In a recent study, “Technical feasibility of powering U.S. manufacturing with rooftop solar PV,” published in the journal Environmental Research Infrastructure and Sustainability, researchers at Northeastern University examined the potential of deploying rooftop solar photovoltaic (PV) systems to meet U.S. manufacturing industries’ electricity needs. The study focuses on evaluating whether the existing roof spaces on manufacturing buildings across various states and sectors can generate sufficient solar power to cover their annual energy demands, contributing to industrial decarbonization.

Billions of square meters of rooftops

A separate 2016 study by the Department of Energy’s National Renewable Energy Laboratory (NREL) stated that “there are over 8 billion square meters of rooftops on which solar panels could be installed in the United States, representing over 1 terawatt of potential solar capacity. With improvements in solar conversion efficiency, the rooftop potential in the country could be even greater. Residential and other small rooftops represent about 65% of the national rooftop potential, and 42% of residential rooftops are households with low-to-moderate income.”  This lays the foundation for an opportunity that the Northeastern University research expands on.

The industrial sector is a major consumer of energy and producer of greenhouse gas emissions, accounting for significant shares of global energy consumption and emissions. The transition to low-carbon energy sources, particularly through the adoption of on-site renewable energy installations, such as rooftop solar PV, is crucial for achieving decarbonization targets. The paper mentions various global efforts and pledges by manufacturing firms to reduce their carbon footprint by integrating more renewable energy sources into their operations.

The Northeastern study uses data from the U.S. Department of Energy’s Manufacturing Energy Consumption Survey to estimate the electricity demand per unit of floor space across different manufacturing sectors. This demand is compared against the potential electricity generation from rooftop solar PV installations, which was simulated using the System Advisor Model from the NREL. The simulations consider factors such as solar panel efficiency, geographic location and local weather conditions to assess the monthly and annual generation potential.

The findings reveal that rooftop solar PV could fully meet the electricity requirements of between 5% and 35% of the manufacturing sectors analyzed, depending on their geographical location. Light manufacturing sectors such as furniture, textiles and apparel are particularly well-suited for complete solar self-sufficiency due to their lower energy intensities. Geographical variation plays a significant role, with states in the Southwest having higher solar generation potentials due to more favorable weather conditions.

Seasonal adjustments and more policy attention

The study also discusses the feasibility of solar PV in different seasons, noting that spring and summer months offer higher solar output, which can potentially expand the list of sectors and locations where solar self-sufficiency is achievable. This seasonal variability is crucial for planning and maximizing the use of solar installations.

The overall viability of solar energy is of growing interest due to declining costs and technological advancements. On-site solar generation helps in meeting decarbonization goals and enhances energy security by reducing dependence on external power sources and maintaining operational capability during grid disruptions.

While the technical potential for rooftop solar PV is significant, its actual implementation depends on economic factors, regulatory incentives and individual firm strategies. The Northeastern research team suggests that targeted policies and incentives could encourage more widespread adoption of rooftop solar in sectors and regions where it is most feasible.