District Heating: What Are They and How They Drive Energy Efficiency in City Councils
More than 50% of the final useful energy demand in the EU comes from the heating and cooling consumption of buildings. The installation of District Heating in cities and municipalities helps improve their energy efficiency, resulting in energy savings and reduced costs for their inhabitants.
If you are thinking of setting up such a core network in your municipality, this article will help you to better understand this concept and learn about examples from other cities, which will inspire you.
What is District Heating?
District Heating also known as heat networks or teleheating, is a system of domestic hot water and heating supply that, through a network of pipes, reaches different buildings from a central plant.
Beyond this definition, it is perhaps easier to understand the concept of a central heating network with a simple example. Think about how heating works in a home with natural gas. The boiler takes water from the network, heats it and makes it circulates it around the house.
In a central heating and cooling network, the water is heated in a central plant that is not in our home. It can be in the building, in the urbanization, or even further away, such as at the entrance of our district.
This type of centralised system can vary both in the energy sources used and in size. And they can cover from a small number of buildings or dwellings to entire metropolitan areas and even large livestock farms.
As with heating, this centralised model can be applied to cooling. This is known as central cooling networks or District Cooling (DC). And, of course, systems combining both are also beginning to be deployed.
District heating and District Cooling structures
To understand how a District Heating (DH), District Cooling (DC) or combined (DHC) system works, it’s necessary to understand its different parts. This is the most common structure in central heating and cooling networks:
- The thermal power station: This is where all the heat, cold or hot water, that the network installed in your municipality or city demands, will be generated. They are usually outside urban areas. In addition, they can produce their own energy based on fossil fuels, renewable energy and the upward trend: biomass.
- The distribution network: It is a network of underground pipes that distributes the product from the thermal power station to the buildings of your city. The pipes have two directions: propulsion and return. The distribution network can be as extensive as necessary to bring heat, cold or hot water from production to consumption.
You must bear in mind that this extension will influence the effectiveness of the network. For example, the closer the two points are, the less energy losses will exist in the network.
- Thermal transmission substations in buildings: These are the ones that allow energy to be distributed to consumers. In a residential building, they provide floor-to-storey distribution, for example. The substations are responsible for adapting the pressure and temperature of the distribution network to the conditions of each building.
Why District Heating and District Cooling are efficient
More than 50% of the final useful energy demand in the European Union comes from heating and cooling consumption. Did you know that district heating consumption represents more than 9% of heating consumed in the EU?
In addition, a district heating system can integrate renewable energies as well as geothermal and solar thermal energies, municipal waste and waste heat. This is very interesting if your city wants to make the most out of the energy sources it already has.
In some cases, these centralized networks also have a supply of chilled water from the same plant where the hot water is produced.
The "Intelligent Buildings" already mentioned in other articles, which are connected to an intelligent network of remote control or automated heating and cooling, will be able to manage more efficiently the appliances depending on the date and time, the humidity, the external wind chill, and of course, the occupation of the building.
Technologies such as the Internet of Things (IoT) are enabling greater flexibility, control and synergies in building management. Intelligent building management systems can be applied not only to an individual building but also to energy supply systems such as DH/DC. These systems can measure consumption in the areas where it is most in demand and where its supply can be adjusted if it is not being consumed at that moment and so on.
Additionally, this type of facility is not just interesting for their installation in residential neighbourhoods.
From the point of view of energy efficiency for municipalities, central heating networks are an ideal solution in commercial, tourist, industrial complexes, hotels or offices. In other words, in any group of buildings that need to be heated and/or cooled.
As the generation of heat energy is done jointly, it is a very efficient option for both the measurement of their energy efficiency and the achievement of improvements for municipalities.
Now, are you curious to know more about building management technologies? Why not take a look at other articles on our blog? Building Technology: Who's Who?
Why cities are implementing District Heating
District heating has a long tradition in countries with cold winters such as Finland, Sweden and Norway. For example, in the city of Helsinki (Finland), 90% of the energy consumption by heating systems is produced by thermal power plants that are distributed through pipe networks throughout the city.
Installations of central heating and cooling networks not only have ecological benefits, by reducing CO2 emissions, they also highlight economic advantages such as:
- Reduces the cost of operation and maintenance of the installation.
- It generates local employment.
- The installations are amortised in less than 10 years and allow access to subsidies within Renewable Energy and Energy Efficiency programs from the EU or at the national scale. The Energy Company Obligation (ECO), a government energy efficiency scheme in Great Britain, is an example, allowing British households to be funded by energy suppliers for the installation of energy efficiency measures.
- It reduces the installed power per dwelling and the consumption per dwelling.
- It avoids the problems associated with low efficiency in old boilers.
- It avoids the manipulation and storage of fuel in the building, improving aspects such as security, dirt and space.
- And it reduces the noise of the installations in the buildings since it does not have thermos installations.
All these benefits are very attractive for your town hall for several reasons:
The existing legislation in Spain is becoming more and more restrictive and forces big cities to reduce emissions, something that can be improved with DH, DC.
It improves energy efficiency in the municipality, with energy savings, and the possibility of being able to control and measure it through energy management applications offered today by technologies such as IoT.
Greater access to subventions and subsidies for municipalities that reduce their CO2 emissions, IDAE 2017 (Spain).
Other examples, at the EU Include:
ELENA (European Local Energy Assistance): The European Commission will provide funding for EUR 97 million to ELENA, in order to support project development services for energy efficiency in privately and publicly owned housing.
Fifteen councils in Scotland have received more than £2 million from the Scottish Government in order to help businesses and homeowners install energy efficiency measures as part of the new Energy Efficient Scotland Programme.
The Affordable Warmth Scheme is available for Northern Ireland and its goal is to help people with an income lower than £20.000 per year live in a targeted area by their council to make their homes warmer, healthier and more energy efficient.
European cities with central heating and cooling networks (DH and DC)
The European average for district heating and district cooling systems is above 12%. Among the pioneering countries, we find the Nordic countries and central Europe, from which we will highlight Helsinki and Vienna as exemplary cities with central heating and cooling networks.
Helsinki has a heat network that covers more than 90% of the city's total heat demand. It covers an area of 1.200 km and supplies more than 10.000 users, reflecting the importance of this type of energy supply system for the city. However, being a city with extremely cold weather conditions doesn’t mean it has missed the option of cohesive heat with cold, so this network also has a distribution of refrigeration. The EU considers it to be an example of an urban heat and cold network.
In the case of Vienna, the city has a heating and cooling network supplied by 3 plants located in the urban area. The Spittelau plant is not only a waste management company that provides the energy for part of the city heating system, it is also a tourist attraction due to the design of the building. An example is not only of energy efficiency but also of the integration into urban architecture.
45% of the energy used for heating and cooling in the EU is consumed in the housing sector, 37% in industry and 18% in the services sector. Each sector has the potential to reduce demand, increase efficiency and switch to renewable energy sources.
UK cities with District Heating
In recent years, the United Kingdom has been making strides towards achieving its carbon reduction goals and promoting sustainable living practices. One key area of focus has been the implementation of district heating systems in various cities across the country.
According to the Energy Saving Trust, there are over 17,000 heating networks already in place in the UK, and almost half a million connections to these networks, most of which are domestic customers.
The majority of these networks are located in England, with 25% in London. As carbon reduction targets are put in place, this number could increase, as the government wants 17% of heating to be provided by district energy by 2030. This would mean that 8,000,000 consumers would receive heating through district energy. (Source)
Several UK cities have embraced district heating as a way to tackle the challenges of rising energy demands, energy security, and carbon emissions. Here are a few examples of UK cities with notable district heating initiatives:
London
As one of the largest and most densely populated cities in the world, London has been at the forefront of implementing district heating systems. The King's Cross district, for instance, has adopted a sustainable heating system that utilises waste heat generated from local industries and a combined heat and power (CHP) plant. This innovative approach reduces the reliance on fossil fuels and helps curb greenhouse gas emissions.
Birmingham
Birmingham's district heating initiatives extend beyond environmental benefits. By centralising heat production and distribution, the city is fostering a sense of communal energy responsibility. Residents and businesses alike are part of a collaborative effort to optimise energy use, contributing to a more resilient and resource-efficient urban environment. Additionally, these initiatives have the potential to create new avenues for job opportunities, as the development, maintenance, and operation of district heating networks require a diverse set of skills and expertise.