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Solar PV FAQs

Find answers to your questions about solar energy in Utah.

Technical Questions

1. What is a kilowatt(kW)?

A. A kilowatt is a measure of electrical power that is equivalent to 1,000 watts. A watt is a unit of power that measures the rate of energy transfer; it is defined as one joule per second. Your electrical bill charges you for electricity in terms of kilowatt-hours (kWh). One kilowatt-hour is a unit of energy that is equivalent to one kilowatt of power expended for one hour of time. For example, an appliance, such as a hair dryer, that is rated at 1,000 watts (1 kW) and operates for one hour will use one kilowatt-hour of energy. If you have a 1 kilowatt solar system and 5 peak sun hours per day (an approximate average for Utah), then your 1 kilowatt solar system will produce 5 kilowatt-hours of electricity per day (after the derate factor is applied for certain system losses, an average 1 kW solar PV system in northern Utah will generate, on average, 1,400 kilowatt-hours a year).

2: How do solar panels work?

Cell-Module-ArrayA. Solar photovoltaic (PV) panels are composed of solar cells that convert sunlight into direct current (DC) electricity. The DC electrical charge is then converted into alternating current (AC) electricity by a power inverter so that it can be used for your household electricity needs. Many cells are assembled to create a module (also called a panel), and many modules can be linked together to form a solar array.

3: What are solar PV panels made of?

DOE DiagramA. The majority of solar PV cells are made from crystalline silicon. Silicon is the second most common element in Earth's crust (after oxygen) and, by mass, is the eighth most common element in the universe. In addition to crystalline silicon cells, solar panels can be made of cadmium telluride, copper indium gallium selenide, gallium arsenide multijunction, thin film silicon, and other materials. The most common type of installation uses a flat-plate module which contains silicon cells encased in an encapsulant material for protection and sandwiched between a transparent glass or plastic cover and a metal, glass, or plastic backing to provide structural support. The entire module is usually encased in a metal frame.

4: How long do solar panels last?

A. Solar panels have an expected lifespan of at least 25 years (there are panels installed in the 1970s that are still generating power), in fact they are warrantied to still be producing 80% of their original amount of power in 25 years. They are generally made with tempered glass that is rated to withstand a direct vertical impact of a one-inch diameter hail stone traveling 50 miles per hour.

5: What is the carbon footprint of solar?

A. Producing solar panels does require energy consumption, which produces pollution and carbon dioxide emissions. It takes from 1 – 4 years for modern solar panels to produce enough pollution-free solar electricity to equal the energy cost of producing the panel.

6: Tell me more about the carbon footprint of solar. How has the carbon footprint of solar changed over time?

A. Most solar cells and modules are made of crystalline silicon, which use wafers of purified silicon. Purifying and crystallizing silicon are the most energy-intensive parts of the manufacturing process, but other parts of the process that consume energy include cutting the silicon into wafers, processing the wafers into cells, assembling the cells into modules, encapsulating them in glass and frames, and the overhead energy used by manufacturing facilities. The PV industry generally uses "off-grade" silicon from the microelectronics industry that is then recrystallized. While producing energy with photovoltaic (PV) cells does not emit pollution or use energy resources, producing the panels themselves does consume energy, which, depending on the energy source, produces pollution and CO2 emissions.

According to a 2004 National Renewable Energy Laboratory study that analyzes several different panel technologies, it takes 1 – 4 years for the energy savings accumulated by producing electricity from solar to equal the energy cost of producing the panel. Solar panels generally have life expectancies of 30 years, so 87% - 97% of the energy produced by the panels is clean energy (i.e. no pollution and/or greenhouse gas emissions). This 2004 NREL study assumes 1,700 kilowatt-hours per square meter of solar insolation, and in northern Utah we receive more sunlight than that (from 1,800 – 2,000 kWh/m2), so solar panels will "pay back" the energy used in the cost of their production more quickly that estimated in this study.

Solar technology has improved even in the years since this study was conducted, and production efficiencies have driven the "energy payback period" down even further. A 2010 study estimated that the energy payback for monocrystalline and polycrystalline cells is 1 to 2 years, assuming 4.7 peak sun hours per day (Utah receives over 5). In 2011, one solar company began offering a solar panel that generates the same amount of energy used to create it in one year (assuming 1,700 kWh/m2 per year of solar insolation).

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7: How are solar panels disposed of?

A. Most solar panels have a 20-30 year warranty (and continue to produce electricity long beyond that time frame), so most solar panels have not yet reached the end of their usable lives. However, solar panels do contain potentially hazardous materials, so as more panels age the solar industry is beginning to discuss disposal and recycling of solar panels.

Learn More:

 

Your Solar Installation

1: What size solar system will work best for me?

A. The size of your system will depend on your current energy usage, your available usable roof space, your budget and financing options, and the percentage of your energy consumption you want to offset with solar. It is recommended that you first take steps to make your home as efficient as possible before (or in conjunction with) making your solar investment. Get some simple tips to help conserve energy and make your home more energy efficient. You can use the Solar Simplified calculator (a project of Utah Clean Energy) to estimate what size solar system will work best for you.

2: How much electricity will my solar system generate?

A. The output of your solar energy system will depend on the amount of sunlight the panel receives, the tilt of the panel, and the type of panel you use. You can use the Solar Simplified calculator (a project of Utah Clean Energy) to roughly calculate how much electricity a given system will produce. The average Utahn uses around 9,000 kilowatt-hours of electricity annually, and a 6.2 kilowatt system would cover 100% of that usage. When the MTCS contractor provides you with a final bid, that bid should include an estimated production for your panels based on your specific circumstances.

3: What kind of maintenance is required for solar panels?

A. There are no moving parts in a standard rooftop solar panel, so there is not much that will break or malfunction under normal conditions. Solar panels should be sprayed down periodically (usually in the spring or summer) with warm water to prevent dust and pollen build-up (the thin film of dust blocks a little bit of light from hitting the panels, reducing the amount of electricity they make). Ensuring that your solar panels are free of debris will help them operate at their maximum potential. Large amounts of snow can block solar radiation to the panels as well, so if you live in a snowy area your winter production may be decreased if you aren't able to remove the snow. As solar panels are black and tilted at an angle, the snow will usually melt fairly quickly.

Most panels have a 25 to 30 year lifetime, and solar inverter lifetimes range from 5 to 15 years (though micro-inverters and some string inverters have 20-25 year lifetime). Depending on the inverter, you may need to replace the inverters once during the life time of the panels (costs for replacement vary depending on the inverter). Solar panels and inverters are usually covered by warranties for the lifetime of the product, so if you need to replace a panel due to manufacturing defect it should be covered by the warranty. If you need to replace a component of your solar system due to damage, the solar contractor should be able to replace that specific component (panel, inverter, etc.) individually.

If you need to replace your roof, you will have to remove the solar panels. Re-installing the panels is less time intensive than the original installation, but there will be a cost to have a solar contractor come to remove and replace the panels. If your roof is in need of replacement in the near future, it is often worth it to have the roof replaced before installing solar.

4: Do solar panels work in the winter? And what about snow removal?

A. Solar panels can operate perfectly well in the winter, especially if you have good sun exposure and many sunny days a year, however large amounts of snow can block solar radiation to the panel, so if you live in a snowy area your winter production may be decreased if you aren't able to remove the snow. As solar panels are black and tilted at an angle, the snow will usually melt fairly quickly. If you are able to safely access your roof, some people use a snow broom to remove snow from the panels. Removing snow from even a small portion of the panels can help the black panel absorb sunlight, warm up, and shed the rest of the show. The contractor can recommend snow removal strategies based on where your system is located and how steep your roof is.

The vast majority of solar installations are "On-Grid" systems. These systems are installed on houses that are still connected to the power grid. Through net metering contracts with Rocky Mountain Power and other utilities, power flows to the house when the solar system is not producing as much electricity, and the panels feed extra electricity back into the grid when they are. In this way, excess generation in the summer can be used in the winter! To learn more about net metering please click here.

5: What's the difference between solar photovoltaic (PV) and solar thermal (hot water) systems?

A. Mountain Town Community Solar is offereing solar PV systems, which convert sunlight directly into electricity using semiconductor technology. Solar thermal systems, also known as solar hot water, use the sun's light to directly heat water and/or space for homes and businesses. There are several solar-thermal system configurations which employ the sun's energy to heat water; the most appropriate for Utah's climate, where freezing temperatures are common, is a closed-loop, active, solar hot water system. Closed-loop solar thermal systems use the sun to heat a heat-transfer fluid in the collector. Heated fluid is pumped from the collector in the bottom of the solar storage tank into a heat exchanger where heat energy is transferred from the fluid to potable water. Heated water is then held in the storage tank ready for use, with a conventional system providing additional heating as necessary. Solar thermal systems are not available through Mountain Town Community Solar, but you can consult a solar contractor to learn more about solar thermal for your home.

6: How will I know if solar energy can work for me?

A. Solar PV works on just about any home, as long as the site gets enough solar potential. Solar PV can be integrated into most existing wiring systems. If the roof is shaded or not conducive to solar, solar PV can be installed on a ground mount systems, on a pole mount systems, or on a garage, shed or adjacent building. Solar can be mounted on almost any roof type. In most cases, solar will be feasible and the contractor will help you to figure out the best solution for you and your energy goals.

Solar panels work best when they are installed facing south or west. If you have a large area of roof that faces either south or west and does not receive significant amounts of shading, your home is probably suitable for rooftop solar panels. East facing panels can sometimes outperform west facing ones, so check with your solar installer to see if this is an option. East facing systems may not be able to take advantage of state tax incentives, however.

Fire codes mandate that there is a minimum distance between solar panels and the edge of your roof for safety purposes--so you can not cover 100% of your roof space with solar panels. If you have a flat roof or a very steep roof, or you do not have optimal roof space due to shading issues, you will either need to mount the solar panels on an angled rack or use a ground- or pole- mounted system located, on an auxiliary structure (like a garage), or in a sunny part of your yard. There may be some extra costs associated with these systems, but the MTCS contractor will let you know about those costs when then visit your home. Most homes can accommodate rooftop solar installations, as long as you have some sunny, south- or west-facing roof space.

The best way to figure out if solar will work for your home is to contact a solar contractor.  A solar contractor will conduct an on-site assessment of your home, provide you with an individualized quote, and help you determine whether or not solar PV makes sense for you.

7: Why are solar permits required?

A. Like many other home improvement projects, solar installations require a permit to ensure the system is safe and meets all applicable codes, standards, and local requirements. Permitting processes and costs differ across jurisdictions, but the Mountain Town Community Solar contractor will take care of the permitting process as part of your solar installation.

 

General Solar Questions

1: What benefits does solar provide?

A. Solar is a fuel-free energy resource, which means it is an infinite and inexhaustible resource with no volatile fuel costs. Solar is also a pollution-free energy resource; the more solar energy we use, the cleaner our air and water. After the up-front initial cost, solar provides immediate energy savings and greater energy stability. Solar also reduces line losses on the grid and provides energy to the grid during the daytime, when energy is most expensive and in high demand.

2: Why do solar panels need to go on south or west facing roof?

A. There are a number of factors related to your roof that can drastically affect the suitability of solar on the roof of your home. Some of these include: orientation (north, east, south, west), pitch, shading, and others. Living in the northern hemisphere, it's ideal to have a roof that faces due south, isn't very steep or flat, and is free of shading from things like trees and chimneys. It's important to understand these unique characteristics before installing solar panels on your home. Of course, a solar contractor can help determine the suitability of solar on your home.
 
More information: 

3: Can solar panels be installed somewhere other than my roof? What about on the ground?

A. If your roof is not suitable for solar, or your HOA does not allow rooftop solar, solar panels can also be mounted on a pole or on the ground in your yard. There is an extra fee to build the structure that ground- and pole-mount systems are installed on, but often ground- and pole-mount systems can be installed in optimal locations for sun exposure. Solar panels can also be installed on accessory structures, like a garage or a shed. If the installtion is on the ground a fence should be considered to keep out wildlife and protect the installation. Another option is to cover the back of the array to keep the wires protected. 

4. What if the power goes out? What the difference between an off-grid and an grid-tied system?

A. A grid-tied system is a solar PV system connected to the utility grid, which allows homeowners to receive electricity from both the solar PV system and the utility. This type of system is made possible through a net metering arrangement with the utility, which allows homeowners to receive fair credit for the electricity they produce. However, a grid-tied system will not continue to provide power during a utility power outage. Due to current regulations and equipment requirements, grid-tied solar PV systems are designed to shut off when any change to the incoming power source (from the utility) is detected. This is a safety measure to protect workers who may be handling electricity lines.

A grid-tied system can have power during blackouts with the use of battery back-up systems. Systems with battery backups allow you to keep using electricity generated by your solar panels when the grid goes down (the electricity produced from the solar PV system is stored in the batteries, for later use). Battery backups are made up of banks of deep-cycle batteries that are charged by both the panels on your roof and by the grid. Battery backups decrease the efficiency of your solar system overall because some of the power you generate must be diverted to charge and maintain the batteries. The batteries also have to be maintained and replaced periodically. The system and the batteries can be customized to cover a certain amount of electricity from key appliances it the home (i.e. refrigerator, lights, stove, etc); the system doesn’t need to be sized to cover the entirety of the home’s electricity usage, as this sort of system is typically used for emergency back-up. However, battery back-up systems are typically more costly than a standard grid-tied solar PV system.

An off-grid solar system does not connect to the utility grid at all. As such, the solar PV system must be sized to cover the entirety of a homeowner’s electricity usage. Almost all off-grid systems require a backup energy source for times of high energy use or low solar production.

To learn more about this topic please click here.

5: How do I connect to the eletrical grid? What happens when I generate more electricity than I use?

A: All investor-owned and cooperative electric utilities in Utah (municipal utilities are excluded) are required to allow residential customers to connect renewable energy systems of up to 25 kWs to the grid and credit them when excess electricity is generated.

For Rocky Mountain Power Customers:

In 2009, improvements to Rocky Mountain Power’s net metering tariff required that customers are given credit on a kWh-to-kWh basis for any excess electricity they produce in a month. The credits roll over month-to-month within the annualized billing cycle, which begins April 1st and ends March 31st. Any unused credits expire at the end of the billing year. Utah net metering laws do not allow you to “sell” electricity back to the grid beyond the amount of electricity you’ve used.

You do not need to renew your net metering agreement with Rocky Mounty Power on an annual basis. Once your net meter is installed Rocky Mountain Power, you are ready to start generating electricity!

Savings will vary annually; you should expect to see higher solar electricity production in the summer and lower production in the winter. For example: If you produce 180 kWhs in June and only use 160 kWhs in that month, you will have 20 kWhs which “roll-over” as a credit on your bill in July. Those credits continue to roll forward until you use them (by using more electricty that your panels produce) or the annualized billing cycle ends on March 31st. At that point, any unused kWh credits will expire and you will start again with a ‘fresh slate’ on April 1st. In a month where you use more electricity (kWhs) than you solar panel produces, your bill will still reflect any kWhs generated by the solar PV system, and your net bill will only reflect the kWhs you used from the utility (i.e. the kilowatt-hours that weren’t provided by the solar PV system).

Learn more about Rocky Mountain Power's Net Metering Policy.

For Heber Light and Power Customers: 

Heber Light and Power's (HLPs) net metering program works much the same as Rocky Mountain Power's net metering program, with a few important distinctions. In a given year, if a HLP customer's solar system produces more electricity than their home uses in that year, they will be paid for the "net excess energy" that their system produced. There are two different rates that a HLP net metering customer may be paid for the net excess energy generation. First, is at the full retail rate for electricity, if that customer has transfered the Renewable Energy Certificates (RECs) associated with their solar system to HLP. The Second rate that HLP customers can be compinsated for net excess energy gneration is at the Feed in Tarrif rate (lower than the retail rate), if the customer does not transfer their RECs to HLP. 

About RECs: In addition to clean energy, your solar energy system also produces Renewable Energy Certificates. If your system is registered with a certified reporting agency, you can receive one REC every time your solar energy system produces 1,000 kilowatt-hours (or 1 megawatt-hour) of electricity. RECs do not impact the price you pay for electricity or the net metering bill credits you accrue each month - you still own the clean electricity produced by your panels and can use it to receive credits towards your electricity bill.

The MTCS contractor will help you determine the best size for your system and complete forms for net metering and interconnection.

6: What is the risk that net metering rules change a few years from now?

A. At this point, Utah maintains strong net metering policies and rules (receiving two A grades in Freeing the Grid for Net Metering and Interconnection since 2010).  There are no indications at this juncture that any changes to net metering rules are forthcoming; but, as with all policies and rules, there is always the possibility that things may change.

7: What happens if the utility power goes out?

A. Unless it is specially configured, a residential solar power system will not provide power during a power outage. When an outage occurs, utility workers may be picking up downed lines or handling electric cables. When the power is out, they are generally safe to handle, as there should be no electrical current running through them. If the system on your roof is still generating electricity, however, it could create a safety hazard. When the grid goes down, your inverter will temporarily turn your system off until the grid comes back online.

A 2008 study done by the Lawrence Berkeley National Laboratory indicates that in the Mountain West region, there is a total of less than two hours (117 minutes) in an entire year that customers experience interruptions to their electrical service. There are more than 8,760 hours in a year, which means that power outages only result in a loss of grid connectivity for 0.0002% of the time. Additionally, less than 1% of these outages last more than 10 minutes.

8: Can I install a battery to back up my system?

A. It is possible to have your house stay powered during blackouts, just as it is possible to take your house completely off of the grid. Systems with battery backups allow you to continue using the energy generated by your solar panels during a blackout, but they are more costly than a simpler system. Battery backups are made up of banks of deep-cycle batteries that are charged by both the panels on your roof and by the grid. Battery backups decrease the efficiency of your solar system overall because some of the power you generate must be diverted to charge and maintain the batteries. Batteries also must be maintained and replaced periodically, adding costs to the system. They add significant complexity to the installation of the system, and therefore add significant cost increases, but they are an option for those who are interested.

 

Financial Questions

1: I'd like to install solar, but I don't have the extra money right now. What can I do?

A. There are many financing options available to help defray the initial upfront costs of residential solar. Mountain Town Community Solar will host a financing workshop after the official project launch to answer all your questions about solar financing. You may also be interested in energy efficiency as an initial first step and smart investment for your home (that will save you money and energy). Energy efficiency investments also help make your home more solar-ready, which means you may not need as large of a solar PV system to meet your energy needs.

2: Are there financing options available for residential solar?

A.There are several financing options available to help homeowners defray the upfront cost of a solar installation. Learn more about solar financing options.


3: What tax credits and incentives are available?

A: A state and federal tax credit are available for solar PV.

  • The state of Utah offers a 25% rebate on residential solar systems, up to a cap of $2,000.

Unused credit can be carried over for up to four years, and the solar system does not have to be installed on your primary residence to receive the tax credit. Learn more about the Renewable Energy Systems Tax Credit.

The Renewable Energy Systems Tax Credit is specifically for renewable technologies (see a list of eligible technologies). You can apply for the Renewable Energy Systems Tax Credit more than once, however the total of all credits you receive is limited to $2,000. If you have applied for this credit before (for passive solar, solar thermal or solar hot water, or other renewable technologies for your residence), you may not be able to receive the full amount of the credit for your solar PV system.

  • The Federal tax credit is a 30% tax credit with no cap.

This credit is for renewable energy systems. The Credit will begin to step down in 2019 and will default to 10% in 2022. Excess credit can generally be carried over into the next year. The credit can be taken against the alternative minimum tax.
Learn more about the Residential Renewable Energy Tax Credit.

  • If you are not able to take state or federal tax credits, there are no other incentives that will be available during the Mountain Town Community Solar timeline.

Learn more about solar incentives.

 

4: When should I expect a return on my investment?

A. Unfortunately, this figure will vary widely: the time it takes you to recover your investment will depend on the technology you select, your energy efficiency and usage habits, your current and future electricity rates, the system size and configuration, and available incentives. Depending on your usage and the size system you put in, you could see a return of 3-8% on your investment in the first year – a very good rate. Overall, your return on investment varies depending on how much electricity you use and what size system you install, however with current solar system costs, assuming you undersize your solar system and can take tax credits, most homeowners will recoup their upfront investment well before the 25 year life expectancy of the panel is reached. Solar is one of the few things consumers can purchase that does provide a financial return on your investment; imagine what the ROI would be for your car that you fill with gas every week! One of the biggest benefits of solar is the fact that it is an inexhaustible, clean, and price stable resource that will last well over 20 years. Investing in solar today helps you mitigate the future risks, fuel volatility, and uncertainty, while also improving your self-reliance and energy independence. Use the Solar Simplified calculator (a project of Utah Clean Energy) to learn more about your particular situation.

5. What is Utah's Solar Energy Resource Potential?

A. Utah has a tremendous and largely untapped solar resource, and the potential for solar development is widespread across the state. The technical resource potential varies for each type of solar technology and application, for example:

  • Concentrating Solar Power (CSP): According to the Utah Renewable Energy Zone Task Force Report, Utah's technical potential for CSP is about 826 Gigwatts (GW) - or 826,000 MW. This represents 16,500 technically potential 50-Megawatt sites, covering appriximately 6,371 square miles of land.

    This amount of concentrating solar potential could generate over 1.5 million Gigawatt hours per year (GWh/yr) - equivalent to the annual electricity demand of over 150 million average Utah homes.

  • Rooftop Solar Photovoltaics (PV): Utah's technical potential for roof-top solar PV (in 2010) is approximately 5 Gigawatts (GW), or 5,000 Megawatts (MW), which could produce 7 million megawatt hours of electricty per year (MWh/yr) - enough to power over 720,000 Utah homes for a year.

6. What is the effect of solar on insurance rates?

A. This will depend on the individual insurace you have. Insurance will, in general, increase a bit to make sure that the solar is covered in the cost of replacement in case of damage/loss. Also your insurance company should be notified of the installation. That way if there is damage to the system it can be filed as an insurance claim.  

 

Footnotes:

1 US Department of Energy, "Photovoltaic Basics." Energy Basics. <http://www.eere.energy.gov/basics/renewable_energy/pv_systems.html>
2 US Department of Energy, "Flat-Plate Photovoltaic Systems." Energy Basics. <http://www.eere.energy.gov/basics/renewable_energy/flat_plate_pv_systems.html>