1. Slayton Solar Project RDF Grant Award EP3-10 Presentation of the Project Results to the RDF Advisory Board January 8,2013 1 Project funding provided by customers of Xcel Energy through a grant from the Renewable Development Fund

2. Presentation Outline Scope of the project and equipment Project goals and objectives How did the project meet the goals and objectives? Project benefits Lessons learned Comments/Questions 2

3. Scope of the Project 2 megawatts DC (at STC) 1.666 megawatts AC 7,040 Trina TSM-PA14 285 w modules 32 SolarBox combiner boxes 4 Advanced Energy Solaron Inverters – 2 x 333 kW inverters – 2 x 500 kW inverters Legrand FAS Rack racking system 3

4. Project Site Plan 4

5. Project Goal “The goal of the Project was to construct and install a 2 MW DC photovoltaic electric generating facility that may be used in a commercial capacity.” 5

6. Project Objectives 1.Advance clean technology in NSP’s service area by demonstrating the benefits of utility scale solar systems 2.Demonstrate the capacity of Minnesota’s solar resources to increase the marketplace demand for solar systems 3.Utilize the solar resources in Minnesota to generate energy during peak demand hours 6

7. Project Objectives 4.Evaluate the technical efficiencies and challenges (or lack thereof) of pairing interconnections, permitting and site development of solar and wind technologies 5.Identify the potential benefits (i.e. pricing, utilization of infrastructure, reliability, etc.) of the complementary nature, or lack thereof, of wind and solar 7

8. Objective #1 “Advance clean technology in NSP’s service area by demonstrating the benefits of utility scale solar systems” Slayton Solar has increased Minnesota’s solar generation capacity from 10,900 kW dc to 12,900 kW dc (18.3%). 1 1 Source: Minnesota Department of Commerce 8

9. Objective #1 2013 only includes Slayton Solar and does not include any other projects that may have come online in 2013 9

10. Objective #2 and #3 #2 “Demonstrate the capacity of Minnesota’s solar resources to increase the marketplace demand for solar systems” #3 “Utilize the solar resources in Minnesota to generate energy during peak demand hours” Implementation of public facing website displaying solar generation information 10

11. Objective #2 and #3 Example screenshots 11

12. Objective #4 “Evaluate the technical efficiencies and challenges (or lack thereof) of pairing interconnections, permitting and site development of solar and wind technologies” Generation Addition Outlet Analysis (Nov. 13, 2009) A wind project was not constructed with the Slayton Solar project Interconnection was challenging due to the geographic locations of Xcel Energy’s Service Territory – Requirement to be near load, substations and wind farms – Lessons learned Few permitting barriers for solar 12

13. Objective #4 Xcel Energy’s Service Territory in Southwest Minnesota 13

14. Objective #5 “Identify the potential benefits (i.e. pricing, utilization of infrastructure, reliability, etc.) of the complementary nature, or lack thereof, of wind and solar” Potential to use same point of interconnection for wind and solar without increasing capacity available on the distribution circuit Increase grid reliability during peak demand periods – The following tables represent a projected generation profile of a 2 MW dc solar project and a 3 MW wind project at the same point of interconnection. 14

15. Objective #5 Peak demand periods: June through September from 2pm to 7pm* * Source: Xcel Energy Saver’s Switch Program 15

16. Objective #5 Once we have actual data from the Slayton Solar project, Renovo Renewable Energy can collaborate with Xcel Energy to create real generation profiles of wind and solar. The data can be used to study how the combined generation of wind and solar impact: – Grid reliability – Economies of scale – Market price reduction (LMP) – Environmental value 16

17. Benefits of Project Clean energy production – Expected to produce over 2,620 MWh per year – This is enough energy to power about 260 homes per year – Expected carbon emission reductions/offsets per year: Carbon dioxide (CO 2 ): 2,133 tons/year* (average) Methane (CH 4 ): 75.45 lbs/year* (average) Sulfur dioxide (SO 2 ): 34,060 lbs/year* (coal only) Nitrous oxide (N 2 O): 72.80 lbs/year* (average) Economies of scale Fuel cost savings 17 *Source: United States Environmental Protection Agency, eGrid2012 Version 1.0 Year 2009, GHG Annual Output Emission Rates, www.epa.gov/egrid www.epa.gov/egrid

18. Benefits of Project Market price reduction – solar is ideal for providing additional generation during peak demand periods O&M cost savings vs. fossil fuel generating plants Fuel price hedge value Security enhancement value – avoided economic impacts of outages due to grid reliability of distributed generation Environmental value – future cost of mitigating environmental impacts of fossil fuel generation 18

19. Benefits of Project Long term societal value – potential value if the life of the PV is 40 years instead of the assumed 20 years for the PPA. 2 Solar can be located close to, and sized to, nearby load. Solar provides unique benefits to ratepayers as compared to other renewables. A detailed study was performed by Clean Power Research for the Mid-Atlantic Solar Energy Industries Association and the Pennsylvania Solar Energy Industries Association to determine the value of these benefits. 19 2 Research indicates that the expected life of PV is 40 years

20. Benefits of Project How do these benefits translate to Xcel Energy and the MN Rate Payer?* 20 *The Value of Distributed Solar Electric Generation to New Jersey and Pennsylvania, Clean Power Research, by Richard Perez, Benjamin L. Norris and Thomas E. Hoff, November 2012, Prepared for Mid-Atlantic Solar Energy Industries Association and Pennsylvania Solar Energy Industries Association

21. Benefits of Project Quantifying the benefits to Xcel Energy and the MN Rate Payer* 21 *The Value of Distributed Solar Electric Generation to New Jersey and Pennsylvania, Clean Power Research, by Richard Perez, Benjamin L. Norris and Thomas E. Hoff, November 2012, Prepared for Mid-Atlantic Solar Energy Industries Association and Pennsylvania Solar Energy Industries Association

22. Benefits of Project Another study was performed by the Clean Coalition and California Solar Energy Industries Association to evaluate avoided transmission and distribution improvements. This study concluded: The value to ratepayers from avoided transmission costs can be as high as 7-8 cents per kWh in some areas of California* 22 * California Public Utilities Commission of the State of California, Clean Coalition and California Solar Energy Industries Association Petition for Modification of D.12-05-035, November 13, 2012

23. Benefits of Project 23 * California Public Utilities Commission of the State of California, Clean Coalition and California Solar Energy Industries Association Petition for Modification of D.12-05-035, November 13, 2012

24. Benefits of Project The Slayton Solar Project will enable Xcel Energy to study and analyze the value of distributed generation solar energy in Minnesota. Questions to be answered: How does the levelized value ($/MWh) of distributed generation solar to the MN Rate Payer compare to that of California, New Jersey, Pennsylvania, etc? Does this benefit/value justify the expansion of distributed generation solar in Minnesota? 24

25. Benefits of Project Questions to be answered (cont.): When combined with wind power, does solar PV help enhance grid reliability during peak demand periods in Minnesota? If so, how does this impact market pricing (LMP) and does it result in a reduction? 25

26. Lessons Learned Interconnecting to a transmission system – Generation Addition Outlet Analysis (Nov. 13, 2009) Interconnecting to a distribution system – Proximity to load/demand – Proximity to substations – 3 phase circuits – System impacts and their uncertainty PV solar design – Efficiencies – Structural design Permitting 26

27. Comments/Questions? 27 Project funding provided by customers of Xcel Energy through a grant from the Renewable Development Fund