Photovoltaic Resources and Technologies
Selecting, Implementing, and Funding Photovoltaic Systems in Federal Facilities: Learn how to select, implement, and fund a photovoltaic system by taking this FEMP eTraining course.
This page provides a brief overview of photovoltaic (PV) technologies supplemented by specific information to apply PV within the Federal sector.
Photovoltaic cells convert sunlight into electricity. Systems typically include a PV module or array made of individual PV cells installed on or near a building or other structure. A power inverter converts the direct current (DC) electricity produced by the PV cells to alternative current (AC) electricity.
PV systems can be found across the globe, from the most isolated locations to the heart of the largest cities. A typical PV cell converts approximately 10% of the solar energy striking its surface into usable electricity.
Visit the Department of Energy's (DOE) Solar Technologies Program for in-depth information about solar energy basics and technologies.
PV arrays are viable sources of renewable energy in the Federal sector. Before conducting an assessment or deploying PV systems, Federal agencies must evaluate a series of questions.
What are my energy goals?
Energy goals range from meeting regulatory requirements to powering remote applications to increasing energy security. PV systems, if applied properly, are suitable for each.
Regulatory Requirements: Electricity produced by solar energy falls under the Energy Policy Act (EPAct) of 2005 definition of renewable energy and can be used to meet EPAct 2005 renewable energy requirements.
Remote Power: PV arrays can stand alone to provide intermittent power for remote applications, or be coupled with wind turbines, battery storage systems, backup generators, or other energy resources to deliver around the clock power for remote applications.
Energy Security: Solar energy is natural and renewable. The energy source is found in abundance across the U.S. and can be leveraged to increase energy continuity.
What kind of energy do I use?
Federal agencies must understand what type of energy is used before determining if photovoltaics are applicable. PV systems generate electricity and are not appropriate for mechanical or thermal power.
When do I need the energy?
Although solar resources can be quite predictable, PV cannot be guaranteed to generate power where and when it is demanded like a fossil fuel generator. For example, PV arrays must be connected to energy storage or backup equipment to provide electricity when sunlight is not available (e.g., evenings).
How much power do I use/need to produce?
The size and nature of an electric load must be well understood to properly select a packaged PV system or to design and specify a custom system. For any system, the following must be known:
- Maximum energy needed at any one time (watts)
- Maximum daily power requirements (kilowatt-hours)
- Availability of solar resources
- Cost of power alternatives
Typical photovoltaic systems deployed by the Federal Government range from several watts to 1.1 megawatts.
Where am I located?
For a broad overview of your facility's solar resources, the National Renewable Energy Laboratory (NREL) provides solar energy resource maps of the U.S. Before initiating a project, solar resources in your area must be measured and verified. Resource maps are a good start, but resources vary at a micro level. It is important to consult an expert for a professional evaluation before implementing energy projects.
Is there rooftop or open land available?
Photovoltaic arrays are typically installed on building rooftops or adjacent to where the electricity is needed. If these areas are not available, PV may not be the best solution. It is important to consult an expert to determine whether PV arrays are a good fit for your Federal facility.
What is my budget?
The installation cost of PV varies greatly depending on the application, system size, and whether it is prepackaged and preassembled or separate components that need to be integrated into a structure on site.
What resources are available for operations and maintenance?
Photovoltaic systems require very little maintenance. Most small PV systems take no more than 2 to 4 hours per year to maintain. A visual inspection of the system and simple battery maintenance should occur every 3 to 6 months.
Visit the project planning section for detailed information on planning and deploying renewable energy projects. Federal case studies are available to provide specific examples of viable solar energy projects.
Detailed information on solar energy resources and technologies is available through:
DOE Solar Energy Technologies Program: Program providing information and resources on solar energy resources and technologies.
American Solar Energy Society: Leading association of solar professional and grassroots advocates.
Solar Electric Power Association: Compilation of more than 560 electric utilities, solar companies, and other industry stakeholders to form a central resource for unbiased and actionable solar intelligence.
Solar Energy Industries Association: Organization working to expand the use of solar technologies, strengthen research and development, remove market barriers, and improve education and outreach for solar.
Procuring Solar Energy: A Guide for Federal Facility Decision Makers: Guide to help Federal agencies turn their interest in solar energy projects into success installations through a concise, easy-to-understand, step-by-step process.
205 kW Photovoltaic (PV) System Installed on the U.S. Department of Energy's Forrestal Building: Fact sheet on the installation of a photovoltaic system providing renewable energy for DOE and demonstrating leadership for meeting Federal goals in the use of renewable energy technologies.
Solar Ready Buildings Planning Guide: Checklist for building design and construction to enable solar photovoltaic and heating systems after the building is constructed.
Building-Integrated Photovoltaic Designs for Commercial and Institutional Structures: Sourcebook for architects on building-integrated photovoltaics into commercial and institutional buildings.
Counting on Solar Power for Disaster Relief: Technical assistance fact sheet on using solar cells to generate electricity during immediate and long-term crisis relief.
Photovoltaics: Details how photovoltaic systems convert sunlight to electricity to meet various energy needs.
Photovoltaics: Federal Technology Alert outlining photovoltaics as a proven technology for providing electricity in remote and difficult to access locations.