Easter winds brought cheap electricity but Haderslev district heating could not benefit

Strong winds over Easter produced abundant cheap and green electricity in Denmark, but Haderslev District Heating was unable to take full advantage due to grid constraints, reports DR.

The company, which has invested in electric heat production to reduce reliance on fossil fuels and biomass, could only run its heat pump at full capacity while its large electric boiler had to operate at reduced output. The limited grid capacity forced the utility to burn wood chips in an older plant—both more expensive and less sustainable.

“We saw the potential during Easter when electricity was essentially free,” said director Morten Hartmann. “We could have replaced wood-chip heating with electric heat, but we lacked the grid capacity to do so. It’s incredibly frustrating.”

Hartmann stressed that the company’s goal is to provide stable and affordable heating, but grid limitations prevent them from using existing infrastructure effectively. Without improvements, he warned, the utility may need to invest in gas boilers—contradicting climate targets and potentially raising prices for customers.

Grid bottlenecks slow green transition

Electricity now accounts for roughly 10 percent of Denmark’s district heating, nearly double the share from two years ago, according to the Danish Energy Agency. However, a survey by industry group Dansk Fjernvarme found that 40 of 188 district heating companies nationwide have faced restrictions on electricity supply, forcing them to burn more gas or biomass instead.

Brian Vad Mathiesen, a professor of energy planning at Aalborg University, called the issue a “major problem” for Denmark’s green transition. “These solutions in district heating are the most critical short-term investments for integrating renewable energy and phasing out fossil fuels and biomass,” he said.

Mathiesen argued that expanding grid capacity alone is insufficient. Instead, he proposed a system akin to congestion pricing—where electricity users pay more during peak demand—to incentivize flexible consumption and optimize existing infrastructure.

“We can’t simply double the amount of copper in the grid as electricity demand grows,” he said. “We need price signals and technical limits to manage usage, and we need them urgently.”

Moratorium on new grid connections

Denmark’s transmission system operator, Energinet, has temporarily halted new grid connections for three months to prioritize existing users, including district heating plants and industries. The pause aims to free up capacity for essential services amid surging demand from data centers and battery parks.

In Haderslev, Hartmann remains hopeful that full use of the electric boiler could further lower heating costs—following a recent reduction of 670 kroner per household—but warned that without additional electricity supply, prices may eventually rise.