LEAST COST ANALYSIS FOR SOLAR PHOTOVOLTAIC MAINTENANCE at the WMU Miller Array

Transcription

1 LEAST COST ANALYSIS FOR SOLAR PHOTOVOLTAIC MAINTENANCE at the WMU Miller Array Kelsey Pitschel Mechanical Engineering Dr. Harold Glasser Western Michigan University Thesis Defense Lee Honors College Spring 2016

2 Agenda - Background Problem Statements Best Practice Methodology Results & Analysis Recommendations

3 Background - Miller Array at WMU 50 kw DC total 18 ground-mounted poles One degree of freedom South facing Microinverters for each module

4 Background - Photovoltaics Directly convert sunlight into DC electricity More efficient in cooler temperatures Not as common in the midwest

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6 Problem Statement Adjusting: Are we currently maximizing WMU s cost savings (or personnel time) at the Miller Array? Do we need to adjust the panels? Do fixed panels produce a competitive amount of annual energy savings? Cleaning: Do we need to clean the panels?

7 Best Practice / Industry Standard Tilt Angle: Slightly less than latitude Cleaning occurrence: 1-2 times/year Annual cost for maintenance: $30/kW-year Method: Scrub brush with deionized water to remove soiling

8 Methodology Assess existing procedures / Determine expectations Develop proposed schedules Facilitate proposed schedules / Data collection Determine energy cost savings / Maintenance costs Provide recommendations

9 Method - Metrics Energy produced (kwh), per panel Electricity Costs ($/kwh), based on annual average Maintenance Rates ($/hr), based on WMU official rates Net annual savings or costs ($/year)

10 Method Cost Savings energy cost savings ($) = energy produced (kwh) x electricity utility rate ($/kwh) Net Annual Savings net annual savings ($) = [energy cost savings ($) - maintenance costs ($)]annual

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12 microinverter Typical daily power trends, spring

13 Existing Procedures

14 Existing - Adjustment Schedule Existing Tilt Schedule Season Date Angle (deg from horiz) Spring Feb Summer Apr Fall Aug Winter I Oct Winter II At first snowfall Near vertical

15 Rates and Costs Typical Labor Hours and Rates, WMU Equivalent hours to adjust entire array Annual Electricity Utility Rates 3.31 hrs 2013 $ /kwh Typical pay rate, 2013 $58.48/hr 2014 $ /kwh Typical pay rate, $60.83/hr 2015 $ /kwh Currently entire array requires 27.2 equivalent personnel hours / year

16 Existing - Adjusting Results

17 Existing - Cleaning Entire array would need to increase its margin of energy generation by 4,000 kwh each year in order to offset cost for cleaning. Currently, no cleaning measures for solar panels at WMU.

18 Proposed Schedule Design

19 Expectations - Tilt According to NREL s PVWATTS Calculator:

20 Adjustment Schedule Design

21 Procedure - Adjustments, Proposed Proposed Tilt Schedule, Group 1 Season Date Angle (deg from horiz) Spring Feb Summer Apr 1 20 Fall Sept 1 40 Winter I Oct Winter II Dec 1 Near vertical

22 Procedure - Adjustments, Proposed Proposed Tilt Schedule, by Group Group 1 Group 2 Group 3 Seasonal Industry Standard Fixed Rooftop Fixed 5 times per year* Fixed at 35 degrees Fixed at 20 degrees Panels 1-7 (west) Panels 8-14 Panels (east) 3 panels cleaned 3 panels cleaned 2 panels cleaned *Refer to Group 1 Seasonal Tilt Schedule

23 Proposed Array Schematic

24 Array Configuration West East Note: Perfect day for solar panels

25 Group 1 Group 2 Group 3

26 Procedure - Cleaning Proposed Cleaning Schedules For: Group 1 Group 2 Group 3 Panel Number 1, 2, 3 12, 13, 14 15, 16 Dates of Cleaning June 1 / Oct 1

27 Process

28 Analysis Adjustments

29 Tilt Adjustment Results

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31 Annual Energy Production, by group

32 Analysis Cleaning

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34 Analysis - Cleaning 0.31% increase in annual energy production when cleaned

35 Cleaning Cost For WMU, 10 hours of available personnel time each year

36 Analysis - Cleaning Difference between clean and dirty net savings = $606

37 Recommendations Adjusting: Are we currently maximizing WMU s cost savings (or personnel time) at the Miller Array? No. Do we need to adjust the panels? Not really. Do fixed panels produce a competitive amount of annual energy savings? Yes. Cleaning: Do we need to clean the panels? No.

38 Annual savings without adjusting... $760 avoided cost of adjusting + $5,400 energy production for entire array = $6,160 total for each future year or 27 personnel hours Without cleaning, we do not require 10 hours of personnel work each year.

39 The least cost maintenance solution is no maintenance at all. $5,400+ annual cost savings from energy production with 27 personnel hours able to be allocated to other tasks

40 Acknowledgements Dr. Harold Glasser, Committee Chair Chris Caprara, Committee Member Elijah Lowry, Student WMU Facilities Management WMU Office for Sustainability WMU Lee Honors College

41 Questions?

42 Pocket Slides

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44 Future Research Suggestions Compare performance between Miller, Wood, and Sangren solar arrays Identify any declines in panel performance over time Determine trends between EV charging consumption and panel production Compare performance on microinverters and string tied inverters

45 Snow is real