par | Déc 28, 2022



Ballard roof solar and heat pumps










The D2Grids pilot will build on the initial work completed through the HeatNet NWE project. It allowed the city to map out heating and cooling loads, identify opportunities for renewable heat sources and develop the concept design of a 5GDHC network. Involvement in HeatNet also resulted in the delivery of infrastructure in Millbay, but also in drilling test wells into the principal aquifer in the underlying limestone within this area.

In one cluster (Civic Centre), as well as serving public buildings, the pilot aims to expand the heat network infrastructure to supply a range of public buildings, including 144 residential units, a commercial area and a theatre with low carbon heat (that can transition to zero).

In another, at Millbay the proposals would supply social residential dwellings (147 units), a hotel, office block and events arena with zero carbon heating & cooling, delivering high levels of comfort at a competitive price.

Renewable energy (alongside waste heat) will be derived from a combination of ground source, marine water and air source using heat pumps (decentralised and centralised).


Total surface served

50 000 m²

Amount of connections


Type of consumers

Commercial, business & residential

Heat sources

Geothermal well + heatpumps 

Cooling sources

Geothermal well


Blueprints and technical datas

Length of Network

1 800 m

Heating Capacity

2 400 kW


Annual Heating Demand

3 800 MWh

Cooling Capacity

1 400 kW

Annual Cooling Demand

1 300 MWh

5GDHC Principles


The network will be set up in such a way that it will be possible to exchange heat and cold requirements between customers in the future expansion with several substations and connected secondary subnetworks. The net flows are balanced by short-term decentralized storage of the substations and by the heat source and low-grade thermal source of the mine water reservoir. The latter also serves as long-term (seasonal) centralized large-scale storage.


Establish a heat network in the Civic Centre cluster to provide district heating and cooling, alongside a private wire network using renewable sources to serve a range of existing buildings.

For more information,
please visit the project website