Back in 2009, when the COP15 (United Nations Climate Change Conference) in Copenhagen was planned, the top management and the political majority of Albertslund Municipality decided on an ambitious climate goal: By 2025, we will have fossil-free electricity and heat supply in Albertslund!
By Steen Westring, Operations Manager, Albertslund Fjernvarme
We felt it was a bit crazy at Albertslund Supply/District Heating Company (ADHC). Albertslund had no direct control over the fuel mix of the electricity delivered to Albertslund – but as a partner of the Greater Copenhagen District Heating Network, we could influence the decisions about the fuel mix when producing DH. We started planning for the future ….
In 2015, a new DH strategy supporting the “Fossil Free Vision for Albertslund Municipality” began full power. The politicians confirmed the 2025 goal of a fossil-free DH supply in Albertslund and accepted a plan for low-temperature DH (LTDH) in the municipality.
Albertslund was built in 10 years
Albertslund Municipality was built from the early 1960s to the early 1970s – with many cheap pre-fabricated concrete buildings – some expected only to last for 20 years. However, the buildings are still here! 60% of the homes are non-profit social housing and to be thoroughly energy refurbished before 2025.
The district heating (DH) supply of Albertslund started in 1964 as a second-generation DH
Since the early 2010s, newly constructed and newly energy refurbished housing areas are supplied with low-temperature DH (60/35). It was not only the houses, which needed to be refurbished, so did the DH network. In many housing districts, built in the 1960s, the main supply pipes were underneath the houses in the crawl spaces. At the time it was considered an intelligent solution, as the houses exploited the heat from the poorly insulated pipes. But today – very outdated floor heating it is!
A year later, it all began:
- Transforming from 2nd or 3rd-generation DH supply to a 4th-generation DH supply (4GDH) by January 2026.
- By the end of 2016 every house owner in Albertslund was informed twice in direct mails: “By 2026, your house will be ready to receive 60 degrees DH water.”We told the house owners how we would support them and guide on how to improve their homes.
- The strategy was approved by the “Users Council” and by the politicians with only little discussion, and we received no formal complaints on the decision from the +7.000 end users.
Why 4GDH in Albertslund?
4GDH is considered vital for a fossil-free future. With lower temperatures, we will reduce the heat loss from the DH network by 50%. Another benefit is the integration of fluctuating electricity production from windmills and photovoltaics. 4GDH can respond to that; heat pumps become more efficient with a higher COP, and heat storage becomes easier with lower temperatures – on a short and a long perspective. It all leads to lower capacity costs for the energy system. We can support the energy system and use the energy system better.
We use a shunt valve for each new LTDH area
With a shunt valve, we can lower the temperatures behind the shunt by mixing hot and cold water, and we can boost the pressure too. Today we have eight active shunts with LTDH areas connected to each of them. We have more shunts in line to be installed.
When we made the plan for 4GDH, more than half the housing stock was about to be energy refurbished. But, in 2025 the majority of the homes will be ready for LTDH.
Now, we have to decide how to continue: One possibility is two parallel DH systems:
- A 3GDH for the non-refurbished houses,
- and a 4GDH for the new houses and the refurbished houses.
We will focus on the privately-owned houses developing energy refurbishment concepts with the local housing organizations – and offering house owners free energy consulting. If we can improve “the rest,” we can reach 100% LTDH.
With 4GDH comes more focus on data.
In 2020 we changed every +7.000 DH meters to smart meters. We built a Wireless M-Bus system in Albertslund. It makes billing easier, and it gives an in-depth knowledge of the energy performance in all buildings.
Smart meters and “No money upfront”
Smart meters are considered a stepstone for lowering temperatures. Another important stepstone towards 4GDH was the “No money up front”: An opportunity for end-users to rent a new DH unit from the utility. To be a part of it we require well-functioning radiators and valves inside the houses. We make sure the new DH unit is installed correctly and take over the maintenance of the units. The customer don’t have to pay anything up front – but only pays a monthly rent and service fee. We improve efficiency, and we get better connections with the end-users.
Albertslund has since 2019 participated in the EU Horizon 2020-financed project called REWARDHeat, (Grant agreement N. 857811), where the focus is on making better use of energy data:
- Can we use historical energy data and weather data for future prognosis?
- And thereby improve the efficiency of the whole DH system?
- Can we spot weak links/end users needing special attention?
- Can we spot pipes with a high heat loss?
With REWARDHeat we have installed our first pre-fabricated shunt from Grundfos in a non-refurbished housing area called Portage. Last winter, we gradually turned down the forward temperature to 100 villas built in the 1960s. When February was freezing cold, the Porsager villas received only 60 degrees. We monitored the energy consumption and the cooling for each villa. Five villas had difficulties. With minor adjustments to the heating systems, they were able to handle the lower temperatures.
It came as a surprise they performed so well.
In the REWARDHeat project, we have a budget for developing skids to improve the conditions in the houses. The skid could be an electric boiler, increasing the temperature when required – but it was not necessary this time.
New pricing system
Albertslund DH buys the heat from VEKS as part of the Greater Copenhagen CHP system. VEKS introduced variable costs for each month a few years back.
For improving the economy of energy refurbishment for the end-users, ADHC introduces a new pricing model: Higher DH prices for the customers in the winter and lower in the summertime. The new pricing system is to be ready within a couple of years.
People should not freeze, so let’s make sure they don’t!
In Denmark, we dimension heat systems for an outdoor temperature of minus 12 °C. But how often is it minus 12 °C? Not often!
And if it becomes minus 12 °C, we can increase the temperature for the few hours needed. LTDH 360 days a year is a vast improvement to HTDH 365 days a year.
What if everyone is not ready for lower temperatures in 2026?
We believe we can find individual solutions for them. It could be an electric boiler at a historic building or some retired people’s home with no wish or money for energy refurbishment projects. If we raise the temperature to one and lower the temperature to 500, it makes sense. It’s not all LTDH or no LTDH.
Albertslund 4GDH is closely connected with the renewal of the town. Houses are refurbished, and the existing 3GDH are too. The additional investment for the next step to 4GDH is profitable indeed. And research agrees with us. With more data, we will prove it!