An energy-neutral building in Sweden thanks to geothermal and hybrid solar coupling

  • 2023
  • Karlskrona, Suède
  • Power output : 76.5 MWh + 422 kWh/sq.m
  • Panels : 84 SPRING hybrid panels + 130 FLASH photovoltaic panels

Located in the Swedish town of Karlskrona, the Blå Port building has 10 floors and 57 rental apartments. Thanks to a Dualsun geothermal/solar hybrid system, the building is now energy-neutral.

Skanska’s most ambitious project to date, the Blå Port building serves as a pilot for the production and long-term management of climate initiatives for buildings.

A look back at this bold project ⬇️

Hybrid solar power and geothermal energy for net-zero building consumption

Here, Dualsun hybrid solar panels convert solar energy into both electricity and heat (hot water). The solar electricity is used to power the building, while the hot water improves the efficiency of the heat pumps and can also recharge the geothermal boreholes.

This coupling is very interesting, as recharging the boreholes prevents the energy in the ground from being depleted, and guarantees high system efficiency throughout the winter!

The result of this coupling is zero net energy consumption: the hybrid solar panels produce at least as much energy as the building consumes in a year. This translates into a carbon footprint of 0 kg per year for operating energy.

This shows that a well-designed building with a good climate makes it very attractive!

Installation information

  • Hybrid panels: 84 Dualsun SPRING 400 Shingle Black
  • Solar panels: 130 Dualsun FLASH 400 Shingle Black
  • Heat pumps: 1 Qvantum Q48RS/2 (37.2 kW at B0/W35) and 1 Qvantum Q65RS/2 (52.4 kW at B0/W35)
  • Boreholes: 6 * 296 m
  • Power and energy coverage: 100%.
  • Heated area (Atemp): 4023 sq.m.

Energy requirements

  • Hot water requirements including VVC: 109.7 MWh (27.3 kWh/m²)
  • Heating requirements: 80.9 MWh (20.1 kWh/m²)
  • Building electricity: 27.4 MWh (6.8 kWh/m²)

Performance simulated via Polysun

  • Electricity production: 76.5 MWh
  • Increase in electricity production for PV-T due to cooling: 5%.
  • Self-consumption of solar electricity for building electricity: 20.3 MWh (27%)
  • Electricity sold: 56.2 MWh
  • Energy surplus: 6.3 MWh (1.57 kWh/m²)
  • PV-T thermal output: 422 kWh/m² (1.57 kWh/m²)
  • Recharging rate: 50%
  • Primary energy: 12.6 kWh/sq.m
  • Weighted energy performance, BBR29: 22.7 kWh/m² (70% below required level)
  • SCOP of heat pump without solar electricity*: 4.3
  • SCOP of heat pump with self-consumption of solar electricity**: 5.0
  • DualHybrid for positive-energy homes

Technical information

Characteristics Residential building
Number of panels 84 SPRING + 130 FLASH
Power output 76.5 MWh + 422 kWh/sq.m
Thermal system Qvantum Q48RS/2 and Qvantum Q65RS/2 heat pumps + 6 x 296 m boreholes