University of Arizona REhnu

Transcription

1 University of Arizona REhnu proud to be affiliated with the Solar Energy Research Center Roger Angel Justin Elliott Peter Strittmatter

2 Research Development Commercialization Astronomy Program in Tucson began in 1916 with founding of Steward Observatory at UA Expanded rapidly after 1955 with the founding of the Kitt Peak National Observatory Led to many observatories in the Tucson area Founding of the UA Optical Sciences Center Development of Optics Industry in Tucson: over 100 optics companies in the Tucson area Now known as Optics Valley Synergy with Astronomy continues

3 Questions/Answers Questions Why is an Astronomer talking about Solar Electricity Why in Arizona? Overall Answer is the Climate in Arizona Clear nights brought Astronomers to Arizona Astronomers brought opticians and telescope builders Developed optics industry Clear nights means clear days good for solar energy Telescope expertise good for solar energy generators Especially Concentrator Photovoltaic

4 Questions/Answers Questions Why is an Astronomer talking about Solar Electricity Why in Arizona? CHILE Overall Answer is the Climate in Arizona CHILE Clear nights brought Astronomers to Arizona CHILE Astronomers brought opticians and telescope builders Developed optics industry Clear nights means clear days good solar energy Telescope expertise good for solar energy Especially Concentrator Photovoltaic CHILE

5 Astronomical Optics -Mirror Lab Program 6.5m mirrors for the MMT (Arizona), Magellan Telescopes (Las Campanas, Chile), possiblytao (Chajnantor, Chile) 8.4m mirrors for the Large Binocular Telescope (Arizona), Large Synoptic Survey Telescope (Cerro Pachon, Chile) and the Giant Magellan Telescope, (Las Campanas, Chile) LBT 8.4m Casting

6 LBT - 2 x 8.4m

7 GOALS FOR MIRROR LAB SOLAR ENERGY PROGRAM - Reduce Fossil Fuel Use CO 2 in Atmosphere Slow Global Warming - Exploit Large Source of Free Energy especially in Arizona/Chile - Accomplish this at Giga-watt scales at a capital cost that is economically competitive without subsidies Capital Cost < $1.0/ Watt Wholesale Cost of Electrical Energy < $0.04/KWh - Develop Technology to Achieve the Capital + Energy Cost Goals

8 Energy to Power the World Clear nights are coupled to clear days good for CPV NREL map of solar resource at direct incidence

9 Issues and Approach Main Issues are: - Generation - Storage - Distribution Each of these involves many potential solutions that vary according to location. There is no universal right solution. Arizona (Mirror Lab) program is focused on Generation using Concentrator Photo-voltaics (CPV) to exploit the very high conversion efficiency (>40%) of triple junctions PV cells. It requires abundant direct solar illumination as in Arizona and N. Chile. It was aimed initially at Utility Scale Generation (Gigawatt-scale) but is now also being applied at smaller scales.

10 Background/Costing Realities Large Collecting Area needed - true for all solar approaches incident energy density low (1KW/m 2 ) High concentration (10 3 ) to make optimum use of efficient triple junction cells - >40% currently commercially available. (Gains still to be made in conversion efficiency may get to > 50%) High concentration also implies low cell area and hence low cost/cell (currently ~ $0.15/w). Capital goal requires that the 10 3 concentrator costs < $0.85/w. Achieving this is a matter of mirrors and structure just like telescopes. But $/m 2 must be ~ 10 4 less. (Telescope ~ $10 6 /m 2 ;Concentrator <~ $10 2 /m 2 to meet cost goal)

11 Telescopes for Solar Energy Structures made of glass and steel Because steel is priced per kilogram, low cost structure implies light weight structure Structure must remain stiff enough to maintain adequate pointing and to survive in storms Concentration ~10 3 requires 2-d paraboloid. Needs to be made inexpensively. Use float glass, made in vast quantities in 3.3m x 3.3m plane sheets for architectural purposes. Typical production rate is ~1 sheet /10 seconds. Need to have inexpensive method to slump to desired shape.

12 Main Picture: Gen 2 demonstration prototype on-sun at UA Inset: Gen 3 production version

13 Optical System 13 Sunlight Paraboloidal Mirror Light Funnels Ball Lens Solar Cells Power Conversion Unit (PCU) Proprietary and Confidential 10-Jul-13

14 The Spherical Field Lens Fused Silica

15 Gen 2 Status Performance summary a huge success 15 Power conversion unit: Flawless operation since June, no failures 36 Spectrolab C3MJ + cells (36-37% eff.), pre-packaged with bypass diode Ball & funnels AR/protection coated >28% system efficiency Unit sealed at ball, proven to withstand mis-pointing and heavy rain 10-Jul-13

16 Path to Commercialization? 16 REhnu Gen-2 Unit A 20kW Dual-axis tracking CPV unit comprising: Modular array of 8 paraboloidal mirrors (10m 2 ) concentrating at 1000x Mounted within an ultra-light high strength space-frame Compact, upgradable Power Conversion Units (PCUs) Environmentally friendly zero water in production, high ground clearance minimizes site disturbance CAN MEET COST TARGETS AT HIGH VOLUME. BUT - TOO CAPITAL EXPENSIVE TO REACH HIGH ENOUGH VOLUME. NEED TO MODIFY FOR GEN-3 Proprietary and Confidential 10-Jul-13

17 Tracker Evolution 17 Gen-3 design is for a 20 m 2 array of eight 1.6 m square second-surface glass reflectors, concentrating sunlight to multi-junction photovoltaic cells clustered above each mirror. Each Gen-3 unit will initially deliver approx 6 kw at 30% efficiency but with small, quick-fit PCUs will be upgradeable to increase output and extend project life Proprietary and Confidential 10-Jul-13

18 PCU Evolution 18 Gen-0 Proves design concept and demonstrates unique and proprietary optical features with 8 cells (20%) Gen-1 Demonstrates full end-to-end design with 36 cells (22%) Gen-2 Improvements yield jump to >28% Gen-3 Designed for manufacture - decouples heat exchanger, reduces cell size, reduces part count, uses chips mounted on flat cards, simple funnels, hybrid operation possible. (33% +) 10-Jul-13

19 The Competition 19 Standard PV array Unique upgradable PCU Uniquely Upgradeable Unique, compact, exchangeable PCU leverages improvement in cell technology, boosts performance & extends plant life. Will produce >2x energy over lifetime for same initial power output 10-Jul-13

20 Overview: Built on a Proven Foundation of Experience: >40-years of world-leading opto-mechanics Highest efficiency PV cells Proven coating mirror technology Existing high-volume solar tracker supply chains Result: Highest Efficiency at Lowest Cost

21 Eight Shooter Intended for Utility and other Large scale Operations: ~6.4-8 KW Two Shooter Intended for specialized individual use, portable version: ~ KW

22 SERC + Arizona Both Programs Multi-Faceted. Combined strength greater than the sum of the individual parts. Exchange of Faculty and Students over wide range of topics. Special Interest in Concentrator PV to exploit N. Chile and Arizona climate conditions. Initial Steps to Jointly Test, Evaluate and Improve CPV Concepts. Develop Use Models. If successful, work with Chilean Industry to Commercialize in Chile.

23 Hot Stuff Results with the 3 m concentrator telescope. A 15 sec solar exposure on 6 mm thick steel resulted in a hole the size of a quarter. The experiment demonstrated that slumping produced sufficient figure accuracy. It also demonstrated the need to protect PV-cell from excessive heating.

24 Generator Farm: Modules will be assembled at a central plant and transported to there final location Assembly plant for generator modules

25 Automotive Credibility If generator units can be built at the same cost per kg as a pickup truck, the power cost will be < $1.60/watt. CPV generators are much simpler than pickup trucks, so $1/watt is credible.