What is Solar 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 thermal which is a separate and distinct technology also using the sun’s energy.
What is Solar Thermal?
Solar Thermal is the process of turning sun energy into heat energy. This is most commonly used as a hot water based system to supplement your home or business hot water heating needs.
How much maintenance is required for Solar systems?
Very little maintenance is required for Solar PV. Occasional visual checks and monitoring the output of the system are typically all that is required in Pennsylvania. In dustier dryer climates rinsing of the panels once or twice a year is required. Solar Thermal also requires little maintenance; visual checks every couple of years and checking the fluid in the closed loop heat exchanger tri-annually.
How long does a typical PV system last?
Most professionally-installed systems will last 30 to 40 years. Most solar modules are warranted to last 25 years at 80% of their original power production.
How long does a typical Thermal system last?
Most professionally-installed systems will last 30 years or more. Most solar thermal collectors are warranted to last 10 years at nearly 100% of their original production.
Why is solar power good for the environment?
Sun-generated power is clean — no pollution, noise or fossil fuels. A typical 6 kilowatt system or 80 Gallon Solar Thermal Hot Water system will eliminate 120 tons of carbon dioxide over its 30+ year lifetime.
Where is the best place on my property to put solar?
Your roof is the best place since it is 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 is a little more due to longer wire runs and more construction cost of the mounting assembly.
Do I need a new roof?
If you are concerned about roof replacement in the next 5 to 10 years we recommend having a new roof installed prior to installation. Two things to consider; the roof under the panels can last twice as long because the sun which degrades your roof is hitting the panels not the roof surface, and you only need to reroof the southern roof where the panels are to be placed.
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 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. In Pennsylvania it is required by law that the utility companies allow customer owned solar generation to utilize net-metering.
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.
Is it true you need batteries for PV systems to work?
No, batteries are not necessary for grid-tied PV systems.
How big of a PV system would I need to run my house?
It depends on your electrical consumption and how much you want to reduce it. Also, you will need enough unshaded space with plenty of southern sun exposure, which sometimes can be limited by trees and adjacent buildings. A good rule of thumb is for each kw of solar installed you will get 1,150 kwh of power production per year. Also, for each kw of solar installed you will need approximately 100 square feet of space. Most homes and businesses cannot cover all their electric power needs with their roof space. If you live in the South Central PA 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.
Do we have enough sun in this area for Solar to work?
Yes! Shade from tall trees or neighboring buildings or objects is the number one cause of poorly performing solar systems in our area not daylight hours. 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. The world leader in solar installations is Germany and they get 3.5 average sun production hours a day. Arizona, the most sunny state in the US, gets 6.5 average sun production hours a day. South Central PA gets 4.5 average sun production hours a day.
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.
Does Solar Thermal work on cloudy days?
Yes! Solar Thermal will still work at close to 100% on partly cloudy days and 60-70% on overcast days.
How long does the installation take?
Installing a Solar PV system can take anywhere from 2 to 5 days, depending on its size. Installing a Solar Thermal system typically takes 2-3 days.
Will I be without electricity or hot water during installation?
Not typically, and if it is required it will only be for a couple hours while integrating the system into to onsite electric or hot water systems.
Will I still have electricity if the power goes out?
With grid-tied PV systems if a storm or accident breaks an overhead electrical wire then your solar system will not send power into the electrical system and endanger people. Photovoltaic solar systems will only keep producing power during a power failure if you have batteries attached to the system.
How much does it cost to install a solar electric system?
PV systems typically range in price from $5.00 – $8.00 per watt installed, depending on several factors including difficulty of installation. >Click here to contact an MSEIA member for information on solar for your home or business!
What rebates or other incentives apply to me?
A federal tax credit of 30% with no limit cap applies to all consumers and businesses. Pennsylvania has a rebate plan called the PA Sunshine Program that gives a per installed watt cash rebate – as more solar is installed Typically these two incentive programs will offset approximately 50% of the installed cost. NJ also has state incentives, but recent changes in government and budget deficits have eliminated the program.
How will I know if I qualify for the incentives and rebates?
Your contractor should take care of all the site analysis and paperwork for the state grant programs and we will get approval from the state before starting any work. Most installers will also provide all the information and forms for your accountant to proceed with the federal tax credit.
How long will it take for the system to pay for itself?
A properly designed and installed solar thermal system can pay for itself in as little as 5 years. A properly designed and installed solar PV system can typically pay for itself in as little as 5 years or as long as 12 years depending on the value of electricity and the value of Solar Renewable Energy Credits (SRECS).
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 that utilities have to construct their own renewable energy plants to provide sustainable electricity, or they will purchase these credits from other suppliers like residences and businesses who have renewable systems such as solar. If a utility does not buy enough SRECs to meet their annual, legislated quota they will pay a penalty, called an ACP (Alternative Compliance Payment). If you are a solar photovoltaic owner you will produce one SREC per each 1,000 kwh your system produces. These SRECs (solar renewable energy credits) are sold on the open market, and vary in price.
How to find
a solar installer?
How does solar work?
1. SOLAR PHOTOVOLTAIC (PV) PANELS – An array of Solar Modules convert the sunlight into Direct Current (DC) electricity. This power is sent to the inverter.
2. INVERTER - The inverter has several important jobs:
- It converts the DC power form the solar panels into Alternating Current (AC) power, which is the standard form of power for homes and businesses.
- It matches the AC frequency to what is coming from the utility grid. Inverters must meet exacting standards in order to be approved for use.
- It ‘watches’ the utility grid so that it can shut down, immediately, if the utility grid shuts down. This way, if a storm or accident breaks an overhead electrical wire then your solar system will not send power into the electrical system and endanger people. Photovoltaic solar systems will only keep producing power during a power failure if you have batteries attached to the system.
- The Inverter sends the electricity to the main circuit breaker panel in the building. From there the electricity can power the building or, if there is more electricity being generated than is being used, it is fed back through the meter, back feeding the utility grid
3. UTILITY METER – The ability to spin the meter backwards when generating excess power and forwards when requiring additional power is called Net-Metering. In Pennsylvania, utilities must offer Net-Metering to residential customers that generate electricity with systems up to 50 kilowatts (kW) in capacity and nonresidential customers with systems up to three megawatts (MW) in capacity.
4. THE UTILITY GRID – At the end of the month, if the customer uses more electricity than is generated, the customer pays the utility on the netkilowatt-hours used at the regular retail rate. If the customer generates more electricity than is used, the utility pays the customer for the net kilowatt-hours produced at the wholesale power rate.