One of the important things that determine if your home solar panels will be successful is whether they are clear of shade throughout the day.
Even in locations that aren’t traditionally thought of as being good for solar, if your property has a clear view of the sun throughout the day, solar panels can generate enough power to provide 100% of your electricity needs. But if shade blocks your solar panels for even part of the day, that can have a drastic impact on your energy production. Play with different shading settings on The Solar Nerd calculator to find out just how big an effect this can be.
If you want to put solar panels on your home, but your rooftop is shaded by trees that are on your neighbor’s property, is there anything you can do about it?
Fortunately, for people in most states in the US, there is something you can do. They’re called solar easements, and they’re voluntary contracts you can enter into with your neighbor that protect your future access to sunlight.
Before explaining how solar easements work, it’s worth mentioning the special case of California, which goes beyond voluntary solar easements and instead actively protect a solar homeowner from shading by neighboring trees.
The Solar Shade Control Act prevents a neighbor from planting a tree or shrub that would shade more than 10% of a neighboring solar collector (meaning, either photovoltaic or solar hot water) between the hours of 10 a.m. and 2 p.m.
This doesn’t apply to existing trees, or newly planted trees that replace a dead tree or one that has been removed for safety reasons. This means that you can’t put solar panels on your home and then demand that your neighbor cut their trees down.
What it does do is require your neighbor to trim back any trees that are planted after your solar system is installed so that they don’t shade your system by more than 10% during peak hours. In other words, they can plant trees after you’ve installed your solar panels, but they can’t let them grow so large that they shade your system.
The peak hour requirement is a fairly reasonable compromise, because even low trees or shrubs can cast shadows on neighboring buildings when it’s late or early in the day. But solar energy production at those times is relatively low, which lessens the impact of shade on overall production.
However, this law may be need to be updated to reflect recent Califoria policy that requires new solar homes to have a time-of-use (TOU) plan. TOU plans mean that solar energy production in the early evening is much more valuable than at other times. The Solar Shade Control Act, with its hours focused on the midday peak, doesn’t protect a homeowner from shade that falls during the evening peak, which is usually about 4 pm to 8 pm.
If you’re a Californian and this situation applies to you, your recourse is to negotiate a solar easement with your neighbor.
A solar easement is a voluntary agreement that you enter into with your neighbor that protects your solar panels from being shaded in the future from vegetation or structures. A majority of states in the US have laws that allow property owners to create solar easements.
While the details of these laws vary from state to state, in general an easement differs from a normal contract because it stays with the property rather than the homeowner. In other words, if you set up a solar easement with a neighbor who later sells their home, the easement will stay with the property and be binding upon the new homeowner.
What goes into a solar easement contract? Again, the requirements vary from state-to-state, but for completeness you want a description and drawings that describe in three dimensions the specific airspace that is protected by the easement.
In other words, the easement should not be written to protect your entire property from shade, but only the specific area needed to give your solar panels access to sunlight. Because the position of the sun in the sky changes throughout the day and also through the seasons, you want your drawings to trace a line from the sun to your solar panels in both the summer and the winter, and at the different times of day when you want your solar panels protected from shade.
You’ll have to negotiate with your neighbor on the contract, so it may not be acceptable to draft a contract that gives your solar panels a clear view of the sky from dawn to dusk. Instead, a reasonable compromise would be to select some peak hours: say, 10 am to 4 pm from Summer to Winter.
What would constitute a violation of a solar easement? Let’s say you have an easement that clearly outlines a 3-dimensional “tunnel” through the airspace of your and your neighbor’s properties. If your neighbor allows a tree to grow or puts an addition onto their home that enters that airspace and therefore shades your panels, that would violate the easement.
What happens next depends on what has been agreed to in the contract. Typically, either compensation will be paid, or the property owner will be required to remove the offending tree or structure.
If the above sounds a little vague, it’s because you should look up the law in your state that pertains to solar easements. Most are very simple, and don’t require you to be a lawyer to decipher. For example, here’s the text of the Virginia Solar Easements Act:
Contents of solar easement agreements.
Any instrument creating a solar easement shall include, at a minimum:
The vertical and horizontal angles, expressed in degrees, at which the solar easement extends over the real property subject to the solar easement;
Any terms or conditions under which the solar easement is granted or will be terminated; and
Any provisions for compensation of the owner of the property subject to the solar easement.
1978, c. 323, § 55-354; 2019, c. 712.
Here’s a list that’s up to date as of 2020:
Because they’re voluntary agreements, you start by talking with your neighbor. Hopefully you’re on good terms! Solar energy is viewed favorably by a majority of people, so you could try explaining that solar panels on your home don’t just benefit yourself, but help to improve air quality and the environment for everyone. Maybe you could even convince them to go solar themselves.
Be sure to keep in mind that you’re asking a favor of your neighbor, and that an easement will follow the property even after it’s sold, unless you include a clause that excludes that. If they’re reluctant, try to think of a compensation scheme that benefits your neighbor. For example, maybe you can offer to pay for tree plantings elsewhere on their property.
The links above are state laws, so it’s worth checking to see if there are any local laws that further govern the creation of solar easements. For example, Santa Clara County in California has a local ordinance that governs solar easements for subdivisions.
Keep in mind that solar easement laws, designed to protect your access to sunlight for energy production, aren’t the same as solar access laws, which prevent entities like homeowners associations from denying homeowners the right to put solar panels on their homes. Many states that have solar easement laws also have solar access laws, but it’s not always the case. Check with your state and local government to find out.