Renewable Energy

Even the Portland area Is Sunny Enough for Solar!
This Q&A is adapted from the solar energy section of Portland's Bureau of Planning and Sustainability's website. 

Q: Does solar work in Portland?

A: Yes. Despite our rainy winters, Portland receives as much solar energy annually as the average U.S. city. Solar is Oregon’s most abundant renewable energy resource. More than 17,000 Oregon households have solar energy systems. It is important to note that renewable energy should be the last step in your energy plan. Your first steps should be energy conservation and energy efficiency measures, which provide the best return on investment.

Q: What is a solar energy system?

A: There are two kinds of solar energy systems for home use: solar water heating and solar electric. A solar water heating system preheats your domestic hot water, which reduces the amount of gas or electricity your water heater consumes. A solar electric system makes electricity, which means you purchase less electricity from your power company. Your connection to the power company acts like a battery; accepting electricity when production from your solar panels exceed your consumption, and in return supplying electricity when your solar panels cannot meet your electricity consumption. This is called net metering.

Q: What are the benefits of using solar energy?

A: Capturing energy right where it is used, at your home, provides numerous benefits. It will reduce your dependence on an increasingly expensive and volatile energy market. It will reduce your carbon footprint at time when we are experiencing record-breaking climatic changes. You are, in effect, pre-paying for your future energy and reducing your future carbon emissions. Sixty-three percent of the current supply of electrical power for Portland comes from fossil-fuel burning power plants. Emissions from these plants are a primary contributor to global warming pollution. Traditional electricity and natural gas generation also have impacts on human health, ecosystems and wildlife.

Q: Does solar add value to my home?

A: Solar is an investment in your home that will increase in value as energy volatility and costs rise. At today’s gas and electric prices, a solar hot water system saves the average family of four $150 - $300 a year. Savings are typically higher for larger families. A 2kW photovoltaic system can trim 15-20 percent or more off your electric bill. In addition, you are adding value to your home that will be reflected in its resale price. Current sales data show that added resale value is about 20 times the annual cost savings of a system.

Q: What size system do I need for my house?

A: Heating water is one of the largest uses of energy in your home. Residential solar water heating systems can save 2,000-2,800 kilowatt-hours (kWh) (100-140 therms of gas) per year. That’s 60% of the energy used to heat water in an average Oregon home. In the summer, your system should provide 100% of your hot water. During the winter months, solar will still pre-heat the water, but not to the temperature recommended for home use. Electricity production is directly proportional to solar electric system size. 1 kW of solar electric panels optimally oriented with minimal shade will produce approximately 1,000 kWh per year in Portland. A typical residential system of 3 kW will supply about 3,000 kWh annually, or a quarter of an average Oregon home’s yearly electricity usage (an average four-member household uses 12,000 kWh/year).

Q: How much do solar energy systems cost?

A: A typical installed solar water heating system costs (ca: 2012) about $9,000 before incentives. Incentives and tax credits can reduce this cost by about half. A solar electric system currently (ca: 2012) costs about $4,000 per kilowatt (kW).

Q: Is my house good for solar?

A: Solar works best on south-facing roofs, though east or west oriented low-slope roofs may be suitable as well. There should be little or no shading from trees, buildings, chimneys or roof gables. Remember, locations with no shading in the winter may be shaded by spring and summer foliage, and young trees will grow.

Q: What is added to my house if I install solar?

A: Solar water heating systems use either flat panels or evacuated tubes to absorb the sun's energy. Each system has its advantages and disadvantages. A typical system will have one or two collectors requiring a total of about 100 square feet of roof area. Typically, an additional 80 gallon storage tank will be installed near your existing water heater. Solar water heating systems can also be used in conjunction with a tankless, on-demand water heater.

Photovoltaic panels require 100 square feet for each kW installed. Your photovoltaic system will have a wall-mounted inverter, about the size of a large briefcase, and two smaller disconnect switches. These can be located indoors near your breaker panel, or outdoors in a shaded location. A solar meter that measures the electricity generated by your system will be located near the inverter.

Q: I have radiant floor heating. Can I use solar to heat my house more efficiently?

A: Because the Willamette Valley receives so little sun during the heating season, solar space heating is not ideal. However, evacuated tubes absorb more energy in low-light cool-temperature conditions and are being used for space heating.

Q: Can I install the system myself?

A: To qualify for an Energy Trust of Oregon incentive, your system must be installed by an eligible contractor. If you install your own system, you will still be eligible for state and federal tax credits. The AC connection at your service panel must be performed by a licensed electrician.



Ten Steps to Solar - Printable Version

Note: From the time you meet with your contractor to the end of installation usually ranges from four to six weeks.

  1. Get bids from approved solar contractors. We recommend you receive competing bids from at least two contractors. Incentives are available from Energy Trust of Oregon for systems installed by approved contractors - visit

  2. Select a contractor.

  3. Sign a contract with your installer, and sign an Energy Trust application if you are eligible.

  4. Your contractor submits an incentive application to Energy Trust of Oregon to secure your cash incentive. To receive the incentive, your application must be pre-approved before the system is installed.

  5. Energy Trust pays your incentive to the contractor. This amount will be subtracted from the cost of your installation.

  6. If you are installing solar electric (PV), sign a net-metering agreement with your utility. Your installer will provide you with the form.

  7. Your contractor installs your system.

  8. Fill out the forms for the Oregon Department of Energy Tax Credit. Your contractor will provide you a form and assist you. Extra forms are here.

  9. When you complete your federal income tax return, claim your federal tax credit with Residential Energy Credit Form 5695. Your contractor will provide you with the form, or you can download it here (PDF).

  10. Tell your friends and neighbors about going solar. Let's make Portland a leader in energy independence!