8/28/2009

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Harry Indig, PMP

Prepared for Nicole and Ret Taylor 156 Northeast 59th Street Seattle, WA 98105

As a class Project Photovoltaic at Shoreline Community College has agreed to review the analyze of cost, efficiency, feasibility, and return of investment using a roof mounted solar photovoltaic module array.

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The customers home at 156 Ne 59th St in Seattle, WA has been owned by the current owners since 2005. They were fortunate this house has had no additions and minimally invasive remodels since its construction in 1909. Being its century year, the owners have sought to do an extensive remodel by lifting its 990 square feet main floor off its original foundation, raising it by 3 feet, upon setting it back down. This will double it’s conditioned square footage by allowing the current basement to become livable space.

Conservation measures such as passive day lighting, increased insulation, improved circulation, the addition of a heating system, and replacement of the existing hot water system, and with the possibility of adding solar electric generation will all be incorporated into the remodel.

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The customer’s objective is to look into the feasibility and long-term return on investment of a roof-mounted solar photovoltaic array. The owners believe the retail expense of power in the Seattle area is relatively inexpensive. However; both owners believe making decisions for the good of our community for the future, needs to be evaluated. The prospect of current energy prices increasing in the near future is also of concern. And with the incentives being offered by our government on federal and state levels coupled with the incentives being paid by the local power distribution companies for selling electricity to them; generating their own solar power becomes an attractive venture.

Over all else, the owners would like to know if they are getting a good return on investment by putting their capital towards solar power versus investing in a security such as a secured bond or growth equity.

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Is Solar Right for You? Yes, if you...

Own the building where you want to install solar; Have a roof in good shape and shade-free; and Are interested in making a long-term investment to protect yourself from rising energy costs and want to reduce your environmental impact.

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Benefits and CostsSolar Energy:

Is a long-term investment that increases in value as energy costs rise.

Reduces your "carbon footprint" -- the amount of greenhouse gases produced by your home or business, which in turn lessens your overall impact on the environment.

Costs (for a solar electric system) between $8,000 and $10,000 per kilowatt (average residential systems are 1 to 3 kilowatts).

Is eligible for incentives offered by Washington State of $0.15 to $0.54 cents per kilowatt-hour (kWh) generated (by a solar electric system) with a cap of $5,000 per year (HB6170).

Is eligible for a federal tax credit equal to 30% of the system cost.

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•27% less electricity will be consumed due to the combination of these upgrades at an initial cost of about $5,500.

•A federal tax credit of $1,640 for the 2009 – 2010 tax years will be earned due to the combination of these upgrades.

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To maximize the PV system investment (by purchasing as little electricity as possible) additional conservation steps will be taken to reduce electrical consumption.

Electrical conservation will be achieved primarily through the migration of thermal loads from electrical to natural gas devices.

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•Increase insulation in attic space• Replace electric space heaters

•Replace electric hot water heater with high volume tankless natural gas unit

Sun Chart: Determination of Solar ExposureOrientation. Azimuth Angles. Altitude Angles. Completing the Sun Chart

Reading the Sun Chart - Client Assistance Memo (CAM) 417 and 420

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Solar AvailabilityWhat we do know about the Seattle solar window can be explained and analyzed with some basic tools of our solar industry.

One is the SunEye™ by Solmetric. The second device used was Solar Pathfinder™ by Solar Pathfinder.

Pathfinder™ provided mathematical precision for accurate shading assessment, solar system sizing, collector placement, and component specification.

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House’s East View

House’s West View

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North Roof South Roof

East Roof 96.1% West Roof 89.8%

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WorkBook on Solar Technical Details lll.xls Solar Inverter Options Solar Modules Financial Calculator = $

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Typical utility interconnected solar electric system

(with optional backup battery storage)

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In the City of Seattle, the department of Planning Development (DPD), there are two client assistance memo (CAM’s) for solar systems covering both Photovoltaic and Thermal designs.•CAM 417 Sun Chart: determination of Solar Exposure•CAM 420 Solar Electric Systems

• Permit Requirements• Electrical Permit• Building Permit

• Land Use Requirements• Nonconforming Residential Uses• Lot Coverage Requirements• Height Requirements

• Interconnection and Net Metering Requirements• Net Metering Benefits• Net Metering Required Forms

• Installation Considerations• Solar Access, Sizing and Performance• Mounting Solar Modules• Structural Considerations• Electrical Considerations

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(8) Silicon Energy 185 Watt Modules w/ racking $8,880

(1) Outback SmartRE 2500 Inverter $4,4402 strings of 4 modules, 121.2 volts, 15.8 ampsSmartRE 2500 Battery Enclosure(4) Group 27 106 Ah batteries

Balance of System Components $1480(1) Combiner box(1) Ground Fault Circuit Interruptor(1) 600 Volt DC Fused Disconnect(1) AC Fused Disconnect(1) 240 Volt Production MeterMiscellaneous conduit and fittings

Labor $1480Grand Total $16,280

($11 / watt installed)

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Notes:1) Meter sockets must be located near each other and outside or otherwise consistent with location allowed by Seattle City LightRequirements for Electric Service.2) Standard utility socket with face cover (no round sockets). Socket wired per sheet 2.3) When production meter is removed, bottom terminals will be energized and line terminals will be de-energized (oppositeof billing meter).4) Billing meter will run backwards and subtract when energy flows to utility, production meter only runs forward.5) Delivered energy flows from utility.6) Received energy flows to utility.

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Production Meter Wiring and New components for Net Metering per Seattle City Light

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OutBack Power Products

Smartre 2500

Up to 93% Inverter Efficiency

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We have seen photovoltaic cells and arrays, also known as solar modules, convert sunlight into electrical energy. Now being used in a number of building applications, including shingles and fenestration, photovoltaic's are becoming a common onsite renewable energy source. Whether roof-mounted or built into the design, solar cells are connected in series to achieve proper voltages. The energy produced can either be stored in batteries or tied directly to the municipal grid. In some cases, you may qualify for tax credits or rebates when purchasing and installing photovoltaic modules. You also may be able to sell the extra energy you produce back to your local utility.

The owner’s electric power consumption of 4845 kWh per year based on the past 2 years. This is 13.27 kWh/day. Several key parameters have been evaluated at this home site, which has excellent solar access. Based on the shade analysis performed we calculated 96.1% solar available sunlight. There is 228 square feet on the east roof for solar array layout.

Application of Solar Photovoltaic

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Table 1 Average Daily Total Solar Radiation for U.S. Cities

City MJ/m²·day23° Tilt

MJ/m²·day45° Tilt

Btu/ft²·day23° Tilt

Btu/ft²·day45° Tilt

Seattle 11.65 11.63 1026 1024

In 1980 the Solar Rating and Certification Corporation (SRCC) was incorporated as a non-profit organization with the primary purpose being the development and implementation of certification programs and national rating standards for solar energy equipment. A simple installation of several PV solar arrays on this project could use the equivalent sun hours per day based on SRCC certification data as table 1 from the Average Daily Total Solar Radiation for City of Seattle with two tilt angles. The infrastructure of the entire system on your roof needs to meet the CAM requirements of the City of Seattle.

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Energy Payback Times for Photovoltaic Technologies

Energy payback time (EPBT) is the length of deployment required for a photovoltaic system to generate an amount of energy equal to the total energy that went into its production. Roof-mounted photovoltaic systems have impressively low energy payback times, as documented by recent (year 2004) engineering studies. The value of EPBT is dependent on three factors: (i) the conversion efficiency of the photovoltaic system; (ii) the amount of illumination (insolation) that the system receives (about 1700 kWh/m2/yr average for southern Europe and about 1800 kWh/m2/yr average for the United States); and (iii) the manufacturing technology that was used to make the photovoltaic (solar) cells.

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Flat-Plate PV Systems

The most common array design uses flat-plate PV modules or panels. These panels can either be fixed in place or allowed to track the movement of the sun. They respond to sunlight that is either direct or diffuse. Even in clear skies, the diffuse component of sunlight accounts for between 10% and 20% of the total solar radiation on a horizontal surface. On partly sunny days, up to 50% of that radiation is diffuse. And on cloudy days, 100% of the radiation is diffuse. One typical flat-plate module design uses a substrate of metal, glass, or plastic to provide structural support in the back; encapsulates material to protect the cells; and a transparent cover of plastic or glass.  The simplest PV array consists of flat-plate PV panels in a fixed position. The advantages of fixed arrays are that they lack moving parts, there is virtually no need for extra equipment, and they are relatively lightweight. These features make them suitable for many locations, including most residential roofs. Because the panels are fixed in place, their orientation to the sun is usually at an angle that practically speaking is less than optimal. Therefore, less energy per unit area of array is collected compared with that from a tracking array. However, this drawback must be balanced against the higher cost of the tracking system .

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I strive to obtain the best price and best technical product for our clients. Moreover, this site could be a net producer of electrical power using any of several systems. Every kilowatt-hour produced will earn at least 18 cents. If the solar modules and inverters are manufactured within the state of Washington the incentive raises to 54 cents per kilowatt-hour. Silicon Energy LLC of Arlington produces such modules, and has been self certified by National Laboratory met this requirement.

The new Silicon Energy design array is highly efficient and the solar cells are encapsulated between two tempered glass plates. With 228 square feet of available roof and modules being 16 square feet each, a total of 8 panels could be installed on your roof with an output of 1.48 kW. Panel size: Silicon Energy = 47 inches by 47 inchesPower output: Silicon Energy = 0.165 kW per panel

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Suggested Solution of Solar

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Use parallel wiring to increase current (power).

This diagram shows a simple parallel circuit to increase current or power. Assume that we are using 12 volt batteries. The power of all 3 batteries add to give us the effect of a battery 3 times as powerful but the voltage stays the same at 12 volts. Parallel wiring increases current but the voltage does not change. This is the wiring used when jump starting a car for example.

Use series wiring to increase voltage

The voltage of all 3 batteries add to give us the effect of a battery 3 times the voltage or in this case a very large 12 volt battery. In this circuit the current is the same as the current in just 1 of the batteries. But since the 4 volt industrial batteries are very large, we have in effect created a huge 12 volt battery.

Use series & parallel wiring in combination

The left to right series connection add the two 12 volt batteries to make 24 volts. And, since we did this 3 times and then connected each group of 2 (now 24 volts) in parallel we end up with one very large 24 volt battery. It has twice the voltage of a single 12 volt battery and 3 times the current or power because all 3 groups are wired in parallel.

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This diagram shows a combination series and parallel circuit to increase both the battery current and voltage level at the same time. Assume this time we are using 12 volt batteries