Solar for Greenhouses
If you’re interested in gardening, off-grid living, or sustainability, a greenhouse might be near the top of your Christmas wish list this year. Or perhaps you already have a greenhouse and are looking for ways to make that greenhouse even greener.
If so, you’ve probably come across the idea of incorporating solar power into your greenhouse design. As legislation surrounding carbon emissions continues to pass and sustainable living becomes more mainstream, solar has become more prevalent. However, many people still have questions about how to use solar for greenhouse power.
Why Use Solar Power for Your Greenhouse?
Greenhouses are awesome. They allow you to cultivate the perfect microclimate for your food and plants to grow. They keep pests out while keeping potentially invasive plant species in. In short: they help you grow food sustainably while protecting the surrounding ecosystem.
However, when designed without sustainability in mind, greenhouses can be incredibly power-hungry. That’s why many are turning to solar power for greenhouse design.
A greenhouse’s primary purpose is to keep the plant life inside at a consistent temperature, usually warmer than the ambient environment. Greenhouses work great during spring and summer days when the sun naturally heats it, but what about nights and during the winter?
To maintain that microclimate year-round, you will need to heat your greenhouse during the winter months. Using conventional methods to heat a greenhouse all winter is expensive and unsustainable.
How Solar for Greenhouses Lowers Your Carbon Footprint
Conventional solar panels are not carbon neutral; their production does create some greenhouse gas. However, the amount of green energy a solar panel produces during its lifetime makes up for the small carbon debt it owes at the beginning of its life.
There are also other ways to use solar to heat a greenhouse, such as storing heat for use at a later time. These passive residual heat methods are almost entirely carbon neutral and do not require solar panels.
Finally, if your solar greenhouse is tied to the grid and is big enough, you could generate energy for your home or even push excess power back to the grid. This is a great added benefit, especially if you qualify for net metering incentives.
Heating Your Greenhouse with Solar Power
Let’s look at the two main ways solar energy can be used to power or heat a greenhouse.
01. Solar Photovoltaic Panels
Using solar panels for greenhouse power is what most people think of when thinking of solar greenhouses. The photovoltaic panels produce electricity that powers electric equipment inside the greenhouse. This equipment could include fans, pumps, or lights. The term “solar-powered greenhouse” typically refers to this method of powering a greenhouse.
When considering solar panels for your greenhouse, you must determine the “electric load” or how much total power you will need to generate. A single solar-powered fan for greenhouse exhaust won’t require too much power and can be run off a small PV (photovoltaic) solar panel system.
Another thing to remember when considering solar for greenhouse design is that a solar-powered system will need an inverter to power large pieces of equipment. Your small fan might be able to run directly off the DC current generated by the solar panels, but bigger appliances will require AC current from an inverter.
The cost of solar panels and a complete installation will depend on the size of your greenhouse, the amount of power you need to generate, and whether you will need to include additional equipment like an inverter.
02. Passive Solar Heating
A passive solar greenhouse is designed to maximize the efficiency of the heat from the sun. The term “solar greenhouse” (as opposed to “solar-powered greenhouse”) refers to this type of design.
Passive solar greenhouses work by capturing the sun’s energy during the day and storing it for use at a later time. One example includes placing large, dark-colored water barrels around the edges of the greenhouse interior.
The barrels act as a solar heaters for the greenhouse. During the day, the sun heats the water in the barrels; overnight, the barrels release that heat into the building.
A passive solar greenhouse might make sense if you just want to keep the greenhouse warm overnight or during the winter and don’t need to use solar to power any lights or appliances.
Remember that although a passive solar greenhouse sounds simpler than a solar-powered one, it may not necessarily be cheaper. Depending on structure size and the quality of the materials used, a passive greenhouse could cost anywhere from a few hundred to tens of thousands of dollars.
Tips on Designing a Solar Greenhouse
There are plenty of reasons to get a solar greenhouse, none of which are bad. Understanding your motivation for having a solar greenhouse will help with planning. This will help you to determine whether you need a traditional photovoltaic panel setup or if simply capturing and storing passive heat is enough.
Will your greenhouse be off-grid?
Perhaps you’re interested in going completely off-grid or like the idea of growing your own food sustainably. You might feel a moral obligation to use less power. Or you may live on a site where hooking up a greenhouse to a conventional power source simply isn’t possible.
Can you benefit from net-metering incentives?
If your solar greenhouse can be tied to the grid, and you haven’t ever considered installing solar panels on your home, you may want to give that some thought. Many people who love the idea of a solar greenhouse may not have considered that their home might be a better candidate for a solar installation. A home installation may allow you to reap many financial benefits of solar energy and can empower your life in many ways.
Does the environment support passive solar?
If you go with a passive heat-storing mechanism, make sure that you understand the limitations of the design and what factors impact its effectiveness. For example, a passive solar greenhouse in Alaska will retain far less heat than a solar greenhouse in California.
Solar is Always the Best Solution
Using solar for greenhouse power is a highly sustainable, cost-effective way of maintaining your greenhouse environment year-round. Whether you install solar panels to power equipment in your greenhouse or design your building to store and use passive heat efficiently, a solar greenhouse is a great solution. Utilizing solar energy will lower your carbon footprint and provide a stable climate for your plants all year.
If you’re looking for solar modules for your greenhouse, Array manufactures Innovative Solar for Modern Houses, ADUs, Prefabs, Tiny homes, Containers, and More.
