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Bates College Solar Initiative Mac McReynolds, Matt Marcus, Jack Martell
32

Solar Final Presentation

Jan 23, 2018

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Page 1: Solar Final Presentation

Bates College Solar Initiative

Mac McReynolds, Matt Marcus, Jack Martell

Page 2: Solar Final Presentation

Table of ContentsI. Contextual Framing and Project Goals

II. Power Purchase AgreementIII. Locations

A. Rooftop B. Off-Campus Site

IV. Savings Projections and Payback PeriodsV. Recommendations and Next Steps

Page 3: Solar Final Presentation

Inspiration

- Environmental and Global Stewardship: A Goal of Bates College

- Climate Change

- Net Carbon Neutrality: Savings in Not Buying RECS

Page 4: Solar Final Presentation

Bates College Context- Bates Current Use → ~ 12.741GWh/yr

in 2016

- Cost of Electricity → ~ $1.3 million/yr for campus loop

- Solar benefits- Clean energy- Economics- Leadership

Page 5: Solar Final Presentation

Project Aims- Feasibility study of the

potential for a photovoltaic solar project for Bates College

- Zero net cost

- On and off campus

Power Purchase Agreement

On Campus Off Campus

Buy Back after 7 Years

Buy Back after 7 Years

No Buy Back No Buy Back

Page 6: Solar Final Presentation

On Campus Power Purchase Agreement

BatesInvestor/InstallerOn Campus Solar Panels

$

30% Tax Break

$ for kW/hr Use

1. 2. 3.

Page 7: Solar Final Presentation

Off Campus Power Purchase Agreement

Investor/Installer Off Campus Installation Grid

$

BatesNet Metering Credits

Net Metering Credits Equivalent

30% Tax Break

1. 2. 3.

4.

Page 8: Solar Final Presentation

Installation Types1. On Campus Rooftop Project

2. Ground mount on campus or

neighboring property (direct

distribution line)

3. Ground mount off site (net metering)

Page 9: Solar Final Presentation

On Campus Rooftop Criteria1. Rooftop oriented within 55

degrees east or west of true south (55 +/- 180°)

2. Adequate rooftop area

3. Lack of exterior shading

4. Electricity Demand Curve

Page 10: Solar Final Presentation

Hourly Energy Load Curves

https://mysolarcity.com/Share/c5e1bfa0-19af-4bde-b597-2e51eac5cd4b#/monitoring/historical/day

*11/3/16

Bowdoin Hourly Solar Generation (kWh)Public vs. Residential Building

Hourly Energy Consumption (kW)

Page 11: Solar Final Presentation

Buildings Suited for SolarMerrill Gymnasium Commons Gray Cage

Pettengill Hall 280 College Street Olin Arts Center

Page 12: Solar Final Presentation

Monthly Variability in Production

Page 13: Solar Final Presentation

On-Campus Capacity and Initial Costs

*Pending second assessment of Merrill Gym rooftop load capacity.

Building Orientation (degrees)

Estimated Pitch (degrees)

Estimated System Size

Estimated Annual Production

Estimated Annual CO2 Reduction (lbs/yr)

Estimated System and Installation Cost ($)*

Merrill Gym* 180 True 25 394 kW 480,564 kWh/year

363,090 922,534

Olin Arts Center 215 True 25 110 kW 134,167 kWh/year

101,370 257,400

Commons 215 True 20 65 kW 71,500 kWh/year 66,667 152,100

Gray Cage 125 and 215 True 25 225 kW 247,500 kWh/year

242,978 526,500

Pettengill Hall 125 and 215 True 25 130 kW 143,200 kWh/year

140,283 304,200

280 College St. 25 25 65 kW 68,500 kWh/year 63,774 152,100

Totals w/ Merrill Gym

n/a n/a 989 kW 1,145 MWh/year 978,162 2,314,834

Totals w/out Merrill Gym

n/a n/a 595 kW 664,867 kWh/year

615,072 1,392,300

Page 14: Solar Final Presentation

Ground mount Location Criteria

1. Size- 3 acre minimum

a. No space on Bates College

2. Proximity to campusa. 1 mile for direct distribution lineb. 10 miles for social/academic utility

3. Current Land Statusa. Use, vegetative cover, pitch, structural

integrityCapped Landfills within 10 mile radius

of Bates College

Page 15: Solar Final Presentation

Off Campus Location 1

LEWISTON MUNICIPAL LANDFILL

1. Property Size- 25 acres2. Distance from Bates College- 4.0

miles3. Ideal Land Status

Page 16: Solar Final Presentation

Off Campus Location 2LISBON MUNICIPAL LANDFILL (NEW)

1. Property Size- 15 acres2. Distance from Bates College- 6.93

miles3. Ideal Land Status

Page 17: Solar Final Presentation

On vs. Off Campus Conclusions

-Prioritize on campus installation to avoid net metering instability.

-On Campus allows for adherence to zero cost goal.

-Reconsider off campus installation once net metering future is determined.

Page 18: Solar Final Presentation

PPA Payback OptionsOption 1: Discounted Purchase After Year 6

Benefits:

- Own system outright with potential for increased savings

- No longer purchasing kWh from solar investor

Risks:

- Potentially large investment to purchase panels (typically 40-60% of original price)

- Responsible for system maintenance following purchase

- Solar production fluctuations

Option 2: PPA Extension (up to 30 years)

Benefits:

- No responsibility for system maintenance

- Fixed photovoltaic electricity rate for extent of PPA

- Decreased demand charge, fewer kWh purchased from the grid

Risks:

- Lower long-term savings

- Solar production fluctuations

Page 19: Solar Final Presentation

Solar Savings Equation without Buyout-Guaranteed savings originate from fewer kWh purchased from grid and lower demand charge

● Total cost: (supply $/kWh)(kWhT) + ($ delivery service/kwh)(kWhT) + ($ demand/kW)(kWT)

● Total cost with solar: (supply $/kWh)(kWhT) + ($ delivery service/kwh)(kWhGrid) + ($ demand/kW)(lower kWGRID)

● Total cost - New total cost w/ solar = Savings

Page 20: Solar Final Presentation

Savings without Purchasing Array– Demand Charge Unchanged

Key Information

- Solar installations on: Gray Cage, Olin Arts Center, Dining Commons, Pettengill Hall, 280 Campus Ave.

-Savings from decrease in kWh purchased from the grid

● Savings without Merrill:○ $3,951.63/year○ $98,790.75 over 25 years

● Savings with Merrill:○ $7,273.29/year○ $181,832.30 over 25 years

Page 21: Solar Final Presentation

Savings without Purchasing Array– Demand Charge Changed

Key Information

- Solar installations on: Gray Cage, Olin Arts Center, Dining Commons, Pettengill Hall, 280 Campus Ave.

-Savings from decrease in kWh purchased from the grid

- Assumes solar array produces–on average–25% of energy potential during times of monthly peak demand

● Savings without Merrill:○ $26,665.63/year○ $666,640.80 over 25 years

● Savings with Merrill:○ $44,691.37/year○ $1,018,494 over 25 years

Page 22: Solar Final Presentation

Savings without Solar Purchase

Savings with Solar Purchase

Annual Savings 25 Year Savings

Identical Demand Charge

Without Merrill $3,951.63 $98,790.75

With Merrill $7,273.29 $181,832.30

Decreased Demand Charge

Without Merrill $26,665.63 $666,640.80

With Merrill $44,691.37 $1,018,494

Page 23: Solar Final Presentation

Solar Savings with Buyout in Year 7● Savings originate from:

○ Savings every year from decreased demand charge and decrease in kWh from grid○ After year six, no longer paying for kWh previously purchased from solar investor

● Savings function:

[($ solar array installation)(fraction of installation $ for buyout) + (maintenance costs/year)(x years)] - [(supply $/kWh)(kWh used from solar/year)(x years) + (savings without buyout/year)(x years)] = 0

Page 24: Solar Final Presentation

Savings from Solar Purchase– Low Fixed CostKey Information

- Assumes solar produces 25% of energy potential during time of peak demand

- Assumes annual maintenance cost of 0.5% of installation cost

● Without Merrill:○ $556,920 fixed cost

● With Merrill:○ $925,933.60 fixed cost

● Savings without Merrill:○ $66,244.80/year○ $1,099,201 over 25 years

● Savings with Merrill:○ $109,315.50/year○ $1,766,216 over 25 years

Page 25: Solar Final Presentation

Savings from Solar Purchase– High Fixed CostKey Information

- Assumes solar produces 25% of energy potential during time of peak demand

- Maintenance cost of 0.5% of installation cost

● Without Merrill:○ $835,380 fixed cost

● With Merrill:○ $1,388,900.40 fixed cost

● Savings without Merrill:○ $66,244.80/year○ $820,740.50 over 25 years

● Savings with Merrill:○ $109,315.50/year○ $1,343,989 over 25 years

Page 26: Solar Final Presentation

Savings with Solar Purchase

Savings with Solar Purchase

Annual Savings 25 Year Savings

Low Fixed Cost Without Merrill $66,244.80 $1,099,201

With Merrill $109,315.50 $1,766,216

High Fixed Cost Without Merrill $66,244.80 $820,740.50

With Merrill $109,315.50 $1,343,989

Page 27: Solar Final Presentation

Off Campus Savings: Calculations and Scenarios

● 500 kW system○ $2.15/Watt→ $1,075,000 upfront cost

■ Maintenance cost→ .5% of initial cost○ High-Expected-Low kWH production

● Purchase at Year 7 or Not○ Buyback Cost-40%-60%

● Annual Lease Cost-$20,000/MW

1. Solar Buyback after 7 Years

60% Buyback 40% Buyback

High kWh Production

Expected kWh Production

Low kWh Production

2. No Solar Buyback

High kWh Production

Expected kWh Production

Low kWh Production

Page 28: Solar Final Presentation

Low Productivity-High Buyback Cost Scenario● Annual Generation: 617,173 kWh

● Annual Savings: $30,003

● 60% Buyback Cost: $645,000

● Buyback Period: 21.5 years

● Net Savings: $355,083.50

Page 29: Solar Final Presentation

High Productivity-Low Buyback Cost Scenario● Annual Generation: 662,334 kWh

● Annual Savings: $33,164

● 40% Buyback Cost: $430,000

● Buyback Period: 12.97 years

● Net Savings: $639,115.25

Page 30: Solar Final Presentation

Expected Productivity- No Buyback Scenario● Annual Generation: 644,230 kWh

● Total Solar Savings: $12,884.6● -Annual Lease Cost: $10,000● Actual Savings=2,884.6

● $.13/kWh Net Metering Credit Rate vs. Currently Paid $.11/kWh Rate

● Net Savings: $72,115

Page 31: Solar Final Presentation

System Purchase vs PPA Extension Conclusions- Extended PPA (25 Years)

- Stability on returns- No high fixed cost- No maintenance responsibility

Page 32: Solar Final Presentation

Conclusions and Next Steps1. Extended Power Purchase Agreement2. Prioritize on-campus installation

a. Projected annual/lifetime savingsb. Net Metering

3. Future large off-campus project

Next Steps:1. Secondary Merrill assessment2. Work with Office of Advancement to

facilitate bidding process3. Legal counsel