FAQ: Solar photovoltaic technology
Frequently Asked Questions about Solar PV
By SOPHIA MOUNDOUS
Sustainability Assistant, UF/IFAS Extension Sarasota County
This Solar PV FAQ was written for those interested in understanding the basics of solar PV technology, investing in a solar system, and more in Florida.
What is solar PV and how does it work?
When people talk about “solar” it can be misleading because there are a few different types of solar technologies. There is solar photovoltaics (PV), solar thermal, or concentrated solar energy. This blog covers the basics of solar PV, which produces electricity generated from sunlight. Residential photovoltaic systems can be stand-alone (“off-grid”) or utility-interactive. While solar power has large-scale applications, this blog focuses on residential, utility-interactive solar PV.
Solar panels produce electricity when they are in contact with sunlight. The photons from the sun excite electrons within the semi-conductor solar cells, which produces electricity. The electric current that is produced is a direct current or DC. This type of current is not compatible with most home electronics and appliances. Each utility-interactive PV system includes at least one inverter, which turns DC power into an alternating current or AC. Once your system has AC power, your home is ready to use a power source that is clean, renewable, and abundant.
What are the components to a utility-interactive system and how do they work?
The arrows in the diagram above represent the flow of electricity. The PV array produces direct current (DC) power, the inverter converts the DC into alternating current (AC) power, then the home loads are powered by this electricity. When there is an excess of electricity produced by the solar system, it is fed out onto the electric grid. When the solar system does not produce enough electricity for all the electric loads in the home, the utility grid provides the additional power needed.
- PV Array: Produces DC electricity when in contact with sunlight.
- Inverter: Converts direct current into usable alternating current that is compatible with common household loads. Residential systems have either string inverters or micro-inverters.
- Service Panel: All electrical loads in the home are fed through the service panel. Electricity from the grid flows into the home through the service panel and excess power produced by the solar system flows out.
- Meter: Monitors and records how much energy the home uses and the solar system sends to the electric grid over a given time period. These values are used when determining an electric bill.
- Utility Grid: The electric power distribution system that supplies homes with electricity by transmitting it over large distances from a power plant.
- Loads in Home: The loads in your home include anything that uses electricity like televisions, appliances, or lights.
What happens when it’s raining or cloudy to solar power collection?
Photovoltaic systems can still produce a small amount of electricity on rainy or cloudy days although in lesser and more intermittent amounts than when in direct sunlight. Rain can, however, help clean off any dust or dirt that accumulates on solar panels. This can help increase their production because dust and dirt build-up block direct sunlight.
What happens when there is an electric grid power outage?
When the electric grid shuts down, utility interactive PV systems without battery back-up shut down. This is required to protect utility employees that may be working on the grid during an outage from electrical shock. If the system has energy storage, then the batteries can serve as a backup electricity source until the grid outage is resolved. Read more about interconnection rules and guidelines on FPL’s Net Metering Guidelines website.
What should I consider before investing in a solar system?
Before you consider getting solar PV for your home, take energy efficiency measures first. The goal is to reduce your average energy consumption. This way, you don’t waste your solar dollars on wasted energy. If you install a solar system for your home before you take energy efficiency measures, the system size is most likely larger than it needs to be. Meaning, you can save money on the size of the solar system needed for your home by just reducing the amount of electricity you use at home first. Learn ways to improve your home energy efficiency on our Energy Upgrade website or by reading our National Energy Efficiency Day and Awareness Month blog.
How do I size my photovoltaic system?
Below are two software tools that can help you calculate estimates of performance potential of a PV system for any given location. Another option is contacting local solar PV contractors to inquire about the solar potential at your location and acquiring quotes and a solar assessment. One key element in sizing a solar system is deciding how much electricity consumption to offset. A system that offsets 100% of the energy used at your home will be larger than a system that is designed to only offset 50%. You will also need to know how much electricity your home uses on average throughout the year.
How long does a photovoltaic system last and what about warranties?
Typical photovoltaic systems should have a functioning life of 25-30 years with a 20-25 year warranty for 80% production. Solar panels do not stop working after 25-30 years, however, their power production typically significantly declines by this time. Inverters typically last about 15 years and usually have a 10-15 year warranty. Labor warranties vary among installers and regional markets. They typically range from three to ten years. Additionally, before installing a solar system on your roof, ensure the roof does not need replacement within the expected life span of the solar panels.
How much will my photovoltaic system cost?
Despite the decreasing cost of installing solar, it is still a large investment with a typically high up front cost and a payback period of many years. Depending on where you live and what utility you belong to can also affect the price you pay for your solar system. The cost of energy in Florida is relatively low, solar is not incentivized heavily by the state or utility, and the price of selling electricity back to the utility is also low. These factors make solar less economically favorable in Florida. System prices vary and depend on the size and chosen equipment. There are also periodic maintenance costs from replacing certain system components like the inverter, batteries, solar panels, wiring, or roof that extend the payback period of the system.
Although the system cost is usually met over many years, the benefits of using and producing clean, renewable energy can be invaluable and for many people, outweigh all the costs.
What incentives are available for solar?
The available financial incentives in Sarasota County for residential solar PV are listed below. Available rebates, financial incentives, and loan programs for renewable energy and efficiency in any area can be found on the Database of State Incentives for Renewables and Efficiency (DSIRE). Read what solar programs FPL has to offer here.
- Residential Renewable Energy Federal Tax Credit : The credit amount is 26% of qualifying system costs. The credit amount will reduce each year after 2019. It will reduce to 22% for systems placed in service after 12/31/2020 and before 01/01/2022.
- Solar Sales Tax Exemption: Solar energy systems are exempt from Florida’s sales and use tax.
- Property Tax Exemption for Renewable Energy Property: Florida offers a 100% property tax exemption for residential renewable energy property.
- Residential Energy Conservation Subsidy Exclusion: Personal tax exemption.
- Property Assessed Clean Energy (PACE): Financing tool for property owners to finance private property improvements related to renewable energy, energy efficiency and hurricane hardening through assessments levied on their property tax bill.
What is net metering?
Net metering allows utility customers with renewable energy systems that are connected to the electric grid, like solar, to buy and sell electricity to the utility provider. When your solar system produces more electricity than is needed for the loads in your home at the time, the excess electricity is sold to the utility provider at a specific rate. The excess amount of electricity that is sold to the utility offsets your electric bill by subtracting the amount of electricity produced from the amount of electricity used or bought from the utility. If more electricity is produced than consumed, then it is credited to the next bill. The excess is sold for the utility’s cost of producing electricity at its own facilities, which is usually lower than the price of buying electricity from the utility. Therefore, it is not typically recommended to install a solar system that will consistently produce more electricity than will be consumed on-site. To learn more about net metering and FPL’s guidelines, visit FPL’s Net Metering website.
How do I go about selecting a solar contractor?
To ensure you are hiring a qualified and trustworthy solar contractor to install solar for your home or business, it’s recommend to look into how many years of experience they have and how many local installations they have completed. Look to see if they have a Solar Contractor’s License on the Florida Department of Business and Professional Regulation website and that they have their NABCEP Solar PV Installer Certification. Check their business reviews and reputation, that they have proper insurance and equipment, and always get multiple quotes before starting a project. SolarReviews provides independent reviews of solar companies and solar panel brands with an objective to promote reputable solar installers to consumers.
What about my HOA?
The Florida Solar Rights Act “forbids any entity—including homeowner associations—from prohibiting the installation of solar or other renewable energy devices on Florida buildings.” Read more about the Florida Solar Rights Act on the Florida Solar Energy Industries Association website.
What are the trends in solar jobs?
According to the 2019 National Solar Jobs Census, as of 2019, there are 249,983 Americans with solar jobs. According to the 2018 Florida Solar Jobs Census, Florida ranks second for the number of solar jobs in the state with 10,358 jobs. Solar installation jobs are the most prominent in Florida. In 2018, solar jobs in Florida grew by 20.6% with 1,769 new solar jobs. There is a projected job growth of 4.1% in 2019. The Tampa-St. Petersburg-Clearwater metropolitan area is the second highest area for solar jobs behind the Miami-Ft. Lauderdale-Pompano Beach area with 1,646 solar jobs in 2018. Learn more about solar jobs in Florida by visiting the 2018 Florida Solar Jobs Census.
Of the 10,358 solar jobs in 2018, 155 of them were in Sarasota County. Pinellas County had the second largest amount of solar jobs behind Palm Beach, with 1,331 jobs. Use the 2018 Florida Solar Jobs Census Interactive Map to discover statistics on solar jobs in every county and state in the US from 2018.
Fun fact: There’s enough solar installed in Florida to power 275,814 homes!
*This information will be updated with the 2019 Florida Solar Jobs Census upon its release in 2020.
Resources, Learn More
Want to learn more about solar power and other solar technologies? Checkout the additional resources listed below.
Don’t see your question about solar PV? You can let us know in the comments below or by contacting us at Sarasota@ifas.ufl.edu.