1) The increased overall generation capacity required to achieve the same generation from current sources. (1.6X). This increase is mainly needed to backup the intermittent wind and solar capacity.
2) The significant dispatchable renewable energy beyond intermittent wind and solar required to get the renewable percentage to 80%. This includes biomass, hydro and storage. (amounting to about 30% of generation)
3) The significant new long distance transmission and distribution required.
4) The significant amount of intermittent generation that has to be curtailed (8%-10%)
This is an attempt to be realistic and not just focus on the wind or solar LCOE isolated from the total system costs paid by customers. Hyping competitive LCOE for intermittent wind or solar as being sufficient for them to be cost competitive with fossil fuel generation is false advertizing that can only destroy the long term credibility of alternative energy.
The study estimates that an 80% renewable energy electricity solution will cost an average of about $0.16/kWh compared to a baseline $0.11/kWh.
To move along a path that involves such comprehensive change with almost every element subject to large and varied political opposition would take political will that is clearly not present today. Because it is a plan that requires customers to accept higher costs it is an uphill battle from the start. It is hard to see how current government subsidy mechanisms would arrive at these carefully balanced solutions. Even a cap and trade or carbon tax solution might not result in a workable outcome without the guiding hand of a central authority. Given the yo yo politics of energy policy driven by the vastly different perspectives of Republicans and Democrats it is hard to see the US maintaining a consistent policy for a forty year effort.
If we modify the NREL plan to replace its assumed wind and solar capacity with StratoSolar capacity we get a plan that produces electricity for less than $0.05/kWh in 2050 and the following advantages.
1) Less StratoSolar capacity is required because of the higher utilization
2) Less excess backup capacity is required because of the predictable supply.
3) Power is local so there is no additional cost to expand the grid. This also avoids the interstate politics of transmission lines that cross state boundaries.
4) Each state can generate its own power so there is less political opposition to imported power.
5) There is much less impact on land which leads to lower cost and less political opposition.
6) With less political opposition overall deployment can be faster.
7) Because the electricity is competitive in cost, market forces drive adoption, not government carrots and sticks.
8) Low cost electricity can make synthetic fuels, making a complete energy solution and not just an electricity solution which only covers about 40% of primary energy.