• A solar electric system installed in an unshaded area typically generates about 1,000 kilowatt-hours (kWh) per year for each kW installed.
• Generally, the larger the system, the lower the cost per kW installed.
• Other factors that can impact costs include design complexity, system configuration, equipment options, and contractor expertise.

All solar installations that connect to the City Light power grid are required to have an Interconnection Agreement. Find the Agreement required for your solar installation below.

Any solar energy you generate that isn't immediately needed by your property goes back onto City Light's grid and is stored on your account's net meter kWh credit balance. This is measured in real-time by a City Light net billing meter. Credits are retained as a balance on your account and are used to reduce billable consumption on future billing statements.

There are three options for your business:

Net Metering

If your solar system is up to 100 kW AC, our Net Metering program provides kWh credits on your bill for the energy you produce. These credits are valued at your retail rate of electricity.

Find your retail rate.

Certain high-performing buildings may receive net metering for solar installations up to 250 kW when they meet the following criteria:

• Buildings within the City of Seattle that meet the terms of Seattle's Living Building Pilot
• Buildings outside the City of Seattle that receive Living Building Challenge certification
• Affordable housing that receives at least 15 points in Section 5.02a of the Evergreen Sustainable Development Standard, v.4.0

Review and submit a Level 1 Interconnection Agreement.

Large Solar

If your solar system is over 100 kW AC and up to 2MW you will receive cash credits through our large solar program for excess generation at an export rate of $0.0496/kWh through the end of 2024. Beginning in 2025, the export rate for new solar customers is subject to change.

The export rate represents the value of excess solar generation to City Light and incentivizes solar energy systems sized to meet building demand. Your business will be compensated for excess generation sold to the grid, calculated each day. Credits appear on your next utility bill.

Review and submit a Level 2-4 Interconnection Agreement.

Meter Aggregation

You may also qualify for net meter aggregation, which allows you to share excess generation with one additional City Light billing meter that is under the same account name and located on the same or a contiguous parcel. Sharing excess generation can reduce utility bills on an account not supported by your solar energy system.

Apply for meter aggregation.

1. Assess your property and current electric service to ensure existing equipment meets code requirements. Explore resources and requirements for adding or upgrading electrical service on your property.
2. Get bids and choose a solar contractor. While we do not recommend or endorse contractors, we do recommend at least 3 bids and reference checks. Here is a resource to help you find an installer: Washington Solar Energy Industries Association.
3. Apply for interconnection with City Light - You will need to submit a Level 1 Interconnection Agreement for arrays up to 100 kW or a Level 2-4 Interconnection Agreement for arrays over 100 kW, a Solar One Line (example), and a Production Meter Wiring Diagram. If you are planning an installation in a network area, your installation has battery backup, or your installation is larger than 10 kW, your application will be reviewed by our Network Engineering Department, which can add additional time to the interconnection approval process. Network installations may also require special equipment. Review our interactive service area map to determine if your project is located in a network area (view the Find Your ESR tab) and find contact information for the assigned Electric Service Representative.
4. If you have multiple meters on your property or own two contiguous properties and are interested in net metering aggregation, submit a Meter Aggregation Application.
5. Obtain permits for your system through your local permitting jurisdiction. In Seattle, contact the Department of Construction & Inspections.
6. Claim your renewable energy tax credit on your next federal tax return. Review system qualifications and credit amounts.

Solar may be a great option if you:

• Own your property
• Have a suitable, shade-free area for solar modules (such as roof space in good condition)
• Are interested in making a long-term investment to produce your own renewable energy and lower your electricity bill

Some other considerations:

• Your electricity usage: Do you want to produce part or all of your power? This will have an impact on the size of the system you choose.
• Your roof space and sun exposure: 1kW of solar typically requires about 80 square feet of unshaded roof space.
• Your budget: Will you finance or pay cash? What's your total budget? The upfront costs can be considerable, but financing can help. You will want to know this before choosing your system.

You are generating electricity when the sun is shining on your solar array! The energy your array harvests travels through your inverter to your breaker box where it immediately supplies electricity to your building. If your solar generation is not enough to meet your needs, your building draws electricity from City Light's grid. When your system is generating, your building uses your solar energy first and then electricity from City Light. If your solar generation is more than enough to meet your energy needs, the excess electricity you generate flows from your breaker box through your billing meter. City Light tracks it on your account as negative kWh usage (negative consumption) for the billing period.

Here is a visual representation of your solar energy system's relationship to your building and the utility grid:

City Light collects the information from your billing meter at the end of each billing period and calculates the difference between the electricity consumed (kWh delivered to customer by City Light) and the electricity generated (kWh received by City Light from customer) to determine the net kWh usage. If generation is greater than consumption (when the negative (-) kWh is greater than the positive (+) kWh on your bill), you will receive kWh credits or cash credits for the excess kWh based on the program in which you are participating.