How Grid-Tied Solar Systems Work in September 2023

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How Grid-Tied Solar Systems Work in September 2023

Leonardo David is an electromechanical engineer, MBA, energy consultant and technical writer. His energy-efficiency and solar consulting experience covers sectors including banking, textile manufacturing, plastics processing, pharmaceutics, education, food processing, real estate and retail. He has also been writing articles about energy and engineering topics since 2015.

Tori Addison is an editor who has worked in the digital marketing industry for over five years. Her experience includes communications and marketing work in the nonprofit, governmental and academic sectors. A journalist by trade, she started her career covering politics and news in New York’s Hudson Valley. Her work included coverage of local and state budgets, federal financial regulations and health care legislation.

Most residential solar panel systems are grid-tied or connected to the local power grid. Grid-tied solar systems have a major advantage: you can source electricity from both sources by using solar energy to power your home during the day and pulling from the grid for electricity at night.

Keep reading to learn more about grid-tied solar systems

A grid-tied solar system is designed to operate at the same voltage and frequency as the local utility grid, meaning you can connect both electricity sources together. You can switch between solar power and grid power seamlessly without interrupting the voltage supply, or you can use both energy sources at once.

Alternatively, off-grid solar systems can operate fully disconnected from the grid. Off-grid systems rely on solar panels alongside a solar battery to store excess energy for use at night or on cloudy days. You can also find hybrid solar systems that can operate on-grid and off-grid.

There are a few main benefits of using a grid-tied configuration when going solar, including:

Grid-tied solar installations have a lower cost than off-grid systems.

Based on our March 2023 survey of 1,000 homeowners with solar, an average solar system costs between $15,000 to $20,000. Incentives like the 30% federal solar tax credit can lower your costs even further.

Off-grid solar systems are more expensive because you have to add an energy storage system large enough to power your home during extended periods. Batteries like the Tesla Powerwall cost around $9,000 without installation, and you may need more than one unit. Assuming you needed three batteries, your off-grid solar system cost would increase to around $47,000 or more.

You can also use battery storage systems with grid-tied solar arrays, but you can use a smaller battery for optimal return on investment. But with grid-tied systems, you can rely on backup power from the utility grid during consecutive days of cloudy weather, which is more cost effective than installing a large battery you may not use at full capacity.

You can claim the federal solar tax credit for all types of solar systems: grid-tied, off-grid and hybrid. However, you may find certain state and local incentive programs are exclusively for grid-tied solar systems. Off-grid systems are not only more expensive but eligible for fewer incentives.

Most states offer net metering or net billing programs, allowing homeowners to sell the excess energy their solar panels generate to local power companies in exchange for billing credits. Net metering allows you to lower your energy bills by using billing credits to offset your grid consumption. You can send excess power to the grid during the day in exchange for power bill credits, which you can subtract from your bills to cover grid energy use at night.

All solar energy systems reduce your utility bills and carbon emissions regardless of the configuration. Under favorable sunlight conditions, a 5 kilowatt (kW) solar system can generate over 7,500 kilowatt-hours (kWh) of electricity per year. If your power company charges 20 cents per kilowatt-hour, you can potentially save over $1,500 each year.

By generating clean electricity, you also lower your home’s carbon footprint. According to the Energy Information Administration, coal releases 2.26 pounds of CO2 emissions per kilowatt-hour, while natural gas releases 0.97 pounds per kilowatt-hour. If the local grid relies heavily on fossil fuels and you switch to solar power, you are offsetting emissions using renewable energy.

Grid-connected solar systems use inverters capable of following the local grid voltage and frequency with high accuracy. Thanks to this feature, your photovoltaic (PV) system integrates seamlessly with the electrical grid. This means that:

Electricity can flow from your solar system to your home, from your solar system to the grid, or from the grid to your home. Your system can automatically accomplish these dynamics without you having to flip a physical switch since a grid-tied solar array is synchronized with the grid voltage.

As previously described, net metering sends excess energy to the local power grid when your solar panels generate more electricity than you will use. Your utility company measures energy exports using a special power meter and then converts the energy into a credit you can subtract from your next bill.

A battery system becomes optional when net metering is available with billing credits at the full retail rate of electricity. In this case, you are essentially using the grid as your solar battery and offsetting consumption with billing credits that cost the same as electricity.

If you hire a qualified solar installation company, connecting a PV system to the local grid is a simple process. Permitting and interconnection requirements vary depending on your location, but you can summarize the general installation procedure as follows:

Electric companies only approve grid-tied solar systems if installed by a professional technician. For this reason, we do not recommend a DIY solar installation for large residential projects. You can, however, purchase DIY solar kits for off-grid projects, such as adding solar panels to your camper.

There are several ways to increase the energy production of a grid-tied solar power system.

The most efficient solar panels can convert over 20% of sunlight into electricity. SunPower and Canadian Solar currently hold the efficiency record in the solar industry, offering panels with up to 22.8% energy conversion efficiency. With a higher system efficiency, your power bill savings will also increase.

Even the most efficient panels will suffer from low productivity if constantly covered by shadows. The best solar companies take the time to analyze shading conditions during your initial site assessment to identify the best locations for your solar panels.

Solar panels generate direct current (DC) power, so you need a solar inverter to convert energy into the alternating current (AC) required to run your home appliances. Most systems use string inverters that wire your solar panels together in circuits and connect to a central inverter that converts the power output. But in this setup, a shadow covering one panel will cause all other panels in the circuit to suffer a performance drop.

If shading is unavoidable, you can use microinverters or power optimizers to improve the efficiency of your solar array. Installers place either device directly on your solar panels to optimize a panel’s individual electricity output. While power optimizers do not convert energy, microinverters convert the power output from DC electricity to AC electricity at the source, eliminating the need for a string inverter.

Enphase is a leading provider of microinverters, while SolarEdge is a leading provider of string inverters with power optimizers.

Accumulated dust has the same effect on your solar panels as shadows, blocking part of the sunlight from reaching the PV modules. Solar systems work best when cleaned regularly — many manufacturers and installers recommend cleaning your system at least two times per year.

Grid-tied solar systems are the most cost-effective option for homeowners who want to generate their own electricity. The best residential solar panels last more than 25 years, and you can achieve a payback period of six to 10 years depending on your system size, cost and local incentives.

With a grid-tied system, you can purchase an optimally-sized battery to cover nighttime consumption and provide power during blackouts, or you can rely on grid power. On the other hand, an off-grid solar system requires a much larger battery since it must power your home for extended periods at full capacity.

You can install a grid-connected system with battery backup for around $20,000 to $30,000, but might spend up to $45,000 or when going fully off-grid. In most cases, the potential savings from going off-grid don’t compensate for increased system costs.

Yes. Even if you can cover 100% of your energy usage with solar panels, you will still have access to the grid if you need backup power. Grid-tied systems are also beneficial if you live in a state with net metering programs, which provide billing credits when you send excess energy back to the grid.

The main disadvantage of grid-tied solar systems is not being able to access power during outages. If you live in an area prone to blackouts, you can invest in a solar battery bank to run your home during grid outages.

According to the results of our homeowner solar survey, you can expect to pay $2.85 per watt of installed solar capacity. So a 6 kW system costs $17,100 on average, while a 10 kW system might cost $28,500. You can lower system costs by taking advantage of solar incentives like the federal solar tax credit.

A solar inverter is an electronic device that converts the DC power your solar panels generate into the AC power required to run home appliances. Grid-tied systems use inverters capable of synchronizing with the local grid to send power back and forth simultaneously.

In most cases, it is safer and more cost-effective to have a professional install a grid-tied solar system. Electrical companies will only approve systems for use if installed by a professional, and DIY installation can be dangerous. A DIY solar system can also compromise the integrity of your roof and void your roof warranty if done incorrectly.

In residential settings, your installer will mount your panels to the roof using a racking system or you can opt for a ground mount.

We closely evaluated seven crucial factors according to our solar panel installation company methodology to rank the best providers in the industry. Based on a 100-point scale, we came up with each provider’s score out of five stars. Here’s how we assessed each company: Cost and payment options (20 points): Companies that offer cash purchases and in-house loan financing earned full points in this category. Companies also receivebonus points if they offer solar panel leasing or power purchase agreements (PPAs). Services (20 points): Besides solar installations, companies offering backup battery and EV charger installations, energy efficiency audits and system monitoring earned the most points in this category. We also allotted points to companies that completed all their installations in-house (as opposed to contracting out installers). Reputation (20 points): We considered each company’s Google star rating, BBB customer review rating, BBB customer complaint response rate and NABCEP certification status to award each company its reputation score. Warranty (15 points): We verified that each company offers workmanship, product and performance warranties on all of its solar installs. Providers earned more points if their warranties were at or above the industry-standard length (10 years for workmanship and product warranties and 25 years for performance warranties). Customer Support (10 points): Solar companies that offered virtual consultations, a mobile app, 24/7 customer support and high customer satisfaction with backend support earned the most points in this category. Industry Experience (10 points): Providers with 10 or more years of experience in the solar installation industry earned a perfect score in this category. Sustainability (5 points): Companies with a detailed sustainability statement, ESG disclosures, end-of-life panel disposal programs and community partnerships earned all five points in this category.

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