Life Cycle of Photovoltaic Systems: Procure a New Photovoltaic System

Goal: Determine site-specific metrics, such as solar potential and available space.

• Ensure project compatibility with future site plans of the agency or developer.
• Review the electricity supply contract.
• Determine contract end date, electricity price, procurement plans, departing load penalties, and restrictions that may impact project feasibility.
• Review and complete agency approval requirements.
• Review and complete land or building requirements.
• Identify any fatal issues that would make the site ineligible.
  • Example: A parking lot may not be suitable for a carport system if there is too much truck traffic.

Goal: Determine estimated energy consumption, energy demand, specifications unique to the system type (e.g., rooftop or ground-mount), site-specific hazards (e.g., weather), site access, and electrical considerations.

• Determine PV system size.
  • System size is based on available land/rooftop space, land ownership, parcel size, weather, energy demand, PV production, site topology, land slope, and existing renewable energy resources at the site.
• Consider construction logistics and requirements.
  • These include construction and operating permits, stormwater management requirements, erosion control measurements, soil type, water drainage, and sediment control measurements.
• Determine site access (e.g., roads).
• Check for module glare requirements, particularly near airports.
• Get approvals from site tenants and neighbors.
• If in a competitive electricity market, review the site’s electricity contract.
• Review zoning rules, land use regulations, ADA/fire lane requirements (e.g., carports), and shipping access.
  • Additional checks for carport include reviewing access with the fire marshal, planning to add protective bollards for collision prevention of large vehicles, and designing for the expected height of vehicles.
• Consult with the site’s utility about interconnection and electrical infrastructure needs.
  • These include whether the project has adequate interconnection capacity, whether the site is on a network distribution system, interconnection options, whether new electrical lines must be built to accommodate interconnection (ground-mounted), site-specific electrical requirements/upgrades, whether a system integration study is needed, acceptable inverter locations and enclosures, and whether the solar project will provide security or resilience benefits or be “microgrid ready.”

Goal: Determine policy and regulatory considerations, utility rates, capital and operation and maintenance (O&M) costs, incentives, life cycle costs, state regulations, and utility policies.

• Review market, state, and utility regulations.
  • Regulations may focus on PV system sizing, power purchase agreement legality, interconnection rules, utility policies such as net metering, power pricing, etc. to ensure that project aligns with local, agency, and/or other relevant requirements.
• Analyze project economics. To conduct a financial analysis for the PV system:
  • Review electricity rate tariff information and net metering policy.
  • Research incentives.
  • Research Solar Renewable Energy Certificate (SREC) markets to find out whether SRECs are valuable.
  • Consider whether there is existing electrical infrastructure capacity that may be used.
• Using the information in the steps above, conduct a project cost analysis.
• Determine whether the National Historic Preservation Act applies.
• Complete an environmental assessment to comply with the National Environmental Policy Act or obtain a categorical exclusion for certain rooftop systems.
  • Environmental constraints may relate to endangered flora and fauna at site, pollinator habitat, or riparian areas.
• Coordinate with local utility on tariffs, incentives, and interconnection requirements. Questions for the utility may include:
  • What incentives and policies are available for my project? Are net metering and feed-in tariffs available? What about virtual net metering or community renewables?
  • What is the allowable renewable energy project size? How do you measure project capacity (in DC or AC)?
  • How will the project impact my utility costs? Will standby charges be used? Will my current tariff change?
  • Is there a template interconnection agreement? Who will need to sign this?
• Consider the project site agreement, i.e., the contract that gives a developer permission to use the site to install and/or operate a PV system.

Screening tools/databases:

• National Laboratory of the Rockies (NLR) National Solar Radiation Database has meteorological data to calculate solar irradiance metrics
   
• NLR PVWatts® calculates the energy generation of grid-connected PV to develop performance metrics for solar projects worldwide
   
• NLR System Advisor Model conducts more detailed technoeconomic analyses to understand the feasibility of projects
   
• NLR REopt® tool helps to evaluate economic viability for distributed energy resources projects
   
• NLR cost benchmarks for O&M costs and availability through the NLR Annual Technology Baseline (updated annually)
   
• North Carolina Clean Energy Center Database of State Incentives for Renewables and Efficiency helps understand the regulatory considerations that may exist at your site
   
• Sandia National Laboratory Solar Glare Hazard Access Tool, now hosted by Sims Industries, LLC, helps to assess systems located near or at airports that may require glare hazard assessments

Project validation tools for installing systems on previously contaminated infrastructure (i.e., brownfields/landfills):

• Environmental Protection Agency Solar Decision Tree: This is focused specifically on installation of PV systems on existing land (e.g., brownfields, landfills), but the process overview applies to a wide variety of PV systems (2015)
   
• Section 4 of Assessing the Solar Photovoltaic Potential in Puerto Rican Brownfields and Reservoirs: Analysis and Modeling, Presentation (2024)
   
• Best Practices for Siting Solar PV on Municipal Solid Waste Landfills, Environmental Protection Agency, Technical Report (2022) 

Other resources:

• Section 2 of FEMP’s 2017 Energy Savings Performance Contract Energy Sales Agreement Toolkit has detailed information about project validation
   
• FEMP Distributed Energy Interconnection Checklist

Weather risk awareness:

• Severe Weather Resilience in Solar Photovoltaic System Design presents lessons learned from field examinations of weather-damaged PV systems, summarizes engineering guidance resources, and summarizes technical specifications by weather event.
   
• Hail Damage Mitigation for Solar Photovoltaic Systems has information about determining hail risk, system design and procurement, and operation and maintenance.
   
• Solar Photovoltaic Hardening for Resilience – Wildfire explores the regions in the United States facing the highest wildfire risks and provides an overview of the diverse strategies available to photovoltaic (PV) system professionals to effectively manage this risk.
   
• Solar Photovoltaic Hardening for Resilience – Winter Weather examines the areas of the United States most at risk from severe winter weather and summarizes approaches to address these hazards throughout the PV system life cycle.
   
• Toward Solar Photovoltaic Storm Resilience: Learning From Hurricane Loss and Rebuilding Better presents applicable lessons learned for other solar arrays across the United States and easy-to-avoid issues in this particular system's design, which could prevent total loss after a storm, using a case study from the U.S. Virgin Islands.
   
• Overview of Opportunities for Co-Location of Solar Energy Technologies and Vegetation.

Weather risk assessment: 

• FEMA National Risk Index presents a map outlining weather risks by location.
   
• FEMA Hazus collects data on earthquakes, floods, tsunamis, and hurricanes and is available to download for free on FEMA’s website.
   
• The American Society of Civil Engineers Hazard Tool helps developers to look at issues from a structural perspective, such as wind and snow loading.
   
• FEMA flood mapping tool has data on 100-year, 500-year, and base flood elevation levels.
   
• The National Oceanic and Atmospheric Administration Sea-Level Rise Viewer tool can be used to estimate future flooding from sea level rise.
   
• FEMP Preventing and Mitigating Flood Damage to Solar Photovoltaic Systems has information on assessing a site for flooding risks, measures to prevent flood damage, and additional resources.

Empirical studies for awareness: 

• PV Field Reliability Status—Analysis of 100,000 Solar Systems, Progress in Photovoltaics (2020)
   
• Evaluation of Component Reliability in Photovoltaic Systems Using Field Failure Statistics, Sandia National Laboratories Technical Report (2020)
   
• Evaluation of Extreme Weather Impacts On Utility-Scale Photovoltaic Plant Performance in the United States, Applied Energy (2021)

FEMP’s Technical Specifications for On-site Solar Photovoltaic Systems tool provides federal agencies with a template for technical specifications based on their system type and site-specific needs.

Operation and maintenance plan requirements and tips are available on FEMP’s Optimizing Solar Photovoltaic Performance for Longevity webpage. The “Tips for Developing an O&M Plan” section of the page contains information that should be present in a comprehensive O&M plan, including:

• Site management and system documentation
   
• Key contact information for responsible parties
   
• Procedure outline for monitoring system performance over the life cycle
   
• Procedure outline for regular preventive maintenance, inspection, electrical testing and cleaning, disposal of consumables
   
• Procedure outline for corrective maintenance, component repair and replacement
   
• Budget for an O&M program, including costs for monitoring and diagnostics, preventive maintenance, corrective maintenance, and means to minimize exposure (i.e., a line of credit) to replace the inverter or perform more expensive corrective maintenance if needed.
   

For budgeting for the O&M program, there are several resources that agencies may refer to:

• Categorized O&M costs on NLR’s most updated U.S. Solar Photovoltaic System and Energy Storage Cost Benchmarks With Minimum Sustainable Price Analysis data files.
   
• Estimates compiled on the NLR Annual Technology Baseline, which has information by technology type about O&M throughout project lifetime, among other items, and is updated annually.

• Best Practices for Operation and Maintenance of Photovoltaic and Energy Storage Systems; 3rd Edition, Technical Report (2018)
   
• U.S. Solar Photovoltaic System and Energy Storage Cost Benchmarks With Minimum Sustainable Price Analysis, NLR data files
   
• NLR Annual Technology Baseline
   
• Optimizing Solar Photovoltaic Performance for Longevity