Solar PV
What is photovoltaic (PV)?
How does PV benefit me?
What is grid-tied PV and how is it different from
stand alone PV (off-grid)?
What is net metering?
What happens if I produce more electricity than
I can use on a given day?
How much maintenance is required for PV systems?
How long does a typical PV system last?
I hear PV produces DC current. So how does it work
with my AC house, and will it negatively affect my electrical appliances?
Can solar systems supply power for 24 hours a day?
Can PV produce electricity on cloudy days?
How big of a PV system would I need to run my house?
Is it true you need batteries for PV systems to
work?
Where is the best place on my property to put solar?
How much sun do you need for PV to work?
What rebates or other incentives apply to me?
What is a solar renewable energy credit (SREC)?
Can I afford to pay for solar electric?
How much does it cost to install a solar electric
system?
What does power factor mean
and why is it important?
What causes low power factor?
Why should I improve my power factor?
How do I improve my power factor?
What’s the payback for power factor optimization
technology?
Why haven't I heard of this before?
What is photovoltaic (PV)?
PV is the technical term for converting sunlight directly into DC electricity.
Typically people refer to PV as solar electricity. This is not to be confused
with solar hot water and passive solar heating systems which are separate
and distinct technologies also using the sun’s energy.
How does PV benefit me?
It allows you to generate electricity for your home or business independent
of the utility company. As energy prices continue to rise due to competition
from growing economies worldwide, it is important to realize that electricity
prices in the U.S. may become unstable and rise unexpectedly. PV
is a great way to become more independent from the utility grid and secure
a more stable electricity price for the future.
What is grid-tied PV and how is it different
from stand alone PV (off-grid).
Grid-tied PV is a solar electricity system that is connected to your utility
meter. Solar generated power from grid-tied systems is first used by your
home or business needs while any excess capacity is sent to the utility
grid (sold at retail price to the utility). During the evening or
times when your power demand exceeds your solar production, your home
will run off of utility power.
Stand alone or off-grid PV systems are not connected to the grid and rely on batteries for storage of electrical power. These systems are significantly more expensive and require much more maintenance than grid-tied systems, but they are the ultimate form of energy independence. Stand alone systems are commonly used in remote areas where utility power is not available.
What is net metering?
A practice used in conjunction with a solar electric (PV) system where
your electric meter tracks your net power usage, spinning forward when
you use electricity from the utility, and spinning backward when your
system is generating more electricity than you need.
What happens if I produce more electricity
than I can use on a given day?
In grid-tied systems, any excess electricity automatically flows back
to the electrical grid and is credited to you at the utility’s retail
price.
How much maintenance is required for PV
systems?
Very little maintenance is required for grid-tied systems. Occasional
visual checks and rinsing of the solar modules (panels) once or twice
year is all you need, in most cases. There are no moving parts to worry
about!
How long does a typical PV system last?
Most professionally-installed systems will last 30 years or more. Many
solar modules are warranted to last 25 years at 80% of their original
power production.
I hear PV produces DC current so how does it work
with my AC house, and will it negatively affect my electrical appliances?
Other than the solar modules, one of the most important pieces of equipment
is the inverter. An inverter converts the DC power from your solar system
to AC for use in your house or power grid. Today’s inverters convert
to a high quality AC which is essentially the same as the utility, and
will not negatively affect your appliances.
Can solar systems supply power for 24 hours
a day?
Yes, if you use batteries to store your power. This is done on a stand
alone PV system that is commonly installed in remote areas without utility
power. If utility power is available, battery systems are typically
not employed except for short-term back-up situations.
Can PV produce electricity on cloudy days?
Yes! On partly cloudy days PV can generate up to 80% of their potential
energy production. On overcast days PV can produce about 25% of its potential.
How big of a PV system
would I need to run my house?
It depends on you electrical consumption and how much you want to reduce
it. Also, you will need enough unshaded space with plenty of sun exposure
( at least 7 hours/day), which sometimes can be limited. A good rule of
thumb is for each kw of solar you will get 1,000 kwh of power production
per year. Also, for each kw of solar you will need 80 square feet of space.
Most homes cannot cover all their electric power needs with their roof
space. If you live in the Philadelphia region, you can calculate the KW
of solar modules needed to provide 100% of your electric bill by dividing
your annual KWh usage (found on your electric bill) by 1,150. For instance,
if you use 10,000 KWh per year, you would need to install 10,000/1,150
or 8.7 KW of modules. Of course you can cover a lower percentage of you
electric bill in order to help reduce the initial cost, and add on later
if desired.
Is it true you need batteries for PV systems
to work?
No, batteries are not required for grid-tied PV systems.
Where is the best place on my property
to put solar?
Your roof is the best place since it’s high and typically has more
unobstructed sun exposure. However, ground mounts and pole mounted units
work very well if roof space is not available, but the expense may
be a little more due to longer wire runs and more equipment needs.
How much sun do you need for PV to work?
You need at least 7-8 hours of unshaded sun per day. Shade from tall trees
or neighboring buildings or objects is the number one cause of poorly
performing solar systems. Professional installers can easily calculate
the amount of shade you have for a given area and determine which trees
to trim in order to reduce you shading.
What rebates or other incentives apply
to me?
A federal tax credit of 30% (no cap) applies to all consumers and businesses.
Many states also have rebate plans in place that payback 25%-35% of the
installed price of your system. Please see our section on
Fed & State Incentives for more details.
What is a solar renewable energy credit
(SREC)?
Most states require or will soon require electricity suppliers to provide
a percentage of their electricity sales from solar generation as well
as other renewable forms of energy through Renewable Portfolio Standards.
This means they have to construct their own renewable energy plants to
provide sustainable electricity, or they will purchase this power from
other suppliers like residences and businesses who have renewable systems
such as solar (more likely). If you are a solar photovoltaic owner you
are producing one REC for each 1000 kwh your system is producing per year.
These SRECs (solar renewable energy credits) are sold on the open market,
thus prices will vary depending on market conditions. To learn more about
SRECs and the market visit our solar finance partner Sol
Systems .
Can I afford to pay for solar electric?
Certainly! With today’s incentives and financing offerings, paying
for a solar system is fairly painless. In fact, many times your new payment
for your PV system including your new electric bill is the same or even
lower than your old electric bill (without your solar system). See our
Financing Options section for more
details.
How much does it cost to install a solar
electric system?
PV systems range in price from $2.50 - $5 per installed watt (DC). Typically,
a simple residential roof system can be installed for around $4.50/watt.
Please call for up-to-date pricing as the market price for solar
modules is constantly changing. See a detailed breakdown of a simple
payback calculation for a 5 kw system in our
Financing Options section.
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What does power factor
mean and why is it important?
Power factor is the ratio of working power to apparent power (KW/KVA).
The KVA fraction consists of power used towards work plus power wasted
in the process of powering equipment. The KW fraction is the power used
towards work only. A power factor of 1.0 is the best you can get, but
many households and businesses have a power factor less than 0.9. We can
easily test to see if your power factor is satisfactory. If not satisfactory,
we can help improve it.
What causes low power factor?
Inductive loads are the culprit. Devices such as transformers, induction
motors (air conditioners and refrigerators), induction generators and
high intensity discharge (HID) lighting cause reactive power which raises
your apparent power KVA, thus lowering your power factor.
Why should I improve my power factor?
There are three main reasons why you should improve your power factor.
1) It will reduce your electric bill by reducing peak KW demand and eliminating
the power factor penalty (for business). 2) It will increase system capacity
and reduce system losses in your electrical system. 3) It will increase
your system voltage level and will allow your motors to run cooler and
more efficiently, thus prolonging your equipment life.
How do I improve my power factor?
Improving your power factor can be done by 1) installing capacitors, 2)
minimizing operation of idling or lightly loaded motors, 3) avoiding operation
of equipment above its rated voltage and 4) by replacing standard motors
as they burn out with energy efficient motors.
What’s the payback for power factor
optimization technology?
In many cases it’s less than one year. We have had cases as low
as four months, but ultimately it depends on your particular situation.
We can help estimate your savings by testing your power factor.
Why haven't I heard of
this before?
This technology has been around for decades, and used in industry for
lowering power consumption. Until recently, capacitors were not considered
cost effective in the residential market because of cheap electrical rates.
Times are changing and electricity is becoming more valuable. In the Philadelphia
area, electric runs about $0.14 per KWh making capacitors a very affordable
way to reduce your utility costs. Therefore it makes sense to install
this product now since the payback period is usually around a year.
If you’re interested in getting a free site visit and quote please click on our Get a Quote section.
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