Solar panels generate electricity. Your TV uses electricity. It’s not quite as simple as running a wire from one to the other. Without a solar inverter, your TV couldn’t use the solar energy from your home solar panels. An inverter must change the direct current electricity to alternating current electricity.
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What else do you need to know about solar inverters? We could go back in scientific and American history to Thomas Edison and Nikola Tesla. More practically though, what do inverters do for watching football, cooking dinner, safety, and making clean, efficient energy possible?
A solar power inverter’s primary purpose is to transform the direct current (DC) electricity generated by solar panels into usable alternating current (AC) electricity for your home. Because of this, you can also think of a solar inverter as a solar “converter.”
Once transformed to AC, solar electricity can power most household electronics and appliances. In the US, the power grid also uses AC, which means your post-inverter solar electricity can be sold to the grid and shared with others.
When a solar-powered system is connected to the grid, the inverter is the middleman between your home and the utility power lines. A grid-tied inverter allows your home to have uninterrupted power, no matter how much electricity your solar panels generate throughout the day.
When your solar power system is producing more electricity than your home is consuming, your solar inverter can transmit that excess power into the energy grid. Likewise, if your panels are producing some electricity, but not enough to run your entire home, you can utilize a mix of solar and grid power.
At night, when solar panels produce no electricity, your home may need to consume 100% of its power from the grid unless your system includes integrated energy storage. With solar batteries, your inverter can draw stored solar energy from your backup reserve at night or during an outage.
No matter if your home is running on grid power or the sun’s energy, your solar inverter can seamlessly switch between power sources to keep the lights on and systems running throughout your property.
For those who want to know precisely how solar inverters work, here are the key principles to understand.
While your solar inverter allows you to use the electricity your solar panels generate, it is also capable of many other essential tasks. A solar inverter can help maximize your energy production, monitor your system’s output, communicate with the utility grid, and detect faults that might otherwise cause damage or personal harm.
Solar inverters can track your panel array’s voltage and maximize the ongoing efficiency of your renewable solar energy system. Today’s premium inverters for homes are very efficient, and can typically transform DC solar power into AC electricity at efficiency ratings up to 97%.
At the electrical level, high-quality grid-tied solar inverters output a pure sine wave, which is a measure of how smoothly the direction of the current can change. On the other hand, low-cost inverters generate a modified sine wave, which can be used to power non-delicate devices without a variable speed motor. Almost always, a pure sine wave inverter is recommended for home solar energy systems.
It's exciting to see your solar panels generate thousands of watt-hours on a sunny afternoon, so naturally, most people want to monitor their renewable energy system’s performance. Today, most solar energy system monitoring is done by the inverter.
With a modern solar inverter, you can typically view how much energy your solar panels are producing at any time through a mobile app or website. In the Palmetto App, users can see precise reports of solar watt-hour production alongside energy bill savings.
If things aren’t working as they should in your solar energy system, many inverters operate ongoing system performance checks to alert you of issues. You can also use your solar inverter’s performance tracking to periodically verify all components are working and generating the amount of electricity expected.
If you have a full solar battery bank, or your household cannot use all the electricity being generated by your panels, your inverter can seamlessly feed this surplus power into the energy grid. If you live in an area with net metering, this can earn you credits that reduce your energy bill.
During a power outage, some solar inverters can separate your home from the grid, keeping the lights on at home while protecting line repair workers from the electricity your solar panels are producing.
When not properly maintained, aging electrical wiring and solar equipment can create potential electrical hazards, like ground faults or arcs. If such an event occurs, the solar inverter will quickly detect the issue and shut down, protecting the rest of the system and alerting you to the need for service before any additional damage occurs.
Inverters are a key feature of a safely operating solar panel system. Correct installation by a professional is a key first step to ensuring a long, safe, and productive life for your system.
The type of solar inverter you get installed at your house will be determined by several factors.
To guide your solar design decisions, the four key solar power inverter technologies to know are string inverters, microinverters, power optimizers, and hybrid inverters.
Also called a central inverter, string inverters are most suitable for simple solar power system designs. The technology gets its name from arrays (or groups) of solar panels connected by 'strings' of wiring. From each string of solar panels, the DC electricity is then fed into one central inverter, where it is converted into AC power all at once.
Pros: String inverters have a few things going for them.
Cons: Here are the main downsides of string inverters.
Best For: A string inverter may be the best option as a low-cost solution for properties with basic roof layouts and little to no shade on-site.
Unlike string inverters (which are centrally located) microinverters are usually installed beneath or next to each solar panel in a system. So instead of power flowing into a single central inverter, microinverters transform DC electricity at each individual panel.
Pros: Here’s why you should consider a microinverter.
Cons: Here are the drawbacks.
Best for: Overall, microinverters are best for maximum energy output on complicated or shaded rooflines, where neighboring panels may generate varying amounts of electricity.
Sort of a compromise between string and microinverters, power optimizers help maximize the performance of individual solar panels within a central inverter system. Like microinverters, power optimizers are installed at the panel-level and modify solar electricity before it is sent to a central location.
Pros: Power optimizers bring the benefits of microinverters.
Cons: They have some of the same drawbacks as microinverters, too.
Best For: String inverters with power optimizers are a great alternative to microinverter-based systems where individual panel performance must be considered.
Hybrid inverters are one of the newest additions to the fast-moving world of solar energy technology. A hybrid inverter combines a traditional solar inverter with a battery inverter component, with configurations optimized for every kind of solar energy system.
Pros: Hybrid inverters add capabilities to the basic inverter design.
Cons: Hybrid inverters have one main downside.
Best For: Hybrid inverters are the best option for those considering solar, battery storage, and EV charging as parts of a whole, comprehensive home energy system.
Want more information on solar inverter manufacturer? Feel free to contact us.
During a solar inverter's DC to AC electricity conversion, some energy is lost in the form of heat. The less energy lost through heat, the greater the inverter’s efficiency.
Solar conversion efficiencies vary by brand, but most quality home inverters have a maximum efficiency of 97% to 99%, so energy loss is relatively minor. While operating in real-world conditions, however, shading, weather, and your other solar equipment will have an impact on your system’s overall energy production efficiency.
Inverter manufacturers always specify the input energy their products can process and their maximum power output. For instance, a string inverter may be able to handle a maximum input energy of 4,000 watts from solar panels, and output 3,000 watts.
In the real world, however, you will rarely achieve your inverter's nameplate power rating, which is measured at Standard Test Conditions, or STC. Instead, your typical daily activities may end up 10% to 20% below the nameplate power rating. To keep costs down, inverters are often selected with an input power rating lower than your solar panel array’s maximum output.
Solar installers will make sure the photovoltaic inverter size matches the capacity of the solar array for optimum power conversion. You may be surprised to learn it’s usually not an exact match. For instance, just because you have 5 kilowatts of solar panels doesn’t mean you will pair them with a 5-kilowatt inverter.
Typically it’s more cost effective to pick an inverter designed to handle slightly less electricity than the maximum amount of power the solar panels can generate. When the panels are generating this extra electricity capacity the inverter can’t handle, it’s called clipping, and the extra electricity is lost to the system.
So while you may throw away this extra electricity, inverter clipping typically occurs only at the height of the afternoon during the most productive days of the year. Therefore, most installers favor solar inverters designed to handle the average amount of daily power to keep total installation costs low, even if it means losing a little bit of solar electricity generation in peak conditions.
In general, local regulations for solar inverters are rarely something you need to worry about as a homeowner. Reputable solar installers will be familiar with the specific rules governing solar energy installations in your area.
Your system size is typically limited by your inverter's size, rather than the number of panels you install. In most cases, your solar inverter’s maximum capacity may be rated to match or slightly exceed your home’s approximate annual electricity demand.
Overall, solar inverters do more environmental good than harm. While there’s an environmental cost to manufacturing anything, inverters’ role in unlocking clean, renewable solar power is more than worth it.
Thankfully, the majority of a solar inverter can be recycled, with many materials retaining their value for scrap at the end of a system’s lifetime. Solar inverters should always be handled by a professional, since some may include hazardous materials.
Narrowing down the price of a solar inverter to a single number can be tricky because every system design is different. Your inverter’s size will be determined by your energy consumption and your system design.
Additionally, installers typically buy in bulk and have direct relationships with suppliers, so their costs may be different than what you’d pay online. When looking at your solar system as a whole, inverters will typically make up around 10% of your total project costs.
String inverter prices usually range between $1,000-$2,000 or slightly more. Power optimizers can boost your total costs $50-$200 per panel. You can expect to pay $200-$400 per panel for microinverters.
Most residential string inverters have an expected lifespan and performance warranty of 10-15 years, but can sometimes last up to two decades. However, most string inverters are replaced within the operating lifetime of the solar panels to which they are connected.
Microinverters and power optimizers are newer technologies, so there is less data on their expected lifespans. That said, most manufacturers are confident their products will outlast the 20- and 25-year warranties included with the equipment. Factor possible replacement costs outside of warranty periods into your system design decision-making.
Solar inverters rarely require maintenance. When something goes wrong, inverters are usually replaced, not repaired.
If your system is working less efficiently than usual or not generating electricity at all, it may be time to contact your solar company to see what maintenance is required. Trying to troubleshoot inverter problems on your own can be dangerous and could invalidate warranties.
If you're looking to invest in a home solar power system and trying to decide what inverter option to utilize, an easy way to get started is with our free solar savings calculator.
In a few easy steps, you will receive an estimate of how much solar can save you. You'll also get connected with a solar expert who can review the different solar options that make sense for your home and help you select the one that's right for your family’s needs.
What does a solar inverter do?
A solar inverter turns DC electricity, coming from the panels, into AC electricity, which is the standard electricity used by grids, homes, and most devices in the US.
Can solar panels work without an inverter?
Scientifically speaking, yes. Practically speaking, to turn the electricity panels generate into electricity you can use, no.
Are string inverters or microinverters better for home solar?
Microinverters are usually better for home solar systems. Microinverters optimize your system’s efficiency as they work better when some panels are in shade at varying times. More positives include having a longer lifespan than string inverters, being able to add panels easier, being easier to do maintenance on, and getting better energy efficiency will, in the long run, more than make up for the higher initial cost compared to string inverters. A string inverter can work as a lower-cost choice for properties with basic roof layouts and little to no shade.
An inverter is one of the most important pieces of equipment in a solar energy system. It’s a device that converts direct current (DC) electricity, which is what a solar panel generates, to alternating current (AC) electricity, which the electrical grid uses. In DC, electricity is maintained at constant voltage in one direction. In AC, electricity flows in both directions in the circuit as the voltage changes from positive to negative. Inverters are just one example of a class of devices called power electronics that regulate the flow of electrical power.
Fundamentally, an inverter accomplishes the DC-to-AC conversion by switching the direction of a DC input back and forth very rapidly. As a result, a DC input becomes an AC output. In addition, filters and other electronics can be used to produce a voltage that varies as a clean, repeating sine wave that can be injected into the power grid. The sine wave is a shape or pattern the voltage makes over time, and it’s the pattern of power that the grid can use without damaging electrical equipment, which is built to operate at certain frequencies and voltages.
The first inverters were created in the 19th century and were mechanical. A spinning motor, for example, would be used to continually change whether the DC source was connected forward or backward. Today we make electrical switches out of transistors, solid-state devices with no moving parts. Transistors are made of semiconductor materials like silicon or gallium arsenide. They control the flow of electricity in response to outside electrical signals.
If you have a household solar system, your inverter probably performs several functions. In addition to converting your solar energy into AC power, it can monitor the system and provide a portal for communication with computer networks. Solar-plus–battery storage systems rely on advanced inverters to operate without any support from the grid in case of outages, if they are designed to do so.
Historically, electrical power has been predominantly generated by burning a fuel and creating steam, which then spins a turbine generator, which creates electricity. The motion of these generators produces AC power as the device rotates, which also sets the frequency, or the number of times the sine wave repeats. Power frequency is an important indicator for monitoring the health of the electrical grid. For instance, if there is too much load—too many devices consuming energy—then energy is removed from the grid faster than it can be supplied. As a result, the turbines will slow down and the AC frequency will decrease. Because the turbines are massive spinning objects, they resist changes in the frequency just as all objects resist changes in their motion, a property known as inertia.
As more solar systems are added to the grid, more inverters are being connected to the grid than ever before. Inverter-based generation can produce energy at any frequency and does not have the same inertial properties as steam-based generation, because there is no turbine involved. As a result, transitioning to an electrical grid with more inverters requires building smarter inverters that can respond to changes in frequency and other disruptions that occur during grid operations, and help stabilize the grid against those disruptions.
Grid operators manage electricity supply and demand on the electric system by providing a range of grid services. Grid services are activities grid operators perform to maintain system-wide balance and manage electricity transmission better.
When the grid stops behaving as expected, like when there are deviations in voltage or frequency, smart inverters can respond in various ways. In general, the standard for small inverters, such as those attached to a household solar system, is to remain on during or “ride through” small disruptions in voltage or frequency, and if the disruption lasts for a long time or is larger than normal, they will disconnect themselves from the grid and shut down. Frequency response is especially important because a drop in frequency is associated with generation being knocked offline unexpectedly. In response to a change in frequency, inverters are configured to change their power output to restore the standard frequency. Inverter-based resources might also respond to signals from an operator to change their power output as other supply and demand on the electrical system fluctuates, a grid service known as automatic generation control. In order to provide grid services, inverters need to have sources of power that they can control. This could be either generation, such as a solar panel that is currently producing electricity, or storage, like a battery system that can be used to provide power that was previously stored.
Another grid service that some advanced inverters can supply is grid-forming. Grid-forming inverters can start up a grid if it goes down—a process known as black start. Traditional “grid-following” inverters require an outside signal from the electrical grid to determine when the switching will occur in order to produce a sine wave that can be injected into the power grid. In these systems, the power from the grid provides a signal that the inverter tries to match. More advanced grid-forming inverters can generate the signal themselves. For instance, a network of small solar panels might designate one of its inverters to operate in grid-forming mode while the rest follow its lead, like dance partners, forming a stable grid without any turbine-based generation.
Reactive power is one of the most important grid services inverters can provide. On the grid, voltage— the force that pushes electric charge—is always switching back and forth, and so is the current—the movement of the electric charge. Electrical power is maximized when voltage and current are synchronized. However, there may be times when the voltage and current have delays between their two alternating patterns like when a motor is running. If they are out of sync, some of the power flowing through the circuit cannot be absorbed by connected devices, resulting in a loss of efficiency. More total power will be needed to create the same amount of “real” power—the power the loads can absorb. To counteract this, utilities supply reactive power, which brings the voltage and current back in sync and makes the electricity easier to consume. This reactive power is not used itself, but rather makes other power useful. Modern inverters can both provide and absorb reactive power to help grids balance this important resource. In addition, because reactive power is difficult to transport long distances, distributed energy resources like rooftop solar are especially useful sources of reactive power.
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