The +CityxChange vision is to enable the co-creation of the future we want to live in

Positive City ExChange

+Trondheim +Limerick +Sestao +Alba Iulia +Pisek +Võru +Smolyan

Welcome to +CityxChange

Our Lighthouse Cities, Trondheim Kommune and Limerick City and County Council are developing feasible and realistic demonstration projects in climate-friendly and sustainable urban environments

The consortium is called +CityxChange (Positive City ExChange)


Produced by JJ Design and Reidar Nygård and published under CC-BY 4.0.

News & Events

This way
to our latest

This “How to PED” cookbook contains experiences, lessons learned, and recommendations gained throughout the 5 years of the +CityxChange EU Horizon 2020 project, specifically focused on the variety of activities necessary to design and build Positive Energy Districts (PEDs) in smart sustainable cities and communities. Over the course of the book we draw on the experiences and joint efforts of our 2 Lighthouse Cities, 5 Follower Cities, and 26 other partners, to demonstrate what it takes to build a PED.

Download it here to get cooking!

The Legacy of +CityxChange

Over five years ago, we came together to embark on a journey to develop and build Positive Energy Districts (PEDs) in smart sustainable cities and communities. Coordinated by the Norwegian University of Science and Technology (NTNU), the smart city project involved two Lighthouse Cities, Trondheim (Norway) and Limerick (Ireland), and

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Trondheim successfully implements local energy and flexibility market

+CityxChange partner, Aneo (formerly Trønderenergi), a Nordic renewable energy company, has successfully developed and deployed a novel solution for local energy and flexibility markets (LFM) in the two Positive Energy Blocks, Brattøra and Sluppen, located in Lighthouse City Trondheim. As a Horizon 2020 project, +CityxChange aims to pilot integrated, innovative,

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Turbine in the water!

From the 19th to the 21st of September 2023, GKinetic Energy deployed a 12kW hydrokinetic tidal turbine just downstream of Sarsfield Bridge on the river Shannon, in central Limerick City. Backed by the Limerick City Council and other local partners, this represents a major step forward towards utilising the river

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+CityxChange Final Conference in Trondheim

We are thrilled to announce the upcoming Final Event for +CityxChange! Join us from 3rd to 5th October* in Trondheim for a series of insightful sessions on the future of Positive Energy Districts and communities. During the event we will share implementation experiences and lessons learned from our project, as

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Who are we?

+CityxChange is a smart city project granted funding by the European Union’s Horizon 2020 research and innovation programme. Norwegian University of Science and Technology (NTNU) is the host and leads the consortium together with the Lighthouse Cities Trondheim and Limerick.

Lighthouse Cities and Follower Cities

+CityxChange brings the two aspiring Lighthouse Cities Trondheim (NO) and Limerick (IE) together with their distinguished Follower Cities Alba Iulia (RO), Pisek (CZ), Võru (EST), Smolyan (BG) and Sestao (ES), to underline their ambition to achieve sustainable urban ecosystems that have zero emissions and establish a 100% renewable energy city-region by 2050.

Click on the cities for more information!

What is a Smart City?

In the future, municipalities must handle a completely different complexity in society. In order to have well-functioning cities, cities must improve how they utilise their resources and how they engage with technologies in different ways. A smart city will use digital technologies to enhance performance and wellbeing, to reduce costs and resource consumption and to engage more effectively and actively with its citizens.

Our project and work

The +CityxChange vision is to enable the co-creation of the future we want to live in. This includes the development of a framework and supporting tools to enable a common energy market supported by a connected community. This leads to recommendations for new policy intervention, market (de)regulation and business models that deliver positive energy communities integrating e-Mobility as a Service (eMaaS).

Our innovation and demonstration projects are organised as 11 Demonstration Projects.


The consortium comprises 33 partners covering the entire value chain for the project. The cities are involved in all aspects of the project. They are supported by two Universities, ten Large Enterprises, two Distributed Network Operators, nine SMEs and three non-profit organisations.


Trondheim is situated in central Norway by the Trondheim Fjord and is Norway’s third most populous city. Trondheim is situated where the river Nidelva meets the Trondheim Fjord, and is known as an important harbour city. The city is the major public transport and logistic hub in Central Norway and Mid-Scandinavia. Trondheim has a population of about 190,500 people, with the wider region exceeding 280,000 inhabitants. The core of the city has a total urban area of just over 340km2, with a population density of 557 per km2. Trondheim is a strongly growing city, with a low unemployment rate (2.5%).


The Municipality of Pisek has a population of approximately 30,000, an urban area of just over 63km2 and a population density of 475 per km2. Písek is considered a mid-sized city situated in the South-Bohemian Region of the Czech Republic, approximately one-hour travel time to Prague. Its economy has been significantly strengthened by foreign direct investment (FDI) in the industrial zone north of the city, with strong influences from the automotive industry and electro-technics. The Technology Centre Písek and Centre of Low Energy Buildings are two innovation centres built as ‘brownfield site investments’ at a total investment cost of €40M.


Sestao City has a population of approximately 28,300 (2016) with an urban area of 3.5 km2 giving with a population density of 8,085 persons per km2. Sestao is located in Bizkaia, one of the three provinces of the Basque Country. Situated on the left bank of the Nervion River, Sestao belongs to the shared conurbation of Bilbao, Barakaldo, Portugalete and Santurtzi. The city is very well connected to the surrounding communities through road, rail and metro, and a future tram development, which will connect the city to the Leioa Campus
of the University of the Basque Country, making the commuting system more efficient and sustainable through an intermodal station.

Alba Iulia

With a population of almost 74,000 and an urban area of 104km2, Alba Iulia has a population density of 713 per km2. Alba Iulia is located by the Mureş River in the heart of Transylvania in the central part of Romania. Cultural heritage and tourism are of significant importance for Alba Iulia. The historical centre is highlighted as a geometric centre and also as the core of the urban organisation. The Alba Carolina Citadel, the most representative Vauban Citadel in Romania, outlines the city of Alba Iulia. After a series of large rehabilitation projects over the last decades of more than €70m, financed by EU funding (ESIF), the Municipality has enhanced the city’s cultural heritage and provide the opportunity for both citizens and tourists to explore an area.


The Municipality of Smolyan is situated in a mountainous region in South Bulgaria on 1000m above sea level, in the heart of the Rhodope Mountains, near on the Greek-Bulgarian border. Smolyan is 250km away from the capital Sofia and 100km from the second largest city in the country – Plovdiv. The cross-border checkpoint with Greece (Zlatograd-Thermes) is situated only 55km from Smolyan. The opening of another point in the near future – Elidge border checkpoint, only 30km away from Smolyan, is on the way, which will be the fastest link with Xanthi and the Northern Aegean coast.


The most problematic issue for Võru town is that people are moving out from Võru town to surrounding municipalities or bigger cities in Estonia. The centre of Võru and heritage area is week and poor from activities, which is why people are moving away from the centre to live in the suburb areas of the town. As there are no universities in town, young people move to other towns in Estonia or abroad. Insufficient public transport, is also an important factor, in residents moving to larger cities. There is urgent need to bring people and life back to city centre, to make heritage area attractive place to live and have business and to reconstruct buildings to make them more energy efficient.


Located on the western periphery of Europe, within close proximity to Shannon International Airport and Shannon Foynes Port, Limerick is Ireland’s third largest city and designated as one of Ireland’s Gateway Cities under the National Spatial Strategy (2002); it has held the title of Ireland’s Smarter Travel Demonstration Area since 2012. The city has excellent
connectivity with the other large urban centres of Ireland through high-quality road and rail networks. Limerick’s historic core, within the contemporary urban centre has grown in a sustainable and resilient manner that has harnessed the unique location as one of international importance.