The fundamental constraints are complexity and cost. While various academic studies show that a clean energy solution is probably technically feasible, the details of particular solutions and how they might be implemented do not exist. They also rely on scaling technologies and solving organizational and political problems that are worsening, not improving.
Implicit in all clean energy plans is the assumption that costs will reduce as scale increases. This has so far proven true for the cost of PV panels and wind turbines which has fueled this optimism. However, as we have pointed out, the costs of integrating solar and wind into existing grids are high, and the evidence already is that the price of electricity to consumers has risen substantially in large economies that have invested in clean energy like Germany, England and California. The reality is that wind and solar already increase the price of electricity with relatively low market penetration.
No economy has yet installed sufficient capacity of intermittent renewables to where further growth requires energy storage. This highlights the fact that as intermittent renewables market share increases new additional costs are added that further increase the cost of electricity in a nonlinear fashion.
There are four stages to replacing fossil fuel generation with intermittent wind and solar, each of which adds substantial additional cost.
- Adding solar and wind to existing grids and using fossil fuel generation as backup. This stage lasts until about 20% to 30% of average generating capacity is achieved. At this point adding capacity mostly leads to generation curtailment.
- At this stage daily storage of about 10 hours needs to be added for any additional generation. Fossil fuel generation is still needed for backup for long duration intermittency. The storage at leasts doubles the cost of added generation. This stage lasts until about 80% of generation is from wind, solar and storage, when long duration intermittency becomes the limiting factor to growth.
- To progress beyond 80% things get fuzzy. The available technology is long distance high voltage transmission to get power from a geography far enough away not to be affected by the long duration intermittency. This adds the cost of storage, transmission and the excess capacity needed along with the control infrastructure to make everything work. This stage gets incrementally more expensive for each percentage of growth in renewable generation.
- Synthetic fuels generated from electricity are necessary for various market segments in transportation and industry. The price of these fuels will be based on expensive electricity and so will be many times the price of fossil fuels. At this stage, it may prove more effective to burn fossil fuels with CCS.
The bottom line is that the price of clean electricity is going to be maybe three to five times the cost of today's (and tomorrows) electricity from fossil fuels. This price is what ensures that the transition from fossil fuels will be slow. Whatever promises are made by politicians don’t matter in the face of economic reality.
The Stratosolar PV solution with gravity energy storage generates electricity for less than the cost of today's PV electricity generation (note cost not price) and can be plugged directly into today's grid and directly displace fossil fuels, thus reducing the price of electricity, not increasing it as is happening with today's wind and solar. With Stratosolar price will reduce with scale, not increase as with today’s wind and solar.
By Edmund Kelly