CASE STUDY: Minnesota DOT Solar Projects
Project Summary
In 2017, Minnesota launched two innovative solar projects on Department of Transportation (MnDOT) properties to generate cost savings, and as part of the state's effort to reduce environmental impacts and increase renewable energy generation. In 2019, MnDOT debuted their first solar project, a 1.4-megawatt (MW) array built on the roof of Ramp A, a state-owned parking garage in Minneapolis (Figure 1). The large solar array covers over half of the parking garage deck without removing any parking spaces. Following the Ramp A project’s success, MnDOT sited its next 1-MW solar array in Afton, at an agency-owned gravel pit that was previously used for storage. Through partnerships with local solar developers, these community solar projects at formerly underutilized properties will provide clean energy to MnDOT and local households while generating substantial cost savings for MnDOT.
Project Motivation
The Ramp A and Afton projects were two of many developed in efforts to reach the environmental and energy goals set forth via state executive order in 2017. MnDOT established a team that included representatives from the Offices of Chief Counsel, Land Management, Environmental Services, and Sustainability. The team was responsible for building out initiatives that explored the potential for solar to support MnDOT’s energy needs, reduce costs, and lower emissions. In collaboration with in-house land management and right-of-way experts, they developed a plan to leverage underutilized state property for innovative clean energy projects.
Project Implementation
The Ramp A garage is owned by MnDOT, operated by the City of Minneapolis, managed by a private parking company, and classified as a bridge by the Federal Highway Administration (FHWA). To lead the Ramp A project to fruition, MnDOT worked closely with the U.S. Federal Highway Administration (FHWA), which provided oversight and ensured that the project followed U.S. Department of Transportation’s (USDOT) permitting requirements and regulations. Through a competitive bidding process, the garage space was leased to Cooperative Energy Futures (CEF), a community-owned clean energy cooperative, to operate a 1.4-MW solar photovoltaic (PV) system as a community solar garden. Eighty percent of the electricity is sold to CEF members who subscribe to the solar garden, and MnDOT subscribes to the remaining 20 percent. Anyone can join Cooperative Energy Futures as a coop member, which allows access to community solar subscriptions and voting ability. The length of the lease is 25 years. The MnDOT team and solar developers worked together to obtain approval from the Minnesota Public Utilities Commission. It is expected that over the course of the 25-year lease, the Ramp A project will benefit nearly 200 households and generate over $600,000 in revenue for MnDOT through electricity savings and rent payments from the developer.
Figure 1. Solar Garden - ABC Ramps - MnDOT (state.mn.us)
For the 1-MW Afton solar project, MnDOT decided to repurpose an 11-acre, unused gravel pit site owned by MnDOT for a solar garden instead of selling the parcel. Through a sole-source process, MnDOT selected Novel Energy Solutions, a local solar developer, to lease the property (Figure 2). The Afton site became the first ground-mounted solar project on MnDOT property and has contributed to the City of Afton’s efforts to offset all electricity used to power buildings, streetlights, wastewater treatment systems, and stormwater lift stations by producing renewable electricity. MnDOT receives lease payments and subscribes to 40 percent of the total subscriptions for energy produced at the site. The project saved MnDOT’s Metro District, which serves the Twin Cities Metro Area, over $80,000 through bill credits during its first year and will reduce nearly 32,000 tons of greenhouse gas (GHG) emissions annually over the solar garden’s lifetime.
Figure 2. Community solar garden in Afton, Minnesota, south of Interstate 94.
Challenges & Solutions
Environmental review of the solar projects took longer than expected for the solar developers to complete. Vegetation management was a challenge at the Afton site because there were noxious weeds present that required complicated weed control and seeding, delaying construction. The MnDOT solar team collaborated with MnDOT’s Office of Environmental Stewardship, which provided support in the form of legal guidance and documentation for native planting and weed control requirements.
For future projects, MnDOT plans to include clearer requirements on vegetation management in the operator selection criteria and lease agreements. MnDOT is hoping this will attract contactors who are familiar with proper vegetation management practices. MnDOT will also broaden the scope of the environmental review process to include a thorough site investigation and paper inspection, reviewing maps and historical documents, before a lease agreement is finalized. Given a relative lack of environmental permitting expertise at some solar development companies, MnDOT foresees a continued need for significant support from MnDOT staff to oversee contracting, compliance, native planting, and weed control.
Environmental stewardship and siting concerns should be considered carefully. The Afton site was an optimal location for solar development due to the property’s lack of trees and south-facing aspect. However, the City of Afton and other property owners had concerns about the solar development when it could potentially have been used for farmland instead.
MnDOT will incorporate sustainability into managing its existing arrays and planning future arrays. Adjacent property owners suggested that the Afton site be used as a learning field trip for local school students, which MnDOT may explore in the future. The Afton property had been previously used for maintenance storage, but MnDOT removed the storage facilities from the site to advance the solar project. MnDOT will consider co-locating future solar projects with maintenance or snow storage.
Lessons Learned
Successful projects spur continued demand to install solar on state property. MnDOT’s solar projects have continued to expand. There are now solar arrays on MnDOT property at the original Ramp A deck, the Afton site, the MnDOT District 4 Central Office in Morris, and the District 6 Maintenance and Operations facility in Rochester. Most recently, MnDOT installed solar panels at MnDOT’s Northfield Truck Station. The 30-kilowatt solar array is expected to generate 37,500 kilowatt-hours annually. MnDOT met more of its electricity needs in 2022 with renewables than any previous year and is on track to continue increasing its share of renewable sources.
Post-project evaluation demonstrates results. MnDOT is a backup subscriber to the Afton solar array and has published extensive analysis on the details of their energy use in the Annual Sustainability Report. The report notes that major benefits of solar development projects include reducing GHG emissions, meeting the agency’s energy needs, reducing long-term operational electricity costs, and improving the agency’s climate resilience.
Strategic planning requires flexibility and a diverse team of experts. In 2022, a combination of community solar garden subscriptions, off-site wind subscriptions, and the Ramp A solar panels accounted for 24 percent of MnDOT’s electricity use. While MnDOT originally intended to add another 1 megawatt of solar capacity to Ramp A, the agency has recently redirected efforts towards standing up additional, independent solar projects. MnDOT stressed the importance of having proper legal and finance staff engagement from the earliest stages of project development. MnDOT anticipates that upcoming clean energy projects will be focused on transmission in transportation rights-of-way and plans to work with the national coalition NextGen Highways.
Figure 3. Minnesota counties included in MnDOT’s recent solar subscription agreements that have a community solar garden and subscribers or subscriptions to a garden in another county. Counties include Anoka, Benton, Blue Earth, Carver, Chippewa, Clay, Dakota, Dodge, Freeborn, Goodhue, Hennepin, Houston, Lyon, Pipestone, Pope, Sibley, Stearns, and Washington.
Conclusion
The success of MnDOT’s solar projects resulted from MnDOT’s effective collaboration with federal, state, and local stakeholders. MnDOT strategically identified underutilized state properties as project locations. A future opportunity to expand on this initiative will be to consider co-location with active MnDOT facilities. MnDOT’s solar projects demonstrate that state DOT’s can invest in clean energy projects under state legislative directives to address climate change, reduce greenhouse gas emissions, and strengthen energy resilience.