Frequently Asked Questions
You have questions, we have answers!
You have questions, we have answers! See some of the more common questions that Berkshire Photovoltaic Services receives with answers below! If you have a question that is not answered here, please visit our Contact page to send us a question!
Where can PV Modules be installed?
PV can be installed anywhere that receives unobstructed sunlight. Roof installations generally work very well because the modules are close to the point of use. Modules can also be installed on ground, pole, or wall mounts.
Is my roof appropriate for a PV installation?
The ideal roof is a south-facing, slanted roof with no shading on the area where the modules will be located. PV can be installed on roofs with other characteristics, but the efficiency may be lower. Please call BPVS to discuss your buildings details and a site assessment.
What is the optimal tilt angle for modules in MA and NY?
The optimal angle of inclination for absorbing solar radiation is latitude of the location plus 15 degrees for winter optimization, or latitude minus 15 degrees for summer optimization. The use of the rule resulted in many of the dramatically tilted solar thermal panels you see on homes in New England (Most of MA is near 42 degrees north latitude, putting winter optimal inclination at 57 degrees). In terms of solar performance, it is important to note that the difference exhibited while varying module inclination between 5 and 30 degrees (28 degrees being about the year-round-optimum for MA) is not more than 8%, and between 12 and 30 degrees it isn’t more than 4%. Between 17 and 45 degrees (covering the range for most residential roofs), you will make use of 98 to 100% of all available sunlight. BPVS will take all factors into account when we design your system, and will work with you to arrive at the system design that is truly optimal.
How big are the solar modules?
1 kW of Panasonic , very efficient , solar modules will occupy an area of approximately 64 square feet. This module is ~ 63 inches tall by 42 inches wide. Solar World modules have a slightly larger footprint.
Do we have enough sun in New England and NY for PV?
Yes, A system rated at 2 kW will produce about 2,400 kWh annually in New England & NY. This is enough to provide one quarter of the average New England home’s electricity. For homes with efficient appliances and lighting, and conservative energy users, a 2 kW system may provide much more of the energy than the household needs. Because New England uses more energy in summer time when photovoltaic production is at its peak, the clean electricity produced by grid-connected systems is especially valuable.
How much energy will my PV modules produce?
A 1 kW PV array installed optimally in Massachusetts or New York should produce on the order of 1,200 kWh per year from 20 year meteorological averages. Our Berkshire customers have averaged 1167 kWh per year per kW in the past four years.
What are the environmental benefits of a PV system?
PV clean energy displaces the carbon dioxide, nitrogen oxide, sulfur dioxide, mercury and heavy metal particulates that result from burning fossil fuels to generate electricity. A PV system in our region produces best in summer when grid electricity demands are highest and when the dirtiest power plants are in peak operation. In Massachusetts every solar kilowatt hour defers on average about 0.73 lbs. of Co2 , 0.74 grams of Sulfur Dioxide, 0.35 grams of Nitrogen Oxides, and 0.03 mg of Mercury.
What are the costs, and why is PV so expensive?
Small, rooftop Residential PV installations cost roughly $5.00 per peak Watt of capacity. Larger residential systems generally cost between $4.00 and $4.80 per peak watt. A lot can depend on the quality of the roof and permitting costs. Pole and Ground mount systems are more expensive and may be as high as $6.50 per Peak watt . Call us for current costs for quality modules and system components. Commercial and institutional systems are typically lower due to economies of scale. We favor manufacturers with ultrapure silicon production in house or from a reputable supplier, financial depth and proven warranty assurances. The energy needed to manufacture the PV modules installed by BPVS will be reclaimed within the first fourteen months of their operation for those concerned with embedded costs. When we examine the external costs to the environment and to future generations for conventional power, PV is a bargain.
Do I need to be connected to the power grid to use PV?
No. If you are not connected to the grid, you can use what is called a stand-alone PV system. This includes a battery bank to store energy for use at night and cloudy days. BPVS is a recognized leader in stand-alone design and installation. PV is versatile, so stand- alone systems may power a full size remote home or a single water pump in a remote pasture.
Does a grid-tied system require batteries to store electricity?
No, a grid-tied system is connected directly to the electric grid. This means that the grid in effect acts as a battery. If at times your system generates more energy than the home is using, the excess energy is sent back into the utility network and your utility bill is credited. This is called net metering.