PGE does not design or sell net metering equipment, so we can’t provide cost estimates for these systems. But we can give you some broad guidelines to help you determine if you want to pursue a net metering system.
How much generation will you need?
Your PGE bill can help you understand your electrical needs. Your bill shows how many kilowatt-hours (kWh) you use each month and your average kWh use per day.
For example, if you use 720 kWh in 30 days, your average use is 24 kWh per day (720 kWh/30 days). If you used electricity at a perfectly constant rate, (with no peak usage for appliances, air conditioner, etc.), you would need a generator that produced 1 kW every hour of every day to meet all your electrical needs.
Of course, loads vary over time, and most solar, wind, or hydro generators vary their output over time. For this reason, you may want to size your system to produce more than 1 kW if you want to cover more of your power needs.
Professional system designers and installers can provide further information on system design. In addition, some retailers of renewable energy equipment have very informative Web sites and catalogs.
What type of generation will you need?
Solar systems for grid interconnection (i.e., no batteries) generally cost about $6 to $9 per watt of rated capacity. For example, a 2,000-watt (2 kW) solar system would cost about $12,000 to $18,000.
Wind generators need a generator, an inverter, a tower, and other smaller components. A wind generator with an inverter will cost in the range of $2.50 to $3 per watt, and a tower can cost $10 per foot or more. It is generally recommended that wind generators be 30 feet or more above all obstructions on the ground to eliminate as much turbulence as possible. These cost ranges do not include installation. To understand the wind potential of your site, visit Wind Power Maps or the American Wind Energy Association.
Hydroelectric generators are very cost effective relative to other types of renewable generation. They typically run 24 hours a day, so a small generator can produce lots of power.
Hydropower is dependent on water flow rates — gallons per minute, or GPM — and “fall,” or the distance the water drops from where it is first available to the generator, usually measured in feet. If you have lots of water flow (GPM) and not much fall, you can make the same amount of electricity as someone who has low water flow and lots of fall. Hydroelectric generators for net metering usually need a minimum flow of 12 GPM and a minimum fall of 3 feet. If your site has more than 3 feet of fall, the minimum flow can be as low as 3 GPM (at 200 feet of fall). Hydroelectric generators cost about $1,000 and up, not including installation. They also require an inverter, which costs about $1/watt. Total installed costs of hydroelectric generators are difficult to estimate because there are so many variables involved.
Incentive programs
Some generation systems are eligible for a tax credit from the Oregon Department of Energy, 800-221-8035, or the Federal Energy Tax Credit.
Additional incentives are available through the Energy Trust of Oregon. Their Web site provides current details of their incentive programs.
Many other federal and state government agencies are active in this arena, so check with your generation designers, suppliers and installers for the latest information.
