Photovoltaic Basics

Community Development Agency

The Marin Solar Program is an outreach and education effort administered by the County of Marin Community Development Agency. The Program does not participate in the design, purchase or sale of photovoltaic systems.

Link to Solar and Battery for Homeowners webinar, recorded October, 2021.


Grid-Tied and Battery Storage PV Systems

Diagram of a gri-tied photovolaic system


  1. Sunlight is absorbed by the photovoltaic array creating direct current (DC) electricity. The array is can be mounted to the roof or the ground.
  2. The inverter takes the DC output and converts it to alternating current (AC). The AC output is then usable either in the building or elsewhere on the utility grid.
  3. Depending on the immediate electricity needs of the home/business, electricity can be used by electrical loads on-site
  4. Any excess power can be fed to a battery back-up system (optional), or to
  5. The utility grid, in a process called 'net metering'. In this case, the utility grid acts as a bank - the power you deposit can be withdrawn from the grid later on, when your PV system is not producing enough power to meet your household's energy needs (in the winter, for instance).

For additional information on Battery Storage Systems and how they compare with generators, read the Marin County Battery and Generator Fact Sheet.

Incentives and Financing

There are a variety of incentives and financing options available to homeowners who wish to install solar systems. Please visit our Incentives and Financing page for more details on programs and rebates.

Components of a PV Collector

Cell Module Array

Photovoltaic Cell - A device that produces electricity from light. Cells are the building block for modules.

Photovoltaic Module - A number of PV cells connected together, sealed with an encapsulant, and having a standard size and output power; the smallest building block of the power generating part of a PV array.

Photovoltaic Array - A group of photovoltaic panels.

Solar Electric Technologies for the Home and Business

For information on each of the solar technologies shown below, please visit the Energy Savers website.

Stand-Alone PV System

Example of a Stand-Alone PV System


Grid-Tied PV System

Example of a Grid-Tied PV System


Building Integrated Photovoltaics (BIPV)

Building Integrated Photovoltaics (BIPV)


Do-It-Yourself Solar Electric Assistance

If you are considering installing a solar electric system on your home or business, there are a couple of questions to ask yourself first:

  1. Do I receive a reasonable amount of sunshine throughout the year? Look for areas that are free from shade, not blocked by trees or buildings. A shadow, even that of a small branch, can decrease the amount of power that is generated by your system. The County has tools to help you determine if your site is appropriate for solar.
  2. What are my criteria for purchasing a PV system? Your criteria will help determine the size, orientation and placement of your system. This criteria might include:
    • Reduction in energy costs
    • Environmental benefits
    • Back-up power
    • Dependent on initial budget
    • Aesthetics
  3. What can I do to increase my household energy efficiency before investing in solar?
  4. Are there financial incentives and rebates for installing solar?
  5. How do I choose the right contractor?

If you are interested in learning how to answer these questions yourself, many edifying resources are available. Start with reading the following photovoltaic guides, made available through the California Energy Commission.

Local Photovoltaic Resources

National Photovoltaic Organizations

Solar Legislation Links

Solar Law Description Reference document
also visit Leg Info, under California Law
Property Tax Exemption for Solar Energy Systems Exempts the value of solar energy equipment from property taxes. Revenue and Taxation Code Section 73
Solar Rights Act Ensures that any covenant, restriction, or condition contained in any deed or other contractual restriction, which affects the sale or value of real property, does not limit the installation or use of a solar energy system.

Civil Code Section 714

Solar Easement Law Provides for easements to ensure the right to receive sunlight for any solar energy system. Please note that an easement must be in place before a request can be made to address obstacles to sunlight. Civil Code Section 801.5
Solar Shade Control Act Provides limited protections against shading from vegetation on adjacent properties. Public Resources Code Section 25980-25986

Additional Energy Resources

Renewable Energy Directory

Online comprehensive buyers guide and business directory to more than 17,000 renewable energy businesses and organizations around the world. You can locate renewable energy businesses by geographic location, by product type, by business type and by name, or search for businesses using keywords.

Wind Energy Conversion Systems

In August 2010, the County of Marin adopted an updated Wind Energy Conversion System (WECS) Ordinance. Get more information on the update and additional WECS information here.

Summary of California Energy

The Energy Almanac website provides energy information on generation, demand, consumption, prices and sources for California. Information available by types of fuel, sector and county. From the CA Energy Commission.

Energy Statistics for the United States

The Energy Statistics website provides energy information on prices, sales, demand and consumption for all energy types (including renewables). From the U.S. DOE Energy Information Administration.