PV -
Frequently asked Questions
Renewable Energy may seem a little fuzzy to some people that are
not familiar with it. To help those who are learning about solar
power for the first time, we have compiled answered to some of
the most asked questions that we hear at Adros Energy. We hope
that the following information will be helpful to you.
Question 1: How do
solar cells generate electricity?
Answer 1: Photovoltaics, or PV for short, can be thought of as
DC current generated by the sun. When light photons strike the
solar cell, they knock electrons free in the silicon crystal
structure forcing them through an external circuit to a load for
usage. The voltage output from a single crystalline solar cell
is about 0.5V with an amperage output that is directly
proportional to the cell’s surface area (approximately 7A for a
6 inch square multi-crystalline solar cell). Typically 30 to 36
cells are wired in series in each solar module. This produces a
solar module with a 12V nominal output that can be wired in
series and parallel with other solar modules for form a solar
array.
Question 2: Can I
generate electric in my area?
Answer 2: The quick answer is yes. Solar power can be generated
in almost every part of the world. Some locations are better
than others due to amount of sun a particular area receives.
Solar power can also be generated in space. Irradiance is a
measure of the sun’s power available at the earths surface after
it has been defused and deflected from the atmosphere and is
assumed to peak at 1000 watts per meter squared. A typical 3KW
solar system in the North East will produce on average about 10
or 11KWH per day.
Question 3: How much
will a solar system cost?
Answer 3: This is not so easy to answer
since the cost of the system actually depends on your daily
energy usage and how many full sun hours you receive per day,
and how much of your usage you want to generate from you new
Adros Energy solar system. We need to conduct an analysis of the
usage and the available space for a system. You can figure
complete installed system price range from $13,000 to $15,000
for a typical roof top system, before rebates, tax incentives,
and grants. These are different in every town and in each state
and can be found by visiting
the WWW.DSIREUSA.ORG website.
Question 4: What
components will I need for my system?
Answer 4: Well, that will depend on if the system is a grid-tie,
a stand alone system, has a battery back-up, or is a hybrid
system. A basic grid-tie system will have an array, a DC
disconnect, an inverter to AC, an AC disconnect and a meter. If
you add batteries to the system you will need a charge
controller. A hybrid system is a system that generates electric
from more that one source like solar and wind, however most of
the components are the same. Most of the equipment goes near the
electrical panel you have now in the home.
Question 5: Can I use
my normal appliances in my home that run off of AC 120/240V?
Answer 5: Yes, however many older homes were not built or
designed with energy efficiency in mind. When you purchase and
install a solar system for your home, you become the power
company, so every KWH of energy you use means more equipment is
required to meet your energy needs. Any appliance that operates
at 240V AC such as electric water heaters, cook stoves,
furnaces, and air conditioners are expensive loads to run on
solar. You should consider alternatives such as LPG, or natural
gas for water/space heating or cooking, or use geothermal for
heating and cooling needs. Refrigeration freezers, and lighting
are typically the largest 120V AC energy consumers in a home and
these areas should be look at very carefully in terms of getting
the most energy efficient units available. Compact fluorescent
lights use a quarter of the power of an incandescent light for
the same output and last ten times longer. The rule of thumb in
the renewable energy industry is that for every dollar you spend
replacing your inefficient appliances; you will save three
dollars in the cost of a renewable energy system to run them. So
you can see that energy conservation is crucial.
Question 6: Should I
wire my home for AC or DC loads?
Answer 6: It depends on the size of the system and what type of
loads you want to run. DC appliances are usually more efficient
than AC since you will not have any loss through the inverter,
but DC loads are typically more expensive and harder to find
than their AC counterparts. Small or remote cabins and RV
systems are typically wired for DC loads and most homes are
wired for AC loads. With improvements in inverters over the past
5 years, AC is the way to go for a home PV system. Another
advantage AC has is that the voltage drop for a 120V AC circuit
is much less than a 12V DC circuit carrying the same power,
which allows smaller wire to be used.
Question 7: What types
of solar module mounts are there for my PV array are there?
Answer 7: There are five basic types of mounting structures:
roof, ground, top of pole, side of pole and trackers, with each
having their own pros and cons. For example, a roof mount system
typically keeps the wire run distances to a minimum, which is
good, but they require an extensive ground fault protection
device to satisfy the National Electric Code. Ground mounted
systems require a fairly precise foundation set-up, are more
susceptible to theft or vandalism and snow accumulation at the
bottom. Next, top of pole mounts are relatively easy to install
by sinking a 6 inch diameter pole in the ground with concrete
and mount the panels on top with a racking system. They are a
better choice over ground mounts in cold climates because they
are less prone to theft and snow slides off them easily. Side of
the pole mounts are easy to install, but are typically used for
small numbers of solar modules for remote lighting systems. Last
are the trackers which come in either single or dual tracking.
They will increase the number of sun hours available and are
usually used for solar water pumping applications. In the
northern US, typical home energy usage peaks in the winter when
a tracker mount makes very little difference as compared to the
other types and is expensive.
Question 8: Can I use
my PV system to heat water or space heating?
Answer 8: No. Photovoltaics converts the sun’s energy into DC
electricity at a relatively low efficiency of 14% to 20%, so
trying to operate a high power electric heating element from PV
would be very expensive and inefficient. Solar thermal is the
best method of heating water from the sun’s energy. See the
section on Solar thermal to learn more.
Question 9: Where
should I mount my PV system and what direction should it face?
Answer 9: If you in the northern hemisphere you need to aim your
solar modules to true south, which is about 195 degrees in the
Northeast. Most mounts are fixed, and usually on a roof with an
angle of between 22 and 45 degrees with 38 degrees being the
most efficient in our area. If you plan to adjust your array
tilt angle seasonally, a good rule of thumb is: latitude in the
spring/fall, latitude minus 15 degrees in the summer, and
latitude plus 15 degrees in the winter. Adros Energy can help to
determine how and where your system should be mounted.
Question 10: Just what
does Adros Energy do in the PV arena?
Answer 10: Adros Energy is a leader in the renewable energy
field. A highly trained team will assess you home for electrical
usage, shading, and placement of your PV array. After a design
is done, our professional installation crews will install the
array and all associated equipment. We will interface with the
utility for an interconnection agreement, the town inspectors
and others. After the system is installed and operating, Adros
Energy can do a required maintenance. We will also help you in
applying for rebates, incentives, grants and town programs. We
are truly a one stop shop for the renewable energy customer.
Wind -
Frequently asked Questions
Question 1: Who should
buy a wind turbine system?
Answer 1: A residential wind system can be large, needs to be
above all buildings and trees, and must abide by the zoning
laws. The economics of a wind system are very sensitive to the
average wind speed and the cost of electric. A sustainable wind
speed of 12 miles per hour is usually required. Residential wind
turbines have been installed in all 50 states, but are primarily
installed in the West, Northeast and Midwest.
Question 2: How would
I have a wind turbine installed?
Answer 2: Adros Energy offers complete turnkey installations or
we can provide kits for owner installation. Most customers will
choose the first option as Adros Energy have qualified
installers and can interface with the building inspector and the
utility.
Question 3: What size
of a wind turbine do I need?
Answer 3: This will depend on the current usage and future usage
of electricity, and the goal of how much independence you want
from the utility company. In general, the average home uses
10,000 kWh of electricity a year, so a 5kw to 10kw turbine
should provide most of the homes power, depending on the average
wind speed.
Question 4: How much
does a wind system cost?
Answer 4. This will depend on many factors such as wind speed,
tower height, size of wind turbine and electrical usage. Small
wind systems cost approximately $30,000 to $60,000 and will
provide most if not all of the power you need. The cost is less
than for photovoltaic, but the payback can be almost the same,
somewhere between 6 and 20 years. It’s important to take
advantage of rebates and incentives.
Question 5: Will a
wind system save me money?
Answer 5: If the systems is designed correctly and installed and
maintained, your wind system will save not only money, but will
help save the environment and our dependence on foreign oil.
Most wind systems will pay for themselves in 6 to 15 years and
have a 30 year plus lifespan. If your electric bill for the year
is $2,500 a year, then the system will save you between $35,000
to $60,000 over the life of the system.
Question 6: What are
the incentives available for wind systems where I live?
Answer 6: For the most up to date information on incentives,
policies, and regulations at the state and federal levels, see
the Database of State Incentives for Renewable and Efficiency at
http://dsireusa.org
Question 7: Is a wind
turbine system a good investment?
Answer 7: Absolutely, as stated the wind system recoups its
investment through utility savings within 6 to 15 years and
after that the electric it produces is free. Over the long term,
a wind system is a good investment because it increases property
value and you are not subjected to increases from the utility.
Question 8: What is
“Vertical Axis” wind turbines?
Answer 8: The vast majority of wind turbines are three-bladed,
“propeller shaped” devices that spin around an axis that is
parallel or horizontal to the ground. These are called
horizontal axis wind turbines. An alternative system features a
rotor that revolves around an axis that is perpendicular or
vertical to the ground.
Question 9: Will I
have to perform maintenance?
Answer 9: Most wind turbines have only 2 or 3 moving parts and
are designed to last up to 30 years. However with any machine,
parts must be maintained and occasionally repaired
Question 10: Will my
local government allow a wind turbine?
Answer 10: A wind turbine is a tall structure that normally
requires a building permit. Zoning regulations often limit the
height, placement, and other items so a special use permit or
variance may be necessary. It is usually best to inform
neighbors about what you want to do and be prepared to answer
questions of how your system will work to clear up any
misconceptions about small wind turbines.
