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faq about renewable energy
frequently Asked
Questions
What should I look
for in a Renewable Energy Installer?
When is it appropriate to use Renewable
Energy (RE)?
Is there enough sun in Ohio and the
Midwest to make electricity?
What kind of site do I need for a
PV system?
How many solar panels will I need
to power my home?
How much does a system cost?
How many solar and wind systems are in
Ohio?
Why is energy efficiency so important?
What kinds of permits are needed for
solar or wind systems?
What kind of maintenance is involved
in a PV system?
When does a wind system make sense?
Is my site right for wind?
How much wind is needed to make a
wind generator worth it?
What about cloudy days and nighttime?
How long does a system last?
Are there any incentive programs or
grants for systems?
What is GLREA certification?
What is Bergey Factory Training?
Can I produce 240 volt power?
What should
I look for in a Renewable Energy Installer?
When chosing a designer and/or installer for your renewable
energy system, look for an installer and company with professional
training and certifications. Third Sun's Owner, Geoff Greenfield,
is a NABCEP Certified Solar PV Installer™, as well
as having training and certification from the Great Lakes
Renewable Energy Association (GLREA). We also employ another
installer who is trained and certified by GLREA. See About
Us for more information on company and installer qualifications.
(The following information is based on
a Home Power article written by Richard Perez, volume #81.
Please see www.homepower.com
to read the full text of the article).
If your renewable energy system is to
be a success, preparation, planning and proper installation
is required. The first step in any off grid system (and
a helpful step in a grid tied system) is the load analysis.
This is basically an inventory of all your electrical uses
in the home, used to determine what size system you will
need. The installer will complete this with the customers
help. If your budget and the load analysis estimates differ,
alterations must be made in one or both. Your installer
should be able to help with this.
The next step is a site visit or survey.
For siting a PV array, a Solar Pathfinder is needed, to
determine seasonal variations, daily changes and possible
shading issues. Your installer should use this to determine
where the best place for your panels will be. Wind is more
difficult to survey, but accurate guesses can be made
by
observation by the customer, talking to other residents
of the area, examining vegetation for “flagging”
and looking into local wind data (from a nearby airport,
for example). The installer will know the space and location
requirements for various sized towers and encourage the
highest possible tower.
After the visit, your installer will produce
a system design, based on your energy requirements and the
site’s potential. This design includes a list of equipment.
There are thousands of different combinations of equipment
to chose from, and your installer should know the best choices
for your specific situation. Good system designers should
know through experience what works and what doesn’t.
They know what pieces work well with other pieces and which
ones don’t. They know details like wire sizes, inverter/appliance
compatibility, and how the battery should be configured.
Paying someone to design your system means you are buying
their expertise, which is invaluable in creating a system
that will work for you. This expertise also knows that the
system requires overcurrent protection, disconnects and
proper conductors. They also know the NEC (National Electric
Code) and design and install systems according to the NEC.
At this point, the installer puts a price
tag on the design and presents an estimate. This can become
a reiterative process, as the design, load requirements
and budget all must come together.
Purchase of the system comes next. Most
installers will require payment up front for the equipment,
or at least a deposit. Before paying for the system, make
sure that the installer has given you a copy of the load
analysis, a site survey report, a system design print out
and schematic, and a copy of the estimate. The installer
will then order the equipment then return to your site to
do the install. This entire ordering and shipping process
could take two to eight weeks, so patience is needed.
During installation, your installer should
allow you to shadow him or her and explain things that you
are curious about. They should show you how to maintain
the system and explain its operation. Some installers will
let you work with them, especially if you are trying to
save some money. The installer should have all the necessary
tools to do the installation.
If an electrical inspection is necessary,
your installer should be ready for the local electrical
inspector and know what they are looking for. There will
most likely be no problems if your system is done to local
specifications.
After the installation, your dealer/installer
should give you all the proper paperwork and manuals for
the components, as well as any other operational guides
you may need. They should offer support on the components
and be able to answer questions which may arise. They should
also be able to troubleshoot on the phone or with a site
visit.
Third Sun Solar and Wind Power, Ltd.,
has built its business around these guidelines. We follow
each step listed above and work very closely with our customers
to ensure that the system will perform as expected and that
we, and you, have a successful installation experience.
[back to top]
When
is it appropriate to use Renewable Energy (RE)?
There are many reasons and circumstances when solar and
wind power makes sense:
- Cost – If the cost is high for
extending the utility power line or using another electricity-generating
system in a remote location, a RE system is often the
most cost-effective source of electricity. The rule of
thumb is that if your site is more than _ mile from the
nearest utility line, then it may be more cost effective
to have an independent system than to extend the grid.
- Reliability—PV modules have no
moving parts and require little maintenance compared to
other electricity-generating systems. A PV system can
also provide an uninterrupted power supply.
- Modularity—PV systems can be
expanded to meet increased power requirements by adding
more modules to an existing system. PV modules can be
added to a wind system to increase power requirements.
- Environmental —PV and wind systems
are non-polluting ways of generating electricity. PV systems
create no noise, and the newer wind turbines create very
minimal sound.
- Ability to combine systems—PV
systems can be combined with other types of electric generators
(wind, hydro, and diesel, for example) to charge batteries
and provide power on demand.
- Ability to tie a renewable energy system into
an already existing grid-tied home or building
– In most states, the newer net-metering laws allow
utility customers to produce some of their own power to
offset their use of utility power. [back
to top]
Is there
enough sun in Ohio and the Midwest to make electricity?
Yes there is. Of course, the usable sun hours in our region
are not as high as in New Mexico or Colorado. We generally
figure that Ohio’s usable sun hours are 4 to 4.5 hours
a day, averaged over the year. In the summer, that number
is up around 6 hours and in the winter, down to 2.5. This
does not mean that there is no production during the rest
of the day, but premium production, or “full sun hours”,
is narrowed to that time period.
There are over 150 sites around Ohio that
are using the sun and wind to produce power. Many of these
sites are off grid and run independent of the utility company.
At Third Sun, we know first hand that a family can live
comfortably with solar power, from the example of our the
owners’ home and from our customers’ experiences.
[back to top]
What
kind of site do I need for a PV system?
First, you must have a southern exposure (in the northern
hemisphere). For maximum daily power output, PV modules
should be exposed to the sun for as much of the day as possible,
especially during the peak sun hours of 10 a.m. to 3 p.m.
Second, the southern exposure must be
free of obstructions such as trees, mountains, and buildings
that might shade the modules. Consider both summer and winter
paths of the sun, as well as the growth of trees and future
construction that may cause shading problems. Third Sun
can assess the exposure on a site visit.
Finally, the unobstructed southern exposure
must also have appropriate terrain and sufficient space
to install the PV system. For a ground mounted system, a
flat, grassy site is appropriate terrain, whereas a steep,
rocky hillside is not. For roof mounting, southern orientation
is best, preferable within 15 degrees of solar south. [back
to top]
How
many solar panels will I need to power my home?
The size system that your home or building will require
varies with the amount of electricity you consume, and whether
or not you are connected to the electric utility “grid”.
For grid connected, we look at the available space or square
footage for mounting the panels, we look at your goal for
power production (e.g. do you want to produce 25% of your
power?), we look at your historical electric usage and finally
we look at your budget for the project. Most of the time,
our first step will to be to look at the energy efficiency
of your home appliances, and reduce your amount of usage
inside the home before we look at system size. See the energy
efficiency question below for more information.
The first step in sizing an off-grid system
is to do a full load analysis, which is basically an inventory
of all of your electric usages in the home or building.
This give us an idea of your usage patterns and how large
a solar array and battery system you will need. Again, we
look at energy efficiency in the building and reduce your
loads as much as possible before designing a system. (See
the energy efficiency question below.) After this, we design
a system based on usage and budget. [back
to top]
How much does
a system cost?
PV system costs range between $5 and $15 a watt for the
equipment. Add onto this $1 to $4 a watt for installation
costs and other small parts. This range varies based on
whether or not the system has batteries, the details of
installing the system, the level of complexity of the system
and economies of scale. For more specific pricing of example
systems, including wind systems, see the Pricing (link)
section of our website. [back to top]
How many
solar and wind systems are in Ohio?
At last count in 2003 for the statewide Ohio Solar Tour,
there were about 135. This number grows every month, and
there are probably many more unaccounted for systems. For
more information on systems in your area, contact Third
Sun or Green Energy
Ohio. [back to top]
Why
is energy efficiency so important?
A general rule of thumb is that for every $1 spent on energy
efficiency in the home, you will save $3 on the total cost
of a renewable energy system. This is because it is cheaper
and more cost effective to improve home efficiency than
it is to buy enough solar panels to power old or inefficient
electrical loads. It is possible, but economically impractical
to run things like electric cook stoves and traditional
air conditionering on an off grid solar electric system.
Using gas appliances and new Energy Star appliances will
help cut down on the cost of your renewable energy system.
[back to top]
For more information on steps you can
take to be more efficient and a listing of efficient appliances,
see these sites:
www.eere.energy.gov/consumerinfo/
www.eere.energy.gov/consumerinfo/factsheets/ve8.html
www.aceee.org/buildings/resappl_type/index.htm
What kinds
of permits are needed for solar or wind systems?
This varies depending on your locality, whether you are
rural or in a city, and what type of system you are proposing.
There may be electrical permits, building permits, zoning
variances for tower installations, FAA requirements for
towers near an airport, or property or neighborhood covenants.
For grid tied systems, there will be an interconnection
agreement between the customer and the utility company.
Third Sun can help you navigate this paperwork and we often
take car of permit applications and engineering when required.
[back to top]
What
kind of maintenance is involved in a PV system?
No PV system is maintenance-free. You will need to check
your system regularly to ensure that the wiring and contacts
are free from corrosion, the modules are clear of debris,
and the mounting equipment has tight fasteners. You will
need to monitor the power output of your PV modules, the
state-of-charge and electrolyte level of your batteries,
and the actual amount of power that your loads use. Keeping
track of this in a special notebook is a good idea. Monitoring
and metering will also help you understand the relationships
between your system's power production, storage capability,
and your own electric usage. [back to top]
When does
a wind system make sense?
Obviously, you need a windy site!
For a stand alone wind system (independent
of the grid)
- You live in an area with average annual wind speeds
of at least 9 miles per hour (4.0 meters per second).
- A grid connection is not available or can only be made
through an expensive extension. The cost of running a
power line to a remote site to connect with the utility
grid can be prohibitive.
- You have an interest in gaining energy independence
from the utility.
- You would like to reduce the environmental impact of
electricity production.
- You acknowledge the intermittent nature of wind power
and have a strategy for using intermittent resources to
meet your power needs, or will add solar PV modules to
form a hybrid system.
For grid connected wind systems
- You live in an area with average annual wind speeds
of at least 10 miles per hour (4.5 meters per second).
- Local building codes or covenants allow you to legally
erect a wind tower and turbine on your property.
- You are comfortable with long-term investments. [back
to top]
Is my
site right for wind?
The U.S. Department of Energy (DOE) has compiled wind resource
maps that are available from the American Wind Energy Association
(www.awea.org). The maps
are good sources for regional information and can show whether
wind speeds in your area are generally strong enough to
justify investing in a wind system. By January of 2004,
the state of Ohio Office of Energy Efficiency Renewable
Energy office will have a new state of Ohio wind map, developed
in partnership with the Department of Energy. This map will
show classes of wind in a more detailed way and with more
accuracy than previous maps. See http://www.odod.state.oh.us/cdd/oee/default.htm
Wind-turbine manufacturers can use computer
models to predict their machines' performance at a specific
location. They can also help you size a system based on
your electricity needs and the specifics of local wind patterns.
It is better to have site-specific data to determine the
wind resource of your exact location. If you do not have
on-site data and want to obtain a clearer, more predictable
picture of your wind resource, you may wish to measure wind
speeds at your site for a year. You can do this with a recording
anemometer, which generally costs $500 to $1500. Because
the most accurate readings are taken at "hub height"
(i.e., the elevation at the top of the tower where you will
install the wind turbine), this means placing the anemometer
high enough to avoid turbulence created by trees, buildings,
and other obstructions. The standard wind sensor height
used to obtain data for the Department of Energy maps is
33 feet (10 meters). Most wind projects only use recorded
anemometers if they are planning utility scale installations
costing millions of dollars.
You can have varied wind resources within
the same property. If you live in complex terrain, take
care in selecting the installation site. If you site your
wind turbine on the top or on the windy side of a hill,
for example, you will have more access to prevailing winds
than in a gully or on the leeward (sheltered) side of a
hill on the same property. Consider existing obstacles and
plan for future obstructions, including trees and buildings,
which could block the wind.
Realize that the power available in the
wind increases proportionally to its speed (velocity) cubed
(v3). This means that the amount of power you get from your
generator goes up exponentially as the wind speed increases.
For example, if your site has an annual average wind speed
of about 12.6 miles per hour (5.6 meters per second), it
has twice the energy available as a site with a 10 mile
per hour (4.5 meter per second) average.
In determining the height of your wind
tower, the rule of thumb is the higher the better. You want
your tower to be at least 30 feet higher than any obstructions
within 300 feet. Putting a wind generator on a short tower
with obstructions is like putting your solar panels up in
the shade. [back to top]
How
much wind is needed to make a wind generator worth it?
Most residential sized wind generators need at least 5 to
8 mph winds to begin turning. Then, they need faster winds
to begin producing at the “rated” output (i.e
1000 watts for a 1000 watt generator). This relationship
of power to windspeed is shown by the power output curve
seen in the wind generator literature. [back
to top]
What
about cloudy days and nighttime?
For off grid homes and buildings, the system requires a
battery bank to provide power at night and on days of no
sun or wind. This battery is sized to provide a certain
amount of power for a certain number of days, usually specified
by the customer. For example, we may set up a system that
can take the home through 3 to 5 days of no sun or wind.
We also may specify the purchase of a back up gas or diesel
powered generator to ensure that you can re-charge your
battery bank if you are using more power than you are producing.
The engine-generator can be run at full power until the
batteries are charged. Adding a fossil-fuel-powered generator
makes the system more complex, but modern electronic controllers
can operate these complex systems automatically. Adding
an engine-generator can also reduce the number of PV modules
and batteries in the system. Keep in mind that the storage
capability must be large enough to supply electrical needs
during noncharging periods.
For grid-connected systems, no battery
is needed for night time or cloudy or windless days. The
power grid acts as the backup power source for these times.
This makes the system a bit simpler to design and install,
more efficient with lower maintenance, and less expensive.
If you live in an area of frequent and long blackouts, we
can also add a battery backup system into the grid tied
system to carry you through these times. [back
to top]
How long
does a system last?
PV panels are generally warranted for 25 years. Wind generator
warranties vary between 1 and 5 years depending on the manufacturer.
Balance of system components, like inverters, are usually
1 to 5 years. Batteries can last between 5 and 15 years,
depending on how well they are cared for and maintained.
This said, a system can last and produce for 30 years or
more, with some change out of batteries and possible maintenance
of equipment over the system life.
To determine the expected life of your
system and its components, speak to an experienced and qualified
renewable energy specialist, like Third Sun. We have experience
with all kinds of components and will be able to give accurate
data on the life of the system. [back to
top]
Are there
any incentive programs or grants for systems?
Yes. To find out what is available in your state, see http://www.dsireusa.org
and click on your state. [back to top]
What is GLREA
certification?
The Great Lakes Renewable Energy Association provides training,
an apprenticeship program and certification of experienced
and professional Photovoltaic Installers. Certification
requires a certain amount of class work and a minimum number
of hands on installations. Participants in this must then
complete and pass an exam to become certified. At Third
Sun Solar and Wind Power, we are proud to have two GLREA
certified installers on staff, Geoff Greenfield and Tim
Dunning. [back to top]
What
is Bergey Factory Training?
Bergey Factory training is a three-day intensive, on-site
(at Bergey’s factory in Oklahoma) training in the
siting, installation and maintenance of Bergey Windpower
wind generators. Owner and Installer Geoff Greenfield is
the only Ohio installer who has completed this factory training.
[back to top]
Can I produce
240 volt power?
While gas appliances should generally replace electric hot
water heaters and ovens, sometimes 240-volt power is needed
for deep wells or special loads. An autotransformer can
make this voltage or sometimes the pump can be changed to
a 110-volt unit. [back to top]
Glossary
AC
Alternating Current – electrons moving back and forth
along the wire in a wave. This is how electricity is provided
from the utility grid and used in our homes and buildings.
Ampere or amp
The standard unit used to measure electrical current, the
rate of electron flow. This is the quantity of electrical
current flowing over a specific time. It is like miles per
hour: 15 amps or 50 amps is analogous to 15 mph or 50 mph.
When we plug in an appliance and measure it on a meter,
we can find out how many amps it “pulls”. For
example, turning on a light may pull 1.5 amps, and starting
microwave may pull 45 amps.
Amp-hours
The unit of measurement of the electrical capacity of a
cell or battery. The amount of charge that is passed through
a circuit, or the measurement to rate deep cycle batteries.
A 240-amp hour battery will charge at a rate of 240 amps
in an hour; or at 1 amp for 240 hours.
Balance-of-System (BOS) equipment
This includes battery charge controllers, batteries, inverters
(for loads requiring alternating current), wires, conduit,
a grounding circuit, fuses, safety disconnects, outlets,
metal structures for supporting the modules, and any additional
components that are part of the PV system.
Battery
The battery stores electricity for use at night or for meeting
loads during the day when the modules are not generating
sufficient power to meet electric load requirements. To
provide electricity over long periods, PV systems require
deep-cycle batteries. These batteries, usually lead-acid,
are designed to gradually discharge and recharge 80% of
their capacity hundreds of times. Automotive batteries are
shallow-cycle batteries and should not be used in PV systems
because they are designed to discharge only about 20% of
their capacity. If drawn much below 20% capacity more than
a few dozen times, the battery will be damaged and will
no longer be able to take a charge.
DC
Direct Current – electrons flowing in one direction.
PV panels and most wind generators produce DC electric,
so a system must include an inverter to turn the electricity
into AC for use in the home or to match grid provided electricity.
Grid
Refers to the electrical “grid”, the power lines,
power plant infrastructure that powers much of our country.
“Off grid” refers to a property or building
beyond the power lines, with an independent electrical system
for power. “On grid” refers to a property or
building connected to the electrical grid. “Grid intertie”
refers to a grid connected building with renewable or independent
power elements (solar or wind) that feed back into the electrical
grid.
Hybrid Systems
A hybrid system combines multiple energy sources, such as
wind and photovoltaic (PV), and offers several advantages
over either single system. In much of the United States,
wind speeds are low in the summer when the sun shines brightest
and longest. The wind is strong in the winter when there
is less sunlight available. Because the peak operating times
for wind and PV occur at different times of the day and
year, hybrid systems are more likely to produce power when
you need it.
For the times when neither the wind generator
nor the PV modules are producing electricity (for example,
at night when the wind is not blowing), most stand-alone
systems provide power through batteries and/or an engine-generator
powered by fossil fuels.
Inverters
Inverters are devices that change the direct current (DC)
electricity produced by photovoltaic (PV) and many wind
and hydroelectric systems, or their battery energy storage
components, into alternating current (AC) electricity, which
powers most home appliances. Inverter technology has been
advancing significantly in the decade, and manufacturers
are continually improving their products. Most inverters
also include a built-in battery charger.
Kilowatt-hour
1000 watt hours. This is the general measure of our electric
usage on the utility bill. You can determine your electric
usage by noting the monthly KWH used figure, and determine
your annual or seasonal usage. This helps us renewable energy
professionals size and design a system to meet your needs.
Load Analysis
An inventory of all electrical uses or “loads”
of a house or building. The type of appliance is listed,
the time of use per day or week, and the amount of electricity
used. These loads are all added to gether to give us an
amount of electricity used and needed. This is an essential
first step in properly designing an off grid system and
identifying load hogs that can be reduced by efficiency
measures. For more information on this important step, see
http://www.homepower.com/files/loadcalc.pdf
NABCEP Certification
The North American Board of Certified Energy Practitioners
(NABCEP) is a volunteer board of renewable energy stakeholder
representatives. NABCEP is working to develop national,
voluntary standards and certifications for renewable energy
professionals, beginning with certification for solar electric
installers. The NABCEP board includes representatives of
the solar industry, renewable energy organizations, state
policy makers, educational institutions, and the trades.
Each member of the board was chosen because of his or her
experience and involvement in the solar energy industry.
October 25, 2003 saw the first certification exam. Geoff
Greenfield of Third Sun sat for the exam and will find out
about certification by Dec 1, 2003. For more information,
see www.nabcep.org.
NEC
National Electric Code – a set of rules governing
the safety of electrical installations, including renewable
energy systems.
Net Metering
When systems installed on homes or buildings that are already
connected to the utility grid, many utilities allow net-metering,
which is buying and selling electricity at the same rate
with the same meter. The building produces a portion of
the electricity used, effectively reducing the electric
bill. If the renewable energy system is producing more than
the building is using, then the meter can run backwards
and the customer is essentially selling power back to the
local utility. Grid intertie and net metering is becoming
increasingly popular as the cost of public power increases
and supply & distibution channels suffer in reliability.
At the present time, roughly two-thirds of all U.S. states
mandate by law the right to sell power to the utility.
Net metering systems convert DC power
generated by the solar array or other renewable source into
grid-quality AC power. The power is fed back into the grid
through the home’s existing power panel and utility
meter. As the power sent to the grid passes through the
meter, it will count slower, or even run in reverse (if
the power generated is greater than household demand at
any instant in time). Utility power is being displaced at
a retail rate in this manner.
Net metering systems can be designed both
with and without battery storage. A battery-less system
is significantly less expensive, more efficient, and easier
to design and install. First of all, a battery-less inverter
has a conversion efficiency of 90% or greater, so more usable
power is delivered to the grid from the solar array. In
addition, battery-based inverters require a power draw from
the grid in order to keep the batteries charged, effectively
increasing the household load and thus decreasing the amount
of power available to the grid from the array. Battery-based
systems also incurr additional costs due to more sophisticated
control and overcurrent protection, and for the batteries
themselves. A battery-based system will cost 30-50% more
than its battery-less counterpart.
PV
Short for photovoltaic. Single PV cells (also known as "solar
cells") are connected electrically to form PV modules,
which are the building blocks of PV systems.
PV module
A series connected group of photovoltaic cells, making DC
electric current directly from sunshine. The module is the
smallest PV unit that can be used to generate substantial
amounts of PV power. Although individual PV cells produce
only small amounts of electricity, PV modules are manufactured
with varying electrical outputs ranging from a few watts
to more than 100 watts of direct current (DC) electricity.
The modules can be connected into PV arrays for powering
a wide variety of electrical equipment.
PV Array
A grouping of PV modules connected together.
PV system
In addition to PV modules, the components needed to complete
a PV system may include a battery charge controller, batteries,
an inverter or power control unit (for alternating-current
loads), safety disconnects and fuses, a grounding circuit,
and wiring.
STC
Standard Test Conditions – The nameplate rating of
a PV module is measured in a laboratory at 25 degrees C
and 1000 watts per square meter irradiance. The real world
performance is affected by temperature (output decreases
with higher temperatures) and reductions in irradiance caused
by weather and the angle of the sun. Along with dust and
efficiency losses in wiring, these factors result in 15-25%
less power in real world conditions than at STC.
Watt
Unit of power, rate of energy use or flow. A measurement
that includes both amperage and voltage. A specific amount
of work done in a specific time. PV panels are measured
in watts, i.e. a 100 watt panel. Ten 100 watt panels would
make a 1000 watt array.
Volt
The unit of electromotive force. Electrical pressure, potential
or potential difference. [back to top]
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