Assessment of Human Resource Utilization in the Expansion of the Danish DH Sector 

Denmark’s district heating expansion is often cited internationally, yet little was known about the actual staffing required. This project documents how Denmark scaled the district heating share of the heat demand for heating buildings from 30% to 50% between 1979 and 1989. The oil crises of the 1970s pushed the country to rethink its energy system, leading to the 1979 Heat Supply Act. This policy framework urged major investments in district heating based on CHP, as well as the development of a new natural gas infrastructure. Understanding the associated human resources clarifies why the transition succeeded and what capacities other countries may need to develop.

Historic drivers behind the expansion of district heating in Denmark

The transformation of the Danish heating sector began in response to the oil crises of 1973 and 1979, which exposed the country’s dependence on imported fuels. Policymakers introduced a coordinated energy strategy centered on energy security, efficient heat supply, and the use of Danish natural gas. Central to this was the 1979 Heat Supply Act, which required municipalities to prepare heat plans and designate areas for district heating, natural gas, or individual heating. This legal framework created a nationwide system for strategic, socioeconomic heat planning.

Within this framework, district heating networks expanded substantially. Collective heat supply grew from 30% to 50% of national heat demand within a single decade, replacing thousands of oil boilers. The success was underpinned not only by investments and technology but also by coordinated staffing across national agencies, municipalities, district heating companies, and newly established transmission companies.

Institutional roles and staffing requirements at national level

The Danish Energy Agency played a significant role, dedicating around 30 FTEs per year to guiding municipalities, preparing legislation, and approving heating plans. This included operating three regional “heat offices” that traveled across the country to support local authorities. The Energy Complaints Board, established in 1982, contributed 1–2 FTEs to ensure price transparency and resolve disputes in a consumer-owned, self-regulating sector.

The Danish District Heating Association expanded its secretariat to 11 employees, shifting from technical cooperation to policy engagement. It became a strong voice in national discussions, supporting heat planning and defending the role of district heating amid the development of the natural gas grid.

Municipal responsibilities and the use of consultants

Under the Heat Supply Act, municipalities became the heat planning authority and carried responsibility for developing and implementing heat plans. Most municipalities relied on existing staff from building permitting or environmental departments, equivalent to around 0.1–0.5 FTEs per year. Because internal staffing was limited, consulting engineers played a major role in preparing heat plans and assessing socioeconomic feasibility. Municipalities also guaranteed loans for district heating investments, linking planning to financing.

This model enabled both local ownership and professionalization. By 1989, nearly all municipalities had completed heat plans, illustrating the effectiveness of combining local authority with consultant support and national oversight.

District heating companies and their resource requirements

District heating companies carried out the practical planning and preparation of expansion projects, including technical design, financial analysis, tendering, and consumer agreements. Resource needs varied significantly depending on company size. Small cooperatives typically had no internal staff for expansion tasks, relying entirely on consultants (1–2 FTEs annually). Medium-sized companies used 1–2 internal FTEs supported by 2–3 consultants, while large municipal utilities could dedicate 5–10 internal specialists plus 3–6 external advisors per year.

These differences reflect the diversity of Denmark’s DH landscape, where both large city systems and small consumer owned networks contributed to national expansion. owned networks contributed to national expansion.

Transmission companies: largescale, consultant driven infrastructure projects scalescale, consultantdriven infrastructure projects

Between 1982 and 1984, four major transmission companies were established: CTR, VEKS, Aarhus, and TVIS. They created some of Europe’s largest transmission systems, enabling efficient use of CHP and waste heat across more than 30 municipalities. These projects required 24–63 FTEs per year over a three-year design period, with 10–15% of project investment spent on consulting engineers. Internal staffing was minimal, making the technical and design tasks in these complex projects highly consultant-driven.

Contemporary case studies: staffing needed today

Two modern cases provide a perspective on current staffing levels. The new consumer-owned system in Bjæverskov relied heavily on volunteer engagement but still required roughly 2 FTEs of consultant input per year during planning and design. In Holbæk Municipality, updating the heating plan required 0.5 FTEs internally plus 0.1 FTEs from consultants. These examples represent that district heating expansion still requires coordinated public and technical capacities.

Impact of the report

• It is important to understand the background and situation in Denmark prior to making any comparisons to the developments seen in other countries today.
• The numbers are very much influenced by Danish framework conditions and the stage of development found in the industry at that time. Denmark already had 30% heating from district heating, an established municipal bank etc., but had to establish the Danish Energy Agency and other institutions.
• The report provides a documented benchmark for the number of staff resources required to expand district heating at a national scale over a 10-year period. It clarifies the historical context behind Denmark’s success, enabling more accurate comparisons with today’s conditions.