With the 2015 Paris Agreement pursuing efforts to limit global temperature increase to below 2°C above pre-industrial levels and the “energy trilemma” goals of energy security, energy equity and ...environmental sustainability, decarbonisation remains a priority across all of the United Kingdom (United Kingdom) energy system, not just electricity. Electricity and thermal energy storage technologies can offer a host of benefits across the energy value chain through the abilityS to capture, store and then release electricity or thermal energy over a period of time. These benefits include helping capture the full potential of renewable generation and providing services such as frequency response and reserve to Great Britain’s (GB) electricity system. In addition, with the aforementioned climate targets in mind, energy storage can also play a role in facilitating the decarbonisation of other activities and sectors. Here we delve deeper into how energy storage technologies can contribute to both energy sector transformation and more broadly, decarbonisation. Furthermore, we discuss the importance of ensuring a technology-agnostic approach to the development of policy and regulation with relevance to energy storage. This ensures that storage technologies with significant potential to contribute to the ‘energy trilemma’ goals are not precluded from entering the market due to unfavourable policy and regulatory frameworks.
This paper presents the results of a life cycle assessment of domestic heat pumps in the UK in comparison with gas boilers. The study considers air (ASHP), ground (GSHP) and water (WSHP) source heat ...pumps. The results show that heat pumps have higher environmental impacts than gas boilers due to the use of electricity. On average, the impacts for the ASHP are 82% higher than from the boiler and 73% for the GSHP and WSHP. The exception to this are the global warming, fossil resource depletion and summer smog impacts which are lower for the pumps than the boilers. For example, up to 36% of CO2 eq. can be saved with the WSHP and 6% with the ASHP in comparison with the boiler. Among the heat pumps considered, ASHP have the highest impacts due to lower efficiencies and higher material requirements for the system. The GSHP and WSHP have comparable impacts, with the latter being marginally better. The life cycle impacts of heat pumps may improve if the UK electricity mix is sufficiently decarbonised; however, they will still remain higher than for the gas boiler. Overall, their potential to contribute to the UK climate change targets is limited.
► Full life cycle environmental impacts of domestic air, ground and water-source heat pumps estimated for the UK conditions. ► Heat pumps do not offer environmental advantages over condensing gas boilers. ► Moderate GHG emissions can be saved by replacing boilers but other impacts increase several fold. ► The potential of heat pumps to contribute to the UK’s climate change targets is limited.
This paper considers life cycle environmental sustainability of solar water heating systems in regions with low solar irradiation, such as the UK. The results suggest that flat plate collectors have ...slightly lower environmental impacts than evacuated tube designs. Reducing the current energy losses of 65%–45% would reduce the impacts by around 35%. Compared to a gas boiler, solar thermal systems are a better option for only five out of 11 environmental impacts considered, with global warming and depletion of fossil resources being lower by 88% and 83%, respectively. Other impacts such as human and eco-toxicity are up to 85% higher. The solar systems score better relative to electrical water heating for eight out of 11 impacts. They are also environmentally more sustainable than heat pumps for seven categories. However, their potential is hampered because they need a back-up heating system, typically gas boiler. For this reason as well as due to a lack of suitable locations and poor efficiency, the potential of solar thermal systems to contribute to a more sustainable domestic energy supply in the UK is limited.
•Full life cycle environmental impacts of solar thermal systems estimated for UK conditions.•GHG emissions can be saved by replacing gas boilers but other impacts increase significantly.•Solar thermal systems are environmentally more sustainable than heat pumps.•They have limited potential to contribute to the UK's climate change targets.
This paper evaluates the life cycle environmental sustainability of micro-wind turbines in the UK in comparison with grid electricity and solar PV (photovoltaics). The results suggests that per kWh ...electricity generated, the majority of environmental impacts from the wind turbines are lower than from grid electricity, ranging from 26% lower terrestrial toxicity to 92% lower global warming. However, depletion of abiotic elements, fresh-water and human toxicities are 82%, 74% and 53% higher than for grid electricity, respectively. The wind turbines are more environmentally sustainable than solar PV for seven out of 11 impacts, ranging from 7.5% lower eutrophication to 85% lower ozone layer depletion. However, depletion of fossil resources, fresh-water, human and terrestrial toxicities are higher for the wind turbine than for the PV, ranging from 5% for the former to 87% for the latter. UK-wide deployment of micro-wind turbines would save between 0.6 and 1% of GHG (greenhouse gas) emissions on 2009 levels. Therefore, the potential of micro-wind turbines to contribute towards UK's climate change targets is limited.
•Life cycle environmental impacts of micro-wind turbines estimated for UK conditions.•The majority impacts are lower for micro-wind turbines than for grid electricity and solar PV.•Some impacts from micro-wind are higher, notably fresh-water and human toxicity.•At the national level, wind turbines would save only 0.6% GHG emissions on 2009 levels.•The potential of micro-wind turbines to contribute to UK's climate change targets is limited.
Micro‐combined heat and power (micro‐CHP) systems have gained prominence in Europe and elsewhere, often attracting government incentives. Of the various micro‐CHP technologies, Stirling engine (SE) ...systems are often preferred over internal combustion engines, but their economic and environmental sustainability is unclear. This study uses life cycle assessment and life cycle costing to analyze SE micro‐CHP units, comparing the results to conventional natural gas boilers and grid electricity. Assuming highly‐efficient operation (77 % thermal; 13 % electrical efficiency), the SE system is preferable to conventional electricity and heat both economically and environmentally (for nine of 11 impacts). However, at more realistic efficiencies (71 % thermal; 6 % electrical), the SE system is uncompetitive, being worse for seven environmental impacts, including global warming, and incurring 9 % higher costs, despite subsidy. The choice of electricity, heat or combined output as a functional unit greatly affects the results. At low efficiencies, per unit of electricity, the SE system has on average 44 % worse environmental performance than grid electricity. However, per unit of heat it is, on average, 30 % better environmentally than the gas boiler, but the global warming potential (GWP) is 19 % worse. For combined energy output, the SE system has on average 3 % lower impacts than conventional alternatives, but the GWP is 16 % higher. Future improvements to the environmental impacts of the electricity grid mix, including its decarbonization, would further reduce any relative benefits of the SE system, calling into question the suitability of subsidy.
Stirling not so sterling? Micro‐combined heat and power (micro‐CHP) systems are gaining in prominence. Life cycle assessment and life cycle costing are used to analyze a Stirling engine (SE) micro‐CHP system, comparing it to natural gas boilers and grid electricity (“conventional” energy system). Micro‐CHP is found to be environmentally and economically beneficial at high efficiencies, but analysis based on real operational efficiencies shows it to be uncompetitive both environmentally and economically.
This research has assessed the environmental and economic sustainability of domestic micro-generation technologies under UK conditions as both individual technologies and as part of a range of future ...energy supply scenarios for the domestic sector extending to 2050. A life cycle approach has been used for both environmental and economic assessment considering the relevant sustainability impacts, which include global warming potential, the depletion of fossil fuels, human toxicity and life cycle cost. The micro-generation technologies studied were selected on the basis of their ability to contribute to current and future energy supply and also their suitability under UK conditions. These technologies were micro-wind, solar photovoltaics, micro-combined heat and power, heat pumps and solar thermal water heating. The technologies were compared with one another and with the incumbent technologies, which were grid electricity and natural gas condensing boilers. Three journal papers have been published as a result of this research. The evaluation of micro-generation technologies on a life cycle basis indicated that despite reducing certain environmental impacts, all technologies increased at least one and as many as eight environmental impacts compared to their current fossil-fuel alternatives. All micro-generation technologies would reduce global warming and fossil fuel depletion compared to conventional technologies, highlighting their potential to contribute to energy policy goals. However, they cannot currently compete with conventional technologies for capital cost, although their life cycle costs - taking into account incentives from schemes such as Feed-in Tariffs - can be competitive. Considering both environmental and economic implications suggested that Stirling engine micro-combined heat and power is one of the most sustainable options for heat and electricity generation. The results also suggested that heat pumps should not be receiving incentives from the Government due to their poor environmental performance. Four potential future energy supply scenarios for the UK domestic sector were studied extending to 2050. The scenarios varied in terms of the level of effort made to improve the environmental and economic sustainability of the sector. Scenario 1 involved no further implementation of micro-generation beyond 2009, increasing energy demand and a grid electricity dominated by fossil fuels. In contrast, Scenario 4 portrayed a future where there is 1 micro-generation technology per dwelling, a 50% reduction in demand and almost complete decarbonisation of the grid mix. The results indicated that a huge transformation of the sector is required to achieve the 80% reduction in CO2 emissions by 2050. This would include halving energy demand, almost complete decarbonisation of grid electricity and the installation of a micro-generation unit in every dwelling. To conclude, despite the level of interest micro-generation is currently receiving, this work suggested their usage may not necessarily be as beneficial as some believe. Their use does reduce greenhouse gas emissions and fossil fuel consumption; however, to have any influence on energy policy goals this use would have to be widespread. Furthermore, reduced emissions will come at the expense of other environmental impacts. Finally, with a number of the technologies not yet cost competitive - even with incentives - the Government focus on measures to reduce demand and decarbonise the grid may prove to be a better option as this work suggested that energy policy goals could be achieved without high penetration of micro-generation.
This research has assessed the environmental and economic sustainability of domestic micro-generation technologies under UK conditions as both individual technologies and as part of a range of future ...energy supply scenarios for the domestic sector extending to 2050. A life cycle approach has been used for both environmental and economic assessment considering the relevant sustainability impacts, which include global warming potential, the depletion of fossil fuels, human toxicity and life cycle cost. The micro-generation technologies studied were selected on the basis of their ability to contribute to current and future energy supply and also their suitability under UK conditions. These technologies were micro-wind, solar photovoltaics, micro-combined heat and power, heat pumps and solar thermal water heating. The technologies were compared with one another and with the incumbent technologies, which were grid electricity and natural gas condensing boilers. Three journal papers have been published as a result of this research. The evaluation of micro-generation technologies on a life cycle basis indicated that despite reducing certain environmental impacts, all technologies increased at least one and as many as eight environmental impacts compared to their current fossil-fuel alternatives. All micro-generation technologies would reduce global warming and fossil fuel depletion compared to conventional technologies, highlighting their potential to contribute to energy policy goals. However, they cannot currently compete with conventional technologies for capital cost, although their life cycle costs – taking into account incentives from schemes such as Feed-in Tariffs – can be competitive. Considering both environmental and economic implications suggested that Stirling engine micro-combined heat and power is one of the most sustainable options for heat and electricity generation. The results also suggested that heat pumps should not be receiving incentives from the Government due to their poor environmental performance. Four potential future energy supply scenarios for the UK domestic sector were studied extending to 2050. The scenarios varied in terms of the level of effort made to improve the environmental and economic sustainability of the sector. Scenario 1 involved no further implementation of micro-generation beyond 2009, increasing energy demand and a grid electricity dominated by fossil fuels. In contrast, Scenario 4 portrayed a future where there is 1 micro-generation technology per dwelling, a 50% reduction in demand and almost complete decarbonisation of the grid mix. The results indicated that a huge transformation of the sector is required to achieve the 80% reduction in CO2 emissions by 2050. This would include halving energy demand, almost complete decarbonisation of grid electricity and the installation of a micro-generation unit in every dwelling. To conclude, despite the level of interest micro-generation is currently receiving, this work suggested their usage may not necessarily be as beneficial as some believe. Their use does reduce greenhouse gas emissions and fossil fuel consumption; however, to have any influence on energy policy goals this use would have to be widespread. Furthermore, reduced emissions will come at the expense of other environmental impacts. Finally, with a number of the technologies not yet cost competitive – even with incentives – the Government focus on measures to reduce demand and decarbonise the grid may prove to be a better option as this work suggested that energy policy goals could be achieved without high penetration of micro-generation.
YOU'VE heard it all before: energy security, climate change, resource depletion. These issues inevitably feature in discussions about energy, not only by international governments and the media but ...also increasingly by consumers. As chemical engineers, we too are acutely aware of these issues and the fact that our current energy supply is unsustainable. But what are the more sustainable alternatives and what role can they play in 'greening' our energy systems?.
As the prevalence of multimorbidity increases, understanding the impact of isolated comorbidities in people COPD becomes increasingly challenging. A simplified model of common comorbidity patterns ...may improve outcome prediction and allow targeted therapy.
To assess whether comorbidity phenotypes derived from routinely collected clinical data in people with COPD show differences in risk of hospitalisation and mortality.
Twelve clinical measures related to common comorbidities were collected during annual reviews for people with advanced COPD and k-means cluster analysis performed. Cox proportional hazards with adjustment for covariates was used to determine hospitalisation and mortality risk between clusters.
In 203 participants (age 66 ± 9 years, 60 % male, FEV1%predicted 31 ± 10 %) no comorbidity in isolation was predictive of worse admission or mortality risk. Four clusters were described: cluster A (cardiometabolic and anaemia), cluster B (malnourished and low mood), cluster C (obese, metabolic and mood disturbance) and cluster D (less comorbid). FEV1%predicted did not significantly differ between clusters. Mortality risk was higher in cluster A (HR 3.73 95%CI 1.09–12.82 p = 0.036) and B (HR 3.91 95%CI 1.17–13.14 p = 0.027) compared to cluster D. Time to admission was highest in cluster A (HR 2.01 95%CI 1.11–3.63 p = 0.020). Cluster C was not associated with increased risk of mortality or hospitalisation.
Despite presence of advanced COPD, we report striking differences in prognosis for both mortality and hospital admissions for different co-morbidity phenotypes. Objectively assessing the multi-system nature of COPD could lead to improved prognostication and targeted therapy for patients.
•In advanced COPD, using objective, systematically collected clinical data, we describe four distinct comorbidity clusters.•Comorbidity phenotypes demonstrated striking differences in mortality and hospitalisation despite similar disease severity.•Objectively assessing the multi-system nature of COPD could lead to improved prognostication and targeted therapy.
Absence of established reference values limits application of quadriceps maximal voluntary contraction (QMVC) measurement. The impact of muscle mass inclusion in predictions is unclear. Prediction ...equations encompassing gender, age and size with (FFM+) and without (FFM-), derived in healthy adults (n=175), are presented and compared in two COPD cohorts recruited from primary care (COPD-PC, n=112) and a complex care COPD clinic (COPD-CC, n=189). Explained variance was comparable between the prediction models (R2: FFM+: 0.59, FFM-: 0.60) as were per cent predictions in COPD-PC (88.8%, 88.3%). However, fat-free mass inclusion reduced the prevalence of weakness in COPD, particularly in COPD-CC where 11.9% fewer were deemed weak.
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