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Frequently Asked Questions
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Solar Energy Benefits and Features
What are the financial benefits of a solar
energy system?
What are the other benefits of a solar energy system?
How much can I expect to pay for a solar energy system?
How much will a solar energy system save me on my utility
bill?
How long will it take for a solar energy system to pay for
itself?
How long will a solar energy system last?
What is net metering?
How do I know if my site receives enough sun to operate a
solar system?
Does solar energy work on cloudy days or during the winter?
If I’m interested in a solar energy
system installation, where do I begin?
What should I do if I am not located
in California or in Sun Light and Power’s operational
area?
Solar Electricity (photovoltaics)
What are photovoltaics
and what do they do?
What is a PV cell? Module? Panel? Array?
What is an inverter?
What is meant by grid-intertied?
Can I use solar electricity to heat my home or business?
What is the energy payback time for PV?
Solar Thermal (Hot Water)
What is solar thermal or
solar hot water?
What are the advantages of solar thermal?
What is a solar thermal collector?
Radiant Heating
What is radiant heating?
What are the advantages of radiant heating?
See also our Links & Resources page.
See also our Glossary of Terms.
What are the financial benefits of a solar energy system?
Several
features make solar energy a sound financial investment:
- You will reduce or eliminate your energy bill for years
to come, providing protection against inevitable future
rate
hikes.
- Cash rebates and government tax credits can pay for
a significant portion of the installation cost.
- A solar
energy system will increase the equity and resale value
of your home without increasing your taxes.
- Your system
will pay for itself within the first half of its life.
- Any
excess electricity you produce is fed into the utility
grid, providing you with credits you may utilize for power
use during times when your system experiences decreased
production or your household has greater need.
- Solar energy systems have almost
no operating or maintenance costs.
- Your energy dollar tends to remain in the community, creating
jobs and fueling local economies.
If financing is utilized, consult your tax specialist about
the possibility of loan interest deductions.
[ Back to top ]
What are the other benefits of a solar energy system?
Besides the incentives outlined above, there are many other
benefits that make solar a desirable alternative:
- Time Proven - Solar energy technology has proven over
time to be safe, quiet, clean, and reliable.
- Long Lasting
- A solar thermal (hot water) system should
function for about 20 years, while photovoltaic (solar
electric) systems are expected to endure at least 30 years.
- Flexible - In most
cases, you can increase or decrease the size of your system
to meet future needs.
- Green… Use of solar energy reduces
the need to burn fossil fuels in order to generate electricity,
resulting
in less air pollution and helping to offset global warming.
- Secure… Solar,
which reduces our dependence on foreign or centralized
sources of energy, is an important strategy
in the process of creating a truly secure and sustainable
energy future.
[ Back to top ]
How much can I expect to pay for a renewable energy system?
The cost of a system varies greatly depending on the type
of system, its size, the complexity or difficulty of the
installation, and the types of components used. Sun Light
and Power will work with you to design a system based on
your past electrical usage, your projected energy requirements,
and the nature of the installation site. Points to bear
in mind:
- The installation cost of a system can vary from
a few thousand dollars to tens of thousands depending
on the specific
energy
needs, site circumstances, and design features of the installation.
- Both
the state of California and the federal government offer
generous incentives for installing solar energy systems.
- The
cost of installation is often offset by the energy savings.
A consultation with an energy design and installation expert
will provide a clear, concise evaluation and estimate.
Please see: “What are the financial benefits of a solar energy
system?” and “What are the other benefits of
a solar energy system?” above.[ Back to top ]
How much will a solar energy system save me on my utility
bill?
In most cases you can significantly lower or completely eliminate
your energy bills. Your actual savings will be specific to
your individual circumstances and will vary according to
your current power usage and the size and type of your new
system. Please bear in mind that:
- The cost of paying for an
installation is sometimes less than what you currently
are paying for energy,
- Renewable energy systems offer many benefits
unrelated to cost (clean, quiet operation, low environmental
impact, energy
independence, etc.) and many people choose them even if
they are more expensive.
- Please see: “What are the financial benefits of
a solar energy system?” and “What are the other
benefits of a solar energy system?” above.
[ Back to top ]
How long will it take for a solar energy system
to pay for itself?
A solar energy system will usually
pay for itself with energy savings (and with any available
installation rebates or tax
credits) within the first half of its estimated lifespan.
The actual length of time will depend on the type and size
of the system. Generally speaking, a commercial system will
pay for itself in less time than a residential system, and
solar thermal (hot water) will pay for itself in less time
than a photovoltaic (solar electricity) system. [ Back to top ]
How long will a solar energy system last?
Photovoltaic
(solar electric) systems are expected to endure at least
30 years with only minimal maintenance. (Currently,
most photovoltaic modules carry a 20-year warranty and
most inverter units have at least a 5-year warranty.) A
solar thermal (hot water) system should function for about
20 years with periodic maintenance. [ Back to top ]
What is net metering?
In California (and
33 other states) consumers can install grid-connected renewable
energy systems under a program
called “net metering”. With net metering, a
system (using a meter that reads inflows and outflows of
electricity) can sell any excess power that it generates
to the utility to offset any consumption. It requires the
utility to give full retail credit for electricity “sold
back” in this manner. Net metering provides a simple,
standardized method for connecting renewable energy systems
into the electricity grid that ensures safety and power
quality and encourages the use of renewable energy systems.
(Visit www.dsireusa.org for a current list of states with
net metering laws.) [ Back to top ]
How do I know if my site receives enough sun to
operate a solar energy system?
Most homes and
businesses receive enough sunlight to meet some or all
of their needs with solar energy systems. You
can get more specific information by contacting Sun Light
and Power to discuss sunlight availability as well as other
particulars of your property, your power requirements, the
types of systems that would suit your needs, etc. [ Back to top ]
Does
solar energy work on cloudy days or during the winter?
In general, solar energy systems produce
energy even under cloudy skies or during periods of inclement
weather, although
energy production is understandably less than under full
sunlight. During periods of low sunlight, solar electric
systems can draw power from the utility grid or batteries
to meet your needs. Solar water heating systems usually
include a back-up water heater. [ Back to top ]
If I’m interested in a solar energy system
installation, where do I begin?
Contact an experienced local solar energy system designer
and installer. Look for a company offering the following:
- A long and successful history with the type of system
you require.
- A customer service policy of explaining and
handling all
the required permitting, inspections, and rebate paperwork.
- A reference list of satisfied local customers for the
type of system you are purchasing.
- An ability to perform
all its own work without relying on third-party subcontractors
to complete the installation.
- A willingness to provide solar energy information and refer
you to the resources you need to familiarize yourself with
solar energy.
Sun Light and Power, with 30 years of success in the business
of solar, offers all of these desired qualifications to
anyone considering solar in the San Francisco bay area. [ Back to top ]
What should I do if I am not located in California
or in Sun Light and Power’s operational area?
You
may be able to find solar companies listed in your local
phone book. There are also web sources that can help you
find a qualified professional, such as:
www.eere.energy.gov/solar (U.S. Energy Efficiency & Renewable
Energy Network
http://www.ases.org/about_ases/chapters.htm (American Solar
Energy Society)
www.consumerenergycenter.org (California Energy Commision)
For a current list of states that have financial incentives
to offset the cost of installing renewable energy equipment,
visit
www.dsireusa.org (Database of State Incentives for renewable
Energy). [ Back to top ]
What are photovoltaics and what do they do?
Photovoltaic
(or PV) technology, also referred to as solar electricity,
produces electricity by collecting electrons
freed by the interaction between sunlight and the semiconductor
materials in a PV cell. “Photo” means light and “voltaic” means
electricity. Photovoltaics are used today to power a variety
of applications from hand-held calculators, to large commercial
complexes, to earth-orbiting satellites. [ Back to top ]
What is a PV cell? Module? Panel? Array?
These
terms are all related to the photovoltaic components that
generate electricity.
- A PV or photovoltaic cell, the basic unit of a
photovoltaic system, converts solar energy into electrical
energy. (Please
see “What are photovoltaics and what do they do?)
- A
module is a group of interconnected PV cells designed to
deliver a selected level of working voltage and current
at its output terminals. Modules are produced in standard sizes
and power outputs, packaged for protection against environmental
degradation, and equipped for incorporation into photovoltaic
power systems.
- A panel is a physically connected “string” of
modules used collectively to achieve a required voltage
and current. However, the term panel is often used informally
to refer to a module.
- An array is any number of photovoltaic
modules connected together to provide a single electrical
output, assembled
to power a home, business, or larger commercial or municipal
load.
[ Back to top ]
What is an inverter?
An inverter is a device
used to change the DC (direct current) electricity produced
by PV (photovoltaic) cells into the
AC (alternating current) electricity that is required to
power lights, appliances, machinery etc. in homes and businesses. [ Back to top ]
What is meant by grid-intertied or grid-connected?
A grid-intertied PV system is a solar electric system that
is connected to the utility grid. The grid is the infrastructure
that supplies power to homes and businesses. A grid-intertied
system is capable of: (1) receiving electricity from the
utility grid when its own output is inadequate to its needs,
and (2) selling excess power to the utility, provided that
the usual utility approval has been obtained and the necessary
specialized equipment has been installed. [ Back to top ]
Can I use solar electricity to heat my water or to provide
space heating for my home or business?
It is impractical to use solar-generated electricity to heat
water. A solar water heating system is a far more cost-effective
choice. Similarly, space heating is best accomplished with
solar thermal strategies or equipment designed for the task:
passive solar designs and radiant heating, for example. [ Back to top ]
What is the energy payback time for PV?
Typically, the energy payback time (the time it takes the
system to generate the same amount of energy that it took
to manufacture the system) for PV systems is 2 to 5 years.
Given that a well-designed and maintained PV system will
operate for approximately 30 years, PV systems produce
far more energy over their lives than is used in their
manufacture. [ Back to top ]
What is solar thermal or solar hot water?
Solar thermal or solar hot water (sometimes referred to
as “solar
domestic hot water” or SDHW) is a water heating system
that heats water within units called “solar thermal
collectors”, either directly with sunlight or by heating
a “working fluid”, such as glycol, that then
heats the water. These flow to a hot water heater, which
is to be used as a storage tank and for back-up heating at
night or during the cold months of the year. A solar thermal
system can be used to heat water for use in the home; in
swimming pools, spas and hot tubs (a particularly cost-effective
application); or to heat water for commercial and industrial
applications. [ Back to top ]
What are the advantages of solar thermal?
Solar thermal is both energy efficient and cost effective:
- A
Solar Thermal system can provide as much as 70-80% of your
hot water needs for the year, greatly reducing the portion
of your utility bill that relates to water heating --
usually natural gas. A full-size system will typically
provide
all the hot water needed between March and October.
- Beginning in 2006, a federal
tax credit equivalent to 30% of the cost of installation
will be available for each
system placed in service (with a $2000 cap for residential systems).
- Solar
thermal is a simple yet time-proven technology. Although
the basic technology has been around for a number of
years, recent improvements make today’s solar hot water
systems even more efficient, reliable, and durable than
those of
the past.
[ Back to top ]
What is a solar thermal collector?
A solar thermal collector, often referred to simply as “a
collector”, is a device designed to receive solar radiation
and convert it into thermal (heat) energy used to heat water.
Generally, a collector is composed of a sturdy frame, an
absorber (heat absorbing panel with channels for the water
or a heating fluid), glazing (protective sheet of glass or
plastic) on the sun-facing side, and insulation on the back
and sides. A typical domestic solar hot water system uses
two 4' x 8' flat plate “collectors” which are
installed on the rooftop of a home or business (but can be
located on the ground if necessary). [ Back to top ]
What is radiant heating?
A modern radiant heating system is an energy-efficient heating
system in which hot water is passed through tubing that is
laid either within a floor, installed beneath it, or run
within baseboard casings. In the former two methods, the
thermal mass of the floor itself stores and radiates the
heat. [ Back to top ]
What are the advantages of radiant heating?
Radiant heating
minimizes temperature swings, eliminates cold pockets of
space, and can be used to "zone" a
system, sending heat to areas that need it most. Hot water
boilers for radiant systems are available with efficiency
ratings as high as 95% to provide efficient and reliable
heating. By not blowing heated air all over the building
(as with traditional central heating), a radiant system
reduces dust, drafts, allergens, and dust mites, while
maintaining a healthier level of humidity. [ Back to top ]
See also our Links & Resources page.
See also our Glossary.
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