HOT | COOL NO. 2/2022 - "Conversion from gas - Diversity...

This magazine was planned just before the crisis in Ukraine, and we did not have the chance to adjust the articles accordingly. Therefore, you may find that we avoid a situation – but we do not. Instead, we have a theme that is even more relevant and of concern to everyone in Europe, where we see strong demands to get rid of natural gas faster now than ever. Germany is on the move with the new heat planning rules; in Denmark, we see a lot of small and large gas areas being converted away from gas one by one. We have a new heat plan called "Heat Plan Denmark 2021" that we now discuss how to make even more robust and faster to reach at least a part of our short-term goal to avoid gas. But we also have other articles that briefly touch on the theme "conversion from gas" – digitalization is essential and will lead to less heat demand and, therefore, less gas. The article is about achieving lower return temperatures – an important matter to become more efficient in our business. Our editorial this time is about women in our industry – and the fact that they are way too few. The lack of diversity in our business is well-known. Now they do something about it in the UK through the DH Divas - an exciting process to follow that already gives results. We all lack all skills; it is important that we invite everyone - who shows interest - into our industry. It is the only right thing to do, and it is also good common sense.

NO. 2 / 2022



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HEAT PLAN DENMARK 2021 – A CO2 NEUTRAL HEAT SUPPLY By Peter Sorknæs, Steffen Nielsen, Brian Vad Mathiesen, Diana Moreno, Jakob Zinck Thellufsen and Henrik Lund 5



This magazine was planned just before the crisis in Ukraine, and we did not have the chance to adjust the ar- ticles accordingly. Therefore, you may find that we avoid a situation – but we do not. Instead, we have a theme that is even more relevant and of concern to everyone in Europe, where we see strong demands to get rid of natural gas faster now than ever. Germany is on the move with the new heat planning rules; in Denmark, we see a lot of small and large gas areas be- ing converted away from gas one by one. We have a new heat plan called "Heat Plan Denmark 2021" that we now discuss how to make even more robust and faster to reach at least a part of our short-term goal to avoid gas. But we also have other articles that briefly touch on the theme "conversion from gas" – digitalization is essential and will lead to less heat demand and, therefore, less gas. The article is about achieving lower return temperatures – an important matter to become more efficient in our business. Our editorial this time is about women in our industry – and the fact that they are way too few. The lack of diversi- ty in our business is well-known. Now they do something about it in the UK through the DH Divas - an exciting pro- cess to follow that already gives results. We all lack all skills; it is important that we invite everyone - who shows inter- est - into our industry. It is the only right thing to do, and it is also good common sense."

12 PODCAST – GAS CONVERSIONS - WE ARE ALL IN THE SAME BOAT! By Jens Andersen and Jesper Møller-Larsen, with moderator Morten Jordt Duedahl




By Carsten Østergård Pedersen, Asbjørn Bjerregaard Ebbesen and Rune Kaagaard Sørensen



DBDH Stæhr Johansens Vej 38 DK-2000 Frederiksberg Phone +45 8893 9150

Editor-in-Chief: Lars Gullev, VEKS

Total circulation: 5.000 copies in 74 countries 10 times per year

Grafisk layout Kåre Roager,

Coordinating Editor: Linda Bertelsen, DBDH

ISSN 0904 9681


There’s a photograph doing the rounds on LinkedIn. It’s a meeting room set for lunch. White linen, flowers on the table, lots of natural daylight. Lots of men. Lots of blue suits. Lots of grey hair.

By Rachael Mills, Co-Founder, District Heating Divas

The birth of a movement Three years ago, over a quiet gin and tonic, my business partner Liz Warren and I wondered if oth- er women working in the DH sector would be interested in getting together. Other women we knew thought it was a good idea, and so in April 2019, we hosted a small lunch, and the District Heating Divas were born. The older I get, the more I become aware of when I’m the only woman in the room. Maybe it’s self-awareness; maybe it’s other strong women opening our eyes. It’s not the fault of those individ- ual men around that table, but everyone has a role to play in making a change. Everyone of those men will have worked hard to rise to the top of their profession and earned their seat at that table. Most of them will have families. Many of them will be vocal advocates of their female colleagues. But where are the women? Where are the people of colour? The photo in question happened to be taken at a security conference, but there are plenty of other male-dom- inated industries – including the district heating (DH) sector. The good thing is that the photo was called out on social media1. The bad thing is that it still needs to be.

The energy sector is undergoing a

transformation, presenting a wide range of challeng- es and opportunities, from digitalisation to decarbon- isation and changing con- sumer demands. Success will mean attracting and retaining a diverse pool of talent capable of bringing the necessary technical and leadership skills, and

Diva: to describe a person who exudes great style and personality with confidence and expresses their own style and not letting others influence who they are or want to be. Urban Dictionary

At its simplest, the Divas is an informal business networking group for all women working in the DH sector. But it’s much more than that. It is connectedness. It’s open and welcoming. It’s friendly and collaborative. It’s inspiring and supportive. It’s fun!

fresh perspectives.” POWERful Women

The Divas have grown into a mighty group of phenomenal women. We now have:

Over 300 women in our LinkedIn group Over 150 women attending regular regional and national meetups (both online and in real life) A hugely successful mentoring programme – the Heat Exchanger – now recruiting its third cohort A STEM careers video that’s about to premiere

Oh – and we run the most interesting, engaging and memorable conferences you’ve ever been to! And it’s all done pro bono – for free – because the women involved value coming together.

1 Photo & source is provided on the final page of this document



The data suggests diversity correlates with better financial performance. Likelihood of financial performance above national industri median, by diversity quartile, % Ethic diversity Top quartile Bottom quartile 58 Why does it matter? Google ‘why diversity matters’. Go on – it’ll only take 30 seconds. You’ll be flooded with ar- ticles, reports and videos about the positive difference having a diverse workforce makes – at all levels of your organisation. International research from McKinsey found that com- panies in the top quartile for gender or racial and ethnic diversity are more likely to have financial returns above their national industry medians. “When companies commit them- selves to diverse leadership, they are more successful. More diverse companies, we believe, are better able to win top talent and improve their customer orientation, employee satis- faction, and decision making, and all that leads to a virtuous cycle of increasing returns. 2 ” In the UK, groups bringing together and promoting women in the sector are gaining momentum. The Department for Business, Energy and Industrial Strategy (BEIS) has even formed a group of groups – the Energy Sector Women’s Networking Group – to collab- orate, share ideas and support each other’s initiatives. Through this we’re now connected to other awesome women working in renewables, oil and gas, and nuclear energy – all of whom are working to improve the visibility of women across the sector. Allies, advocates and a call to action The DH sector is an exciting place to be working right now. And we’re lucky to be support- ed by many male colleagues who also want to promote and support talented women in the sector. They know that diversity and inclusion don’t just mean that women get top billing: it means that men get a fairer work/life balance, too – and let’s be honest, we all need more of that. Equality isn’t just for women: men benefit too. Let’s break the gender norms for everyone. So my challenge to you is this – what difference can you make? Right here, right now. Check to your left and to your right. Be mindful through your day. Participate with your eyes open. The change you can make may be big or may be small. It might be on a corpo- rate level or on a personal level. But it all matters. It all makes a difference. Together we all want the heat network industry to become more vibrant, more diverse, more mature, more talented, more thoughtful. Without us all being involved, nothing will change.

Feedback from our 2019 Conference

Adriana: What made me laugh was to see how uncomfortable

the room was at the beginning of the session with the drag queens. We were all like 'oh, this is so weird...' And I was sitting next to people that I'm negoti- ating with or consultants that I work with and we were all like 'aaah....this is not what we do...". And as time went by, things just changed. People embraced it and were designing their dolls…

Lina: ...there was dancing…

Adriana: …dancing - that made me laugh a lot! We were just so awkward and out of our com- fort space as soon as we had to do something with glitter and glue and paper!



Gender diversity Top quartile Bottom quartile




Gender and ethic diversity combined Top quartile All other quartiles




Source: McKinsey Diversity Database

1 Photo of men at board meeting from social media: inclusion-activity-6901111290907947008-ZbS-?utm_source=linkedin_share&utm_medium=member_desktop_web

2 Quote and the graphic both from


HOTCOOL no.2 2022

HEAT PLAN DENMARK 2021 – A CO2 NEUTRAL HEAT SUPPLY CO2 neutral energy systems also mean CO2 neutral heating sectors. However, this raises questions about what technologies should be utilized and to what extent energy savings should be implemented. In Heat Plan Denmark 2021, we investigate these questions and more.

By Peter Sorknæs, Associate professor, AAU. Steffen Nielsen, Associate professor, AAU. Brian Vad Mathiesen, Professor, AAU. Diana Moreno, PhD-fellow, AAU. Jakob Zinck Thellufsen, Associate professor, AAU and Henrik Lund, Professor, AAU.

Like many other countries, Denmark has long-term political goals for going towards a low-carbon society with an energy system based on renewables. The Danish goals are a 70% re- duction of CO 2 emissions in 2030 compared to 1990-levels and a net zero-carbon society in 2050. Such a transition raises many questions about what should be done in each CO 2 emitting sector. Investigating this is especially important for the sectors expected to lead the CO 2 reductions in the coming years. Here, the heating sector is especially interesting as the goal is to get this sector to near-zero CO 2 emissions in 2030. However, a tran- sition of the heating sector raises a slew of different questions, such as: Where is the balance between investments in heat savings and CO 2 neutral heat supply? Where should district heating (DH) be, and where should individual solutions be? What should the individual heat supply be based on? Which heat sources should the DH be based on? What are the in- novative challenges, e.g., low-temperature DH, smart meters, digitization, Power-to-X, data centers, geothermal heat, etc.? In the context of the overall energy system, it is also a question of how the heating sector best can help to integrate renewable energy sources. These questions encouraged us to investigate the future heat- ing system in Denmark and make a new heat plan for Den- mark, Heat Plan Denmark 2021. Besides investigating these questions, the heat plan should also assist authorities and utility companies in planning the heating sector’s transition.

Energy savings in the building stock are impor- tant. A good balance between energy savings and renewable energy must be achieved with low costs and low fuel consumption. This means that a continued focus on building energy renovation is important to implement 32-40% savings. District heating should be expanded to cover 63-70% of the heat market as individual natural gas, and oil-fired boilers are phased out in exist- ing urban areas and as new urban areas emerge. Outside the DH areas, the heat should come from individual heat pumps supplemented by solar thermal. This combination provides the most en- ergy-efficient and flexible solution. In DH, a targeted focus should be placed on a transition to 4th generation district heating with lower temperatures. It provides the lowest cost and most efficient use of geothermal heat, waste heat, and large heat pumps. In future low-carbon energy systems, there is great potential for utilizing geothermal and waste heat from industry, data centers, and Power-to-X. These opportunities should be exploited.



District heating should be expanded In Heat Plan Denmark 2021, we also analyze where DH should be utilized. We do this by using the estimates for heat demands for all buildings in Denmark and finding the heat density for each area without DH. We then make five scenarios for DH ex- pansion. Specifically, in Heat Plan Denmark 2021, we analyze the following expansion scenarios:

In Heat Plan Denmark 2021, we both map the geography of the heating demand and supply, as well as relate these to the integration potential in the Danish energy system. The map- ping involves seven different detailed geographical informa- tion system analyses covering all of Denmark. These include estimates for annual heat demands and energy saving poten- tials of all Danish buildings and costs and heat loss of DH grids in about 3,000 areas, which currently are without DH. These mapping data provided input for making over 1,000 hour-by- hour energy system simulations for a future Danish decarbon- ized energy system. Heat savings in the building stock In Heat Plan Denmark 2021, heat-saving options are estimated for each building in Denmark. This is done based on the Danish heat atlas, a detailed GIS mapping of estimated annual heat demands in nearly 2 million Danish buildings 1 . The estimates for each building’s demand are based on a heat consumption model that uses average heating needs based on the build- ings’ use, age, and size. The heat consumption model is linked to the building-specific data from the national Building and Housing Register. The main principle behind heat savings in buildings is that they should only be implemented until the cost of decarbonizing the heat supply is cheaper than the cost of increased heat savings. In Heat Plan Denmark 2021, we find that heat savings should be done regardless of whether DH is expanded or not. The reason is that heat savings are important for reducing costs in the energy system and keeping biomass consumption at a sustainable level. The results show that the costs in the energy system are lowest, with heat savings between 32% and 36% in the building stock. These are flat optimums, and a sensitivity analysis shows that increasing heat savings to 40% can result in further reductions in biomass consumption with only a mar- ginal increase in the energy system’s cost. The heat savings can include improvements of the buildings’ climate screen (exterior walls, roofs, etc.) and a more optimized operation of the heating systems through, e.g., intelligent me- ters and control equipment.

Buildings currently registered with DH (~ 50%)

All buildings in areas designated for DH (~ 59%)

Extensions to urban areas with heat density above 15 kWh/m2 (~ 63%)

Extensions to urban areas with heat density above 10 kWh/m2 (~ 70%)

Extensions to urban areas with heat density above 5 kWh/m2 (~ 74%)

More than 3,000 areas without DH are evaluated, and for each area, a DH grid layout is modelled, including pipe sizes, costs, and grid losses. The five expansion scenarios have been simulated in a national energy system analysis tool, simulating the entire energy sys- tem hour-by-hour. This is done to identify how the different expansion levels affect a future Danish energy system based on 100% renewable energy sources. We find that expanding DH from the current approx. 50% of the total heat demand in buildings to 63-70% will most bene- fit the energy system. The expansion is primarily at the expense of individual heating with natural gas, but also oil, biomass, and direct electric heating. In Heating Plan Denmark 2021, we propose an expansion to 70% as the main suggested expan- sion. 70% provides the lowest costs in the energy system while reducing the pressure on the need for biomass and wind pow- er in the overall energy system.


HOTCOOL no.2 2022

The spread between 63-70% is due to uncertainties in the na- tional model. Local conditions, such as the placement of new buildings, can affect the most appropriate level of district heat- ing in each area. Transition to 4 th generation district heating Though it is relevant to expand the DH system in Denmark, it is also essential that existing DH systems transition from the cur- rent temperature levels of around 80°C in the supply and 40°C in the return, corresponding to 3 rd generation DH temperature levels, to 55-60°C in the supply and 25-30°C in the return, cor- responding to the 4 th generation DH temperature levels. Such a transition must take place in conjunction with an ongoing energy renovation of the building stock. The analyzes show that reduced temperature levels in the DH system provide increased synergies for the end-user and throughout the supply chain for DH. The transition to lower temperatures reduces the grid loss in the DH pipes, making a more efficient supply. However, the crucial advantage is that it ensures a much more efficient utilization of current and future DH sources. These are mainly waste heat, geothermal, heat pumps, and solar thermal. Utilizing geothermal and waste heat Utilizing waste heat and geothermal heat allows for low fuel consumption in DH. Waste heat has previously been from electricity production and industrial processes. However, new waste heat potentials are likely to be relevant in the future, such as waste heat from Power-to-X facilities. In Heat Plan Denmark 2021, we estimate the possibilities for waste heat, partly using GIS analyses, for industrial waste heat and geothermal heat, and partly via own and others’ estimates for the development of Power-to-X and data centers. We find that in 2045 the total potential for waste heat and geothermal heat is between 12 and 42 TWh/year. This is on top of the amount of industrial waste heat currently utilized in Denmark, less than 1 TWh/year. The high potential can theoret- ically cover the entire current need for DH. In a future system, the DH demand depends partly on the DH coverage and the

energy consumption of the building mass. In the main Heat Plan Denmark 2021 scenario, DH has been expanded, and the building stock has been made more energy-efficient, resulting in the DH demand being at the same level as today. To accelerate the green transition, DH should be significant- ly expanded already before 2030. In 2045, it is estimated that waste heat from industries, data centers, and Power-to-X and geothermal energy will cover half of the DH production, corre- sponding to 19 TWh/year. While the Heat Plan Denmark 2021 focuses on Denmark and Danish conditions, it can be seen as a good indicator for the role of energy efficiency in the building sector and the role of DH in achieving the goal of decarbonization of the energy supply in Europe. Previously we have constructed analyses for Europe in the Heat Roadmap Europe projects 2 .

For further information please contact: Peter Sorknæs, Steffen Nielsen, Brian Vad Mathiesen, Diana Moreno, Jakob Zinck Thellufsen, Henrik Lund,

2 Access to European maps and reports:


FROM AMBITION TO ACTION – How Germany intends to use heat planning for its ambitious Green Agenda

By Christian Bjerrum Jørgensen, Energy Counsellor, Embassy of Denmark, Berlin

By Willy Winkler, Energy Policy Advisor, Embassy of Denmark, Berlin

Eight years, eight months, and counting down – That is how long is left until 2030, a crucial year in German climate and energy policy. By then, Germany wants to have decarbonized half of its heating sector. A task for which the German Federal Government attributes district heating a decisive role. A Danish perspective on the German trans- formation: the strategy, the benefits, and challenges to the heating sector.

The German energy transition (“Energiewende”) is a success story. Within only twenty years, Europe’s biggest economy was able to transform its electricity production from being 95% fossil fuel-based to being almost halfway towards climate neu- trality. This is a major achievement, especially considering the electricity sector’s central role in the pursuit of overall decar- bonization.

However, a look at Germany’s heating sector reveals some significant challenges still lie ahead. Accounting for more than 50% of the final energy demand, it does not take advanced statistical skills to realize that there will be no complete energy transition without a heating transition in Germany (“Keine Energiewende ohne Wärmewende”) (Figure 1).


HOTCOOL no.2 2022

Benefits to district heating However, affordability is only one aspect of DH in which the new government sees great value. An article recently pub- lished by BMWK praises the degrees of freedom DH brings as an infrastructure. Not only does the diversity of possible heat generation technologies (large-scale heat pumps, so- lar thermal, geothermal sustainable biomass, etc.) allow adapting to local circumstances with unmatched efficien- cy. DH enables the utilization of sources such as indus- trial surplus heat and deep geothermal heat. The minis- try’s conviction is that a mix of these technologies should replace the vast amount of fossil-fuelled combined heat and power (CHP) plants that currently dominate the DH landscape in Germany. The future CHP will be climate neu- tral; they will play a part as a peak load provider and create security of supply.

While this has become an idiomatic expression in the German energy policy debate, triggering a dynamic comparable to the transformation in the electricity sector has been notoriously difficult (Figure 2). Throughout the last decade, the share of re- newable energy within the German heating mix has more or less remained the same. What does it take to accelerate the heating transformation? Germans like to say: Awareness is the first step to improve- ment. A notion that the new Minister for Economic Affairs and Climate Protection (BMWK), Robert Habeck, took seriously while taking stock of Germany’s climate protection status. “We are currently a very long way from where we need to be,” Minis- ter Habeck said at a press conference. “We can predict that we will fall short of our climate targets in 2022 and 2023. But we are doing our utmost to catch up.” The Green Party politician is

Final energy consumption in Germany in 2020 after electricity, heating, and transport in billions of kilowatts hours, electricity consumption for heating and transport is included in final energy consumption electricity.

Figure 1. Source: own representation based on AGEB, AGEE-Stat; Status: 3/2021

Net electricity consumption: 487.7 billion kWh 21.4%

Heating and cooling (excluding electricity): 1,185.9 billion kWh 52.1%

Traffic (excluding electricity and international air traffic): 603.5 billion kWh 26.5%

© 2021 Agentur für Erneuerbare Energien e. V.

eager to triple Germany’s annual rate of CO2 reduction to bring the country back on track to reach its ambitious climate goal of reducing emissions by 65% compared to 1990 levels. For the heating sector, the minister plans an unprecedented transformation. By 2030, the share of renewables in the heat- ing mix shall be 50%. Considering that the share has been stuck at about 15% for the last seven years, it is hard to down- play the ambitious goal Germany has set itself (Figure 3). To rise to the challenge, the Federal Government has identi- fied district heating (DH) as the crucial puzzle piece. “Heating grids are the key to an affordable heating transition. They rank high on the government’s agenda for this legislative period”, explains Christian Maaß, Director General for Energy and the key regulator for the heating transition in BMWK.

Furthermore, the diversified generation portfolio shall be com- bined with heat storage of all shapes and sizes (days, weeks, months underground, and above). This shall provide the heat- ing sector with more flexibility and independence from dra- matic price shocks like those currently keeping gas consumers in suspense. A look towards Denmark indicates that this is a reasonable line of argumentation. According to Dansk Fjernvarme (Danish District Heating Association), due to the multitude of sources in the Danish systems, 90% of DH consumers have not expe- rienced an increase in prices despite the dramatic develop- ments in the global energy markets.

The advantages that district heating offers in terms of efficien- cy, diversity, flexibility, local value creation, and security of sup-


Share of renewable energies in gross electricity consumption, in final energy consumption for heating and cooling and in final energy consumption in the transport sector Development from 1990 to 2020

Figure 2. Source:

Federal Environment Agency (UBA) based on AGEE-Stat as of 10/2021

Share of electricity

Share of heat

Share of traffic

ply are nothing fundamentally new. Therefore, and in light of the stagnating progress in recent years, one can question if this actually could be a tipping point in Germany’s efforts to decar- bonize its heating sector. However, it is not just the well notice- able drive of the new German Federal Government that should nurture optimism. In fact, there are several reasons to assume that Germany means business in the heating transition and that district heating is at the core of the government’s strategy. Germany’s strategy for the heating sector First, climate protection recently gained constitutional status in Germany. In an infamous ruling last year, the Bundesverfas- sungsgericht, Germany’s constitutional court, declared its cli- mate policy partially unconstitutional as its lack of ambition violated inter-generational justice. The Federal Government ramped up its climate goals in response to this decision. In- stead of a CO 2 reduction by 55% by 2030, the new aim is set to 65%. And instead of aiming at achieving climate neutrality by 2050, the new end goal is already the year 2045. Besides the higher ambition, the architecture of the climate law itself should lead to changes in the heating sector. The law breaks down the overarching goal for 2030 into separate annual emission budgets for every CO2-related sector (indus- try, buildings, energy, etc.) to create accountability. Should a sector exceed its budget, it cannot hide in the mix. Instead, the responsible ministry is obliged to take immediate action to bring the numbers back on track. In 2020, all sectors except the building sector reached their goal. Hence, immediate ac- tion is required in this sector. Second, we can see that several alterations are already under- way. Many of the German local utility companies (“Stadtwerke”) have taken on the responsibility and adopted the climate goals from the federal level or created more ambitious goals. They have started to create their own roadmaps to climate neutrali- ty by drawing up transformation plans. A study commissioned by AGFW, the German DH Association, estimates that invest-

ments by the magnitude of 33 billion Euros are needed for DH to support Germany’s 2030 goal adequately.

A federal support scheme for efficient heating grids (Bundes- förderung effiziente Wärmenetze, BEW) will soon come into operation to supply the Stadtwerke with funding. The scheme will cover investments connected to the expansion, densifica- tion, and decarbonization of heating grids. Furthermore, the scheme includes an operation bonus (payment per kWh) for solar thermal plants and large-scale heat pumps. To be eligible for any funding, companies either need to present a transfor- mation plan for an existing grid or a feasibility study regarding a planned grid - a pre-requisite the support scheme also partly finances, which is quite noteworthy. Moreover, the planning does not stop at the company level. Germany increasingly looks towards heat planning as a pivotal instrument to prepare the heating transition at the municipal level. The states of Baden-Württemberg and Schleswig-Hol- stein have already made it mandatory for their larger mu- nicipalities to engage in heat planning. In addition, Minister Habeck announced that his ministry would work towards a nationwide rollout. This new focus is all too understandable. Heat is a predomi- nantly local commodity that can hardly be traded across vast distances. Considering this, the heating transition can be un- derstood as a mosaic consisting of a great myriad of local tran- sitions, each unique in their preconditions. Therefore, putting the municipalities as the true experts of the particular local circumstances into the driver’s seat makes sense. But let us not ignore the challenges of delegating this kind of responsibility down to the lowest level of governance. Challenges and possible first solutions By a rough estimate, Germany’s plans for mandatory municipal heat planning could confront about 700 German municipali- ties with a new task. For some of them, especially the medium

10 HOTCOOL no.2 2022

and small-sized ones, this could mean serious capacity issues. To alleviate this problem, a new competence center for the heating transition (Kompetenzzentrum Wärmewende, KWW) took up its work in the city of Halle at the beginning of the year. The center will pool expertise on heat planning and offer guidance to municipalities on how to approach the manner. This is a thoughtful initiative, but the municipalities are still in charge of producing the heat plans. They may, of course, choose to source this task out. However, the combination of mandatory heat planning and transformation plans being a re- quirement for access to funding will probably fill up the order books of the consultancy companies quite quickly. Additionally, the complexity of heat planning needs to be borne in mind. As an excellent tool to solve various techni- cal issues using a holistic approach, heat planning combines scanning the local building stock, identifying potential heat sources, and developing measures that lead to optimal match- making of supply and demand. But technical feasibility does not automatically result in pipes in the ground. In other words, heat plans need to be more than accurate technical drawings and neat mathematical calculations. The Danish approach to heat planning In Denmark, stakeholder involvement and partnerships across sectors have proven to be crucial for the successful implemen-

tation of heat plans. Bringing together local administrations, utilities, housing companies, and citizens to chip in with ideas and concerns alike can significantly increase the acceptance of heat planning. Of course, inviting different interest groups to sit at the same ta- ble can spark disagreements. To limit the possibility of conflict, the Danish Energy Agency maintains a technology catalogue comprising a set of common assumptions regarding general aspects of planning, such as the development of fuel prices or technical components. The state Baden-Württemberg is intro- ducing a German technology catalogue, which might develop over time to a nationwide catalogue. Without having to get lost in these kinds of discussions, heat planning can be a strong tool for municipalities to take matters into their own hands, strengthen communal ties and promote local empowerment. Furthermore, pursuing a bottom-up approach and involving different perspectives leads to a better quality in planning and ultimately to greener and more affordable communities. All the above shows that there are many boxes to be ticked off to lift the great potential in heat planning. However, it appears that Germany has come to a pivotal realization: Awareness and ambition can only be the first steps to improvement. Eventual- ly, change is needed, and actions need to be implemented – in this case, rather sooner than later. The time for action is now.

Renewable Energies – share of heat supply in Germany 1999-2020 and the 2030 target Share in percent

Figure 3 Source:

Results based on public data

For further information please contact: Christian Bjerrum Jørgensen,


Gas conversions – we are all in the same boat!

Conversion from gas is a topic that is highly relevant and important, unfortunately, even more, so these days. There are not many lights in the dark these days, but one small positive story is that now Europe has been forced to look at the dependency on gas. Thereby the green transition has been accelerated significantly. We want to get away from gas, not only to be green but also for strong political reasons. This podcast will introduce you to how we already today convert buildings from gas heating to district heating in Denmark. The aim is to inspire others to start their gas conversions and, as always, an invitation to knowledge sharing. We will focus on how the conversion is done.

In short, the key to unlocking this, is planning, customer relations and creating trust. The more specific recommendations from the two experts are…. No, now you must listen to the podcast

Meet the experts To shed light on how this conversion can be done, I have invited two colleagues who are working with converting more of their cities from gas to district heat- ing every day. Jens Andersen, managing director in Næstved District Heating will discuss with Jesper Møller-Larsen, managing director of the district heat- ing company in Aalborg - a somewhat larger city.

Customer interaction From this podcast, I learned how both experts work dedicated and deliberated with customer interaction. Internation- ally, I sometimes feel that planners are a bit afraid or reluctant to talk to their cus- tomers directly – but don’t be! You will learn that in Denmark, we are not afraid to interact with customers.

We are all in the same boat All countries are determined to de- carbonise their societies with different deadline, and that deadline is very, very soon. Heat is an essential factor in this decarbonisation as heat is responsible for more than 40% of the energy used in Europe. We already have solutions to decarbonisation for heat – district heat- ing. District heating is a necessity to be successful in the conversion away from natural gas.

In Germany, all municipalities will soon have to make energy and heat plans. In the Netherlands, they will stop their own natural gas production and need to find other solutions. Both England and Scotland implement planning laws, subsidies and much more to drive this development. Today, it is even more evident that we need to get started. So, we are all in the same boat – we must get rid of natural gas and find other solutions. And when I say “same boat” – I mean it, we are ALL in the same boat – no matter if you are Danish, German, or Chinese.

Listen in and learn a lot more!

Welcome to DBDHs district heating podcasts. In this series of podcasts, we invite experts from the industry to highlight important and current developments in our industry. The goal is to share knowledge, to inspire and maybe also to provoke a bit – to give insights. And I always ask the experts to share one recommendation each.

This is the DBDH district heating podcast, and your host is Morten Jordt Duedahl.

12 HOTCOOL no.2 2022

Meet the experts

Jesper Møller-Larsen, managing director of Aalborg Forsyning Video about Aalborg Forsyning (7 min.) Member’s profile at DBDH

Jens Andersen, managing dirctor of Næstved Fjernvarme Video about Næstved Fjernvarme (6 min.) Member’s profile at DBDH 43.000 inhabitants Owned by the customers, 6.000 customers 250.000 MWh. 200 km pipe network, app 2.000.000 m2. Heat comes only (98%) from a nearby waste incineration plant (CHP). The rest is from gas boilers for peak and reserve load. Gas conversion: 1,700 houses should be converted by 2024..

250.000 inhabitants Multiutility company In the city itself, 99% are connected 2.000 km pipes

Three major heat suppliers, CHP on coal but will be taken out in a few years, 25% from WtE, 20 surplus heat suppliers another 25%. Expansions (5% growth per year) connecting other cites, organic growth in the city. Owned by the municipality – political organization, the city council is very ambitious.

Podcast links:

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IN CITY AREAS WITH LOW-TEMPERATURE DISTRICT HEATING: RETURN TEMPERATURE OPTIMIZATION OF RADIATORS IN MULTI-FAMILY HOUSES For the district heating (DH) network to become more energy efficient in the future, it is relevant to improve the DH technology further. By lowering the temperatures, the production of heat and surplus heat is available from an even greater amount of variable energy sources, and the renew- able sources and network become even more efficient. When the DH temperatures are lowered, it is, however, essential to ensure that the thermal comfort in the buildings is maintained.

implementing new innovative thermostats from Danfoss. The thermostats have been developed to ensure better radiator performance and obtain a lower return temperature into the DH grid, thereby a more energy-efficient system. Compared to the existing electronic thermostat design availa- ble in the market, this new one is equipped with an additional temperature sensor connected to the return side of each radi- ator and an algorithm to secure more accurate control of the opening or closing of the valve based on a maximum return temperature setting. The purpose of this functionality is two- fold. First, it should help ensure low return temperature from the space heating systems by keeping a high delta-T across the radiator (Delta-T). This will help obtain a low DH return temper- ature and provide convenience for the occupant since it will ensure proper heating system operation even when windows are opened, or holiday setbacks are applied. Second, due to the automatic flow limiting effect of the return temperature control, the thermostat should help provide au- tomatic hydronic balancing of the heating system. This new thermostat could provide one combined solution for some of the essential issues in space heating systems in buildings con- nected to future low-temperature DH systems. The return temperature control functionality is becoming in- creasingly relevant for both the primary and secondary sides of larger heating systems, as there are implications related to sys- tems’ optimal performance (e.g., boilers operating in conden- sation mode are using less energy), environmental factors (less energy used means less CO 2 impact), as well as comfort-related factors (e.g., experienced by tenants in residential multi-family buildings, as well as in light commercial or public buildings).

By Ida Bach Sørensen, Project manager, Damgaard Consulting Engineers

The main barrier to lowering the temperature is a lack of knowledge on how to implement this in existing areas with- out compromising thermal comfort in the buildings. It is also a lack of knowledge on the use of low-temperature DH in build- ings other than single-family houses. Former projects have aimed at single-family houses, mainly with floor heating. Until now, no one has solved the challenge in most existing homes, i.e., multi-family houses with radiators. Low-temperature DH is challenging in the existing building stock with radiators which requires a higher supply temperature than floor heating. Another massive problem in multi-family houses is a lack of hydronic balancing in the building, which leads to poor distri- bution of heat between all radiators on all floors in multisto- rey buildings. Today mechanical balancing valves are on the market that can be adjusted to control the proper flow, but they have the disadvantage that their (manual preset) settings are adjusted to cope with the coldest day of the year – which seldom occurs. This leads to non-optimal balancing in partial load situations most of the year. This is due to the lack of technology to cope with this segment, and not due to the relevance: By far the biggest part of living space, and most of the energy spent for space heating is con- sumed in cities with older multi-family buildings equipped with radiators. Field testing This project has investigated how the control of a given heat- ing system within an apartment building can be improved by

Lowering the return temperature will lead to higher efficiency in DH applications and save the building owner the ‘incentive

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Transition towards low-temperature operations Key strengths & differentiators are that this concept is a world 1 st type of solution that allows for dry installation, provides con- tinuous valve commissioning, and solves both hydronic imbal- ances & return temperature optimization. However, there is a mass of opportunities with the solution: its unmatched versatility - as it can be used as a stand-alone solution without connecting it to the internet. In public build- ings, the solution can be bundled with accessories, such as tamper-proofing (protective cases) and main power supply modules. The concept endeavors to solve key pain points with hydronic imbalance removing costly installer calls and labor needed to fix claims that may arise. It provides preemptive maintenance, live access, and monitoring in a simple and eas- ily integrated, digitally fit solution.

costs. In boiler applications, the boiler’s efficiency will be in- creased, and the solution implementation will also have a larg- er positive effect on the hydronic balancing in buildings. The concept will address both buildings with known problems with return cooling and balancing issues, as well as typical buildings where cooling and energy efficiency can be at least optimized, if not radically improved. Testing the functionality The prototypes of the thermostat were installed on all radia- tors in part of two buildings to test the functionality of the new thermostat. Measurements on the heating system operation before, during, and after the test were collected and analysed to document how the thermostats performed to limit the re- turn temperature to the district heating substation and ensure hydraulic balancing in the heating systems. The new electronic thermostats were tested in two multi-fam- ily buildings in Denmark, both connected to the local DH net- work. The results documented that this prototype thermostat can embed the functionalities of the traditional thermostatic radiator valve and the riser balancing valves in the same de- sign. Integrating an extra return temperature sensor ensured better flow control through the radiators and the lowest pos- sible return temperature. In addition, installing these thermo- stats can allow the automatic hydronic control of the heating system, making the risers balancing valves redundant. It was found in Building A that the DH cooling – defined as the dif- ference between the supply and return temperature – was 4-12 °C higher in 2019 during the test compared to winter and spring 2020 when the prototypes were replaced with state-of- the-art thermostats. The measurements also suggested how the optimal oper- ation in large buildings is sensitive even though the build- ings have a well-controlled heating system. Only two un- controlled radiators out of 175 were able to contaminate the overall return temperature in Building B. In one case, the reason was a manufacturing problem – which was an acceptable issue in the development of a new product – whereas, in the second one, it was due to the end-user tam- pering with the thermostat. This last aspect can be poten- tially critical for any space heating system control. The results highlighted the importance of remotely connected devices. The measurements from the thermostats helped pinpoint the faults in the heating system, although the end-users were not experiencing any discomfort. By also correcting the pump setting and closing the string balancing valves in the two risers to limit the flow to the uncontrolled radiators, it was possible to reduce the overall return temperature to 35°C, neutralizing the negative effect of the malfunction- ing thermostats. Hence, the digitalization of the demand side represents a critical element for the transition towards low-temperature operations and can support and improve the quality of the activities of the building service person- nel, currently, labor and time-consuming because manually performed.

The concept is also ground setting for savings through sched- uling in large-scale public buildings.

These learnings will lead to further improvements of the sys- tem and give a lot of learnings of the effect in district utility grids and larger gas-boiler-fired installations. Furthermore, based on the massive amount of data gathered in the two test buildings, we can now see that the data can be used to diagnose various kinds of errors in how the heating systems are built and used. This could potentially lead to ad- vanced diagnostic systems that can monitor vast amounts of radiators and buildings. Having this in place could save a lot of time for janitors and en- gineers to supervise and troubleshoot installations, saving time and money in housing associations, municipalities, etc. The key finding for future product development is to secure the most robust design that could minimize the negative im- pact of the end-user’s misuse of local controllers in the heat- ing elements. An improved design may integrate a new safety functionality that closes the valve or limits the flow to a min- imum in case of damaged thermostats or wrong signal from the sensors. This will not be detrimental for the indoor com- fort in the flats and avoid a few radiators compromising the low-temperature operation of an entire building. The assessment of implementing low-temperature district heating grids shows that the existing grid can lower the tem- peratures. It might be legally possible for the district heating companies to support the transition to low temperatures by investing in intelligent thermostats. Furthermore, the results showed that the digitalization of the demand side represents a critical element for the transition towards low-temperature operations and the overall green transition.

For further information please contact: Ida Bach Sørensen,


ENERGY EFFICIENCY SHOULD BE PRIORITIZED FIRST IN HEATING Dependence on foreign energy supply to the European Union is not sustainable, not for social Europe nor the climate. The heating sector is one of the most important sectors to make sustainable, as it is heavily dependent on natural gas and has a significant im- pact on the average citizens’ economy. Therefore, the Energy Efficiency First principle is very important for the future of Europe.

By Carsten Østergård Pedersen, Business Development Director Asbjørn Bjerregaard Ebbesen, Advisor, Public Affairs Rune Kaagaard Sørensen, Student Assistant

The best weapon against a growing problem Consolidation of the Energy Efficiency First principle in EU’s Fit- For-55 negotiations is becoming significantly more important as the climate, social Europe, and our energy security calls for a change in how we get our energy and how we use it. IEA ar- gues that 40% of our carbon reductions towards 2050 should come from energy-efficient solutions; however, we need to double the pace of energy-efficient solutions to stay within the Paris Agreement goals1. Energy efficiency also plays a crucial role in our energy securi- ty. Prior to the Ukraine conflict, we saw unprecedented prices on natural gas, which is the most used energy source in the European Union after oil 2 . However, experts only expect higher prices due to the current geopolitical conflict. The situation is expected to have made more than 80 million Europeans living in energy poverty, which will only get worse. However, 1% in energy savings is expected to reduce natural gas imports by 2,6%, and energy efficiency has proven to be the most impact- ful measure on lowering natural gas imports. The heating sector is the most important sector to focus on. It represents 50% of Europe’s total end-use consumption, and fossil fuels still deliver 75% of all heating within the European Union 3 . Moreover, putting energy efficiency first in the heating sector can therefore lower carbon emissions, lower import of natural gas, and lower citizens’ energy bills.

How to create energy-efficient heating To create a more energy-efficient heating sector, the EU should focus on deploying fourth-generation district heating individual heat pumps and lowering the total heat demand. Luckily, all the technologies are ready for deployment today. First, local authorities should make strategic heat plans that can secure a fast and cost-effective transition of local heat- ing towards energy-efficient solutions that run on renewable energy and surplus heat. There is a massive untapped ener- gy potential in local communities such as geothermal ener- gy and surplus heat from industries, data centers, and soon Power-to-X. Surplus heat alone is expected to deliver 25% of the future energy demand for district heating4. Strategic heat planning should incorporate that future heating needs can run at lower temperatures to lower heat losses and more efficient integration of heat pumps and more renewable en- ergy. Therefore, the deployment of fourth-generation district heating plays a significant role in reducing our dependency on natural gas import and getting cost-effective to climate neutrality. Second, the EU should promote energy efficiency measures in buildings and industry to lower heating demand. Nine out of ten buildings we have in 2050 have already been built to- day 5 . Therefore, retrofitting buildings with more efficient sys- tems plays a significant role in reaching the Fit-For-55 target.

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