Not every solar energy installation goes on top of a roof. Utility scale systems, community solar, and some residential systems often are mounted on the ground rather than up in the air. What many of the owners of such systems tend to forget is that steps need to be taken to control the vegetation that will inevitably start to grow up underneath and around the panels as soon as the project is completed.
Take a look at the picture above. Weeds have been allowed to grow between the panels, casting shadows that may reduce efficiency of the system. Each system needs a maintenance plan to deal with vegetation . According to James Huff ar Abakus Solar, there are 7 ways to so it, but only two of them are effective.
The first is to plant low growing grass. It is quite inexpensive and requires little maintenance. The only drawback is that weeds always find a place to grow, so occasional efforts will be needed to keep them in check. The grass has secondary benefit. It helps to keep the underside of the solar panels cool by controlling reflected heat from the ground. If panels get too hot, they will operate less efficiently.
The second method is to allow sheep to graze in and around the panels. Each sheep consumes about 1,500 calories a day of vegetable matter. Leave the bottom edge of the installation about 32″ above the ground to allow the sheep to graze in and under the entire system.
Sheep cost about $100 a head and each female will produce 2 lambs a year. Not only are the sheep self tending if the area is properly fenced, after a year or two the excess sheep can be sold at a profit. Huff strongly recommends not using goats, as they have a tendency to climb up on the panels, damaging them. Goats are also fairly rambunctious and like to eat things — like wires. Not only that, the males tend to have an unpleasant aroma. Sheep are mild mannered and smell nice.
Other farm animals are also not recommended, as they like to rub up against the panels, pushing them out of proper alignment. Huff tells one anecdote about a moose who attempted to mate with an especially attractive solar panel.
Some companies use herbicides to prevent vegetation from growing, but the impropriety of using a cousin of Agent Orange to maintain a source of renewable energy should be obvious to anyone. Mechanical mowing is expensive and can damage the panels by kicking up rocks and other debris. Small systems may make ideal places for vegetable gardens, but that is clearly not an option for utility scale operations.
If you are contemplating a ground mounted solar system, make sure you allow for maintaining the grounds around it after it is completed.
Source: Ecolocalizer Photo and graph credit: James Huff