FAQs

QUENTLY ASKED QUESTIONS

1) Is solar energy a good choice for the Pacific Northwest?
2) Why is having more distributed energy systems a very good idea?
3) I am interested in renewable energy, so why should I care about the efficient use of energy?
4) What affects the performance of a photovoltaic system?
5) What is the photovoltaic effect?
6) What are the components of a grid-tied, battery-less, photovoltaic system? What are their benefits and disadvantages as compared to a battery system?
7) What incentives does the state of Washington provide for renewable energy systems?
8) What incentives does the Federal Government provide for solar energy systems?
9) What is net metering?
10) How do I find a qualified solar installer?

i) Where can I find good websites for home energy efficiency?
ii) What is a home energy audit?
iii) How do I know if I am using too much energy?
iv) How much electricity does your TV use?
v) What is phantom load?

1) Is solar energy a good choice for the Pacific Northwest ?

Yes, because solar energy systems can provide us with significant amounts of energy when and where we need it. With a yearly average of 3.7 sun hours a day, it may seem at first that the Seattle area’s solar potential is less when compared to sunnier locations such as Los Angeles, which has a 5.6 hour daily average (National Renewable Energy Laboratory). That difference narrows significantly however when the focus turns to the important months of May through September; with a 5.22 sun hour average for Seattle and 6.26 sun hour average for Los Angeles. Fortunately for us this seasonal productivity arrives just when additional sources of energy is most needed, due to the convergence of high electricity demand and low hydroelectric output, Washington’s primary source of electricity. Note that this situation is only going to become more acute over time, on account of the expected drop in summer stream flows due to climate change (Climate Impacts Group, University of Washington). Our relatively cooler weather is another important advantage, by providing greater efficiency to the technology. This is because solar cell efficiency declines when cells gets hotter, since higher temperatures act as resistance to the flow of electrons (Solar Energy International). This is an area worthy of more research; data for which can come from the photovoltaic system operating at Sakai Intermediate School on Bainbridge Island. But from what is already known about the technology, the advantages of sunnier but hotter climates is less than first thought. So contrary to first impressions, solar energy is a very good fit for the Pacific Northwest.

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2) Why is having more distributed energy systems a very good idea?

Relying on energy systems which are distributed near where their energy is needed has clear strategic economic and security advantages. There should be no secret that the nation’s electrical grid infrastructure is highly stressed and operating close to its technical limits. The scale of the problem is enormous, requiring many billions of dollars of past due investment. Washington State is nowhere near immune to this problem. By increasing the utilization of distributed solar energy systems, investments in transmission and distribution networks can be deferred and even reduced. It should also not be a secret that having many distributed energy systems reduces the danger of catastrophic loss coming from a terrorist or other form of attack on our energy system. Investing in distributed energy systems such as solar is nothing less than good long-range strategic planning (Benjamin Sovacool Phd).

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3) I am interested in renewable energy, so why should I care about the efficient use of energy?

As with any energy producing technology (fossil fuel and renewable), solar energy systems are expensive. A system’s size thus its cost will go down measurably with the efficient use of energy. For example a water heater may be rated around 2,500 watts and operate 25% of the time. This sort of load is cost prohibitive for a residential photovoltaic system. Water heating and space heating can be better accomplished through means other than electricity, such as solar thermal, gas, propane and wood. Generally speaking, the cost of a photovoltaic system will be reduced by avoiding the following appliances:

  • Electric space heaters
  • Electric water heaters
  • Electric clothes dryers
  • Electric ranges
  • Inefficient refrigerators

In addition to the above load shifting and increased reliance on efficiency (e.g. replacing incandescent lamps with compact fluorescent lamps) the need for electricity can be substantially reduced by:

  • Living without unnecessary items
  • Reducing the use of appliances when appropriate
  • Doing some tasks during daylight hours (Solar Energy International)

Remember that the most valuable watt is the one you don’t need to produce.

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4) What affects the performance of a photovoltaic system?
Common issues to be aware of include the following:

  • Sunlight Intensity A module’s current output is proportional to the intensity of solar radiation to which it is exposed. More intense sunlight will result in greater module output. Note that voltage does not change appreciably by variations in sunlight intensity.
  • Cell Temperature As the cell temperature rises above the standard test conditions of 77 degrees Fahrenheit (25 Celsius), the photovoltaic module operates less efficiency and voltage decreases. Heat may be thought of as electrical resistance to the flow of electrons. Note that because of this, it is very important to allow for airflow around all sides of the module, so as to remove heat build-up which causes high cell temperatures.
  • Shading Even partial shading of photovoltaic modules will result in a dramatic reduction in output. For example, the shading of just one cell of a 36 cell single crystalline module can reduce its performance by 75%. Because of this it is extremely important to locate all shading obstacles at the site. Remember, that the site for a photovoltaic system should not be shaded from 9:00 am to 3:00 pm; a time known as the “solar window”. Note that if there is shading, more modules will be needed to produce the desired amount of power (Solar Energy International).

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5) What is the photovoltaic effect?
One of the significant attributes of photovoltaic systems is that they do not need any moving parts to create electricity from the sun’s energy. This is because electrons can be emitted simply due to sunlight being absorbed by semiconducting materials, such as silicon. When the photons from sunlight strike the surface of a photovoltaic cell they impart their energy to the cell. The photons have just enough energy to bump the electrons within the cell to its conducting wire. This one-way movement of electrons generates an electric voltage and current, which is then carried through the wires within the cell to an electrical circuit (Solar Energy International and other).

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6) What are the components of a grid-tied, battery-less, photovoltaic system? What are their benefits and disadvantages as compared to a battery system?
The most common photovoltaic systems being installed in the Pacific Northwest are those which are connected to the utility grid but do not have batteries. These systems are designed to displace all or a portion of the building’s electricity needs. The energy generated is first used within the building, with any surplus being “pushed” onto the utility’s wires. The main components of these systems are the photovoltaic modules, inverter and system (AC and DC) disconnects. The main benefits that battery-less systems have over battery systems is that they are simpler and cheaper to install & maintain, and that they provide higher (10 to 15%) efficiency. Their main disadvantage is that when the utility grid goes down, the inverter automatically shuts off. This results in no power, solar or otherwise, being available. This is done as a safety measure, so as to protect the linespersons who will be working on the grid. Note that when the utility grid goes down for a battery system, pre-selected loads are automatically backed up by the batteries (Solar Energy International).

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7) What incentives does the state of Washington provide for renewable energy systems?
In May 2005, Washington enacted Senate Bill 5101, establishing production incentives of $0.12 to $0.54 per kilowatt hour (kwh), capped at $2,000 per year for individuals, businesses, and local governments that generate electricity from solar power, wind power or anaerobic digesters. The incentive amount paid to the producer starts at a base rate of $0.15/kwh and is adjusted according to how the electricity was generated by multiplying the incentive by the following factors:

  • For electricity produced using solar modules manufactured in Washington state: 2.4
  • For electricity produced using a solar or wind generator equipped with an inverter manufactured in Washington state: 1.2
  • For electricity produced using an anaerobic digester, by other solar equipment, or using a wind generator equipped with blades manufactured in Washington state: 1.0
  • For all other electricity produced by wind: 0.8

Ownership of the renewable-energy credits (RECs) associated with generation remains with the customer-generator and does not transfer to the state or utility. The state's utilities will pay the incentives and earn a tax credit equal to the cost of those payments. The credit may not exceed the greater of $25,000 or 0.25% of a utility’s taxable power sales. The incentive amount may be uniformly reduced if requests for the incentive exceed the available funds. The Washington Department of Revenue (DOR) is responsible for submitting a report measuring the impacts of this legislation, including any change in the number of solar energy system manufacturing companies in Washington, and the effects on job creation, such as the number of jobs created for Washington residents. The incentives apply to power generated as of July 1, 2005, and remain in effect through June 30, 2014. A utility may not claim any tax credits for incentive payments after June 30, 2016 (DSIRE, Database for State Incentives for Renewables and Efficiency).

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8) What incentives does the Federal Government provide for solar energy systems?
The Energy Improvement and Extension Act of 2008 extended through December 31, 2016 the 30% residential energy tax credit available to individuals for expenditures for qualified solar electric property and qualified solar water heating property. Importantly, the $2,000 cap on the tax credit was also removed. Note as well that the Act authorized the issuance of up to $800 million of new clean renewable energy bonds and up to $800 of qualified energy conservation bonds (Stoel Rives).

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9) What is net metering?
Net metering allows for the exchange of any surplus energy produced by the photovoltaic system for future utility energy credit, to be then used during periods when the photovoltaic system is not producing enough energy to meet the building’s needs. This means that the meter can spin “backward” when power is flowing from the building to the utility and spin “forward” when electricity is flowing from the utility into the building. At the end of the month only the net consumption is billed. Net metering allows the utility grid to act like a battery, crediting the energy “account” for later use if production exceeds consumption (Solar Energy International).

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10) How do I find a qualified solar installer?
There are number well-qualified solar installers in the Puget Sound area. An on-line listing is available at www.find-solar.org We do recommend that you talk to the growing number of people who have had a photovoltaic system and/or solar hot water system installed. Go on solar tours and listen to the owner’s experiences. In addition, find out if your prospective installer has been certified by the North American Board of Certified Energy Practitioners. Although not all qualified installers have NABCEP certification, it is the highest level of competency assessment available in the industry, with experience and/or education requirements (for more information see www.nabcep.org).

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i) Where can I find good websites for home energy efficiency?
Try the following:
- Home Energy Savers by Department of Energy: Energy Efficiency & Renewable Energy at www.energysavers.gov/your_home/energy_audits/index.cfm/mytopic=11170
- Energy Star, a joint program between the Environmental Protection Agency and the Department of Energy at www.energystar.gov

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ii) What is a home energy audit?
Every house is different. From the design of the building, how well it has been maintained, the type of heating and cooling systems, appliances, to occupants' behavior, etc..., all of these factors play a part in affecting the performance in terms of energy efficiency, water efficiency, and indoor air quality. If you are paying too much in energy, water and sewage, or if you simply want to have healthier and more comfortable indoor environment, a home performance evaluation can help you identify and prioritize your attention.

Home performance evaluation usually involves an energy audit. You can perform a simple energy audit yourself, or have a professional energy auditor carry out a more thorough analysis. A simple do-it-yourself energy audit can give you some idea of the state of the energy performance of your home. Puget Sound Energy has an online Do-It-Yourself Home Energy Audit program that can help you to compare with your neighbors in terms of energy consumption.

A professional certified energy auditor employs uses whole-house science with a variety of techniques and equipment to determine the energy efficiency of a structure.

Thorough audits often involve equipment such as blower doors (this test simulates when the wind is blowing about twenty miles per hour or a 50 pascal depressurization) which measure the extent of leaks in the building envelope, and infrared cameras, which reveal hard-to-detect areas of air infiltration and missing insulation. A professional energy audit will help identify problems that may, when corrected, save you significant amounts of money over time.

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iii) How do I know if I am using too much energy?
You can use online home energy analysis tools to assess your home energy consumption. A very reputable site is

The Home Energy Saver by Lawrence Berkeley National Laboratory
http://hes.lbl.gov/

Many utility companies also offer online analytical tools. The advantage of using the utilities’ online tools is that they already have your energy consumption data. The drawback is if you have non-utility fuel such as heating oil, propane, and wood, or cross-utilities fuel sources such as different electricity and natural gas providers.

These interactive programs can also show you practical ways to save money and energy and give you advice about both low-cost improvements and smart investments you can make.

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iv) How much electricity does your TV use?

Type Annual kWh(ave. 2hr/day) Annual Phantom load (plugged in but not on)
Plasma > 50” 409.5kWh 84 kWh
Plasma < 50” 319 kWh 42 kWh
LCD > 50” 166 kWh 16.8 kWh
LCD < 50” 120 kWh 16.8 kWh
Tube < 37” 142 kWh 67 kWh

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v) What is phantom load?
Phantom load is also known as standby power. Most electronic devices draw phantom load so that they are ready to operate when we push to “on” button. Next to the TV, which can draw 12 watts of electricity even after you turn it off, the biggest standby energy hog is the home computer and its suite of devices. A printer can draw 11.5 watts when idling, and a subwoofer, 10.8. The most simple way is to plug them all into a power strip and, when you're done for the say, turn off the power strip.

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