Living Lab for the Energy Transition IW3
Supplying the Neighbourhood with Sustainable Heat

While a large proportion of electricity in Germany (around 50 %) is already generated from renewable energy, the heating and cooling supply is still largely based on fossil energy carriers. Successfully transforming the heating sector may prove a key contributor to transforming the energy sector.

According to a study commissioned by the German Environment Agency (UBA), medium-deep and deep geothermal energy could generate 150 terawatt hours of energy per year by 2050. Anyone thinking only of the deep geothermal projects in southern Germany would be mistaken: the North German Basin with its large hydrothermal resources could play a decisive role here. How this can be achieved is being researched and demonstrated in the living lab for the energy transition “Integrated Heat Transition Wilhelmsburg” (IW³ for short) in Hamburg. In the format of living labs for the energy transition, pioneering projects are implemented on an industrial scale. In the energy research program, they are intended as a funding format to support the practical implementation of innovative technologies and processes for the energy transition and to accelerate the transformation of the German energy system.

Holistic view of urban heating system

Producing and distributing renewable heat in an urban setting has been difficult to implement to date because of the high costs for the necessary space, infrastructures, and power plants. This is where IW³ comes in. The Elbe island of Wilhelmsburg is Hamburg’s largest district in terms of area. With over 50,000 inhabitants and due to its geographical location, Wilhelmsburg can be compared to a medium-sized city in many senses. The living lab for the energy transition will show how innovative technologies and business models can facilitate a climate-friendly, energy-efficient, and affordable heat supply even in large and medium-sized cities. New production and storage technologies, smart sector coupling, and innovative business models provide the foundation for major CO₂ savings and consequently enable a sustainable transformation of the heating and cooling supply.

IW³ pursues an integrative concept here. The fundamental idea of sustainably transforming an urban heating system is approached from a holistic point of view: energy generation, systems integration, and the market sector are intertwined. Existing and new renewable energy producers are combined with each other and integrated into a virtual power plant. Innovative concepts offer the opportunity to trade energy from different sources and providers in a transparent, automated, and efficient manner. The heating, electricity, and transport sectors are smartly coupled with each other.

Using geothermal potential in urban areas

A crucial part of IW³ is the construction of a geothermal plant. In future, it will harvest geothermal energy from a thermal water reservoir at a depth of around 1,300 metres and feed it into the district heating network.

The project was initially planned as a deep geothermal energy project. The original target reservoir was sandstone, which was expected at a depth of around 3,200 metres according to the preliminary exploration. In spring 2022, the first exploratory borehole was drilled to a final depth of 3,067 metres. However, the original target reservoir was too shallow and the project had to be redesigned. Since the temperature of the medium-deep geothermal reservoir is not sufficient for the heating water temperature required in the district heating network, a heat pump system will be installed.

This will be implemented in two parts, each with several heat pumps, to account for the predominantly seasonal fluctuations in the power consumption. In combination with a combined heat and power unit, the aim is to achieve the highest possible efficiency and accordingly a lower electricity consumption. From a depth of around 1,300 metres, more than 6,000 households in Hamburg-Wilhelmsburg could theoretically be supplied with heat from the new geothermal plant.

Further generation and storage components are already available in Wilhelmsburg and can be integrated into the system as required. Solar thermal energy, biomethane, and industrial heat for a renewable heat supply are connected with power-generating wind energy and photovoltaic systems via a new coupling station.

The pipeline connecting the geothermal plant to the Wilhelmsburg energy bunker has been under construction since September 2023. Construction of the geothermal boiler house will start in spring 2024. Geothermal energy will then be supplied from 2025.

Compared to deep geothermal energy, medium-deep geothermal energy has the advantage that drilling costs, drilling risks, and project development times are significantly lower. These points speak in favour of scalability. When the first geothermal plant was planned, a second well doublet was already taken into account spatially and technically, so that with increasing heat demand in the course of the densification of the heat network and the development of new residential areas, another geothermal heat source can be tapped into with little effort.

Digital support

Aside from the structural aspects, IW³ uses systematic digital networking. This will allow the production and consumption of heat energy, along with the interface between the heating and electricity markets, to be designed as efficiently as possible. A digital heating network connects the different energy producers. These are coordinated through a common control system, similar to in a virtual power plant. Detailed forecasts of the heating sales and demand make it possible to optimally control the use of the individual plants. This system integration is a decisive measure for the efficient operation of a green heating system.

The project partners use the latest digital technologies for planning and forecasting. Using machine learning, which is a practical area of artificial intelligence, they model the complex interaction of the district heating network’s plants. The result is a “digital twin”. With these options, the partners can respond both to fluctuating renewable energy and to the constant expansion of the sector-coupled system.

The researchers are also investigating new types of heating and flexibility markets and testing a pilot register for the forthcoming register of guarantees of origin for heat.

Transferable to suitable cities in Germany

The living lab in Wilhelmsburg could become a model for a sustainable transformation of urban spaces with an impact beyond just Hamburg. The technologies and processes applied here could be used in future as a blueprint for districts and cities all over Germany. Particularly with regard to the use of geothermal energy, which in the past has only been implemented in a few locations in Germany because of the high economic risks associated with its exploitation, Wilhelsmburg could become a pilot site.