District Heating & Cooling Systems

Description

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

Supporting 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 upon 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

EU 

      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.

UK

       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)