Wind and Solar current status

The US DOE has published a 2015 US Wind energy report that documents the declining cost of wind electricity, especially in the windy middle of the US where PPAs are down to 2 cents/kWh. Similarly, the cost of solar electricity is continuing its decline as documented by LBNL with utility solar PPAs falling below 5 cents/kWh in sunny locations. Solar and wind have accounted for the majority of new US generation for several years with wind at about 8GW/y and solar growing to 12GW/y. Wind and solar are now the status quo incumbent, not the plucky insurgent. The total installed US wind capacity is currently 74GW and solar is 23GW. The total US electricity generating capacity is about 1TW with about a 50% capacity factor. If wind added 10GW of capacity a year that would replace 1% of capacity a year. Solar has come on strong and allowing for a lower capacity factor is also approaching 1% of capacity a year. This would total 2% a year or 50 years to replace current electricity generation. If policy support (subsidy) could be maintained it might be possible to see a path to electricity generation in 25 years, a timeframe necessary to keep CO2 below agreed limits.
Already new long distance transmission has been added but much more would be needed. The other requirement is storage for which a solution does not yet exist but progress is being made. Wind cost is not reducing much so the total US generation budget would be about $50B/y and about the same again for transmission and storage. That is about $100B/y for everything. That’s not really a big bill for US. GDP is about $18T/y. The federal budget is $2.6T/y and defense is $700B/y of that.
As the costs become apparent and the limits of the grid to absorb intermittent power are reached, incremental alternatives like StratoSolar that solve the problems might get some attention. Solar in particular has always been an underdog and has only very recently come to the fore. As it starts to behave like an incumbent with a lot to lose and starts to reach deployment limits, an incremental change to StratoSolar might seem an attractive alternative.

​By Edmund Kelly