Solar Power FAQs
Solar Energy Basics
The key benefits are:
- Environmental benefits
- Energy for our children and grandchildren
- Jobs and the economy
- Energy security
The increased use of fossil fuels has significantly increased greenhouse gas emissions creating an enhanced greenhouse effect known as global warming. Renewable energy technologies, however, can produce heat and electricity with a very low or no amount of carbon dioxide emissions.
Energy use from fossil fuels is also a primary source of air, water, and soil pollution. Pollutants take a dramatic toll on our environment.
U.S domestic oil production has been declining since 1970. In 1973, the United States only imported about 34% of its oil. In 2011, our country imported more than 45% of its oil.
The total daily Irradiation (Wh/sq-m) is calculated by the integration of the irradiance values (W/sq-m).
Click here for the Solar Radiance map of the USA
Shading: If your solar collectors experience any shading during the day the output of your solar system can be dramatically reduced. This is especially true of photovoltaic (PV) solar panels since a partially shaded PV panel can result in a loss of power across the PV array. Some solar incentive programs, such as the California Solar Initiative (CSI) reduce the incentive available to you if your solar system is impacted by any shading.
We reference NASA Surface meteorology data from the Atmospheric Data Center. This data is based upon satellite-derived data over a 22-year period. The data is compiled for each degree of latitude and longitude (each degree represents about 69 ground miles).
Reference Height: The wind speeds are for a reference height of 50 m (164 ft) for USA locations and 10m (13 ft) for Canadian locations.
Note: Because wind varies, sometimes dramatically, from location to location the wind rating provided is only an estimate. Elevation, trees, mountains, valleys, thermal variations and other geographic and weather pattern factors will affect the actual wind you will realize at your location.
CSP's relatively low cost and ability to deliver power during periods of peak demand when and where we need it means that CSP can be a major contributor to the nation's future needs for distributed sources of energy.
For more information see Energy.gov
A therm is 100,000 BTU. The average heat value of natural gas is 1000 BTU per cubic foot. A BTU (British Thermal Unit) is enough heat to heat one pound of water one degree (F). Natural gas is sold to the customer in units of 100 cubic feet (therm) or in a unit called MCF. A therm represents approx. 100,000 BTU of heating power, enough to heat a normal home for about 2 hours during colder weather.
Please contact your utility if you have questions about your rate. Or, contact a renewable energy Professional who can help you develop a strategy to minimize your utility bills.
National average emissions factor for electricity is 1.64 pounds CO2 per kilowatt-hour. Source: The Cadmus Group, 1998. Regional Electricity Emission Factors Final Report.
Typical annual CO2 emissions of 20,000 pounds per household based on 1,000 kWh/month, which is the average used in most utility rate cases. Source: U.S. Environmental Protection Agency
Automobiles: Studies indicate that the average car produces about one pound of CO2 per mile driven. Source: Progressive Policy Institute
The Equifax Risk Level Indicator Score ranges from 1 to 5, with lower scores indicating lower business risk. Variables used by Equifax to develop the RLI include:
- Industry (SCI code)
- Geographic region (state)
- Years in business
- Annual sales volume
- Total number of employees
To remain Pre-Screened, a listed Pro must maintain a credit risk score indicating Low or Medium Risk. If no credit risk score is available for the listed Pro, they can remain Pre-Screened if they indicate to us they have no bankruptcies nor liens against them (as indicated on their company profile stored on our site). In this case the Credit Risk score defaults to Average/Medium.
Solar Hot Water or Pool/Spa Heating
Therefore, as a general guide, each person in your home would use 20-30 gallons of hot water per day. If your home is water efficient then you would be toward the lower end of this scale.
Your renewable energy Professional will make a more accurate assessment based on the number of people as well as the number of bedrooms and bathrooms.
Other helpful information is available at: Energy.gov and Florida Solar Energy Center
An actual site assessment by a renewable energy Professional is recommended to better determine your specific needs.
For example, if your water heater is fueled by natural gas and your solar water heater produces 100 Therms of energy per year, the natural gas saved would be 100 Therms/0.70, or about 143 Therms of natural gas. This is our estimate for the amount of natural gas you would save on your utility bill in a year.
Please note: The actual efficiency of water heaters run on natural gas, fuel oil, propane, electricity or other fuels varies. We recommend you work with a renewable energy Professional who can better analyze your specific situation.
For Spa sizes less than 5 sq-meters, we assume one panel will be used. For pool sizes less than 24 sq-meters we assume 3 panels will be used. And, for pool sizes from 25-80 sq-meters we assume 8 panels will be used.
However, often a ballpark estimate can be quite inaccurate and so we also have approximately 100 installation companies all around America that have agreed to share their real time pricing with users of this site.
These installation companies require your phone number and email address as occasionally they have to call you and ask you questions (i.e often suggested system sizes do not fit on your roof, sometimes there are shading issues and sometimes rebate programs are put on hold because their annual budgets have been exhausted). These installers will email you accurate pricing for a system that will fit on your roof once they establish you are a real person and not a competitor simply trying to get their pricing.
Your data will not be used for any other purpose and will never be sold to other third parties. See "Privacy" section under Terms and Conditions
Please see the Notes, below the Estimate, for the many assumptions we have made for this simplified cost estimate.
|Item||Cost for less than 2kW||Cost for more than 2kW|
|PV Panels||$5.00 per watt||$5.00 per watt|
|Inverter||$1.20 per watt||$1.20 per watt|
|Installation Cost||$3.80 per watt||$1.80 per watt|
|Total||$10.00 per watt||$8.00 per watt|
The actual rates, taxes and surcharges you pay are probably different. We suggest you review a recent utility bill and change the "Assumed Electric (or Gas) Rate" as needed to better match your situation.
Please reference your utility bill or contact your utility for more details on your actual rates.
See Energy.gov for more information on programs that may be available in your location.
For residential (non-business) applications we assume utility savings are in Gross Income dollars ("pre-tax" or what you earned).
For business (commercial) applications we assume utility savings result a lower expense write-off against income tax liabilities.
To calculate IRR, we take the Net Purchase Cost (after rebates and incentives) of your solar system, and the estimated annual utility savings or other cash in-flows, for each year, then find the rate of return on your money that makes the cash flow zero over the system`s life.
Utility Savings Assumptions: For residential (individual) situations we assume utility savings are in Gross Income dollars ("pre-tax" or what you earned).
Operating Cost Assumptions: For solar electric (PV) systems we assume the power inverter is replaced at year 15 in the systems life. No other operating or maintenance costs are assumed.
Buying Solar Systems
Also use a service such as ContractorCheck.com to verify the company's status.
Check with your State or County to make sure your Professional is properly licensed or certified for the work (which can vary from local to local). If you plan to use any incentive programs to help pay for the cost of your system, check to make sure the Professional you choose qualifies for that incentive program.
Contact your Homeowners' Association, if your community has a homeowners association (HOA), you will want to contact them to ensure you file the proper architecture request forms and obtain approvals. They cannot prevent you from installing a PV system.
If no ContractorCheck report is available for the listed Professional, they can remain Pre-Screened if they indicate to us they have no bankruptcies nor liens against them and have listed licensing details (as indicated on their company profile stored on our site).
For more information, please go to ContractorCheck.com
- Their business has been in operation at least 3 years, or they have equivalent professional experience.
- Good professional and customer references: The firm has provided a minimum of three (3) customer references, and those references resulted in a minimum of an AVERAGE ("OK") overall rating (2 is considered average on a rating scale from 1 to 4). To remain Pre-Screened the listed Pro is asked to update its references at least every 12 months.
- The business has passed criteria established by ContractorCheck.com. This service verifies such things as licensing, bonding, and financial health. If not listed with ContractorCheck.com, the listed Pro has certified to us that they have not had liens or disputes with creditors in the past 5 years, nor filed for bankruptcy in the past 7 years, and has listed their licensing details.
- The listed Pro has certified their Profile information is true and correct as of the date of application.
Note: Any person or business may be listed on our site. For the Pre-Screened insignia we rely upon a "self-certification" process (the Pre-Screened listed Professional has, by signing an agreement with us, warranted to us that the information is correct). We screen listed Professional profiles to see if they match our screening criteria to gain the Pre-Screened insignia. Wherever possible, we provide links and references so you, as a consumer, may verify the information yourself, and we encourage you to do so. We reserve the right, but not the obligation, to verify/screen selected information provide by a listed Professional through third-parties services such as ContractorCheck.com local and state licensing agencies, and customer references.
Who is eligible? The program is designed to assist farmers, ranchers and rural small businesses that are able to demonstrate financial need. All agricultural producers, including farmers and ranchers, who gain 50% or more of their gross income from the agricultural operations are eligible. Small businesses that are located in a rural area can also apply. Rural electric cooperatives may also be eligible to apply.
What types of projects are eligible? Most rural projects that reduce energy use and result in savings for the agricultural producer or small business are eligible as energy efficiency projects. These include projects such as retrofitting lighting or insulation, or purchasing or replacing equipment with more efficiency units. Eligible renewable energy projects include projects that produce energy from wind, solar, biomass, geothermal, hydro power and hydrogen-based sources. The projects can produce any form of energy including, heat, electricity, or fuel.