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Putting wastewater heat recycling on the map to join the dots.

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Nick Meeten's picture
Director, Applied Energy Ltd

I am not an electricity expert. My expertise is in the fields of thermal energy usage within buildings and industries, and thermal energy recycling from wastewater. I am a director of Applied...

  • Member since 2022
  • 25 items added with 8,932 views
  • Feb 14, 2022

Every single day, every city on the planet is flushing vast and valuable quantities of thermal energy literally down the drain, wasting the opportunity to recycle wastewater heat. In response, a new information and global mapping portal for wastewater heat recycling has been launched by a leading group of experienced engineers and expert map-makers.

This free-to-access and easy-to-use resource provides both general information about the wastewater heat recycling topic (written in non-technical language to make it easy to understand for people from all sectors) and a web map portal for displaying detailed wastewater network heatmaps, city by city.

The portal at is truly global, showing case studies from around the world and the map shows the built environment of every city in 3D and allows any address in the world to be searched in the search bar. The wastewater network heat maps provide details on the thermal energy available within any portion of the wastewater network, and the accompanying website provides supporting information on how to capture and recycle this resource as well as showing instructions on how to navigate and use the maps. Three wastewater network heatmaps for cities in New Zealand have already been uploaded, for Christchurch, Dunedin, and Nelson.

The portal allows building owners or designers to go to the city wastewater network heatmaps and perform a simple search for their site address. If their city has a heatmap uploaded, they can quickly assess whether wastewater might be an option to supply the heating or cooling they need via heatpumps and so transition off fossil fuels. If it does look like it might be an option, then starting a conversation with the wastewater utility concerned would then be the next step. The portal aims to join dots and bring people together.

This also has implications for city electrical infrastructure authorities, as wastewater source heating/cooling systems are typically more energy efficient than air source heating/cooling systems, allowing the thermal loads to be met with less demand on the electrical network. The infrastructure networks of cities are all interconnected, and all these dots need to be better joined.

With multiple improvements and additions planned over the next couple of months — including more case studies and map markers with information links — the portal remains a work in progress, but offers dynamic opportunities for interaction and collaboration, explains one of the Founders of, Nick Meeten:

“We are excited to see people using the portal and giving us some early feedback. It is a great way for cities to quickly decarbonise using existing infrastructure and existing energy by harnessing the untapped thermal energy in wastewater for super-efficient heating and cooling. This thermal energy is an increasingly valuable asset and the wastewater heat involved must start being recycled sustainably to stop this precious resource being wasted all around the globe.”

The thermal energy potential of wastewater

The amount of thermal energy available within wastewater is enormous — typically 20%-35% of total housing energy and up to 40% of low-temperature heat used in commercial and industrial sectors gets turned into hot water, which then goes down the city sewers, simply flushed away, every single day.

The high-level value of this energy was recently estimated to be worth around £30 million a year to a large UK water utility, based on actual prices currently being paid for wastewater heat at a UK site.

According to the team behind, the barriers to recycling this energy are:

  • Lack of awareness — many people just do not know about wastewater heat recycling; and
  • Disconnects that exist between different sectors, or ‘worlds’ — namely, the worlds of water and buildings, of above and below ground infrastructure, of public- and private-sectors.

The portal and associated heatmaps effectively form the bridge needed to bring these worlds together. "We welcome any cities with wastewater network heatmaps already prepared, to contact us and we are happy to host the data on this portal. Then it is a simple matter to just link this back to the city's own website if they want. If there are cities who do not yet have a wastewater network heatmap in place and would like to get this done, again just contact us and we can connect them up with service providers who have the necessary expertise. It is probably not as expensive as they might think."

Ultimately, it is a matter of recognising the resource hidden in the so-called waste, concludes Meeten:

“There is an old saying in English ‘Don’t throw the baby out with the bathwater’, which means ‘Don’t discard something valuable along with something undesirable’. This fits perfectly with wastewater heat recycling — the water may be dirty, but the energy within it is clean! So, don’t throw out the clean energy with the dirty water.

Much of this content is credited to Jim McClelland at McClelland Media Ltd. See his original here

Matt Chester's picture
Matt Chester on Feb 14, 2022

Can you share an example of a city that's used this type of energy particularly effectively? And what are the key characteristics that would have made a city such a prime opportunity? 

Nick Meeten's picture
Nick Meeten on Feb 14, 2022

Hi Matt, from our experience and knowledge, to date most of the projects using this energy have been 'one-offs' developed on an ad-hoc basis. There is typically a lack of real integrated planning around identifying this energy as being available as a supply and finding the supply & demand opportunities, and it is exactly this issue that we are tackling with the wastewater network heat-maps.

Some examples where it has been kind of planned are:

  • Hobart, Australia: Where they have used wastewater thermal energy at 4x sites (note: only 1 of these 4 are shown on the map, but there are indeed a further 3x sites in Hobart consisting of the Hobart Town Hall, The Grand Chancellor Hotel & a retirement home). These 4x sites in Hobart cover both council owned and privately owned buildings, and there would therefore seem to have been some integrated planning taken place.
  • Vancouver, Canada: The SE False Creek district heating system taps into the thermal capacity from a large trunk sewer and distributes heat around a large area with a number of buildings. This system is being enlarged and extended in a phased manner over about a number of years in about 3 phases.

Thanks for asking the question.

Nick Meeten's picture
Thank Nick for the Post!
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