Modelling Scenarios for Low Carbon Heating Technologies in the Domestic Sector Towards a Circular Economy

The UK Government’s Net Zero strategy requires strong commitments to avoid catastrophic impacts of climate change. The built environment puts major pressure on the natural environment, especially with space heating-related emissions; therefore, transitioning to a circular economy is vital. In this direction, the heat pump market in the UK has been growing gradually whereas the number is still low (43,000 units in 2021). The UK Government aims to reach 600,000 heat pump installations per year by 2028, and according to the Climate Change Committee (CCC), this number should reach 1 million by 2030. In order to accelerate the transition, the Boiler Upgrade Scheme (BUS) has been introduced to provide a £5,000 grant in the UK, and the Scottish Government granted Home Energy Scotland (HES) loan and cashback scheme providing a £7,500 grant and a £2,500 interest-free loan for heat pumps. Islands are facing environmental, economic and social pressure due to the lack of connection to the mainland and dependency on fossil fuel imports. Exploring the benefits of renewable energy and low carbon heating technologies is crucial to overcome these issues. Orkney has a huge potential for renewable energy by producing electricity more than its needs. Therefore, this study chooses Orkney as a case study to explore potential heat pump uptake scenarios in line with government targets towards Circular Economy (CE). The study aims to create a comprehensive holistic approach to evaluate the environmental, energy and economic impacts of heat pump deployment scenarios. The consequences of replacing conventional heating technologies with heat pumps have been assessed through (i) comparative life cycle assessment (LCA) of heat pumps with gas boilers in UK houses, (ii) energy systems modelling (ESM) to optimise the performance of a heat pump coupled with thermal energy storage (TES) tank to reduce use phase related impacts in Orkney, (iii) building stock modelling (BSM) of Orkney’s domestic sector to understand the housing condition, (iv) economic modelling to analyse life cycle cost of an air source heat pump and potential savings when existing conventional heating systems are replaced with heat pumps in Orkney, and (v) heat pump diffusion model to quantify hourly electric load curves of variable heat pump operation optimised by the energy model. The integrated methodology creates a more holistic and life cycle-wide approach to both demand, supply and end-user side of the system; therefore, the results are illustrated in both individual house archetypes level to provide guidance to the end-users and at the Orkney level to calculate cumulative savings for the policymakers. The results show that the use phase is the major contributor to the environmental impacts; therefore, increasing the renewable share in the UK’s electricity mix could help to reduce negative impacts in most of the categories. However, the high deployment of wind farms also creates toxicity and metal depletion problems. The heat pump uptake scenarios in Orkney shows that 82% reductions in energy supply could be achieved when ambitious energy efficiency improvement measures are taken in the CE scenario. The use phase-related emissions could be reduced by 98% when the heat pump becomes the only heating technology in Orkney. However, the life cycle-wide approach suggests that strong commitments are required in the manufacturing stage of these technologies through implementing circular principles such as including the use of secondary materials, eco-design and reusability of all components. Moreover, a market introduction program should be provided before shifting from one technology to another so greener production lines could be achieved. Total heating costs paid by consumers in Orkney could be reduced by 84% in the CE scenario when heat pump uptake is coupled with energy efficiency improvement measures; however, it requires a £130 million investment to insulate the unrefurbished housing stock of Orkney. Therefore, subsidies and incentives are also required for efficiency improvements such as reductions in VAT on equipment and labour costs, grants similar to BUS/HES and interest-free loans for the remaining costs. Future scenarios indicate that decision-making has significant importance on overall results; therefore, CE standards for heat pump manufacturing and deployment are crucial to reduce the negative impacts of fuel poverty and reach the Net Zero target

Circular Economy and Eco-Innovation Solutions for Low-Carbon Buildings in Cities: The Case of Kayseri

An analysis of eco-innovations solutions for efficient low carbon buildings through circular economy principles (reduce, reuse, recycle), that also consider economic and social indicators has been performed at the national (Turkey) and urban scale (Kayseri). The framework for the city of Kayseri and the implementation of the circular economy for construction chain were determined that the three enabler tools which are policies, funding and awareness and collaboration could help to implement circular city model in Turkey. Reducing energy intensity and understanding the factors that can influence this (such as urbanization and industrialisation) will help mitigate future climate changes, improve local air pollution and health

An Integrated Methodology for Scenarios Analysis of Low Carbon Technologies Uptake towards a Circular Economy: The Case of Orkney

This study aims to create a comprehensive, holistic approach to evaluate the environmental, energy, and economic impacts of air source heat pump deployment scenarios through: (i) a life cycle assessment of air source heat pumps in Orkney houses, (ii) energy systems optimisation modelling to optimise the performance of an air source heat pump coupled with thermal energy storage tank to reduce use phase related impacts in Orkney, (iii) modelling of Orkney’s domestic building stock to understand the housing condition, and (iv) economic modelling to analyse the life cycle cost of an air source heat pump and potential savings when replacing conventional heating systems. The results show that an 82% reduction in energy supply could be achieved when ambitious energy efficiency improvement measures are adopted in the circular economy scenario. The use phase related emissions could be reduced by 98% when the air source heat pump becomes the only heating technology in Orkney. However, the life cycle-wide approach suggests that strong commitments are required in the manufacturing stage of these technologies through implementing circular principles, such as including the use of secondary materials, eco-design, and reusability of all components. Moreover, total heating costs paid by consumers in Orkney could be reduced by 84% in the circular economy scenario when air source heat pump uptake is coupled with energy efficiency improvement measures, but it requires a £130 million investment to insulate the whole housing stock of Orkney. Future scenarios indicate that decision-making has significant importance on overall results. Therefore, circular economy standards for air source heat pump manufacturing and deployment are crucial to reduce the negative impacts of fuel poverty and reach the net zero target

Comparative Environmental Impact Assessment of Heat Pumps with Gas Boilers and Scenario Analysis Towards a Circular Economy in the UK

This research compares the environmental impacts of heat pumps with gas boilers and scenario analysis through a life cycle approach. Our study shows that the use and disposal phase is responsible for 60% and 21% of all environmental impact on average. Manufacturing phase of heat pumps accounts for only 14% of all impacts. However, these emissions occur outside of the UK as they are manufactured in Europe. Even though the electricity mix of UK has decarbonised substantially during the last decade heat pumps has still higher lifetime impacts than gas boilers in all environmental categories except climate change impact. Replacing gas boilers with heat pumps in the domestic sector could provide a reduction in carbon emissions in future scenarios with more decarbonisation measures, however, in other impacts categories, they do not present advantages. Gas boiler has 79% lower impact than hat pumps on average in all categories but in climate change category boiler results 156% higher GHG emissions than heat pumps. Future scenarios offer significant reductions in most of the impact categories. CE scenario has the highest potential with a 54% reduction on average. RE and LG scenarios have smaller potential than CE scenario relatively (49% and 43% respectively). The highest reductions are expected for particulate matter formation and climate change impacts with 88% and 87% in CE scenario. However, future scenarios do not have an impact on ozone depletion category as the amount of refrigerant is the same for all scenarios.</p