Solar Energy 101

Yes! Even Portland and the rainy Willamette Valley receive as much sunshine annually as the average U.S. city. In fact, solar is Oregon’s most abundant renewable resource. Today, more than 17,000 Oregon households use solar energy systems to generate electricity or heat water.

Half of the electricity we use in Oregon is generated by power plants that burn fossil fuels. The emissions from these plants contribute to climate change and pollution. The sun is a clean, renewable source of energy that can help us reduce our dependence on fossil fuels.

Solar works best on south-facing roofs, though east- or west-oriented roofs may be suitable as well. There should be little or no shading from trees, buildings, chimneys or roof gables on or adjacent to your home. Remember, locations with no shading in the winter may be shaded by spring and summer foliage.

The three most common solar energy systems that you can add to your home are solar water heating, solar pool heating and solar electric.

A solar water heating system preheats the water that goes into your existing water heater, which reduces the amount of gas or electricity your water heater consumes.

Solar pool heating systems use the sun's energy to directly heat your pool during the spring, summer and fall. Most systems are for seasonal use only, and must be drained in the winter.

A solar electric system generates electricity that can be used throughout your home, which reduces the amount of electricity you need to purchase from your power company. When your system generates more electricity than you use, the excess goes into the grid and you receive a credit from your utility.

The size of a solar electric system is often described in watts (W) or kilowatts (kW). One kW = 1,000 W. Watts are a unit of power, just like the horsepower of an engine. They express the maximum possible output of energy the system can produce at any point in time.

When sunlight strikes solar electric panels, they produce electricity that is measured in kilowatt hours (kWh). Kilowatt hours are the units of energy you buy from your utility and use in your home to run your appliances, lighting and electronics.

In Oregon, a good rule of thumb is that 1,000 watts of solar electric panels require about 100 ft2 of space and will typically produce 1,000-1,300 kWh if electricity each year. If you double or triple the size of the system, you will double or triple the amount of electricity it produces.

System prices vary. Before incentives and tax credit, a typical solar water heating system costs $6,500–$10,000.

Solar pool heating systems vary in price depending on the size and condition of your pool, with before incentive costs ranging from $3,000-$9,000.

For a solar electric system, the cost depends on the size of the system and the ease of installation. Before incentives and tax credits, typical costs range from $6,500–$10,000 for each kilowatt (kW) of capacity.

Incentives and tax credits can cover up to 80% of the cost. And low-interest rate financing is available with GreenStreet Lending through Umpqua Bank.

Read more about costs, tax credits, incentives and financing.

For a solar electric system, size is arbitrary—you can pick any size you want, You'll still be connected to the utility, so you don't have to generate 100% of your electricity 100% of the time. In fact, most people don't. You can install a system that produces 80%, 50% or just 10% of your needs, and still reduce your energy bills while doing something good for the environment.

Solar water heaters are sized to match your family's hot water consumption. If you have a lot of people in your home or use a lot of hot water, you will benefit from a larger system. Smaller homes that use only a little hot water need smaller systems.

Your solar contractor will size your system to meet 40-70% of you hot water energy needs with solar energy. For most homes, that means one or two collectors that are 30-50 ft2 in size each.

Solar pool heating systems depend on the surface size of your pool and how many months out of the year you use it. Typically, the area of collectors is 50%-100% of the surface area of your pool.

Energy Trust incentives and state and federal tax credits can reduce project costs by up to 80%, making an investment in solar much more affordable. Energy Trust cash incentives are applied to the up-front cost of you system, similar to a coupon. Your federal tax credit will come when you file your tax returns for the year the system was installed, and the state tax credit will come over four years. If you are not a customer of one of Energy Trust’s participating utilities, go to www.solaroregon.org to learn about opportunities in your area

Financing can be a great option to help cover the initial purchase of a solar energy system. Not sure where to find affordable financing? Check out GreenStreet Lending, brought to you by Energy Trust and Umpqua Bank (an Equal Housing Lender). GreenStreet loan products are designed specifically for solar and energy efficiency projects, and feature preferred rates, no closing costs and no fees.

Some companies offer customers the option of a solar electric power purchase agreement in lieu of you purchasing a system outright. In this arrangement, the company purchases and installs the solar electric system on your behalf and you pay them for the electricity produced by the panels. Any additional energy you need that isn't provided by the panels is purchased from your utility as usual.

Depending on the company, you may pay nothing or a small fee upfront to have the system installed. Because the solar company pays for the equipment and installation, the company owns the system and receives any incentives or tax benefits the system may be eligible for. They are also responsible for any maintenance or repairs on the system during the term of your agreement.

When your agreement ends, you usually have the option to renew the agreement, remove the system, or purchase the system. If you choose to purchase the system from the solar company, you will not be eligible for any incentives or tax credits.

A solar system reduces your energy costs and may add value to your home. The added value is up to 20 times your annual energy cost savings, according to The Appraisal Journal. An ongoing study in Oregon by Energy Trust is showing similar results.

At today’s electricity and gas prices, a solar water heating system or a 2-kilowatt solar electric system could each save the average family of four $175 or more a year. Based on these savings, each system could add up to $3,000 to the value of a home.

A solar water heating system is one of the most affordable ways to go solar and can offset one of the biggest energy users in your home. Residential solar water heating systems typically save 1,500–3,000 kilowatt hours (kWh) of electricity or 80–150 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 may meet 100% of your hot water needs.

In addition, cash incentives and low-interest rate financing are available from Energy Trust for eligible homeowners. Water heating incentives are available to Oregon customers who heat their water with electricity from Portland General Electric or Pacific Power or gas from NW Natural or Cascade Natural Gas. Solar electric incentives are available to Oregon customers of PGE and Pacific Power. And financing options with GreenStreet Lending through Umpqua Bank are available to qualified borrowers who are customers of PGE, Pacific Power, NW Natural or Cascade Natural Gas.

With a solar electric system, energy production is directly proportional to system size. In Portland, a 1-kilowatt solar electric system, optimally oriented with minimal shade, will produce approximately 1,000 kWh per year. A 3-kilowatt residential system will supply about 3,000 kWh annually, or 25% of an average Oregon home’s annual electricity needs (an average four-person household uses 12,000 kWh/year). Improving your home’s energy efficiency will reduce your energy use so your solar system will meet a higher percentage of your needs.

Both solar electric and solar water heating systems utilize panels that are most commonly mounted on your roof. Solar water heating panels, called collectors, are usually 30-50 square feet in size. A typical system has one or two collectors. Solar pool heating collectors are made out of UV-treated plastic and are much larger, with an area typically 50%-100% of the surface area of your pool. Photovoltaic panels require about 100 square feet of area for each kW installed.

A solar water heating system typically includes an 80-gallon solar storage tank that is installed near your existing electric or gas water heater. Both conventional tank and tankless units are compatible with solar water heaters. If you don’t have room for a second tank, units that contain the solar storage and an electric water heater in a single 120-gallon tank are available.

A solar electric system includes a wall-mounted inverter to change the DC electricity produced by the panels into AC “household” electricity. The inverter is a little bigger than a briefcase and can be installed indoors near your breaker panel or outdoors in a shaded location.

Solar pool heaters include a filter and pump (which you may already have installed), a flow control valve and sensors.  The sensors and valve divert water through the collectors when the collector temperature is greater than the pool temperature. When the collector temperature is similar to the pool temperature, filtered water bypasses the collectors.

Yes. However, to qualify for an Energy Trust incentive or an Oregon state tax credit, your system must be installed by an eligible contractor.