Environmental Impacts of Solar Power

Land use

PV systems on homes or other buildings have minimal land use impact, while the land and habitat impacts of large-scale solar facilities depend on a variety of factors. Total land area requirements for a given amount of solar capacity depend on the technology and the topography of the site. Analysis of large-scale PV systems in the United States through 2019 found average land use of 2.9 to 4.2 acres per megawatt (direct current; one megawatt generates enough electricity for up to a couple hundred households).

The impacts of that land use depend in part on what a solar project is replacing. For example, displacing water-intensive agriculture in drought-prone regions can free up water for other needs, while a solar installation that involves dramatic changes to the landscape could have large impacts on wildlife and habitats. For large-scale PV systems, which can offer more electricity at lower costs, some projects may be able to reduce their impacts through siting in locations such as brownfields, abandoned mining land, or existing transportation and transmission corridors.

While solar projects have traditionally offered less opportunity to share land with agricultural uses than wind projects, in which the land footprint of wind turbines occupy only a small fraction of a project area, some opportunities are emerging. Early experiences with mixed-use “agrivoltaics” projects show how strategic deployment of PV on agricultural land can contribute to higher crop yields, reduce water use, and provide additional income for farmers.

In areas with greater land constraints, floating solar installations—sometimes known as “floatovoltaics”—can be deployed on bodies of water including reservoirs, wastewater storage ponds, and agricultural irrigation/retention ponds. While more expensive to build, floating solar can preserve land area and help reduce water evaporation and algae growth. The cooling effect of the water can also increase solar generation.

In general, siting decisions for larger projects should consider competing land uses, land ownership, and the cultural/historical significance of the area, and be made with the active participation of local communities and stakeholders to ensure that benefits and burdens are equitably distributed.