Development of a systems approach for studying decarbonisation pathways of heat demand in the UK

In the UK, 45% of the total energy demand in 2016 was used for heating purposes, 68% of which was supplied by natural gas. Credible alternatives for decarbonising heat include district heating combined with low carbon heat sources, heat electrification using heat pumps (with a decarbonised electricity system), or hydrogen-fuelled heat technologies. Adoption of these technologies must proceed alongside network infrastructure investment and developments in the broader energy system, such as increased renewable power generation. At the time of writing, no systematic framework exists that trades off individual building and district heat supply technologies and their associated infrastructures at high spatial resolutions. This work formulates and applies such framework. It presents a mixed integer linear optimisation model that decides on investments and operation of gas, electricity, heat, and hydrogen technologies and associated network infrastructures, for supplying commercial and domestic heat and electricity demands in spatially-resolved urban areas, minimising the net present cost through 2050. This model is implemented to study four key issues related to heat decarbonisation: Comparing different temperature heat networks for decarbonising heat; the effect of spatial resolution in outcomes of energy systems models for heat; the role of hydrogen in heat decarbonisation pathways in the UK; and the sensitivity of heat decarbonisation outcomes to uncertainty in techno-economic parameters. Results show that adoption of heat technologies depends, among several factors, on linear heat density, zone-to-zone connectivity, and scenario-specific techno-economic assumptions such as technology, fuels, or electricity prices. Linear heat density adoption thresholds were found for individual technologies. Medium and high temperature heat networks were adopted in high and medium/high linear heat density zones, respectively. Hydrogen boilers were adopted when enabling gas networks to be retrofitted to transport hydrogen. Finally, spatial resolution was shown to be a determining factor for finding cost-effective heat decarbonisation pathways through energy systems models.Open Acces

The effect of spatial resolution on outcomes from energy systems modelling of heat decarbonisation

Spatial resolution is often cited as a crucial determinant of results from energy systems models. However, there is no study that comprehensively analyses the effect of spatial resolution. This paper addresses this gap by applying the Heat Infrastructure and Technology heat decarbonisation optimisation model in six UK Local Authorities representing a range of rural/urban areas, at three levels of spatial resolution, in order to systematically compare results. Results show the importance of spatial resolution for optimal allocation of heat supply technologies and infrastructure across different urban/rural areas. Firstly, for the studied cases, differences of up to 30% in heat network uptake were observed when comparing results between different resolutions for a given area. Secondly, for areas that generally exhibit the high and low extremes of linear heat density, results are less dependent on spatial resolution. Also, spatial resolution effects are more significant when there is higher variability of linear heat density throughout zones. Finally, results show that it is important to use finer resolutions when using optimisation models to inform detailed network planning and expansion. Higher spatial resolutions provide more detailed information on zones that act as anchors that can seed network growth and on location of network supply technologies

Spatially-resolved urban energy systems model to study decarbonisation pathways for energy services in cities

This work presents the COMET (Cities Optimisation Model for Energy Technologies) model, a spatially-resolved urban energy systems model that takes into account energy service demands for heating, cooling, electricity, and transport, and finds cost-effective pathways for supplying these demands under carbon constraints, trading-off energy supply, network infrastructure, and end-use technologies. Spatially-resolved energy service demands were obtained for the city of Sao Paulo, and six scenarios were modelled. Results show that district cooling is cost-effective in the highest linear cooling density zones, with full penetration in zones with over 1100 kWh/m by 2050. This threshold diminishes with tighter carbon constraints. Heating is electrified in all scenarios, with electric boilers and air-source heat pumps being the main supply technologies for the domestic and commercial sectors respectively by 2050. In the most carbon constrained scenario with a medium decarbonised electricity grid, ground source heat pumps and hydrogen boilers appear as transition technologies between 2030 and 2045 for the commercial and domestic sectors respectively, reaching 95% and 40% of each sector’s heat installed capacity in 2030. In the transport sector, ethanol cars replace gasoline, diesel, and compressed natural gas cars; compressed natural gas buses replace diesel and electric buses; and lorries continue using diesel. In carbon constrained scenarios, higher penetrations of electric cars and buses are obtained, while no change is observed for lorries. Finally, the most expensive scenario was only 6% more expensive than the reference scenario, meaning that achieving decarbonisation targets is not much costlier when comparing scenarios from a system-wide perspective

Carbon sequestration potential from large-scale reforestation and sugarcane expansion on abandoned agricultural lands in Brazil

Since 1850, over 145 ± 16 PgC (μ ± 1σ) has been emitted worldwide due to land-use change and deforestation. Besides industrial carbon capture and storage (CCS), storing carbon in forestry products and in regenerated forest has been recognized as a cost-effective carbon sequestration option, with an estimated worldwide sink potential of about 50–100 PgC (15–36 PgC from tropical forest alone). This paper proposes the expansion of a Brazilian integrated assessment model (MUSE-Brazil) by integrating a non-spatial biomass-growth model. The aim is to account for carbon sequestration potential from either reforestation or sugarcane expansion in abandoned agricultural lands. Modelling outputs suggest that Brazil has the potential to liberate up to 32.3 Mha of agricultural land by 2035, reaching 68.4 Mha by mid-century. If a sugarcane expansion policy is promoted, by 2050, the largest sequestration rates would come from above and below ground biomass pools; gradually releasing to the atmosphere around 1.6 PgC or 1.2% of the current Brazilian land carbon stock due to lower SOC carbon pools when turning agricultural lands into sugarcane crops. On the other hand, a reforestation-only scenario projects that by 2035 the baseline year carbon stock could be recovered and by 2050 the country’s carbon stock would have been increased by 3.2 PgC, reaching annual net sequestration rates of 0.1 PgC y−1, mainly supported by natural vegetation regeneration in the Cerrado biome

Organic waste to energy: Resource potential and barriers to uptake in Chile

Achieving net-zero greenhouse gas emissions by 2050 requires a step-change in resource management, and the utilisation of organic waste is currently an untapped opportunity in Latin America. This study carries out a quantitative and qualitative assessment of organic waste-to-energy potentials for the Chilean context. First, it produces a comprehensive quantification of organic waste, including annual crop residues, horticulture residues, livestock manure and OFMSW by region; then it estimates the energy potential of these bioresources; and finally, it conducts a series of stakeholder interviews determining barriers to greater waste-to-energy utilisation. The results show that the total bioenergy potential from waste is estimated at 78 PJ/yr (3.3% of annual energy demand), being livestock manure (41%) and annual crop residues (28%) the main sources, arising mostly from three regions. The stakeholder elicitation concluded that financial, technical, and institutional barriers prevent waste utilisation, highlighting the needs to address elevated investment costs and high reliance on landfilling practices, which together with public policies could enable the full exploitation of these resources to ensure energy security and resource efficiency.This research was supported by the Sustainable Gas Institute at Imperial College London and by Universidad de Santiago de Chile through the DICYT (Dirección de Investigación Científica y Tecnológica) grant 021812GL. X. Schmidt Rivera is supported by the Institutional QR Global Challenges Research Fund. F. Jalil-Vega acknowledges the support of ANID through Complex Engineering Systems Institute PIA/BASAL AFB180003, and through ANID/FONDAP/15110019 SERC-Chile

Detrimental effects of tropisetron on permanent ischemic stroke in the rat

<p>Abstract</p> <p>Background</p> <p>Recent <it>in vitro </it>evidence indicates that blockade of 5-hydroxytryptamine (5-HT) receptor 3 (5-HT₃) is able to confer protection in different models of neuronal injury. The purpose of the present study was to investigate the effect of tropisetron, a 5-HT₃receptor antagonist, on infarct size and neurological score in a model of ischemic stroke induced by permanent middle cerebral artery occlusion (pMCAO) in the rat.</p> <p>Methods</p> <p>Two different doses of tropisetron (5 and 10 mg/kg) or vehicle were administered intraperitoneally 30 min before pMCAO. Neurological deficit scores, mortality rate and infarct volume were determined 24 h after permanent focal cerebral ischemia.</p> <p>Results</p> <p>Tropisetron failed to reduce cerebral infarction. Animals receiving tropisetron showed a significant increase (p < 0.05) in neurological deficits and mortality rate.</p> <p>Conclusion</p> <p>Data from this study indicate that blockade of 5-HT₃receptors with tropisetron worsens ischemic brain injury induced by pMCAO. These findings could have important clinical implications. Patients taking tropisetron, and possibly other 5-HT₃antagonists, could potentially have a worse outcome following a brain infarct.</p

Spatially resolved optimization for studying the role of hydrogen for heat decarbonization pathways

This paper studies the economic feasibility of installing hydrogen networks for decarbonising heat in urban areas. The study uses the Heat Infrastructure and Technology (HIT) spatially-resolved optimisation model to trade-off energy supply, infrastructure and end-use technology costs for the most important heat-related energy vectors; gas, heat, electricity, and hydrogen. Two model formulations are applied to UK urban area: one with an independent hydrogen network, and one that allows for retrofitting the gas network into hydrogen. Results show that for average hydrogen price projections, cost-effective pathways for heat decarbonisation towards 2050 comprise including heat networks supplied by a combination of district level heat pumps and gas boilers in the domestic and commercial sectors, and hydrogen boilers in the domestic sector. For a low hydrogen price scenario, when retrofitting the gas network into hydrogen, a cost-effective pathway is replacing gas by hydrogen boilers in the commercial sector, and a mixture of hydrogen boilers and heat networks supplied by district level heat pumps, gas, and hydrogen boilers for the domestic sector. Compared to the first modelled year, CO2 emissions reductions of 88% are achieved by 2050. These results build on previous research on the role of hydrogen in cost-effective heat decarbonisation pathways

Spatially resolved model for studying decarbonisation pathways for heat supply and infrastructure trade-offs

Heat decarbonisation is one of the main challenges of energy system decarbonisation. However, existing energy planning models struggle to compare heat decarbonisation approaches because they rarely capture trade-offs between heat supply, end-use technologies and network infrastructure at sufficient spatial resolution. A new optimisation model is presented that addresses this by including trade-offs between gas, electricity, and heat infrastructure, together with related supply and end-use technologies, with high spatial granularity. The model is applied in case studies for the UK. For the case modelled it is shown that electrification of heat is most cost-effective via district level heat pumps that supply heat networks, instead of individual building heat pumps. This is because the cost of reinforcing the electricity grid for installing individual heat pumps does not sufficiently offset heat infrastructure costs. This demonstrates the importance of considering infrastructure trade-offs. When modelling the utilisation of a decarbonised gas, the penetration of heat networks and location of district level heat supply technologies was shown to be dependent on linear heat density and on zone topology. This shows the importance of spatial aspects. Scenario-specific linear heat density thresholds for heat network penetration were identified. For the base case, penetration of high temperature heat networks was over 50% and 60% by 2050 for linear heat densities over 1500 and 2500 kWh/m. For the case when medium heat temperature networks were additionally available, a mix of both networks was observed. Medium temperature heat network penetration was over 20%, 30%, and 40% for linear heat densities of over 1500, 2500, and 3000 kWh/m, while high temperature heat network penetration was over 20% and 30% for linear heat densities of under 2000 and 1500 kWh/m respectively

A dupla serpente: poder político e poder econômico na formação do capitalismo.

This paper analyzes the historical links between political and economic power in the formation of capitalism, from the standpoint of long-time periods and the role that power had in shaping the economy and society in Europe since the sixteenth century. The result of this process is an capitalist interstate system whose expansive dynamic reached the entire globe and whose entanglement we need to solve in order to overcome naturalized readings on the formative process of global economic and political order.Resumo O presente artigo analisa a relação histórica entre poder político e econômico na formação do capitalismo, desde a perspectiva do tempo longo e do papel que o poder teve na configuração da economia e da sociedade na Europa desde o século XVI. O resultado desse processo é um sistema interestatal capitalista cuja dinâmica expansiva atingiu a totalidade do globo e cujo entrelaçamento precisamos desvendar de forma a superar leituras naturalizadas sobre o processo formativo da ordem econômica e política mundial. Resumen El presente artículo analiza la relación histórica entre poder político y económico en la formación del capitalismo, desde la perspectiva del tiempo largo y del papel que el poder tuvo en la configuración de la economía y la sociedad en la Europa del siglo XVI. El resultado de ese proceso es un sistema interestatal capitalista cuya dinámica expansiva alcanzó la totalidad del globo y cuyo entrelazamiento precisamos desvelar de forma que superemos lecturas naturalizadas sobre el proceso formativo del orden económico y político mundial