Sustainable built environment within reach

Published on 8 November 2017

Hybrid heat pumps can reduce the demand for natural gas in existing homes and buildings at an advantageous and accelerated rate from 15 billion cubic metres to possibly 1 billion cubic metres in 2035. This goes hand in hand with a significant but manageable electrification to prevent peaks in electricity demand. This is apparent from a recent study by Berenschot.

In recent months Berenschot has conducted research into the sustainability of the built environment through the use of heat pumps. The incentive was to gain an understanding of the integrated costs, CO2 reduction and implementation possibilities of the heat pumps in existing buildings.

For the sustainability of the built environment, Berenschot has calculated four visions (growth paths), with every growth path working towards a CO2-neutral built environment in 2050. The four visions vary in choice of heat pump, growth path and penetration speed. The degree of insulation and heat network penetration have been kept the same in all visions. Also, the visions do not take gas networks in new builds equipped with all-electric heat pumps into account. The visions therefore only differ in existing buildings, calculated using the Energy Transition model:

  • Vision 1 All-electric, linear: assumes a linear installation of approximately 220,000 all-electric heat pumps a year up to 2050.
  • Vision 2 Hybrid mix: assumes a linear path for the installation of hybrid heat pumps: approximately 160,000 a year up to 2035 in existing buildings. From 2035, only all-electric heat pumps will be included; from then on the number of hybrid heat pumps will remain the same.
  • Vision 3 All-electric ingrowth: has a low start-up speed with acceleration due to scale advantage towards 2050. Less rapid penetration of heat pumps until 2035, approximately 150,000 a year. From 2035 this will be overtaken by the acceleration of approximately 315,000 heat pumps a year until 2050.
  • Vision 4 Hybrid instead of high-efficiency boilers: no more separate high-efficiency boilers will be installed here, only in combination with a heat pump. Penetration of hybrid heat pumps until 2035, approximately 300,000 a year in existing buildings. From 2035, only all-electric heat pumps will be installed and part of the already installed hybrid heat pumps will be succeeded by all-electric.

From the calculation it appears that COemissions can be reduced in 2050 by more than 95% with both all-electric and hybrid heat pumps. Due to the hybrid solution, the reduction of natural gas demand can be accelerated from the current 15 billion cubic metres to possibly 1 billion cubic metres of natural gas in 2035, together with the addition of 3 billion sustainable green gas. This can be achieved by no longer installing or replacing gas boilers, but instead by installing hybrid heat pumps in existing homes everywhere. Despite the fact that the gas consumption of a hybrid is still low, the reduction of Dutch gas consumption is still very high due to the large numbers and the relatively low costs. The remaining consumption can therefore largely be provided with green gas.

The visions all result in a complete reduction of natural gas consumption by 2050; however, the speed, cumulative CO2 reduction and costs vary. Half of the visions assumes all-electric heat pumps. In the other two visions, a small heat pump is used as an addition to the (existing) boiler (hybrid heat pump). This is cheaper, also because no conversion to underfloor heating is required in the home.

The hybrid visions therefore have the lowest costs per tonne of CO2 savings and a faster reduction. Another major difference concerns the extra peaks in the demand for electricity. During cold winters, the calculated all-electric scenarios have an extra peak demand of approximately 17 gigawatts, a doubling of the current demand, for which extra power stations and/or foreign connections are needed. This extra peak demand is half that amount in the hybrid solutions.

In the enclosed article, the results of the study have been visualised and explained, as well as the effect and required adaptations for the integration of the all-electric or hybrid heat pumps in the homes.

Bert den Ouden

Bert den Ouden

Managing director