How a Wastewater District is Saving Money with Solar Power

Size: px

Start display at page:

Download "How a Wastewater District is Saving Money with Solar Power"

Marcia Small
6 years ago
Views:

Solar Power APWA Sustainability Conference

PE, PMP, Brown and Caldwell Curtis Bosick,

Solar Project Results APWA Sustainability:

1 Sustainability in Public Works How a Wastewater District is Saving Money with Solar Power APWA Sustainability Conference May 15, 2013 How a Wastewater District is Saving Money with Solar Power Adam Ross, PE, PMP, Brown and Caldwell Curtis Bosick, PE, Union Sanitary District How a Wastewater District is Saving Money with Solar Power: Agenda Before the Solar Project: Big Picture Approach Solar Design Issues Solar Project Results APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 3 1

Union Sanitary District Wastewater District in Union City, CA (SF Bay Area) Serving 330,000 people 24 million gallons per day $30M annual operating budget APWA Sustainability: How a Wastewater

2 Union Sanitary District Wastewater District in Union City, CA (SF Bay Area) Serving 330,000 people 24 million gallons per day $30M annual operating budget APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 4 Union Sanitary District Irvington Pump Station Major pumping station 8 to 10 million gallons per day, with a reliable capacity of 43 MGD for PWWF $250,000 annual electricity cost 3 acre emergency overflow basin APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 5 Conclusions! Irvington Pump Station Solar Project 460 kw, 1,680 solar panels, single-axis tracking system 900,000 kilowatt-hours per year Goal: Zero electricity cost And most notably: In a wastewater basin; District-owned APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 6 2

Before the Solar Project: Big Picture Approach A pragmatic approach to sustainability starts with a big-picture approach and works

existing performance Identify areas for improvement Compare opportunities on a cost-perunit-benefit basis APWA Sustainability: How a

Don t start with solar Energy efficiency projects typically cost less per kwh-saved ($/kw or $/kwh basis) Combined Heat and Power

3 Before the Solar Project: Big Picture Approach A pragmatic approach to sustainability starts with a big-picture approach and works toward specific projects Set Goals Reducing costs Reducing carbon footprint Or, just doing a green project Understand and quantify existing performance Identify areas for improvement Compare opportunities on a cost-perunit-benefit basis APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 8 Most bang for your buck? Don t start with solar Energy efficiency projects typically cost less per kwh-saved ($/kw or $/kwh basis) Combined Heat and Power (cogeneration) with biofuels Wind, if applicable Solar START HERE! Lowest Cost, Greatest Benefit Highest cost per unit benefit APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 9 3

USD implemented a series of projects, in logical order, to reduce energy costs and move toward sustainable operations Energy Efficiency

heat and power project New engine facility to utilize on-site biogas Solar Test Project Carport Green Energy Feasibility Study APWA

Energy Feasibility Study looked at two large-scale projects at USD s pump stations Solar power at Irvington Pump Station Wind Power at

financially feasible, but is on hold pending a wildlife study Adequate wind resource Acceptable turbine height Grant funding 225-kW wind

4 USD implemented a series of projects, in logical order, to reduce energy costs and move toward sustainable operations Energy Efficiency Projects Variable frequency drives at major pump stations Aeration system improvements new blower, improved controls LED lights Combined heat and power project New engine facility to utilize on-site biogas Solar Test Project Carport Green Energy Feasibility Study APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 150 kw Solar Carport Aeration System Improvements 10 The Green Energy Feasibility Study looked at two large-scale projects at USD s pump stations Solar power at Irvington Pump Station Wind Power at Newark Pump Station APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 11 Wind project proved to be financially feasible, but is on hold pending a wildlife study Adequate wind resource Acceptable turbine height Grant funding 225-kW wind turbine, $1M, 12-yr payback But close proximity to National Wildlife area APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 12 4

Next Step: Solar Energy efficiency projects typically cost less per kwh-saved ($/kw

a Wastewater District is Saving Money with Solar Power 13 Irvington Pump Station

Tracking Financing/Ownership Grants and incentives Level of Design Detail

5 Next Step: Solar Energy efficiency projects typically cost less per kwh-saved ($/kw or $/kwh basis) Combined Heat and Power (cogeneration) with biofuels Wind, if applicable Solar START HERE! Lowest Cost, Greatest Benefit Highest cost per unit benefit APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 13 Irvington Pump Station Solar Project: Design Considerations Design Considerations Location Size Fixed v. Tracking Financing/Ownership Grants and incentives Level of Design Detail Competitive Bidding Performance specifications Operation & Maintenance Security APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 15 5

6 Location: Emergency Wastewater Overflow Basin Approximately 3 acres Rarely used Paved 4 to 8 feet deep No shade APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 16 Location: Challenges Continued operation of the basin - Keeping panels and electrical equipment above water Providing access for basin wash down Poor soils, underground debris (old plant site) P APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 17 Location: Solutions Land is not free achieved dual use of basin All electrical equipment is elevated above high water elevation: 4 to 8 feet above basin floor Inverter and switches located on berm Panels are above high water in their stow position Access for basin washdown Clearance between berm and security fence Panel array split into two sections Access below panels Bottom of fence elevated 6 inches above grade APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 18 6

Location: Solutions APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 19 Size: Off the grid, or off the balance sheet?

year This works with Net Energy Metering Time of use rate schedule Always connected to the grid Daytime export Nighttime import APWA Sustainability: How a Wastewater District is Saving Money with

7 Location: Solutions APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 19 Size: Off the grid, or off the balance sheet? Off the grid implies that the facility can operate independent from the grid and that solar power can satisfy peak demand Off the balance sheet means zeroing out the power bills over the course of a year This works with Net Energy Metering Time of use rate schedule Always connected to the grid Daytime export Nighttime import APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 20 Size: Achieve net-zero bill Determine annual electricity cost Determine future cost with time of use rate schedule Model solar power production using geographic inputs Determine system size and configuration that zeroes out the bill aim for annual kwh, not nameplate capacity 900,000 kwh PV - GENERATED $0 ANNUAL COST 1,225,000 kwh CONSUMED APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 21 7

8 Fixed v. Tracking: Fixed panels are stationary and mounted at a specific angle to optimize generation Single-axis tracking systems rotate the panels from morning to evening to track the sun Dual-axis tracking systems track the sun daily and make adjustments seasonally APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 22 Fixed v. Tracking: Single Axis Large format actuation allows a single drive system to move a lot of panels Low maintenance Simple components Robust Tracking can achieve the same ANNUAL kwh as a larger (nameplate) fixed system 460 kw tracking is the same as 590 kw fixed Tracking system adds 8-10% capital cost on a dollarsper-kw(nameplate) basis, but 20% less panels are required APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 23 Single-axis Tracking System APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 24 8

9 Financing and Ownership: 3 routes Ownership Power purchase agreement (PPA) Solar Lease APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 25 Financing and Ownership: What is a PPA? Popular financing method for solar projects, and increasingly so for other energy projects Power provider installs the solar system on the purchaser s property No up-front cost to the purchaser Purchaser agrees to buy the power for a contract period and predetermined rate Power provider benefits from grant funding, tax credits, steady income Purchaser gets a green project and potentially saves money APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 26 Financing and Ownership: What is a PPA? PPA terms and conditions vary site-by-site, but typically include the following: 20 year term Low introductory rate typically a few cents per kwh less than current rates Annual rate increase assumed to be less than inflation What is a PPA, really? A bet against future inflation Can you lose money with a PPA? Yes, if PPA rate escalation exceeds utility rate escalation APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 27 9

10 Financing and Ownership: What is a PPA? PPA Saving Comparison $350,000 $300,000 $250,000 $200,000 $150,000 Annual Savings, Original PPA $100,000 Annual Savings Adjusted PPA Annual Savings BC Conservative $50,000 $ $(50,000) $(100,000) Years APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 28 Financing and Ownership: Incentives California Solar Initiative USD s facility will receive $650,000 over 5 years as a performance-based incentive The grant reservation was made in early design stages before funding ran out Federal Tax Incentives USD is ineligible as a special district / non-profit APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 29 Level of Design: Goal: Find the level of design detail that is just right Define the elements that matter to the District Performance (annual kwh) Layout Warranty Grant eligibility items Interface with pump station (interconnection) Maintenance Security Leave the details undefined Open for competition, innovation, creative solutions Reduce District s design costs Leave the details to the experts APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 30 10

Level of Design: Not Design-Build! Low-bid selection meeting the performance requirements Bids included panel selection, inverter selection, tracking system, number of panels, etc.

11 Level of Design: Not Design-Build! Low-bid selection meeting the performance requirements Bids included panel selection, inverter selection, tracking system, number of panels, etc. Bids were checked against specification requirements System performance was modeled in the prescribed modeling tool to confirm annual kwh production APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 31 Operation and Maintenance: Ability to clean panels to maintain high generation of electricity Low maintenance on equipment Tracking system has one motor per array Standard components One inverter Ten year maintenance agreement Reliability of system Only one inverter, if it breaks down the entire system breaks down Twenty year warranty for inverter and tracking system; twenty five year warranty for panels Brown and Caldwell 32 Security: Black market for green products All the things that make solar easy to install (modular, easy to mount), also make it easy to steal Unmanned pump station Adjacent to a road, near a major freeway Needed a solution to protect the District s investment APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 33 11

Security: Lots of ideas Deterrents Guard dogs Fences More fences Lights Perimeter detection and alarm Laser beam (trip detection) Motion sensing cameras Microphonic cable system Theft alarm

Additional lighting in overflow basin Microphonic cable system Fence-mounted Detects cutting, pulling, or climbing action Zero false alarms Connected to SCADA for monitoring Plant can use

12 Security: Lots of ideas Deterrents Guard dogs Fences More fences Lights Perimeter detection and alarm Laser beam (trip detection) Motion sensing cameras Microphonic cable system Theft alarm continuity sensor APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 34 Security: Security fence around solar array in addition to station s perimeter fence Additional lighting in overflow basin Microphonic cable system Fence-mounted Detects cutting, pulling, or climbing action Zero false alarms Connected to SCADA for monitoring Plant can use existing cameras to check on the system APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 35 Security: APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 36 12

75M (SPG Solar) APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 38

13 Results Bidding: Competition drove down bid price 6 bids received Engineer s Estimate: $3.3M Winning bid: $2.75M (SPG Solar) APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 38 Irvington Pump Station Solar Project 460 kw 1,680 solar panels Single-axis tracking system Performance goal: 900,000 kwh annually APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 39 13

Performance Monitoring and Reporting APWA Sustainability:

14 Performance Monitoring and Reporting APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 40 Performance Monitoring and Reporting APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 41 Performance Monitoring and Reporting APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 42 14

Results: First Year Production 894,839 kwh generated in 12-month period Total production exceeds 1 gigawatt-hour APWA Sustainability: How a Wastewater District is

$109,407 Represents 10 months only APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 44 Results: Simple Payback Construction Cost:

15 Results: First Year Production 894,839 kwh generated in 12-month period Total production exceeds 1 gigawatt-hour APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 43 Results: First Year Financial Electricity charges: $307,532 Higher due to construction Generation credits: $254,371 Rebate payments: $109,407 Represents 10 months only APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 44 Results: Simple Payback Construction Cost: $2,750,000 CSI Rebate: $650,000 Annual savings: $250,000 Simple Payback = 9 years 20-year life APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 45 15

16 How a Wastewater District is Saving Money with Solar Power: Take a Big Picture Approach Tackle the Solar Design Issues Get Solar Project Results APWA Sustainability: How a Wastewater District is Saving Money with Solar Power 46 Questions? Thank You! Brown and Caldwell 47 16

TOWN OF NEWPORT SOLAR PROJECT A 2-MEGAWATT DC NET-METERED PV SYSTEM

TOWN OF NEWPORT SOLAR PROJECT A 2-MEGAWATT DC NET-METERED PV SYSTEM AN HISTORIC PROJECT NH s Largest Municipal Solar Project Town & Schools Would Be Net-Zero 2 AN HISTORIC PROJECT The largest municipal