Facilities

Topics• Why?• Types of Solar Electric Systems• Solar Panel Types• Solar Panel Purchase Resources• Inverter Types• Racking / Mounting Resources• Site Assessment Tools and Charts• Interconnection Advice• Permitting Advice• Presenting next on May 10th @ 3PM in

Dan Nicholas Park Nature Center for the Simple Living Festival.

Why...

Why... (continued)

Types of Solar Electric Systems• Grid-Tied• Battery-Based or Direct• Grid-Tied with Battery Backup• Hybrid: i.e. Sunny Island and UPS

Grid-Tied• Most Common• No batteries• What I do...

Battery-Based• Simple• Off-Grid• Ideal for remote cabins, etc...• Batteries for entire home can Batteries for entire home can

add $8,000 to cost!add $8,000 to cost!• Battery life is 8-10 years!Battery life is 8-10 years!• Consider something new/old: Consider something new/old: http://www.ironedison.comhttp://www.ironedison.com

for batteries with a 30 year life...for batteries with a 30 year life...•

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Grid-Tied w/ Battery Backup• Always have power• No backup generator required• Good for areas with frequent outages

PV Optimizers• Tigo Energy Optimizer System• http://www.tigoenergy.com/content/resources/guides-and-manuals

Types of Solar Panels• Mono-Crystalline

• Poly-Crystalline

• Amorphous (thin-film, multiple types)

– Flat Plate

– Roll (Solar Shingle)

– Tube Collectors

Mono-CrystallineThe most common material used in solar cells is single crystal silicon. Solar cells made from single crystal silicon are currently limited to about 25% efficiency because they are most sensitive to infrared light, and radiation in this region of the electromagnetic spectrum is relatively low in energy. Most commercial monocrystalline panels are between 11-14 % efficiency.Image

PolycrystallinePolycrystalline ("many crystals") solar cells are made by a casting process in which molten silicon is poured into a mould and allowed to cool, then sliced into wafers. This process results in cells that are significantly cheaper to produce than single crystal cells, but whose efficiency is limited to less than 20% due to internal resistance at the boundaries of the silicon crystals. Commercial polycrystalline modules usually run at about 12 % efficiency.

Amorphous (Thin-film)Amorphous cells are made by depositing silicon onto a glass substrate from a reactive gas such as silane (SiH4). This type of solar cell can be applied as a thin film to low cost substrates such as glass or plastic. Thin film cells have a number of advantages, including easier deposition and assembly, the ability to be deposited on inexpensive substrates, the ease of mass production, and the high suitability to large applications. Since amorphous silicon cells have no crystal structure at all, their efficiencies are presently only about 10% due to significant internal energy losses.

Solar ShingleUnisolar

Flat-Plate Amorphous

Solyndra Tube Array

Solar Panel Sources

● Affordable Solar: http://www.affordable-solar.com/

● Alt Energy Store: http://www.altestore.com ●Clean Energy Brands: http://www.cleanenergybrands.com

● Solar Panel Store: http://www.solarpanelstore.com/

● Spherical Solar (solar shingles): http://www.spheralsolar.com/products/Solar-Shingles-and-Roofing-Membrane.html

● Wholesale Solar: http://www.wholesalesolar.com

Inverters

● Microinverters (grid-tie UL 1741/IEE1547): Connect to a single solar panel. Currently 215 watt, reduce shading losses and more power at sunrise/sunset individual panel feedback. Enphase: http://www.enphase.com/

● String Inverters (grid-tie UL 1741/IEE1547): Connect to a single string of solar panels (can be any system less than 15kW, range 1kW to 15kW. Example Fronius: http://www.fronius.com/cps/rde/xchg/SID-148C04F4-AE78A597/fronius_usa/hs.xsl/2714_1446.htm

● Stand Alone (battery): Also called sine-wave, don't sync to the grid. You are your power company. Example Outback: http://www.outbackpower.com/products/sinewave_inverter/off_grid/

Charge Controllers

● Needed if doing DC Solar Power System or Inverter with Battery Backup

● A charge controller controls the charge from the PV array in to the battery bank by controlling the current and voltage to from the array to the batteries. A good charge controller will also disconnect the load (i.e. inverter when the battery level is too low.Examples:● Midnite Solar:

http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=21&productCatName=Charge%20Controllers

● Morningstar:http://www.amazon.com/gp/product/B002MQSTQ2/ref=s9_simh_gw_p263_d3_i3?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-3&pf_rd_r=1115ZWQ1MPG4GP02QJG3&pf_rd_t=101&pf_rd_p=470938811&pf_rd_i=507846

● See previous slide #8 on battery-based system for location in the system

Charge Controller Example

Racking / Mounts

● Roof Mounting: Adv: Usually best access to sun, make use of unused space, close proximity to power panels, minimal effect on site. Disadv: Increased roof weight, limited array tilt, potential for water damming and orientation.Visit: http://www.ironridge.com or http://www.quickmountpv.com http://www.snapnrack.com/

● Ground Mounting: Adv: Unlimited orientation, adjustable tilt, no roof penetration, solar array runs at lower temperature.. Visit: http://www.dpwsolar.com

● Top of Pole Mounting: Adv: Very easy to adjust tilt and orientation, solar array runs very cool, allows for use of solar trackers, yard work does not bother array.Visit: http://www.sunarx.com/

Trackers● Array Technologies Trackers: Adv: 20-40 percent more power, require power to track. Disadv: Increased maintenance and not recommended where children play.Visit: http://arraytechinc.com/residential-trackers

● Zoneworks: Adv: No electricity used, tracks using heated liquid to cause movement, no motors, no gears and no controls to fail.Visit: http://www.zomeworks.com/photovoltaic-tracking-racks/

Roof Mount Example

Ground Mount Example

Top of Pole Mount Example

Site Assessment

● Shading evaluation: Consider not only current, but future. Examples small trees, land that is not owned but could block sky.

● Site restrictions: Homeowners' associations, city covenants and historical districts

● Approval of agencies: local codes, firefighter access, zoning, power utility approvals.

Effect of Azimuth on Efficiency

Shading Evaluation

Sun Chart Analysis

Sun Chart Analysis

Site Assessment Tools

● ASSET: Acme Solar Site Evaluation tool is a shading-analysis tool that uses a digital camera and software to evaluate the site. (Discontinued – newer technologies are available)

● PowerPredictor: Measures solar and wind energy at your site. It comes with a data logger and one year's free access to an online account where your data will be analyzed. The report compares the main wind turbines and solar panels on the market today, in terms of payback, annual energy generation, cost savings and effect on your carbon footprint.Visit: http://www.talcoelectronics.com/p-135-power-predictor.aspx

● Solar Pathfinder: Consists of a plastic base that integrates a level and a compass and holds a paper sun chart. Can trace obstructions onto chart or take digital photos to analyze shading with optional software.Visit: http://www.solarpathfinder.com

● Solmetric SunEye: a hand held electronic device that allows users to assess total potential solar energy given the shading of a particular site. Identifying the shading pattern early in the process reduces the expense of system and home design and improves the efficiency of the final system or house.Visit: http://www.altestore.com/store/Meters-Communications-Site-Analysis/Solar-Site-Analysis-Tools/Solmetric-SunEye-210-Site-Analysis-Tool/p8182/

Building Assessment

● Roof area available, orientation of roof

● Condition of roof, age of roof is important.

● Roof framing (evaluate early in process!). Most modern homes build since mid-1970s have adequate framing to support he weight of a PV array so long as a single layer of lightweight roofing material is used.

Pre 1970s homes may require a structural engineer review to verify that the structure can support the weight of a solar array

Electrical Assessment

● Amperage rating of Main Distribution Panel and its main breaker (200 amp is usually required)

● Load analysis of the Main Distribution PanelDoes the sum of the amperages of installed breakers exceed the rating of the panel? If so, a completely new panel may be required...

● Does the Main Electrical Panel have at least two open circuit breaker slots?

● Evaluate spots for placement of disconnect switch outside the home (must be close to the power meter).

Final Assessment Questions

● Will the available roof space support the solar array size that you have in mind? Note: Solar panel efficiency plays a big role here. Thin-film is less efficient so often requires more space. Also, solar arrays cannot be mounted close to the roof edges due to wind load issues (set back).

● Will the building structure need to be upgraded to support the solar array?

● How will the electrical lines be run to the panel?

● Will the solar array produce the power desired? See PVWatts Calculator: http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/

● Check with Duke Energy and building inspector for acceptance of components proposed. (see later slides)

Interconnection Advice

● Interconnection is a progressive process with several steps. It requires patience, planning and attention to detail. Note: Certain metropolitan area power systems may not allow for interconnection. Plan and check early!

● VERY IMPORTANT: Consider the whole value payback and speak with someone who actually has a system prior to going with NC GreenPower. I do Net Metering please ask for an explanation.

● Duke Interconnection Information Page:http://www.duke-energy.com/customer-owned-generation/nc-main.asp

● NC Utilities Commission: http://www.ncuc.netExample report of proposed construction: http://ncuc.commerce.state.nc.us/cgi-bin/webview/senddoc.pgm?dispfmt=&itype=Q&authorization=&parm2=SAAAAA46201B&parm3=000133775

● Hint: Request a one-line drawing when you order your solar system. Most dealers will include this at no-charge when you make the purchase. For example see drawing included with report of proposed construction (above).

Interconnection AdviceDisconnect Switch

● The disconnect switch required by Duke can be an expensive proposition. You should plan for this in advance and also plan for it to be located close to your power meter!

● Example disconnect switch:

Interconnection AdviceDisconnect Switch

● If you have ground mount or pole mount systems, it is a good idea to have a disconnect at the pole too.

Permitting Advice

● Ensure circuit breakers allow for backfeeding. Some breakers only work in one direction.

● If trenching start permit and call for site inspection before filling the trench where wires are buried.

● Have all equipment and racking spec sheets and your one-line drawing handy for the electrical inspector to review.

●Several labels are required on disconnects and at the main distribution panel where the solar power will backfeed. See subsequent slides for examples.

Permitting Advice (labels)

● The following labels are required on the main disconnect switch by the National Electric Code. Electrical inspectors will check for these!

Permitting Advice (labels)

● The following labels are required on circuit breaker panel where the solar system backfeeds the home: Electrical inspectors will check for these!

Don't Forget Lightning Protection

● Each solar array should have lightning protection! (Your home should have this too!

Why NOT PV?(I would not do this because...)

Why NOT PV?(I would not do this because...)

• Solar Panels in Series (like XMAS lights)

• Shading Issues

• Manufacturing tolerance differences

• Sunrise/ Sunset

• DANGEROUS!!! (high DC voltage)? How can you work on this in the daylight...? What about troubleshooting a prob w/ 24 panels

• Big Expensive Wire

• Cost to Expand System

• Average Service Life of String Inverters(10 years the norm)

Solar PVThe only way I was interested

 

Solar PVThe only way I was interested

 

PV the Only Way I Was Interested.

PV the Only Way I Was Interested.

http://enphase.com/products/microinverters/m215/

Getting It By the Neighbors...

Getting It By the Neighbors...

Getting It By the Neighbors...

Questions?✔ Visit: www.kenclifton.com, then click

Renewable Energy!

Help Save Solar in NC!

• Power Companies are trying to prevent/discourage new solar installs!

• Current Power Company Proposals have stopped most (if not all) new residential solar in North Carolina.

• Visit the NC Conservation Network Siteto VERY EASILY add your name to a petition to help stop this: http://action.ncconservationnetwork.org/page/speakout/DropALEC

Next Steps

• Solar tax credits are set to expire in 2014 !

• Don't miss a chance to have almost 2/3rds the cost of a system covered by tax credits.

Special Thanks to:

RCCCContinuing

Education for thisWonderful LEED

Building!