Stratosolar plan is to have a buoyant concentrator collecting solar energy from the cloudless stratosphere and direct the solar energy into a buoyant light pipe. The light pipe both tethers the concentrator and directs the solar energy to the ground where it is absorbed and converted to electricity using conventional turbo-generators.
What the system does:
* Weather independent, 24/7 electricity from concentrated solar power (CSP)
* Locations up to latitude 60 (as far north as Stockholm)
* Electricity in utility scale systems up to 1 GWe (one Giga Watt Electrical Power output)
* Cost competitive with the lowest-cost coal-fired systems
Why it comes at a reasonable cost:
For solar-power plants, almost the complete operating cost is the loan payment for the construction loan used to build the plant. The StratoSolar system has a reasonable operating cost mostly because the solar concentrator (which dominates CSP cost) has a reasonable capital cost, with a resulting reasonable loan payment. The reasons for this are:
* The concentrator in the stratosphere is exposed to 3X the solar radiation intensity (or more) of ground-based CSP systems.
* By tracking the sun it also captures more than 2X equivalent mirror size ground-based CSP heliostat concentrators (no cosine losses).
* The combination of these two advantages means each square meter of StratoSolar concentrator mirror gathers over 6X the power of each square meter of a ground-based CSP heliostat mirror.
* The StratoSolar concentrator uses very little land resulting in very little land cost and site development cost. Ground based CSP needs many square miles of land all of which needs to be developed.
* A StratoSolar concentrator uses very little material due to its lightweight structure.The structure is lightweight because it is buoyant and does not have to support the force of it’s own weight. It is also subject to very light wind forces and experiences no rain, hail, snow, or condensation in the low stratosphere.
* All StratoSolar materials used are standard, off the shelf, and low cost.
* This results in a StratoSolar mirror structure that is 2X lower cost per square meter than ground-based CSP heliostat mirrors.
The combination of these four big advantages (more energy, less energy loss, less material cost, less land) results in an overall concentrator cost advantage over ground-based CSP concentrators exceeding 15X. See the section in the tutorial document (CSP cost ) for more detail on this topic and a detailed description and analysis of many other aspects of a StratoSolar design.
This is potentially the first commercially competitive alternative energy solution. Electricity from current CSP systems costs $0.35/kWh to $0.25/kWh and is not commercially viable without massive subsidy. StratoSolar will cost $0.06/kWh initially, and less than $0.005/kWh when mature, considerably cheaper than any alternative including existing fossil fuel plants.