By Annemarie Mannion, ENR Midwest
Minnesota Power has officially broken ground on a $450-million modernization project for its critical high-voltage direct-current (HVDC) transmission system, marking a pivotal moment in the modernization of the Upper Midwest’s energy infrastructure. With construction firm Mortenson serving as the general contractor, the project aims to overhaul aging, 50-year-old assets that have served as a backbone for regional power distribution since the late 1970s.
The scope of the project is extensive, involving the replacement of legacy converter stations and substations at both ends of a 465-mile transmission line that stretches between Center, N.D., and Hermantown, Minn. This infrastructure project is not merely a maintenance upgrade; it is a strategic repositioning of the regional grid to accommodate shifting energy demands, most notably the potential arrival of a $2-billion Google data center in Hermantown.
The Scope of the Modernization
The core of the project involves the implementation of advanced HVDC technology supplied by Siemens Energy. The existing infrastructure, which dates back to 1977, was among the first of its kind in the United States. Today, it remains one of only five overhead HVDC lines in the country.
The primary function of the converter stations at Center and Hermantown is the conversion of electricity between alternating current (AC) and direct current (DC). While power is generated as AC, the HVDC system converts it to DC for long-distance transport, which is significantly more efficient than traditional AC transmission. Upon reaching the destination, the station converts the energy back into AC for integration into the local distribution grid.
According to Minnesota Power, the modern HVDC technology will significantly reduce energy loss—which can be 15% to 30% lower than traditional AC lines over such vast distances—thereby enhancing the efficiency of transporting renewable energy from the Bison Wind Energy Center in North Dakota to Minnesota’s load centers.
Chronology of a Critical Infrastructure Initiative
The road to this $450-million ground-breaking was long and methodical. The project timeline reflects the complexity of utility-scale infrastructure planning and the regulatory rigor required for interstate transmission projects.
- 1977: The original HVDC line begins operation, establishing a vital link for North Dakota-generated power to reach Minnesota consumers.
- Early 2010s: Minnesota Power begins long-term internal assessments, identifying the inevitable need for a full-scale replacement of equipment nearing the end of its operational lifecycle.
- 2025: The North Dakota Public Service Commission formally grants the necessary permits for the modernization project, clearing the way for procurement and mobilization.
- March 2026: Minnesota Power signs a landmark agreement with Google to supply power to a proposed data center in Hermantown, providing a specific, high-demand catalyst for grid reinforcement.
- September 2026: Groundbreaking occurs for the $450-million project, with Mortenson initiating the replacement of converter stations and substations.
Supporting Data and Technical Specifications
The technical requirements for this project are as significant as the financial investment. By replacing the 1970s-era components, Minnesota Power is moving from a unidirectional flow model to a flexible, bidirectional system. This allows the grid to react to volatility in both supply and demand.
Efficiency and Resilience
HVDC systems are the "highways" of the modern electric grid. By minimizing the electromagnetic losses associated with long-distance AC transmission, this project ensures that the wind energy harvested in North Dakota arrives in Minnesota with maximum efficacy.
Beyond efficiency, the project serves as a hedge against climate-related volatility. The ability to move power in both directions provides the utility with a "failsafe" mechanism: should a weather event or technical failure occur in one region, the transmission line can be reconfigured to shunt power to where it is needed most.
The Data Center Connection
The proposed Hermantown data center represents one of the largest single-load additions in the region’s history. To support the 700 MW of new clean energy demand requested by the project, the plan includes:
- 300 MW of dedicated wind energy resources.
- 400 MW of advanced battery energy storage systems (BESS).
The involvement of Kimley Horn Associates as the engineer and landscape architect for the Hermantown project signals the scale of the site development, which must integrate heavy industrial power requirements with local environmental and community planning standards.
Official Responses and Strategic Vision
Leadership at Minnesota Power views this project as a bridge between the legacy energy era and a sustainable future.
"One of the most important benefits of this modernization is flexibility," said Josh Skelton, CEO of Minnesota Power, during the groundbreaking event. "When extreme weather hits, when system conditions change quickly, or when energy is needed in a different place than expected, the ability to move power both ways on this line becomes a real advantage."
The partnership with Mortenson, a firm with deep roots in the Midwest’s industrial and energy sectors, ensures that the construction phase—which is concurrent with a broader $900-million investment in Minnesota’s transmission grid—remains on track. Siemens Energy’s role as the technology provider underscores the project’s reliance on cutting-edge power electronics to manage the high-capacity, high-voltage load.
Implications: The Data Center Controversy
While the modernization project is technically lauded, it exists within a larger, more contentious conversation regarding the proposed Hermantown data center. The project, while promising a massive influx of tax revenue and high-tech jobs, has met with significant local resistance.
Community Concerns
Residents of Hermantown have raised several vocal objections, focusing on three primary areas:
- Economic Incentives: The proposed $80-million property tax break for the data center has been a focal point of public ire, with some residents arguing that the corporation should not be subsidized by local taxpayers.
- Resource Consumption: Concerns have been expressed regarding the environmental impact of the data center, specifically regarding water usage for cooling systems and the potential for increased noise pollution.
- Power Reliability: Critics have questioned whether prioritizing such a massive consumer of energy could lead to rate hikes or supply instability for current residents and small businesses.
Despite this opposition, Minnesota Power maintains that the HVDC upgrade is a "no-regrets" project. The utility emphasizes that the modernization is essential for the reliability of the grid regardless of whether the specific data center project proceeds. By upgrading the line now, they are ensuring that the regional grid can support whatever future energy loads emerge, whether they be from industrial growth, increased electrification of transport, or residential demand.
Conclusion: A Grid for the Future
The $450-million investment in the North Dakota-to-Minnesota HVDC line is a testament to the changing nature of the American energy landscape. As the utility moves away from the static, centralized power models of the 20th century, it is embracing a dynamic, flexible, and highly efficient network capable of handling the demands of a digital economy.
While the debate over the Hermantown data center continues, the infrastructure supporting it is already being transformed. The integration of modern Siemens HVDC technology, the partnership with expert builders like Mortenson, and the strategic foresight of Minnesota Power’s leadership highlight a trend that is likely to repeat across the United States: the massive, necessary, and complex task of rebuilding the electrical backbone of the nation to meet the challenges of the next 50 years.
Whether the data center eventually breaks ground or not, the "super-highway" of energy between North Dakota and Minnesota is undergoing a necessary evolution—one that promises to keep the lights on, the air cleaner, and the grid more resilient in an increasingly unpredictable future.
