Strato solar introduction 2011 6 30


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Presentation from CSP USA conference in Las Vegas on June 30th 2011

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Strato solar introduction 2011 6 30

  1. 1. StratoSolar Geographically independent Reliable Cheap Solar Energy Ed Kelly
  2. 2. StratoSolar systems StratoSolar-PV StratoSolar-CSP A giga Watt electrical power, utility scale PV A buoyant solar concentrator floating at 20km altitude in system tethered and floating at 20km altitude over the stratosphere near Colusa in Northern California Northern California. The system is 3600m in diameter, assembled from 100 arrays, each 360m in diameter and 100m thick.6/29/2011 StratoSolar 2
  3. 3. What the CSP 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  Concentrate Sunlight in the Stratosphere with a large mirror concentrator  Pipe the concentrated light down to the ground with a hollow tube Light Pipe  Receive and store the concentrated energy at high temperature  Convert the high temperature stored energy to Electricity at high efficiency6/29/2011 StratoSolar 3
  4. 4. CSP status  Feedback: too risky to fund  Lots of new ideas untested at scale  Lots of big risky pieces  No low cost incremental investment  Possibility of catastrophic loss  Evaluated the feedback and came up with a PV option that reduced risk in many dimensions  Only one untested idea  Only one risky piece  Low initial and incremental investment  Very reduced risk of catastrophic loss6/29/2011 StratoSolar 4
  5. 5. What the PV system does  Weather independent, photovoltaic solar power (PV)  Locations up to latitude 60  Electricity in utility scale systems from 10 MW to 1 GW in modular increments  Cost competitive without subsidy  Easily integrated into the grid, no backup generators or long transmission lines required  Convert sunlight to electricity in the stratosphere with a large array of PV panels mounted on a rigid buoyant platform  Connect the panels to produce electricity as HVDC  Transmit the HVDC electricity down a 20km combined HVDC cable/tether to the ground  Control the cable length with a winch6/29/2011 StratoSolar 5
  6. 6. Why it comes at a reasonable cost:  The PV panels are exposed to 1.5 to 3.5X the solar radiation of ground-based PV panels  This means each square meter of PV panel gathers 1.5 to 3.5X the power of ground-based PV panels  The PV array uses no land. No land cost, or site development cost.  The PV array support structure uses very little material due to light structural loads.  All construction materials are standard, off the shelf, and low cost  The PV panels are lower cost than ground-based PV panels due to reduced panel packaging cost  The electricity produced is predictable and does not require backup generation6/29/2011 StratoSolar 6
  7. 7. Why it works: weather in the Stratosphere The stratosphere is a permanent inversion layer in the earth’s atmosphere. Inversion layers effectively isolate gas bodies. The calm weather free stratosphere is isolated from the turbulent troposphere below. There is no rain, hail, snow, or moisture in the stratosphere and wind force is much reduced and stable. This means that buoyant platforms suspended in the stratosphere can be permanently stationed there without needing to be winched down in bad weather. It also means that PV panels in the stratosphere don’t suffer water based weather effects and can be simpler and cheaper to manufacture.6/29/2011 StratoSolar 7
  8. 8. Wind deflecting the tether and platform 10MW platform Average troposphere Worst tropo Average tropo Worst tropo Average stratosphere Average strato Worst strato Worst strato 1GW array Worst tropo Worst tropo Average strato Worst strato6/29/2011 StratoSolar 8
  9. 9. Sunshine in the Stratosphere Light from the sun at 20km altitude is both strong and constant from dawn to dusk. At 20km a platform is above over 90% of the atmosphere, so sunlight is not significantly scattered or absorbed and there are no clouds to interrupt power generation. This means that on average PV panels produce multiples of the energy they can generate on the ground, and just as important, the energy is highly predictable and not subject to interruption by clouds or storms.6/29/2011 StratoSolar 9
  10. 10. Benefit of 20km Altitude for Direct Normal Solar Insolation  Latitude 60 Winter Solstice: Stockholm Helsinki vs. 6,  Latitude 38 Winter Solstice (SFO) 4, vs. 11,  These assume clear sky, so actual benefit is much higher. SFO average Dec/Jan daily average is 2, from NREL 30 year data. 20km is 4X better. The multiplier for Stockholm is 15X.  These locations are unsuitable for terrestrial CSP because of clouds, moisture, and wind, so the real benefit is a new option previously unavailable.6/29/2011 StratoSolar Confidential 10
  11. 11. PV Electricity cost($/kWh) vs. capital cost($/W) for different sunlight(kWh/m2/year) $0.70 $0.60 $0.50 $/kWh busbar $0.40 worst 800 $0.30 average 1300 best 1950 $0.20 StratoSolar 3100 $0.10 $- $1.00 $1.50 $2.00 $2.50 $3.00 $3.50 $/W (peak) Construction Cost Assumes 20 year life, 8.5% working average cost of capital (WACC) and 2% of capital cost for annual operation and maintenance (O&M). Worst sunlight is northern Europe, best is US southwest. Sunlight is in in average kWh/m2/year. This chart illustrates well that the same plant with the same capital cost produces electricity with highly variable cost depending on location. StratoSolar has the best location.6/29/2011 StratoSolar 11
  12. 12. PV electricity cost chart interpretation  The PV plant capital cost axis ranges from $3.5/W to $1.0/W, from todays $3.5/W cost to costs likely over the next ten years  PV is far from competitive without subsidy even in the best locations over this timeframe  StratoSolar is competitive using todays PV costs  StratoSolar is geography independent so its efficiency can apply to the location with the worst sunlight . The same solar cells in a plant costing the same overall can bring brighter than the desert sun to the far north  The cost advantage for northern Europe exceeds a factor of 36/29/2011 StratoSolar 12
  13. 13. Impact of taxes on LCOE (California 2010) $600 $500 $142 $400 20-yr levelized $/MWh $75 $300 Tax Credit $90 5-yr MACRS $77 Busbar $47 $200 $40 $308 $25 $36 $28 $100 $195 $19 $158 $94 $97 $75 $- CCGT StratoSolar-PV Utility scale thin Rooftop PV ($5/W) Solar thermal Onshore Wind ($3/W) film PV ($3.4/W)Renewables source: source: StratoSolar 13
  14. 14. 1G Watt 100 module array 3600m diameter6/29/2011 StratoSolar 14
  15. 15. 10M Watt modular platform 360m diameter6/29/2011 StratoSolar 15