Residential Heating Sector Research Articles

Potential and costs of decentralized heat pumps and thermal networks in Swiss residential areas

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.

FTT:Heat — A simulation model for technological change in the European residential heating sector

We introduce a new bottom-up model for simulating Future Technology Transformations in the European residential heating sector, FTT:Heat. The model simulates the uptake and replacement of heating technologies by households in all individual Member States up to 2050, and allows to simulate the potential effect of real-world policy instruments aiming at an increased uptake of low-carbon technologies. It features an explicit representation of households' technology choices, based on observed preferences and non-linear diffusion dynamics. Decision-makers are modelled as individual households, which are subject to limited information and bounded rationality. Their decisions reflect behavioural factors and preferences at the micro level, and may result in sub-optimal outcomes from a macroeconomic perspective. For demonstration, we simulate policy mixes for reaching the EU's 2030 renewable heating targets in each Member State. Under current diffusion trends, some countries are estimated to continue an ongoing transition towards renewable heating, while others would hardly see any decarbonisation. For increasing the share of renewable heating by at least ten percentage points until 2030, 20 Member States need to introduce additional policies, the necessary stringency of which differs between countries. Due to the slow turnover of heating systems, resulting cost increases faced by households could persist over decades.

Exploring the trade-offs between electric heating policy and carbon mitigation in China

China has enacted a series of policies since 2015 to substitute electricity for in-home combustion for rural residential heating. The Electric Heating Policy (EHP) has contributed to significant improvements in air quality, benefiting hundreds of millions of people. This shift, however, has resulted in a sharp increase in electric loads and associated carbon emissions. Here, we show that China’s EHP will greatly increase carbon emissions. We develop a theoretical model to quantify the carbon emissions from power generation and rural residential heating sectors. We found that in 2015, an additional 101.69–162.89 megatons of CO2 could potentially be emitted if EHP was implemented in 45–55% of rural residents in Northern China. In 2020, the incremental carbon emission is expected to reach 130.03–197.87 megatons. Fortunately, the growth of carbon emission will slow down due to China’s urbanization progress. In 2030, the carbon emission increase induced by EHP will drop to 119.19–177.47 megatons. Finally, we conclude two kinds of practical pathways toward low-carbon electric heating, and provide techno-economic analyses.

Assessment of techno-economic feasibility of centralised seasonal thermal energy storage for decarbonising the Swiss residential heating sector

Abstract A major part of heat in Swiss residential buildings is supplied by fossil fuel boilers, leading to large CO 2 emissions. Heat supply can be decarbonised by replacing boilers with renewable energy sources (RES) such as solar thermal, but the mismatch between heat supply and heat demand needs to be overcome. Seasonal thermal energy storage (STES) can be used to store heat from solar collector (SC) thereby reducing the usage of boilers. A centralised heat pump (HP) is also an attractive alternative for heating. This paper assesses the techno-economic feasibility of different heating systems for decarbonising the Swiss residential heating sector. It uses the simulation method for assessing hourly energy flows in 500 and 1,000 multifamily households connected by a district heating (DH) system. Four different configurations of DH system are assessed by simulating hourly energy flows. The required capacity of equipment, cost of different systems, and the cost of decarbonisation of heat are calculated. Levelised cost of heat, CO 2 emissions and share of RES are compared. Peak electricity load due to use of HP and the impact of using different emission factors for electricity is examined. Results show that the heating system with a centralised HP has the least cost of decarbonisation but it adds a high peak load on the electricity grid infrastructure. A heating system with a SC, a STES, HP and a boiler emerges as a cost competitive option for decarbonising heating for 1,000 dwellings.

Study on the forecast model of electricity substitution potential in Beijing-Tianjin-Hebei region considering the impact of electricity substitution policies

In recent years, China has introduced a series of energy substitution policies, aiming to achieve a fundamental change in the way of energy development. Firstly, based on the world energy model constructed by IEA, this paper determines the main driving factors in the field of power substitution, including economy, technology, policy, energy price and environmental factors. Secondly, based on the principle of system dynamics, a causal relationship diagram of five driving factors is constructed to clarify the feedback and linkage relationship between the factors. Finally, this paper proposes a hybrid prediction model combining Salp Swarm Algorithm (SSA) and Least Squares Support Vector Machines (LSSVM), namely SSA-LSSVM, which fully considers the influence of relevant factors of electric energy substitution, while avoiding the subjectivity of model parameter setting. The results show that the future development of electric energy substitution in the Beijing-Tianjin-Hebei region has maintained a rapid pace. The potential for electric energy substitution in the industrial production sector is large, and there is a large space for mining and operation optimization in the residential heating and transportation sectors. This paper provides a basis for the future development and improvement of the strategic plan of electric energy substitution in Beijing-Tianjin-Hebei region.

Electrification of transport and residential heating sectors in support of renewable penetration: Scenarios for the Italian energy system

The integration of significant shares of renewable energies poses remarkable issues related to the intermittent nature of these sources. Nonetheless, solutions in support of renewables integration exist and become particularly effective if conceived under a smart energy system perspective, to exploit potential synergies among different energy sectors. With this respect, shifting programmable consumption from fossil fuels to electricity represents one measure to exploit otherwise-curtailed renewable generation. In this study, the impact of electrification of both private transport and space heating is assessed for the Italian energy system with the help of EnergyPLAN software and quantified in terms of critical environmental and techno-economic indicators, evaluating to what extent increasing the electricity demand supports the development of renewables. Results confirm that both transport and heating electrification can lead to significant reductions in CO2 emissions, around 25–30% if pursued independently. However, smart charge allows managing transport electricity demand more flexibly than heating demand, which makes the former more effective than the latter in fostering an increased renewable penetration, unless additional technologies are deployed to enhance flexibility in the heating sector. A techno-economic optimisation identifies possible optimal scenarios capable to reduce emissions by up to 47% with an increase in annualised costs of 34%.

Correction to: Evaluation of bottom ash slagging risk during combustion of herbaceous and woody biomass fuels in a small-scale boiler by principal component analysis

In the short- and mid-term perspective, drastic measures for the reduction of anthropogenic emissions including extensive decarbonization of the residential and industrial heating sector have to be implemented. To replace fossil fuels, solid biogenic residues and wastes will have to be increasingly utilized. Compared to clean woody biomass, these biomass assortments are commonly characterized by higher Si and alkaline metal contents recognized as major driver for low ash melting temperatures resulting in elevated risk of bottom ash slagging. To facilitate the prediction of bottom ash slagging during combustion, several fuel indices have been proposed. Based on empirical correlations with parameters relevant for slagging behavior, e.g., ash melting temperatures or slag fraction of the bottom ash, these fuel indices were subsequently enhanced and adapted for an increasing range of biomass fuel characteristics. In this study, analysis data of 26 woody and non-woody fuels and experimental data derived from two combustion test campaigns with an automatically stoked small-scale boiler were investigated through principal component analysis. Thus, the complex interdependencies between the fuel composition and the resulting bottom ash characteristics and the applicability of existing fuel indices were evaluated. The chemometric analysis highlighted that Si, Ca, K, Mg, and also the remaining Al and S in the bottom ash are crucial fuel components in the context of bottom ash melting. On this basis, the molar ratio (Si + P + K)/(Ca + Mg) was adapted and correlated with the susceptibility to slag formation which is a new parameter derived from ash content, slag fraction > 16 mm in the bottom ash, and slag category. Thus, the applicability of a newly developed fuel index was evaluated with respect to the bottom ash slagging risk during real-scale combustion. Three ranges were distinguished for the fuel index corresponding to a specific susceptibility to slag formation (i.e., low 75 mol/g for straw-like fuels and blends with wood). The linear regression of the fuel index with susceptibility to slag formation exhibits a high coefficient of determination (i.e., 0.99 for woody biomass and 0.84 for straw-like fuels and their blends with wood).

Cost comparison and optimization of gas electric hybrid heat pumps

AbstractThe residential heating sector can offer significant load‐shifting possibilities to the energy system. Currently 400,000 households in Denmark are heated by natural gas boilers. The power consumption corresponding to these boilers can offer high value to the stabilization of the wind intensive Danish energy system. Gas electric hybrid heat pumps (GEHHPs) are individual heat pumps consisting of an electric heat pump and a gas boiler. They enable a fully flexible operation of electric heat pumps by supplementing electricity with gas when necessary. In this paper, we construct a cost optimization model of a GEHHP and compare the levelized cost of heat of this system with other individual heating systems. We investigate the changes in the operation schedule of the GEHHP, both from a socio‐ and a private‐economic perspective, and analyze how certain economic and technological framework conditions influence their operation schedule. Our article shows that the end‐consumer's optimal operation schedule uses the gas boiler component of the GEHHP 24% of the time. Additionally, comparing the levelized cost of heat of the GEHHP with other heating alternatives proves that the GEHHP setup is the most cost efficient individual heating alternative.This article is categorized under: Energy Systems Analysis > Economics and Policy Energy Systems Economics > Economics and Policy Energy Systems Economics > Systems and Infrastructure

Flexible Multi-Energy Scheduling Scheme for Data Center to Facilitate Wind Power Integration

Due to the intermittent and uncontrollable nature of wind resources and inflexible operation of conventional generation units, they present challenges for the power system to integrate more wind power. With its unique flexibility on the demand side, the data center can be considered as an effective solution to relieve wind curtailment. Moreover, with the help of waste heat recovery module, the data center can reduce the utilization of conventional thermal units especially in the residential heating sector which increases the flexibility of system operation and facilitates more renewable integration. In this paper, a flexible workload management and resource scheduling model are proposed to achieve a multi-energy co-optimization for data center and enhance the integration of wind power. A two-stage stochastic programming model is formulated to address the uncertainties involved in this process. The proposed model is examined by a simulative data center microgrid and the numerical results demonstrate its effectiveness and robustness.

Urban pollution in the Danube and Western Balkans regions: The impact of major PM2.5 sources

The SHERPA tool was used to assess the major pollution sources and the geographical areas impacting on the PM2.5 of the main cities in the Danube and Western Balkans regions. The activity sectors influencing most the PM2.5 levels in the study area are energy production (22%), agriculture (19%), residential combustion (16%) and road transport (7%). The energy production in inefficient coal-fuelled power plants was identified as one of main source of PM2.5 in the Western Balkans. As for the geographical origin of PM2.5, the transboundary pollution is confirmed as the main origin of PM2.5 (44%) in the investigated cities, while the city own emissions and the national sources outside the concerned city impact on average 22% and 15%, respectively. An association was observed between the long-range transport and the impact of agriculture and energy production, while both local urban emissions and long-range transport were associated with the residential sector. A special attention is given in this study to biomass, a renewable source, which use is often promoted in the frame of climate and energy policies. Nevertheless, the combustion of biomass in inefficient small appliances has considerable particulate matter emissions and therefore this type of practice impacts negatively on air quality. Considering that biomass is traditionally used in South-East Europe as fuel for residential heating, the interpretation of the model results was supported with the estimation of biomass burning contributions to PM2.5 obtained with receptor models and data on biomass fuel consumption from the literature. The analysis of the contributions from biomass burning derived from receptor models suggests that biomass burning is the dominant source within the residential heating sector in the studied area and that the emissions from this source are likely underestimated. This study concludes that more effort is needed to improve the estimations of biomass burning emissions and that policies to improve air quality in the cities should involve a geographic context wider than the city level.

Individual motivations underlying the adoption of cleaner residential heating technologies: Evidence from Nanjing, China

To reduce pollutant emissions and improve air quality, the Chinese government has enacted new energy policies (e.g., “coal to gas” and “coal to electricity”) concerning the residential heating sector to introduce cleaner residential heating technologies (RHTs). In practice, stimulating the diffusion and adoption of cleaner RHTs among homeowners might be crucial for the successful implementation of such energy policies. This study employed diffusion of innovation theory to explore the individual (rational and emotional) motivations behind homeowners’ adoption of cleaner RHTs. We conducted a field survey of Nanjing households that intended to decorate their newly built homes in the period from December 2017 to December 2018. The empirical results showed that the total cost, technical attributes, and influence of peers were important factors underlying the adoption intention of cleaner RHTs. However, this study failed to find any statistically significant effects of the relative advantage or personal environmental awareness on the adoption intention of cleaner RHTs. Our findings might provide some useful implications for market managers and policy makers.

Optimization and operation of integrated homes with photovoltaic battery energy storage systems and power-to-heat coupling

Abstract Renewable energies from residential photovoltaic systems can be used in the electricity sector as well as in the residential heating sector. Therefore, sector coupling, for example by using heat pump systems, is mandatory. Integrated homes use photovoltaic energy for space heating and domestic hot water to contribute to the decarbonization of the heating sector. The economics are a key to increasing the market penetration of integrated homes. Combined operation strategies for the electricity sector as well as for the heating sector can enhance the economics of these systems. This paper analyses different operation strategies for both electrical and thermal systems and examines the gain in efficiency by combined strategies. Furthermore, the dimensioning of the different system components heavily influences the economics of the integrated home. Capital-intensive components, such as photovoltaic generators, battery storage systems, heat pumps, and thermal storage units, play a major role for the profitability. Therefore, the optimization of component sizing is necessary in order to enhance the economics of the system. This paper presents optimization results based on the covariance matrix adaptation evolution strategy. The results of the paper indicate that combined operation strategies as well as the optimization of the component sizes strongly influence the economics of photovoltaic battery energy storage systems with power-to-heat coupling. The impact of the optimization on the economic efficiency is higher compared to the influence of advanced combined operation strategies. The optimization indicates that relatively small storage units are more economical. The use of the heating sector as additional storage for excess photovoltaic energy is only economical to a minor degree, because it reduces the coefficient of performance of the heat pump.

Evaluation of impact of residential heating on air quality of megacity Istanbul by CMAQ

Residential heating is one of the major sectors that contribute to emissions of harmful air pollutants in urban areas. In Istanbul, local sources are the main contributors of particulate matter levels. To quantify the contributions of residential heating sector to ambient particulate matter concentrations, we have developed an up to date spatially distributed high-resolution emissions inventory based on local activity data. The air quality simulations were conducted using the CMAQ (version 5.2).Our study results showed that our high-resolution emissions of the residential heating sector significantly improve the spatial distribution and concentration of air pollutants (SO2, PM10, PM2.5) for Istanbul. Air quality model simulations with our high-resolution emissions underestimated PM10 concentrations throughout the study episode on average by only 4.16% with a mean bias of 2.23 μg/m−3 while base inventory underestimated PM10 concentrations on average by 35.1% with a mean bias of 18.91 μg/m−3.Results show that our spatially distributed high-resolution emissions inventory produces more realistic results for Istanbul during wintertime when residential heating has the most influence on local air pollution.

Consumer behaviour in the residential heating sector in Austria: Findings from a bottom-up modelling approach

Energy system models usually have to rely on technical parameters like building standards. This kind of technical approach leads to an overestimation of energy demand for heating in the Austrian building sector. Consumer behaviour has been identified as one of the major reasons for this overestimation. In this analysis, a bottom-up energy system model for the residential heating sector has been built with the model generator TIMES and expanded by findings on consumer behaviour. The model is used to investigate the effect of consumer behaviour on residential space heating demand in Austria from 2007 to 2030, and to quantify the implications on possible future energy savings. Model results show that (1) energy demand for residential heating is slightly decreasing, (2) consumer behaviour greatly affects energy demand, (3) neglecting consumer behaviour leads to a significant overestimation of possible energy savings due to building-standard improvement. This analysis provides a better understanding of the interaction between thermal improvements of buildings and consumer behaviour and enables better founded outlooks on possible future energy savings.

Scenarios to decarbonize residential water heating in California

This paper presents the first detailed long-term stock turnover model to investigate scenarios to decarbonize the residential water heating sector in California, which is currently dominated by natural gas. We model a mix of water heating (WH) technologies including conventional and on-demand (tank-less) natural gas heating, electric resistance, existing electric heat pumps, advanced heat pumps with low global warming refrigerants and solar thermal water heaters. Technically feasible policy scenarios are developed by considering combinations of WH technologies with efficiency gains within each technology, lowering global warming potential of refrigerants and decreasing grid carbon intensity. We then evaluate energy demand, emissions and equipment replacement costs of the pathways. We develop multiple scenarios by which the annual greenhouse gas emissions from residential water heaters in California can be reduced by over 80% from 1990 levels resulting in an annual savings of over 10 Million Metric Tons by 2050. The overall cost of transition will depend on future cost reductions in heat pump and solar thermal water heating equipment, energy costs, and hot water consumption.

The national scenarios for emissions reduction in residential heating sector in Poland

Today’s residential heating sector (RHS) in Poland is based mainly on fossil fuels combustion, both in individual and large-scale heat sources. The RHS emissions significantly contribute to the outdoor air quality deterioration, especially by low-stack emissions in the heating season. Following the example of other EU countries, the national scenarios for emissions reduction in RHS are an effective tool for outdoor air quality improvement. The scenarios contain a replacement of the existing heat sources in RHS with heat generation technologies in the scale of the country, like high-efficiency gas boilers, biomass boilers or heat pumps. The study takes into account today’s RHS structure in Poland, the scenarios feasibility and achieved emissions reduction.

Greenhouse Gas Abatement Cost Curves of the Residential Heating Market: A Microeconomic Approach

In this paper, we develop a microeconomic approach to deduce greenhouse gas abatement cost curves of the residential heating sector. Our research is based on a system dynamics microsimulation of private households’ investment decisions for heating systems to the year 2030. By accounting for household-specific characteristics, we investigate the welfare costs of different abatement policies in terms of the compensating variation and the excess burden. We investigate two policies: (i) a carbon tax and (ii) subsidies on heating system investments. We deduce abatement cost curves for both policies by simulating welfare costs and greenhouse gas emissions to the year 2030. We find that (i) welfare-based abatement costs are generally higher than pure technical equipment costs; (ii) given utility maximizing households a carbon tax is the most welfare-efficient policy and; (iii) if households are not utility maximizing, a subsidy on investments may have lower marginal greenhouse gas abatement costs than a carbon tax.

Electricity, gas, heat integration via residential hybrid heating technologies – An investment model assessment

Integrating gas, electricity and residential heating sectors through hybrid heating technologies equipped with smart controls could provide energy system planning and operational benefits. Hybrid heaters combine different heating appliances in one device and can switch between those appliances during operation. Different configurations are possible: B-R (gas boiler-resistance), HP-B (heat pump-gas boiler), and HP-R (heat pump-resistance) heaters. A linear programming investment model is formulated and applied to an Irish test system with 40% wind energy generation to determine the optimal capacities and dispatch for the power and residential heat systems, including thermal storage. No technology is a silver bullet, but this paper finds that the widespread deployment of hybrid HP-B systems delivers a wide range of cost and strategic benefits: This hybrid technology minimises total system cost, reduces gas consumption and CO2 emissions compared to B-only, and, compared to HP-only, reduces power generation capacity requirements and heater capital cost. Other hybrid heaters are effective in addressing a specific challenge, although with drawbacks: Hybrid B-Rs considerably reduce wind curtailment, but increase the use of carbon-intensive coal generation; HP-Rs mainly only benefit consumers by reducing heater capital cost compared to HPs and require more generation capacity additions and thermal storage tanks.

Household preferences of hybrid home heating systems – A choice experiment application

The residential heating sector presents considerable energy savings potential, as numerous heating solutions for reducing electricity consumption and utilizing renewable energy sources are available in the market. The aim of this paper is to examine determinants of household heating system choices and to use this information for policy planning purposes. This paper investigates residential homeowner attitudes regarding innovative hybrid home heating systems (HHHS) with choice experiment. Heating system scenarios are designed to represent the most relevant primary and supplementary heating alternatives currently available in Finland. The choice sets include six main heating alternatives (district heat, solid wood, wood pellet, electric storage heating, ground heat pump and exhaust air heat pump) that are described by five attributes (supplementary heating systems, investment costs, operating costs, comfort of use and environmental friendliness). The results imply that HHHSs generally appear to be accepted among households; however, several factors affect perceptions of these technologies. The results reveal differing household attitudes toward the main heating alternatives and show that such views are affected by socio-demographic characteristics (age, living environment, education, etc.). The results suggest that households view supplementary heating systems (especially solar-based) favorably. The other attributes studied also play a significant role in decision making.

The wood pellet market in Austria: A structural market model analysis

EU bioenergy policies and oil price hikes have resulted in a significant increase of installed pellet boilers for residential heating. Hence, European demand for wood pellets has been growing faster and more steadily than supply leading to rising market prices in recent years. This article presents an econometric analysis of demand and supply of wood pellets in the residential heating sector in Austria, one of the most dynamic markets for residential pellets. Annual and monthly time series data between 2000 and 2014 are used in a two-stage least-squares (2SLS) regression to estimate supply and demand elasticities of wood pellets. In all model specifications, pellets demand is found to be inelastic (from −0.66 to −0.76) and pellets supply unit-elastic (from 1.03 to 1.18). Thus, consumers are highly exposed to price changes resulting from supply shocks. Policies which support investments in pellet boilers will shift the demand of wood pellets and likely leading to higher prices for consumers.