Q: How does PV work?
A: Simply sun strikes the cells made of silicon a semiconductor and knocks electrons loose from their
atoms, which flow through the material to produce electricity. This DC electricity is then converted to
AC electricity through the inverter.
Q: Can I use PV for backup power when the grid goes down?
A. No, not practically. The inverter shuts down when power is lost so that it doesn’t back feed the grid.
The PV arrays output fluctuates so much that you can’t power anything. The only way to do it is by
using the PV array to charge batteries so that there is a steady power supply to pull from. Batteries
are very expensive and it is more cost effective to use a generator.
Q: What’s the Warranty on the panels?
A: The Warranty for the panels is 25 years. The Warranty states that it will produce at least 80% of its
rated power for 25 years and historically they have produced electricity for 30 or 40 years
Q: What is the Warranty on the Inverter?
A: Generally, 10 years.
Q: Is there a lot of paperwork with the rebates?
A: Yes. But I will help you with it.
Q: How much do the panels weigh?
A: 280+/- watt panels weigh about 45 pounds.
Q: What are the dimensions of a panel?
A: A 280 watt panel is +/- 36 – 40” wide and about 60-65” tall.
Or SunPower = 32” x 62” – Most efficient
Q: How long does it take to get the State Rebate?
A: About 4 to 6 weeks after the Power Company sets the net meter.
Q: Is there any maintenance to the panels?
A: Not much. There are no moving parts so other than some occasional cleaning – maybe some snow
Removal on low slope roofs - there is no maintenance.
Q. Which way does the Array have to face for the best solar gain?
A.This is called Azimuth and its 195 Mag degrees South = True South in New Hampshire. This degree changes depending on where you are in the world.
Q. What is Azimuth?
A. It is the orientation your house faces. On a compass reading, it is 195 degrees magnetic south due to the magnetic pull of the earth - that reading is 15 degrees off to the West, as True South which is 180 degrees. You must be careful when talking to someone if they are talking True South 180 degrees or Magnetic South 195 degrees, where they are same orientation.
Q. What is an acceptable amount of sun/shade?
A. 80% sun (20% shade) is generally the lowest level you want. A PV system will work at lower levels but obviously with a lower output. You want good Sun from 9:00 AM to 3 PM all year.
Q. What does the State mean when they ask for an 80% efficient job?
A. This is based on what the best possible output production would be in NH. If your array faces 180 degrees true south and tilt of 42.5 degrees (actually 38 degrees is the best) and 100% sun all day (No shade on the array). Then you will have an efficiency of 100% where that is the most you can possible produce with a stationary array. As you move away from true south and/or the tilt, or have more shade, then the efficiency goes down. The shade is the largest factor. It is a one to one ratio by itself – so if you have 80% annual sun (20% shade) then you have an 80% efficient site if you r Azimuth and tilt is perfect. But if tilt and azimuth are a few degrees off (in this case) then it will be less than 80% efficient and might disqualify you for a rebate.
Q. What are REC credits?
A. Renewable Energy Credits. Like carbon credits, the Power Company (only NHEC now) will buy the KWH you produce at a wholesale rate (.05KWH), if you take the NHEC Rebate that is in exchange for REC revenue. The REC rate changes every year, so most people take the rebate. The value for the REC is .05KWH presently and they charge you $3.00 per month for the meter, or you can sell the REC’s toAn independent broker.
Q. Do I get a new Meter?
A. Yes. Your present meter will be replaced (at no charge) with a Net Meter which will have the ability to go forwards or backwards depending if you are making more power than you are using. You will notget paid for excess power that you produce it will be banked as KWH’s until you need it. For example, you typically will make more power during the day than you are using so at night you are
basically buying back the power from the power company that they just gave you credit for that day.
You generally do not want to bank more power in the course of a year than you would normally use because they don’t pay you for the excess power. Presently, you can bank power for years and years and then you can use up this banked energy if your electrical needs increase (electrical vehicle, heat pump). If the account changes names, any banked KWH’s cannot be taken with you or transferred to the new owner.
Q. Do I get a meter to record what the PV produces?
A. Sometimes. If you sell REC credit to the Power Company, (see #13) we install a meter socket and the
Power Company installs a meter (presently it is just NHEC). If you sell REC to the COOP, then they
Charge you $11.00/month for the meter. If you take the rebate for the REC, then they don’t charge for
the meter (and you don’t get revenue for the REC).If you sell the REC’s to an independent broker
there is no meter charge.
A. RESIDENTIAL: Federal - There is a 30% Federal Tax credit that you can get when you do your taxes.
It is a simple Form # 5695 residential energy credit . The Tax Credit is based on the entire cost of PV
Project. Check with your Tax person on all deductions and rebates.
State – Rebate is $.50/Watt up to 9999 Watts of PV installed and a maximum $2500. This is the maximum size array to qualify for the Rebate. If you need more you would have to install less than 10KW now and then install more at a later date (after the rebate). The State rebate runs out of money from time to time. The fiscal year is July when it should receive more money in the fund. You can still be approved when the State runs out of money and you can be first in the queue when the State receives more money for the fund. You can do the installation prior to the State having allocated money for your project, but you run the risk if they don’t come up with enough money, you may have to wait another year to get it – or there may be no money at all.
There is a Step 1 Application for Approval of the installation that I will help you fill out. You have one
year (from approval date) to complete the installation or you will have to reapply for the rebate. When
completed, the Power Company and Local Inspector (where applicable) need to inspect the installation
and sign off on it. .
Step 2 for Completion of the Job needs to be completed and sent in before the State will send you a
check for the rebate. You can expect a check from the State about 3-4 weeks later.
Power Company – The NHEC presently has a rebate. It is $.25/watt up to $1375 max. The Coop
has a Step 1 and a Step 2 – similar to the State Application. The job needs to be done by the end of the
calendar year of the Coop approval. For new construction, the structure needs to be up before the
Power Company will approve it.
The rebates are taxable.
Q. Should I use Solar Thermal to heat my hot water or PV?
A. Solar hot water is more efficient and costs less but depending on the application and different rebates, PV may make more sense. Solar hot water will heat about 60-75% because you can’t size it large enough for the winter because it will be over sized for the summer unless you have a place to put excess heat in the summer (pool). Also you need to use the hot water within a day or 2 when you produce it or you loss it to heat loss. PV on the other hand, can produce 100% of your hot water, and all power produced is accounted for through net metering and use. The best scenario is using a hot water heat pump which is 240% +/- efficient in conjunction with an electric hot water tank. Now you only need 1/3 - ½ as much PV to offset the domestic hot water and you have 100% of the energy needed. The cost of the smaller PV system and heat pump will be comparable to the solar hot water which only does maybe 60- 75% of your hot water.
Q. What is meant by the efficiency of solar panels?
A. The efficiency is based on how a panel can convert the thermal solar energy to electricity based on a square meter of PV. SunPower is the highest efficiency at about 20%, then Sanyo at 17%, and the re of panels are about 15%. This means that with Sun Power you can fit more watts per square foot on an array, because it is 15-20% smaller for the same output.
Q. Which is more cost effective – a roof mounted array or a ground mounted array?
A. The roof mounting is generally costs less because I don’t have to build a structure to mount the panels on. However, a pole mount or ground mount will usually produce more because it can be located in a location with less shade and at the perfect Azimuth for the best production. So eventually the pole or ground mount will become more cost effective after it is paid for itself.
Q. What is the advantage of SunPower?
A. SunPower is one of the largest PV manufacturers and produces the most efficient panel on the market, so you can fit more on your roof. For every five conventional panels on an array, you can fit six SunPower panels. SunPower uses some higher quality components in their panels and different manufacturing procedures to achieve the higher efficiency. SunPower sells a complete system which includes the panel, inverter and rail which is all covered under their Warranty. SunPower is a US based company with manufacturing plants in the Phillipines, Mexico and the USA. I am a SunPower Premier Dealer. SunPower works with and trains Dealers rather than selling to Distributors that will sell to anyone.
Q. What about snow on your panels?
A. Depending on the roof pitch will determine how the snow slides off the panels. At 40-45 degrees, (10- 12 pitch) it generally slides off on its own. For 30-40 degrees (7-9 pitch), this will require a little snow maintenance. Light fluffy snow will be off the next day, where freezing rain/snow will freeze to panels and might be several days before it slides off. Roof pitches flatter than that will have snow on panels for days and maybe weeks if not helped along with a soft roof rake.