon. The sharp drop in PV prices over the last few years have stopped, and there is no rational basis for them to fall further for a long time.  A good thing about the recent price drops is it has raised awareness of PV and its potential for further improvement. A bad thing is it has created over optimistic and unrealistic assessments of PV’s chance to be a significant energy provider in the short term.  

In the end, energy is all about politics and economics. StratoSolar PV panels have an average utilization of 40%. Ground PV panels have an average utilization of about 13%. Based on a simple analysis, ground PV electricity costs three times as much, and importantly this is significantly more than electricity costs today. That means that it can only be sold with the help of subsidies.  As Germany has demonstrated, profitability drives investment.  By providing subsidies that guaranteed profitable investment, German private industry jumped at the opportunity and installations grew very rapidly. Japan and China are following Germany’s lead.

But things are actually worse than this.  Its always tempting measure solar with the best utilization from sunny places, but unfortunately with solar its all about geography.  There are very few places with good solar near population centers.  Southern California is a rare example.

Take Germany as a more representative example.  PV utilization in Germany is around 11% from the published data.  Germany could do a deal with a sunny location and build HV transmission lines to transport the power.  This has numerous problems. On purely money terms, as panels have reduced in cost, and transmission lines have not, its likely that the better PV utilization in the desert will not cover the HV transmission costs.  Don’t forget that the transmission lines will have the low PV utilization, which more than doubles the cost compared to conventional HV transmission lines. On top of this are the political constraints. HV transmission lines are not liked, and the countries where the panels and HV transmission lines are placed may not be the most politically stable.

Even in the US, politics and economics will favor New York, for example, building in New York rather than dealing with getting power from New Mexico via transmission lines through many states.  What this means is that ground PV discriminates, and northern climes get to pay twice as much, or more for electricity.  Economics will also dictate that southern climes will get most of the synthetic fuel business.

Because of the lower utilization, ground PV electricity will always cost 3X StratoSolar electricity.  This factor makes StratoSolar economic for electricity, and then fuels long before ground PV.  The learning curve is good but not that good. The learning curve will not continue for ever, and when it slows it will create a permanent cost barrier that ground PV will never overcome.

StratoSolar is far less variable with geography, so Germany or New York, for example could provide all their  energy needs, both electricity and fuel, locally.

So to summarize, ground PV is too far from viability today, and too variable with geography to ever be an easy political choice. StratoSolar is viable today, and does not discriminate against geography. The StratoSolar capital investment for both PV plants and synthetic fuel plants will average a sustainable $0.6T/year, in line with current world energy investment. $2T/year capital investment for ground PV is a lot harder to imagine.
By Edmund Kelly