Converting Forests to Solar Facilities: Causes, Potential, and Implications

Anticipated growth in renewable energy will substantially curtail the US energy sector’s greenhouse gas emissions but has implications for land-based sectors of the economy. US climate policies and energy markets now provide especially strong incentives for expanding solar photovoltaic (PV) capacity. As a result, conversion of agricultural and forested lands to utility-scale solar facilities has accelerated over the past decade. Energy projections indicate a rapid expansion in the rate of solar development and land use changes, especially where high electricity demand coincides with access to transmission infrastructure. This implies a concentration of effects on ecosystem services. Rising public alarm regarding solar siting, initially focused on agricultural land, portends challenges for land-based sectors and the clean energy transition.This report provides a rapid assessment of potential conversions of forestland to solar facilities. We evaluate the current land use footprint of solar facilities in the United States and land use conversions to support solar production. We examine the policy structures that currently organize the development of solar capacity and evaluate the potential for future land use change. And we explore the associated economic and ecological implications of changes, social concerns, and emerging policy responses.Our analysis starts with a survey of the literature on solar land use, compilation of available data, and development of a simple projection model. Because the published literature on forest conversion is sparse, we also sought out experts in state forestry organizations, the land trust community, and the energy sector, and we interviewed them about the scope and scale of forest conversion to solar farms, as well as ways in which stakeholders may be affected. We specifically sought insights into patterns of conversion, data sources, and societal issues (e.g., equity, loss of wildlife habitat). Interviewees also weighed in on emerging policies aimed at mitigating the consequences of solar conversions.As is the case for land development more broadly, converting forests and native grasslands to solar facilities alters the provision of ecosystem services, ranging from commodities such as timber and carbon storage to public goods related to water quality, species’ habitat, recreation, and aesthetics. Consequences include those that accrue to deforestation in general but also issues specific to solar operations. The spatial concentration of solar development implies an uneven distribution of effects. As well as balancing the provision of renewable energy with loss of valuable ecosystem services, best practices for the design of new facilities need to address local communities’ concerns. At all levels of government, policy is still adapting to the challenges associated with solar-driven land use change.