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FAQs

Many customers choose to install their own electrical generating array of rooftop solar panels. Rooftop solar panels alone will not meet your electricity needs so you will still need to be connected to Tacoma Power through a “net metering” connection. Net metering involves the interconnection of electricity generating devices (i.e., solar panels) to the utility electric grid. Through the installation of an Advanced Meter that separately records energy delivered from energy consumed, net metered customers can purchase electricity from Tacoma Power when needed and send electricity generated by their system back onto the electric grid when they don’t have need for it. To help you better understand how this works, we have compiled a list of frequently asked questions below. Don’t see your question listed? Get in touch with us via email or call 253-502-8363.

Getting Started

Are rooftop solar panels a cost-effective choice?

Cost effective means different things to different people, but most hope that their rooftop solar panels will pay for themselves over time. We offer a solar investment application on our website called The Wattplan Solar Estimator through an independent third party to help you make informed decisions about investing in roof top  solar panels.

Will solar power lower my electric bill?

Solar power will reduce the energy you purchase from Tacoma Power during sunny times of the day and year. However, rooftop solar panels won’t help make your home more energy-efficient. Before you look into buying rooftop solar panels to help you save money on your electricity bills, it’s a good idea to investigate how to improve your home’s energy efficiency. Tacoma Power offers heating and weatherization rebates and loans to help you cover the costs. Improving the energy efficiency of your home can help you use less electricity and lower your utility bills.

What is Net Metering?

Net metering is the process of connecting electricity generating devices like solar panels to the utility’s electric grid. The State of Washington Chapter 80.60 RCW N allows you to offset your electricity use with the electricity produced from your own solar (most common), wind, or other (renewable) power sources. When you use more electricity than you produce during a given billing cycle, you pay Tacoma Power. When your solar panels produce more electricity than you use, Tacoma Power will reduce your utility bill. Any excess electricity that you don’t use to lower your utility bill is banked for future utility bills.

By state law, your net metering credit expires on March 31 of each year. We recommend you install rooftop solar panels that generate no more electricity than your average yearly use.

How much electricity does a typical set of rooftop solar panels produce?

A typical set of 20 to 30 rooftop solar panels in Western Washington produces about 4,000 kilowatt hours (kWh) of electricity a year. A typical electrically heated house in Tacoma uses over 12,000 kWh of electricity a year. Most of the energy your rooftop solar panels will generate will be during the summer when most of our customers use less energy.

What does a typical set of rooftop solar panels cost?

The cost of a typical set or array of rooftop solar panels depends on the number of solar panels, other equipment such as inverters and batteries, and the installation and location of the panels. The price can range from $20,000 to over $40,000, so it’s important to get several bids from solar contractors!

Installation & Operation Information

What should I consider before investing in rooftop solar panels?

Seek advice to help you make an educated choice before installing rooftop solar panels. As with any home improvement project, your ultimate success depends on the installer you choose. We recommend that you work with a reputable solar installer who is licensed, bonded, and insured, and that you seek more than one bid. You can click here to view a list of rooftop solar installers who work within the utility’s service area. The list is not an endorsement or guarantee by Tacoma Power, so it’s still a good idea to request references, and check online reviews and comments. Other items to consider:

  • The condition of your home and roof. When was the last time your roof was replaced or repaired? The method of mounting solar roof panels can also impact roof warranties and home insurance policies.
  • Maintenance. Rooftop solar panels require ongoing maintenance. Ask your solar installer about the manufacturer’s recommended maintenance schedule and take those costs into consideration when selecting your system.
  • Panel location. It’s important that your rooftop solar panels receive the greatest amount of sunlight. Consider factors that will impact the sun’s ability to shine on the panels, including shade from obstructions such as trees, the angle of the panels, and the direction of the panels (western and southern exposures work best).
  • Homeowner’s Association (HOA) rules. Your HOA rules may affect the rooftop solar panels you can select, buy, and install. Review your plans with your HOA before choosing, buying, and installing your rooftop solar panels.

How many rooftop solar panels should I install? 

Three factors affect the size of your rooftop solar panels – your electricity use, space availability (1 kW of solar panels requires about 80 square feet of space), and your budget. The typical home in Tacoma Power’s service area uses about 12,000+ kWh each year. Ultimately, the contractor you select should help you size your array of rooftop solar panels.

Will I have electricity when there is no sunlight?

Your array of rooftop solar panels won’t provide power in the dark, but your home remains connected to Tacoma Power’s electric grid even with solar power. This ensures your home has reliable power when the electricity in your home is not powered by your rooftop solar panels.

Who should I contact if my rooftop solar panels are not operating correctly?

Your solar installation contractor is responsible for the performance of your array of rooftop solar panes that you purchase and can help you determine what actions you can take, and any parts and labor warranties, etc. Your solar installer should provide you with a comprehensive maintenance plan based on the manufacturer’s recommendations for the rooftop solar panels and other equipment you bought.

If you have a Tacoma Power electric meter, call 253-502-8363 or email BizRebates@CityofTacoma.org for questions about billing.

Tacoma Power Grid Information

Is it practical to take my home off the Tacoma Power grid?

Rooftop solar power in Western Washington tends to generate more power during the longer summer days. Due to our northern latitude and dark, rainy seasons, the typical solar power system doesn’t produce enough electricity all year to power a typical home in the Pacific Northwest.  Being connected to the Tacoma Power grid ensures you have reliable renewable electricity when you need it all year.

What must I do to connect my solar power system to the Tacoma Power grid?

Before installing your rooftop solar panels, ensure your contractor submits a Tacoma Power Solar Application and Interconnection Agreement online, and all the supporting documentation. You will also need to apply for an electrical permit from Tacoma Power before installing your roof top solar panels. Check with your city or jurisdiction to determine whether you need a building permit. Call 253-502-8363 or email BizRebates@CityofTacoma.org for more information.

If I move into a home with rooftop solar panels am I automatically part of the Tacoma solar program?

No. You would need to complete a New Owner Solar Application and Interconnection Agreement.  Call 253-502-8363 or email BizRebates@CityofTacoma.org.

Billing Information

Will I still get an electricity bill from Tacoma Public Utilities after my rooftop solar panels are installed and operating?

Yes, you will get an electricity bill from Tacoma Public Utilities as long as your home remains connected to the Tacoma Power grid. You will also be responsible for paying a service charge (like all customers) that covers the costs for your electric meter, the electricity supplied by Tacoma Power, billing, and distribution facilities.

How much will Tacoma Power pay or credit my utility bill for excess solar power?

 For a set of roof top solar panels less than 100 kW, Tacoma Power will credit your TPU account at our retail power rate, which is set by the Tacoma Municipal Code TMB 12.06.215.

Can I use Budget Billing with my solar power system?

Budget Billing is incompatible with solar net metering. Your Budget Billing will discontinue when your account is set up on our net metering.

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