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Summary: Globally, there has been an increasing trend toward electricity production from renewables, hence promoting the opportunity for the electrification of the residential heating sector as opposed to fossil fuels' combustion. Decentralized heat pumps and district heating networks could play a key role in the Swiss future approach to heating. This study provides a detailed enviro‐economic assessment of the application of heat pumps and district heating systems based on renewable sources in different Swiss building archetypes on different scales. The results show that the levelized costs of heat from individual heat pumps and large‐scale district heating networks (using industrial excess heat with a lower energy price than for the other energy carriers) are 7% to 20% and 65% to 75% higher than individual fossil fuel boilers for single‐family houses, respectively. However, for multifamily houses, individual heat pumps, small thermal grids, and large‐scale district heating networks are competitive. The district heating network coupled with a large centralized water source heat pump is found to be the most expensive solution (0.24‐0.29 CHF/kWh) for residential heating today. The sensitivity analysis suggests the economic feasibility of different heating technologies significantly overlaps with each other depending on the boundary conditions, hence justifying not only the mixed opinions by experts in Switzerland but also the disagreements over costs of these technologies in international literature. It can be concluded that, based on the levelized cost of heat, there are sufficient economically viable options for decarbonization and electrification of the residential heating sector. While this is an important finding for policymakers, the barriers, for example, high upfront cost, need to be addressed. Highlights: Low‐carbon heating technologies are investigated for residential heating supply.Levelized costs of heat from heat pumps and district heating networks are computed.Levelized costs of the heating technologies significantly overlap with each other. [ABSTRACT FROM AUTHOR]

Abstract Heating and cooling contributed to about 50% of the final energy consumption in EU 28 countries. In Switzerland, about 295 PJ of heat was consumed in buildings in 2016 which emitted about 17 million tonnes CO 2. However, if the Swiss nationally determined contributions (NDCs) have to be met, the country's aggregate CO 2 emissions should be between 8 and 16 million tonnes in 2050. Reduction of specific space heating demand in buildings; integrating renewable energy and increased heat distribution by district heating networks (DHNs); and use of heat pumps are three strategies which have been examined for decarbonising the Swiss heating system. It is estimated that an annual reduction of 1.5%–2.5% in the aggregate heating demand for different categories of buildings would be required. DHNs would have to be expanded from 53 networks in 2016 to about 159–212 networks in 2050 to enable integration of 53–70 PJ of ambient heat. This would require 390–520 heat pumps of 2–50 MW capacity with a coefficient of performance between 3 and 4. If these strategies are implemented, it is estimated that the aggregate CO 2 emissions from heating would be between 1.25 and 3.06 million tonnes by 2050 thereby significantly decarbonising the heating system. Highlights • Undertakes a comprehensive assessment of heating supply and demand in Switzerland. • Analyses the characteristics of existing Swiss district heating networks (DHNs). • Assesses the required rate for aggregate heat demand reduction in residential buildings. • Estimates the reduction in CO 2 emissions from heating in 2050 in decarbonisation scenarios. • Evaluates the number and capacity of DHNs and heat pumps for decarbonising the Swiss heating system. [ABSTRACT FROM AUTHOR]

This paper analyses optimal electricity investments (PV and battery storage) to decarbonise heat supply in residential buildings under different heat pump and energy retrofitting scenarios in a detailed representation of the Swiss power and heating system. The sensitivity of PV and storage deployment, including lithium-ion (LiB) and vanadium redox flow batteries (VRFB), with respect to distribution network capacity is also investigated. We propose an open-source dispatch sector coupling model (GRIMSEL-AH) to minimise energy system costs (social planner perspective) for heating and electricity supply in Switzerland with hourly and daily time resolution for electricity and heating respectively. Moreover, our representation of the Swiss energy system includes various types of consumers and urban settings which are represented with monitored electricity demand data for each sector and simulated heat demand data at the building level for the residential sector. We find that under a "business as usual" heat pump deployment and retrofitting rate, the optimal electricity investments correspond to 27.8 GW p of PV combined with 16.9 GW (33.8 GWh) for LiB and 1.9 GW (7.6 GWh) for VRFB. For this case, 57% (13.3 TW th /year) of the residential heat demand is covered by heat pumps with a total installed capacity of 19.7 GW th by 2050 (capacity exogenously set with its operation optimised). With increasing heat pump deployment, retrofitting rates are found to have a large impact on the investment in storage and a 100% heat pump scenario for the residential sector appears to be feasible. Our results show that heat pumps do not only decarbonise heat but also provide extra flexibility to the power system, since they increase local PV self-consumption, resulting in higher PV deployment. The model and the methodology presented in this study can be applied to other countries. • Open-source sector coupling modelling framework with flexible heat pump operation. • Impact of heat pump and energy retrofitting scenarios on electricity investments. • Retrofitting rates have a significant impact on the storage investment. • Heat pumps provide extra flexibility by increasing local PV self-consumption. • Trade-offs between storage and distribution grid upgrade are discussed. [ABSTRACT FROM AUTHOR]