As stated in the opening blog posting, the StratoSolar-PV alternative is the result of studying the concerns raised by the original CSP based design which was perceived to be too risky on several fronts.
· The risk of catastrophic loss from extreme weather events
· The complexity of developing many technologies at untested scales and new environments
· The complexity of needing many costly and risky elements to build a system
· The inability to demonstrate and develop a system on a small scale
The PV system attacks these concerns directly. The design reduces catastrophic risks, has many fewer technology development elements, has very few elements to build a system, and provides incremental engineering development and incremental system deployment starting from a much lower initial cost in order to reduce financial risk at each stage.
Catastrophic risks are reduced by reducing the wind loads on the tethers and the PV array platform to where the system can sustain winds beyond worst case known winds simultaneously at all altitudes. The tethers have a very low cross section, and the platform is horizontal with a low cross section and static with no moving parts.
The development can start with a small engineering test platform and simple tether for that will cost less than $1M, with another $1M for R&D engineering. This gets across the psychological barrier of actually tethering something useful at 20km altitude. It also develops and tests all the platform structural and electrical elements.
The 10MW power platform will cost around $20M with another $20M for R&D. This expenditure will be incremental in nature.
Finance and Insurance costs depend on the risks and the rewards. Unlike nuclear power, liability insurance should be low. Understanding the probabilities of damaging or destructive events will only come with time and experience. The R&D process should provide a degree of confidence as it progresses over several years and the technology becomes familiar. A successful R&D program that results in a product that demonstrates competitive economics for solar power will be a powerful incentive to overcome what should by then be imagined risks. The first systems will be relatively small investments. If the market finds it too difficult to fund or insure the early deployment stage, it is reasonable to expect that government assistance perhaps in the form of loan guarantees will fill that gap. Governments currently seem happiest supporting alternative energy at the early deployment stage.