Rooftop Solar Could Power Manufacturing-Sector Electricity Demand

Researchers from Boston-based Northeastern University recently published a study showing that roof-mounted solar photovoltaic (PV) arrays could serve the annual electricity requirements of up to 35% of America’s manufacturing base.

 

Corning’s manufacturing plant in Vineland, New Jersey, hosts one of the world’s largest rooftop solar installations, covering 11 acres on top of five buildings. Image used courtesy of Corning

 

Nearly every U.S. facility manufacturing furniture, textiles, and apparel has the potential to draw a portion of its power from on-site rooftop solar panels, according to U.S. Department of Energy (DOE) data used by the researchers.  

Most industrial firms currently source their renewable energy via off-site power purchase agreements. On-site installations are another potential avenue, albeit less common and more capital-intensive. According to the study, those installations represent less than 0.1% of America’s industrial electricity demand. 

However, this trend could change, given the incentives for switching to renewable energy resources. More manufacturers are looking to reduce their emissions to meet decarbonization targets. They’re also motivated to tap into newly available subsidies through the Inflation Reduction Act. For new solar installations, including at commercial facilities, the federal government extends a 30% investment tax credit to cover project costs and a per-kilowatt-hour production tax credit. 

That context aside, the researchers noted that the results suggest a substantial opportunity for industrial companies to leverage rooftop solar PV to meet their emissions-reduction goals. The U.S. industrial sector uses various energy sources, primarily natural gas, petroleum, and electricity. Industrial activities account for around 35% of all end-use energy consumption in the U.S., according to U.S. Energy Information Administration data, with manufacturing activities claiming an 81% share.  

 

Powering Up to One-Third of the Manufacturing Sector

The Northeastern University study, published in Environmental Research Infrastructure and Sustainability, found solar could fulfill 5% to 35% of the annual electricity requirements in the U.S. manufacturing sector, assuming net metering and depending on geographical location. 

To model the electricity supply intensity of solar arrays against the corresponding average power demand per unit of manufacturing floorspace, the researchers used data from the DOE’s Manufacturing Energy Consumption Survey, which represents around 98% of U.S. manufacturers. 

 

Intensity ranges of electricity demand and roof-mounted solar supply in different manufacturing subsectors. Green indicates high-efficiency supply, purple shows low-efficiency supply intensity, and red signifies the standard error for each sector. Image used courtesy of Institute of Physics (IOP) Publishing

 

Furniture, textiles, and clothing production can be powered through on-site solar in nearly every factory—accounting for 2% of the country’s manufacturing electricity usage and 6% of floor space. The net of possible sites widens when considering summer seasonal patterns, especially in southwestern states such as Arizona, Nevada, New Mexico, and California, which have high solar output in warmer months. The study found that nearly 40% of U.S. manufacturing subsectors could use solar PV for their electricity needs in the Southwest during the spring and summer. 

In addition to fulfilling 100% of electricity demand across several sectors, the study also found that on-site PV installations can open up the ability to maintain limited operations during grid disruption compared to off-site sourcing of renewable energy. Adding on-site energy storage systems boosts those benefits even more. 

 

Corporate Solar Installations Trending Upward

The study’s findings come as commercial solar installations at corporate offices, retail centers, manufacturing facilities, and other sites are increasing nationwide. A recent Solar Energy Industries Association (SEIA) report tracks the rise of corporate solar installations, covering some 18.5 gigawatts (GW) of installed solar capacity and comprising more than 70% of all commercial installations in the U.S. 

Though on-site installed corporate capacity has grown steadily since 2018, its pace falls behind off-site solar amid the expansion of off-site procurement. Over 70% of all off-site solar came online within the last 2.5 years. Still, half-year data from January to June 2022 shows a relatively even share between the two, with 647.78 MW of annual installed on-site capacity and 706.9 MW off-site. 

 

Annual installed corporate capacity for on- and off-site solar installations. Image used courtesy of the Solar Energy Industries Association

 

Tech and retail dominate corporate solar installations, with Meta, Amazon, Walmart, and Target leading capacity in SEIA’s report. Uptake is much lower in the manufacturing sector. EVRAZ North America ranks first in this category, with 300 MW capacity. The Chicago-headquartered steel producer launched its $285 million Bighorn Solar project in 2021, adding 300 MW of capacity via 750,000 solar panels at its Rocky Mountain Steel factory in Colorado. At that time, it was among the largest on-site solar projects in the country and the world’s first steel mill to be almost entirely powered by solar energy. 

The second-highest corporate solar adopter in the U.S. manufacturing sector is L3Harris Technologies, with 100 MW. The Florida-based aerospace and defense contractor recently initiated work on an on-site solar project and a value of distributed energy resource (VDER) community solar-style project—both expected to be built before 2025. In 2021, L3Harris completed its 163-MW Elm Branch solar project in Texas. The company’s 2022 sustainability report notes contributions from that site helped it surpass its 2026 target to reduce emissions by 30% ahead of schedule. 

Next is Solvay, with 91.8 MW of installed capacity. Its 2022 integrated annual report mentions 63 of its sites sourced a share of their electricity supply from solar, wind, or other renewables. It currently has several on- and off-site solar projects underway at its plants worldwide, expected to come online over the next few years. 

Corning ranks fourth, totaling 88.9 MW. Its Corning Pharmaceutical Technologies plant in Vineland, New Jersey, was one of the world’s largest rooftop solar arrays when installed in 2012, totaling 2.8 MW from 11,300 solar panels spread atop five buildings spanning 11 acres. The company has another rooftop solar array in Amsterdam, with 1,700 panels providing 60% of the plant’s energy needs. These are just a few of several solar installations at Corning’s facilities. 

The Clorox Company is another corporate solar user, totaling 71.6 MW. In 2019, the company signed a 12-year virtual power purchase agreement with Enel Green Power to source 70 MW annually from the Roadrunner solar plant in Texas.