Photovoltaic ballast is a heavy-duty, non-penetrating solution for installing solar energy, and installers use concrete blocks to install the array instead of punching holes in the roof or screwing into the ground. Ballast systems are flat roof racking systems typically used on flat or low pitched roofs. This racking system is typical on large commercial projects, where many homeowners don't want to poke holes in the roof on low-slope, flatter roofs. Ground-based solar installations have some of the same issues. Solar panels mounted on top of the landfill cover cannot penetrate this lining. In a ballasted racking system, concrete blocks are placed in the system to reduce the weight of the solar panels and protect the panels from weather elements such as wind or snow.

No roof is completely flat. The roof is built with a slight slope so water can drain to avoid settlement, which could damage the structure. When installing solar on larger "flat" roof installations, limiting penetration is key to further preventing damage from leaks. Roof ballast racking system are built for these types of projects. By using proper weight distribution, low-to-floor single module mounts for use on roofs with slopes between 1 and 3° can be installed without a single penetration. If the roof is in the 4 to 7° range, some penetrations and attachments may be required, and anything above that is considered pitched or pitched.

The use of ballasts in ground-mounted installations has opened up a new market, including landfills, superfunds, and brownfields on different types of land.
Ground mounted ballasts can be installed using all concrete block types. The first step is to determine how much weight a site can handle, including the weight of the equipment. Installers have to transport precast concrete blocks or pour them on site, sometimes driving 70,000 pounds. On-site cement trucks are not possible. The installer should ultimately decide on the best type of ballast for a particular site. Using cast-in-place concrete, installers avoid shipping costs and do not have to physically move precast blocks to each array. They can use cement pumps and fill pots to keep the shelves in place. As for precast concrete, you can buy pavers in bulk from a home improvement store or supplier. Installers can hire unskilled workers on these projects, since a lot of the work is just placing concrete blocks on the bottom of the racks.