Privacy Notice

Welcome on BABLE

We put great importance to data protection and therefore use the data you provide to us with upmost care. You can handle the data you provide to us in your personal dashboard. You will find our complete regulations on data protection and clarification of your rights in our privacy notice. By using the website and its offers and navigating further, you accept the regulations of our privacy notice and terms and conditions.



District heating and cooling systems distribute thermal energy in the form of steam, hot water, or chilled liquids, from central or decentralised sources of production through a network to multiple buildings or sites, for the use of space or process heating or cooling. For a lower environmental impact, a combination of recycled and renewable heat is the focus for district heating systems. Following the Paris Agreement in 2015 and the EU target to cut emissions by at least 40% below 1990 levels by 2030, there has been an increased effort from member states to foster district heating and cooling using alternative fuel sources and carbon-neutral heat producing technologies. This transition is challenging as district heating supplies only 12% of the EU´s heat supply, with most of the energy produced from CHP plants powered by natural gas and solid fuels such as lignite.

Problems to be solved


Carbon emissions

Low-efficient heat supply

Fossil fuel dependency

GHG emissions


Potential Benefits
  • Reducing use of fossils

  • Reducing GHG emissions

  • Increasing share of renewables

  • Improving energy supply efficiency

  • Shaving peak energy demand

  • Enhances grid stability

  • Reducing local air pollution


Functions help you to understand what the products can do for you and which ones will help you achieve your goals.
Each Solution has at least one mandatory function, which is needed to achieve the basic purpose of the Solution, and several additional functions, which are features that can be added to provide additional benefits.

Mandatory Functions
    Operate with at least 32.5% energy efficiency

    Minimum efficiency established by regional directives

    Supply heating temperature between 80 and 120°C

    Temperature range for an appropriate distribution and utilisation

    Supply cooling temperature between 6 and 7°C

    Temperature range for an appropriate distribution and utilisation

    Connect decentral systems to district network

    These systems must be capable to be incorporated into the city's DH network

Potential Functions
    Recover up to 40% of energy

    Recovery of wasted thermal energy

    Utilize renewable energy sources for heat and cooling production

    To reduce energy production through fossil-fuels

    Generate low-temperature District Heating supply

    Reducing variable costs of heat and cooling energy production



Carbon neutral and low carbon fuels such as biomass, waste, and biogas are becoming an attractive alternative for reducing the environmental impact of firing systems. Although these energy sources produce carbon emissions, they have life-cycle neutrality. Biomass energy is carbon neutral if growing the biomass removes as much CO2 as is emitted into the atmosphere from its combustion. Waste and biogas are recovered materials that would otherwise be disposed. 

Use Cases

Energy Efficient District Heating and DHW retrofitting

Renovation of the whole district heating system (i.e. boilers room, district heating network, heat exchange substations and dwelling interventions)

District Retrofitting in Eskişehir

Aiming to achieve a sustainable districts in Tepebasi through deep retrofitting, the improvements in building envelope's designs were implemented. Minimizing heat transfer through the building envelope is crucial for reducing the need for space heating and cooling.


The popularity of P2H plants is growing thanks to the increased installed capacity of renewable energy sources such as wind and solar PV energy. P2H plants harness generated renewable electricity and transform it into heat either by heating resistors, electrode boilers or heat pumps. For an effective integration of P2H, the ratio of renewable energy to fossil-fuel production is to be considered. A higher installed capacity of renewable energy would favour a P2H plant feasibility.  
P2H provides an alternative for Demand Side Management system. When there is excess electricity production from renewable sources, P2H plants are powered to produce heat.


Solar thermal energy harnesses energy from the sun to generate thermal energy for use in industry, and in the residential and commercial sectors. In locations where there is high solar irradiance (annual GHI above 1000 kWh/m2), solar thermal plants installations are the most favourable. Nevertheless, in northern European countries such as Denmark (with annual GHI below 1000 kWh/m2) solar thermal energy contributes significantly to the district heating network. Solar thermal energy usually contributes up to 20% to the total heat supply, although including seasonal storage units can increase the percentage of heating that can be met by solar energy on an annual basis to 50% (SDH 2020). Large urban district heating networks typically source thermal energy from large-scale solar thermal plants. Solar thermal flat plate collectors are the most commonly installed systems.   


This variant of heat production was conceived for harnessing the thermal energy from pipes carrying the return flow from district cooling systems or sewage pipes. This is achieved by using a heat exchanger and a heat pump powered by solar PV panels, in which heat was recovered to produce hot water in residential buildings.

The feasibility of heat waste recovery is largely dependant of the levelised costs of heat for conventional heat production sources. These implementations carry high capital costs, so economic incentives are required to allow scaling up. 

Use Cases

Sustainable District Cooling Solution that uses residual heat

A highly energy efficient district cooling system was installed in the densely populated city center of Tartu using the river cooled chillers. The system was made more energy efficient by Fortum, using a heat pump that reuses the residual heat from cooling system for the district heating system.


Low temperature district heating is a heat supply technology for efficient, environmentally friendly, and cost-effective community supply. In comparison to conventional district heating, the network supply temperature is reduced down to approximately 50 °C or even less.

Use Cases

Low Temperature District Heating (LTDH) and Smart Controllers

Developing an efficient low temperature heating system out of the returning flow of a high temperature heat network.


The novel concept of cold district heating networks aims to combine the advantages of a centralised energy distribution system with low heat losses in energy supply. This combined effect is achieved through the centralised supply of water at relatively low temperatures which is then heated up by decentralised heat pumps. These circulation pumps withdraw water from the warm line, uses it in a heat pump to reach temperatures suitable for space heating and then discharges the cooled water to the cold line.


Absorption chillers use the collection of waste heat from other processes or equipment to drive a thermodynamic process that allows water to be chilled and distributed for HVAC needs. Absorption chillers do not require the installation of a city-wide district cooling system. They must be installed close to a consistent stream of waste heat, such as near to the effluent of an industrial plant or university campus.

Driving Factors

  • Reduce market competition: Removal of subsidies and other incentives for fossil-based heating systems
  • Access to capital: Provide demonstration projects, innovative funding, and debt guarantee mechanisms for the further development of large infrastructure projects in cities.
  • Citizen’s acceptance: The acceptance by local citizens needs to be raised by improving awareness and highlighting the advantages of district heating and cooling. Adequate citizen engagement activities, such as local information events, might be suitable tools to achieve approval.
  • Municipal support: Enabling access to roads and public land to build networks and heat sources. As well as ensuring municipal buildings are connected to the DH system.
  • Transparency: Data on local energy audits, research and development, and performance must be made available.  
  • Pashing-out of fossil fuels: High tax on fossil fuels makes implementations, such as those presented under variants, competitive. 

City Context

General requirements for the implementation of District Heating:

  • High heat load density: As heat networks are very capital intensive, the heated area has to be densely built to minimize the required pipe-length.
  • Economic viability: As a rule of thumb the heat load density for DH should be higher than 23MWh per metre of planned network length to be commercially viable.
  • Location of building stock: The buildings to be connected to the DH networks should be close to the existing network to minimize the connection pipe length. This will reduce both investment and operational costs.
  • Location of heat sources:  Modern heat sources have high quality flue gas cleaning systems. Therefore, subject to planning conditions, heat sources can be located near or in the centre of urban areas to minimize network length. The location of heat sources has to be agreed in advance.

District heating has several land use requirements for its implementation:

  • It is very useful to develop a heat demand map, and a corresponding heat plan for a town or city to identify which areas are most suitable for DH, and which areas are best served by individual building systems
  • Heat sources should be close to the customer (economy) but should consider noise prevention and transportation logistics
  • Underground networks require space that is already partly occupied by other infrastructure: e.g. electricity, telecommunications, sewage, water
  • Possible booster pump stations
  • Fuel and ash transportation routes should minimize any harm and risk to the population

Government Initiatives


      1. RHC-ETIP

The European Technology and Innovation Platform on Renewable Heating & Cooling (RHC-ETIP) brings together stakeholders from the biomass, geothermal, solar thermal and heat pump sectors – including the related industries such as district heating and cooling, thermal energy storage, and hybrid systems – to define a common strategy for increasing the use of renewable energy technologies for heating and cooling.

      2. International Energy Agency (IEA)

The Technology Collaboration Programme on District Heating and Cooling including Combined Heat and Power[JH1] , deals with the design, performance and operation of distribution systems and consumer installations. The Agreement is dedicated to helping to make district heating and cooling and combined heat and power powerful tools for energy conservation and the reduction of environmental impacts of supplying heat. The programme offers a platform for online reports and an exchange of best practices.


       1. The Heat Networks Delivery Unit (HNDU)

The Heat Networks Delivery Unit was established in 2013 to address the capacity and capability challenges which local authorities identified as barriers to heat network deployment in the UK. The Unit provides funding and specialist guidance to local authorities who are developing heat network projects.

       2. Heat Networks Investment Project (HNIP)

The Heat Networks Investment Project is delivering £320 million of capital investment support to increase the volume of heat networks built, deliver carbon savings for carbon budgets, and help create the conditions for a sustainable market that can operate without direct government subsidy. The pilot phase of the Heat Networks Investment Project ran for 6 months and awarded £24 million to 9 successful Local Authority projects in March 2017.


Stakeholder Mapping

Stakeholder Map for a district heating or cooling system (BABLE,2021)

Value Model

The following list of benefits are accompanied by an importance ranking. A value of one, translates to high importance. 

Value model for a district heating or cooling system (BABLE, 2021)

The creation of this Solution has been supported by EU funding

Use Cases

Sustainable District Cooling Solution that uses residual heat

A highly energy efficient district cooling system was installed in the densely populated city center of Tartu using the river cooled chillers. The system was made more energy efficient by Fortum, using a heat pump that reuses the residual heat from cooling system for the district heating system.

Open District Heating for Sustainable Heat Recovery

This Open District Heating aims to recover waste heat to the existing DH network by developing an innovative business model for plug and play heat pumps and contracts where the DH provider buys waste heat from local sources like data centres and supermarkets.

Energy Efficient District Heating and DHW retrofitting

Renovation of the whole district heating system (i.e. boilers room, district heating network, heat exchange substations and dwelling interventions)

Low Temperature District Heating (LTDH) and Smart Controllers

Developing an efficient low temperature heating system out of the returning flow of a high temperature heat network.

Related Solutions

Local Energy System

Approximately one-quarter of the energy price is owed by the transportation of the energy. The implementation of a local energy system can shift the energy production from a centralised system to a decentralised system.

Energy Efficient Retrofitting of Buildings

Improving energy efficiency of the building stock in a city needs strategic and long-term thinking. Complex ownership structures, market barriers, diversity of building typologies, consumer preferences and multiple stakeholders involved makes energy efficient retrofitting a big challenge.

Smart Microgrids

Microgrids are emerging as an attractive, viable solution for cities, utilities, and firms to meet the energy needs of communities by leveraging more sustainable resources, while increasing resilience, reducing emissions, and achieving broader policy or corporate goals.

Energy Storage Systems

Energy storage systems are used to store energy that is currently available but not needed, for later use. The goal is to create a reliable and environmentally friendly system. As the share of renewables increases, so does the need for storage. With storage, energy can be used when it is needed.

Bi-directional Electric Vehicle Charging

Bi-directional electric vehicle (EV) charging refers to EV chargers that allow not only for charging the battery of the EV but also for taking energy from the car battery and pushing it back to the grid when needed.

Peer to Peer Energy Trading

Peer-to-peer (P2P) energy trading creates an online marketplace where energy can be traded with low barriers. This makes local renewable energy more accessible.

Municipal Energy Saving Systems

The supply of energy to households, public buildings and services accounts for the majority of GHG emissions in the majority of municipalities. Energy Saving Systems represent punctual solutions to optimise energy consumption.

Virtual Power Plant

VPPs are a response to the growing number of distributed energy resources (DER) making their way onto the grid, as VPPs allow their production to be pooled to achieve the flexibility and scale needed to trade in the electricity market; unleashing gains for prosumers, aggregators, and grid operators.

Smart Home System

The majority of public funding for energy efficiency within the EU is proposed in the building sector. The federal funds for energy efficiency in residential buildings added up to €97 million in 2019. A Smart Home System is one possibility to improve residential energy efficiency.

Smart Lighting

Smart streetlights enable the reduction of running expenses associated with public lighting by delivering several value-added services to cities and citizens.

Building Energy Management System

According to the Energy Performance of Buildings Directive (EPBD), buildings are responsible for approximately 40% of energy consumption and 36% of CO2 emissions in the EU.

Public Charging System for Electric Vehicles

The current EU regulation on emissions for cars is the strictest worldwide. Along with further restrictions the thresholds cannot be meet with conventional cars only anymore. One alternative technology, reducing the local emissions, are electric vehicles.

Something went wrong on our side. Please try reloading the page and if the problem still persists, contact us via