Going solar doesn't mean going off the grid unless you choose to.
Grid-connected systems have a give-and-take relationship with the larger electrical system, drawing from it when needed and giving back excess energy. An off-grid system puts you on your own solar island, which means you're responsible for generating all of your energy yourself. Whether or not you want your solar panels to operate off the grid is something to consider when buying solar panels .
The US power grid , a network of power plants, transmission lines, and distribution centers, supplies more than 150 million customers across the country with electricity. By understanding how solar panels and grids work together, you can decide whether you want to be energy self-sufficient or grid-connected. Programs like net metering , where your utility pays you for the excess electricity you feed into the grid, and battery usage allow utilities to work closely with solar panel owners – a decision that according to experts is mutually beneficial.
According to Sam Evans-Brown, executive director of advocacy group Clean Energy New Hampshire, grid-connected solar systems tend to be cheaper and allow for more flexibility. "Most electricity consumers don't want to go offline," Evans-Brown said by phone.
However, you can choose to leave the network altogether. Depending on your reasons for using solar power and your proximity to the grid itself, off-grid solar power may be the best option for you.
If you're in the solar panel market and considering whether or not to connect to the grid, here are a few things you need to know to help you make up your mind.
What is the relationship between your solar system and the grid?
The relationship between your solar system and the electrical grid determines whether you are an independent energy producer or at least partially dependent on public energy. According to a 2015 study by the MIT Energy Initiative, most solar panels are integrated into the electricity grid. Read on to learn more about their differences.
A solar system connected to the grid
As the name suggests, grid-connected systems connect to the grid through net metering, which allows for bi-directional movement between the solar system and the grid, or some other method. This allows you to get electricity from your energy supplier when you need it. Since solar panels rely on sunlight to generate electricity, this is especially important if you live in an area where cloudy or rainy days are common.
Grid-connected solar systems are usually the cheapest and most flexible option. Because you're not entirely dependent on your panels for all of your energy needs, there's usually a lower initial cost in the form of an energy storage system. However, your energy provider may charge you a connection fee.
Many solar panel owners choose to stay connected to the grid so they can take advantage of metering, which offers credits in exchange for energy sold back to customers. You can find a list of grants in your federal state at the Renewable Energy and Energy Efficiency State Funding Database.
As long as you're connected to the local grid, you don't have to worry about generating your own power. If your panels don't produce enough electricity, you will be disconnected from your utility and charged for the electricity used. The credit you get for putting excess energy from your panels into the grid can significantly or even fully offset these costs.
"That extra power has to go somewhere and the network has to have something to do with it, but they're willing to pay us for it, which is great," Kim Quirk said on the phone. Quirk is a branch manager at ReVision Energy, a New Hampshire-based solar energy provider.
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off-grid solar system
People who live in remote locations or want to use 100% clean energy can opt for an off-grid system.
With an off-grid solar system, you don't have physical power lines or wires leading to your home (other than those for your solar panels), nor do you get bills from utility companies or electricity providers. Off-grid solar power systems work independently by generating electricity and storing that electricity in batteries. If your panels are less productive, use this storage as if it were a network via net metering.
If you choose an off-grid solar system, you are responsible for meeting your energy needs. Off-grid solar systems require an extensive energy storage system to ensure that no outage occurs during periods of low solar radiation. Depending on the size of your home and your energy needs, you may need more batteries. Some owners also choose to install a backup generator.
Grid-connected or off-grid solar panels
| Grid connected solar system | off-grid solar system |
|---|---|
| Connected via power cord and net metering | There are no physical power lines or utility meters |
| You don't have to generate all of your energy yourself | Generate your energy |
| The solar storage system is optional | A solar storage system is required |
| Contributions to the connection to any public services | There are no connection costs to utilities |
How solar panels affect grids
Grid-connected solar systems impact the way utilities generate and distribute their electricity, especially during periods of peak energy consumption.
According to a 2018 report from the National Renewable Energy Laboratory, solar panels help the grid by smoothing out the supply curve, which represents the cost of energy sources and the amount of energy available at that cost.
Electricity generated by grid-tied systems and stored in batteries can balance or reduce demand and put less strain on the grid. Utilities must adjust consumer demand and energy production in real time to maintain grid stability. This causes prices and system pressure to fluctuate significantly throughout the day. The increased demand for electricity, usually in the morning and evening, often occurs when prices are higher due to pressure on the electricity grid.
This is where spot trading comes into play. When the sun is shining and solar panels produce more energy than a home can consume at one time, the excess energy goes back to the market. By increasing utility power during peak loads, solar panels help mitigate those peaks.
Can solar panels damage grids?
Just as solar panels can smooth out the peaks in a grid's supply curve, they can also remove them. When solar panels can't produce enough energy, homeowners have to disconnect the grid, which puts a strain on the grid system. Especially during shorter winter days, when solar panels are less efficient, people rely more on the electricity grid during peak hours, climbing the so-called duck curve .
The duck curve is a measure of solar production and energy demand. Drawn on a diagram, it looks like a duck. Solar panels work best in direct sunlight, usually in the middle of the day, when electricity demand is lowest. The duck curve deepens as more solar panels regenerate during off-peak hours, but decreases as the sun goes down and electricity demand increases.
"We have to understand the team's point of view," said Quirk. "If everyone depends on solar energy, the grid will have too much electricity in the summer and too little in the winter."
Solar panels and backup batteries can make financial sense even if you don't expect to shut down your home.
Imagine/Getty ImagesAdditionally, while excess energy from solar panels can benefit the grid during peak periods, there is potential for overgeneration, especially in solar-intensive states like California. If too much power is fed into the grid, the frequency will go beyond its typical equilibrium. Such frequency changes, faster or slower, can damage the entire energy infrastructure.
How solar batteries can help you (and your grid).
Energy storage makes it easier to rely on solar energy, even when the sun isn't shining. While solar batteries are essential for off-grid solar systems, they offer benefits to any solar system .
“If people have both solar energy and batteries, they can use solar energy during the day to power their homes and recharge their batteries. And at night, the batteries will power their homes, not the grid,” Quirk said. “It makes people a little more grid-agnostic when big spikes are likely to happen.”
The system connected to the grid depends on the electricity company. In the event of a power outage or grid failure, solar panels without a battery become unusable . However, with a solar battery system, you can safely power your home during a power outage.
Solar panels can be an expensive investment, ranging from $12,000 to $22,000 depending on size and type. To reduce your initial cost, you can claim a 30% solar tax credit for solar batteries. Some states, such as California and Maryland, offer financial incentives in the form of tax credits and rebates to ease access to energy storage.
It's important to work with a reputable PV installer to help you choose the battery that meets your needs, whether you're completely disconnected from the grid, have a backup power source in case of a power outage, or want to reduce your electric bills during peak periods.
How to connect solar panels to the grid
While requirements may vary from vendor to vendor, it's fairly straightforward to connect solar panels to the grid.
- Get Your Electrician's Approval : First, you need to get your electrician's approval and apply for interconnection. Most solar installers will handle the grid connection process for you, but it's worth checking.
- Site Inspection : Many utilities require site inspections as part of the interconnection process. In most cases, an inspection will be performed to determine the wiring and equipment required for the solar power system.
- Two-Way Meter : When installing solar panels, a two-way meter from your utility provides a connection between your home and the grid. Depending on the solar energy provider, these meters may be included in the installation process. Your energy supplier uses this meter to see how much energy your solar panels are producing and how much electricity you are using from the grid.
Frequent questions
How much do solar batteries cost?
The average cost of a home solar battery ranges from $12,000 to $22,000.
Can you save money by going offline?
Turning off the electricity can potentially save you money if you live in a remote area where power lines are inaccessible. The cost to extend the power line to your home can range from $15,000 to $50,000 per mile. The farther you are from the network, the more expensive it becomes to connect to it. Not only can your solar panels provide reliable electricity in rural areas, but you don't have to pay for utility hookups.
Do I have to log out?
While less common, going offline is still a viable option. It mainly depends on the reasons why you use solar energy and your geographical location.
100% clean energy : With an off-grid solar system, you generate and use 100% clean energy, unlike grid-connected solar systems which depend in part on non-green sources.
Rural Areas : Off-grid solar panels can reliably supply off-grid areas with electricity, and you don't need to pay for many utility connections.
