Imperial College London


Faculty of EngineeringDepartment of Chemical Engineering

Professor of Process Systems Engineering



+44 (0)20 7594 6621n.shah




Miss Jessica Baldock +44 (0)20 7594 5699




ACEX 522ACE ExtensionSouth Kensington Campus





Publication Type

657 results found

Yliruka M, Moret S, Shah N, 2023, Detail or uncertainty? Applying global sensitivity analysis to strike a balance in energy system models, Computers and Chemical Engineering, Vol: 177, Pages: 1-22, ISSN: 0098-1354

Energy systems modellers often resort to simplified system representations and deterministic model formulations (i.e., not considering uncertainty) to preserve computational tractability. However, reduced levels of detail and neglected uncertainties can both lead to sub-optimal system designs. Herein, we present a novel method that quantitatively compares the impact of detail and uncertainty to guide model development and help prioritisation of the limited computational resources. By considering modelling choices as an additional ‘uncertain’ parameter in a global sensitivity analysis, the method determines their qualitative ranking against conventional input parameters. As a case study, the method is applied to a peer-reviewed heat decarbonisation model for the United Kingdom with the objective of assessing the importance of spatial resolution. The results show that while for the optimal total system cost the impact of spatial resolution is negligible, it is the most important factor determining the capacities of electricity, gas and heat networks.

Journal article

Hoseinpoori P, Hanna R, Woods J, Markides C, Shah Net al., 2023, Comparing alternative pathways for the future role of the gas grid in a low-carbon heating system, Energy Strategy Reviews, Vol: 49, Pages: 1-25, ISSN: 2211-467X

This paper uses a whole-system approach to examine different strategies related to the future role of the gas grid in alow-carbon heat system. A novel model of integrated gas, electricity and heat systems, HEGIT, is used to investigate fourkey sets of scenarios for the future of the gas grid using the UK as a case study: a) complete electrification of heating; b)conversion of the existing gas grid to deliver hydrogen; c) a hybrid heat pump system; and d) a greener gas grid. Ourresults indicate that although the infrastructure requirements, the fuel or resource mix, and the breakdown of costs varysignificantly over the complete electrification to complete conversion of the gas grid to hydrogen spectrum, the total systemtransition cost is relatively similar. This reduces the significance of total system cost as a guiding factor in policy decisionson the future of the gas grid. Furthermore, we show that determining the roles of low-carbon gases and electrification fordecarbonising heating is better guided by the trade-offs between short- and long-term energy security risks in the system,as well as trade-offs between consumer investment in fuel switching and infrastructure requirements for decarbonisingheating. Our analysis of these trade-offs indicates that although electrification of heating using heat pumps is not thecheapest option to decarbonise heat, it has clear co-benefits as it reduces fuel security risks and dependency on carboncapture and storage infrastructure. Combining different strategies, such as grid integration of heat pumps with increasedthermal storage capacity and installing hybrid heat pumps with gas boilers on the consumer side, are demonstrated toeffectively moderate the infrastructure requirements, consumer costs and reliability risks of widespread electrification.Further reducing demand on the electricity grid can be accomplished by complementary options at the system level, suchas partial carbon offsetting using negative emission technologies

Journal article

O'Dwyer E, Kerrigan E, Falugi P, Zagorowska M, Shah Net al., 2023, Data-driven predictive control with improved performance using segmented trajectories, IEEE Transactions on Control Systems Technology, Vol: 31, Pages: 1355-1365, ISSN: 1063-6536

A class of data-driven control methods has recently emerged based on Willems' fundamental lemma. Such methods can ease the modelling burden in control design but can be sensitive to disturbances acting on the system under control. In this paper, we extend these methods to incorporate segmented prediction trajectories. The proposed segmentation enables longer prediction horizons to be used in the presence of unmeasured disturbance. Furthermore, a computation time reduction can be achieved through segmentation by exploiting the problem structure, with computation time scaling linearly with increasing horizon length. The performance characteristics are illustrated in a set-point tracking case study in which the segmented formulation enables more consistent performance over a wide range of prediction horizons. The computation time for the segmented formulation is approximately half that of an unsegmented formulation for a horizon of 100 samples. The method is then applied to a building energy management problem, using a detailed simulation environment, in which we seek to minimise the discomfort and energy of a 6-room apartment. With the segmented formulation, a 72% reduction in discomfort and 5% financial cost reduction is achieved, compared to an unsegmented formulation using a one-day-ahead prediction horizon.

Journal article

Cooper J, Bird M, Acha S, Amrit P, Chachuat B, Shah N, Matar Oet al., 2023, The Carbon Footprint of a UK Chemical Engineering Department – The Case of Imperial College London, The 30th CIRP Life Cycle Engineering Conference, Publisher: Elsevier, Pages: 444-449, ISSN: 2212-8271

As the UK strives towards net-zero it is important that all sectors, including Higher Education, take immediate measures to cut their greenhouse gas emissions. The greenhouse gases emitted by different Higher Education institutions are studied and are shown to be large. However, these studies are based on aggregated data, and it is therefore uncertain how effective institute-wide policies to cut emissions are at department level. Herein, we present a generic framework for university departments to calculate their carbon footprint considering Scope 1, 2 and 3 emissions. We estimate the carbon footprint of the Chemical Engineering Department at Imperial College London to be 7,620 and 8,330 tCO2eq in 2018/19 and 2019/20, respectively. Scope 3 emissions account for 54% of the Department's emissions with Scope 1 and 2 accounting for the remaining 46%. Scope 3 emissions are largely driven by purchased goods and travel, while Scope 1 emissions are predominantly from electricity usage.

Conference paper

van de Berg D, Petsagkourakis P, Shah N, del Rio-Chanona EAet al., 2023, Data-driven coordination of subproblems in enterprise-wide optimization under organizational considerations, AIChE Journal, Vol: 69, Pages: 1-24, ISSN: 0001-1541

While decomposition techniques in mathematical programming are usually designed for numerical efficiency, coordination problems within enterprise-wide optimization are often limited by organizational rather than numerical considerations. We propose a “data-driven” coordination framework which manages to recover the same optimum as the equivalent centralized formulation while allowing coordinating agents to retain autonomy, privacy, and flexibility over their own objectives, constraints, and variables. This approach updates the coordinated, or shared, variables based on derivative-free optimization (DFO) using only coordinated variables to agent-level optimal subproblem evaluation “data.” We compare the performance of our framework using different DFO solvers (CUATRO, Py-BOBYQA, DIRECT-L, GPyOpt) against conventional distributed optimization (ADMM) on three case studies: collaborative learning, facility location, and multiobjective blending. We show that in low-dimensional and nonconvex subproblems, the exploration-exploitation trade-offs of DFO solvers can be leveraged to converge faster and to a better solution than in distributed optimization.

Journal article

Leonzio G, Mwabonje O, Fennell PS, Shah Net al., 2023, Corrigendum to “Environmental performance of different sorbents used for direct air capture” [Sustain. Prod. Consum. 32 (2022) 101–111], Sustainable Production and Consumption, Vol: 36, Pages: 415-415, ISSN: 2352-5509

Journal article

Sarkis M, Fung J, Lee MH, Bernardi A, Shah N, Papathanasiou MMet al., 2023, Integrating environmental sustainability in next-generation biopharmaceutical supply chains, Computer Aided Chemical Engineering, Pages: 3405-3410

Maximizing product availability to the public and minimizing costs are primary objectives in the biopharmaceutical sector. Nevertheless, awareness of the environmental sustainability of supply chain operations is becoming increasingly relevant in recent years. To assist decision-makers in balancing financial and environmental sustainability we present an optimization framework which determines candidate supply chain structures network designs and operational plans. Supply chain structures are assessed with respect to total cost and environmental score, with the latter integrating environmental impacts related to climate change, water usage and energy consumption. A Pareto set of candidate solutions is found which provides insights in complex trade-offs between impact categories and cost: centralized manufacturing is selected to lower unit production cost and better use water resources, whilst decentralized manufacturing improves energy usage. Emissions from CO2 are lowered through cost minimization.

Book chapter

van de Berg D, Jimbo RXJ, Shah N, del Rio-Chanona EAet al., 2023, Tractable Data-driven Solutions to Hierarchical Planning-scheduling-control, Computer Aided Chemical Engineering, Pages: 649-654

Using numerical optimization for the hierarchical integration of decision-making units is crucial to provide feasibility and optimality of all levels. However, realistically modelling hierarchical decision-making calls for multilevel formulations, which are numerically intractable and mathematically difficult. In this work, we show how to leverage two data-driven techniques – derivative-free optimization and optimality surrogates – to decrease the computational burden of multilevel problems. We reformulate a tri-level planning-scheduling-control problem into a single-level black-box problem wherein each evaluation calls a scheduling instance with embedded optimal control surrogates. We show that solving this integrated problem instead of the single-level instance leads to changes in the optimal production planning and scheduling sequence, and discuss trade-offs associated with both techniques.

Book chapter

Lyons B, Bernardi A, Shah N, Chachuat Bet al., 2023, Methane-to-X: an economic assessment of methane valorisation options to improve carbon circularity, Computer Aided Chemical Engineering, Pages: 2435-2440

Methane side streams are produced in many different chemical processes and are normally combusted to provide process heat or to generate electricity. However, this practice is becoming less and less attractive as the industry strives towards net-zero targets and increasing the circularity of chemicals. Methane could instead be recovered and used as a valuable feedstock to produce other platform chemicals, such as H2 or ethylene, which could be beneficial both for the economic performance and the carbon circularity of the system. In this work, seven different methane valorisation routes to produce additional chemicals are investigated. The considered routes include: i) five syngas-based routes combined with methanol synthesis and a methanol-to-olefins process; ii) plasma methane pyrolysis; and iii) oxidative coupling of methane. The results suggest that oxidative coupling of methane is the most profitable, with methane pyrolysis, tri-reforming and autothermal reforming also being more profitable in the base case. All routes have lower scope 1 and 2 emissions than the base case, however, dry-reforming and bi-reforming have the lowest emissions thanks to credited CO2 feed streams.

Book chapter

Soh QY, O'Dwyer E, Acha S, Shah Net al., 2023, Modular stochastic optimization for optimal rainwater harvesting system design, Computer Aided Chemical Engineering, Pages: 697-702

Rainwater Harvesting (RWH) systems can serve a dual functionality as a flood mitigation structure as well as providing local water availability. Optimisation-based design strategies must be transferrable enough to incorporate the influence of the local climate and case-specific catchment area characteristics into the design process, which can be a significant endeavour when required for every individual implementation. To increase the accessibility of optimisation methods in the appropriate sizing of RWH systems, this paper presents a modularised optimisation model, where tank components and dynamics are contained as individual blocks. These blocks can then be pieced together to produce a full system model, allowing optimisation models to be easily built for any combination and design of RWH system. This is implemented with a multi-tank RWH system, where an evaluation of the optimised system configuration showed a good balance between the dual objectives of providing improved flood mitigation and local water reuse, in comparison to an existing system derived through alternative sizing strategies.

Book chapter

Hoseinpoori P, Woods J, Shah N, 2023, An integrated framework for optimal infrastructure planning for decarbonising heating, MethodsX, Vol: 10, Pages: 1-18, ISSN: 2215-0161

This paper presents the HEGIT (Heat, Electricity and Gas Infrastructure and Technology) model for optimal infrastructure planning for decarbonising heating in buildings. HEGIT is an optimisation model based on Mixed Integer Linear Programming. The model co-optimises the integrated operation and capacity expansion planning of electricity and gas grids as well as heating technologies on the consumer side while maintaining the security of supply and subject to different environmental, operational and system-wide constraints. The three main features of the HEGIT model are:• It incorporates an integrated unit commitment and capacity expansion problem for coordinated operation and long-term investment planning of the electricity and gas grids.• It incorporates the flexible operation of heating technologies in buildings and demand response in operation and long-term investment planning of gas and electricity grids.• It incorporates a multi-scale techno-economic representation of heating technologies design features into the whole energy system modelling and capacity planning.These features enable the model to quantify the impacts of different policies regarding decarbonising heating in buildings on the operation and long-term planning of electricity and gas grids, identify the cost-optimal use of available resources and technologies and identify strategies for maximising synergies between system planning goals and minimising trade-offs. Moreover, the multi-scale feature of the model allows for multi-scale system engineering analysis of decarbonising heating, including system-informed heating technology design, identifying optimal operational setups at the consumer end, and assessing trade-offs between consumer investment in heating technologies and infrastructure requirements in different heat decarbonisation pathways.

Journal article

Hofer M, Criscuolo P, Shah N, ter Wal A, Barlow Jet al., 2022, Regulatory policy and pharmaceutical innovation in the United Kingdom after Brexit: initial insights, Frontiers in Medicine, Vol: 9, ISSN: 2296-858X

Brexit was presented as an opportunity to promote innovation by breaking free from the European Union regulatory framework. Since the beginning of 2021 the Medicines and Healthcare products Regulatory Agency (MHRA) has operated as the independent regulatory agency for the United Kingdom. The MHRA's regulatory activity in 2021 was analyzed and compared to that of other international regulatory bodies. The MHRA remained reliant on EU regulatory decision-making for novel medicines and there were significant regulatory delays for a small number of novel medicines in the UK, the reasons being so far unclear. In addition, the MHRA introduced innovation initiatives, which show early promise for quicker authorization of innovative medicines for cancer and other areas of unmet need. Longer-term observation and analysis is needed to show the full impact of post-Brexit pharmaceutical regulatory policy.

Journal article

Baker W, Acha S, Jennings N, Markides C, Shah Net al., 2022, Decarbonisation of buildings: Insights from across Europe, Decarbonisation of buildings: Insights from across Europe, Publisher: The Grantham Institute

This report considers four key challenges facing the UK in reducing carbon emissions from its building stock, and shares insights from across Europe that have the potential to help the UK to decarbonise and increase the energy efficiency of its buildings.


Leonzio G, Fennell PS, Shah N, 2022, Air-source heat pumps for water heating at a high temperature: State of the art, Sustainable Energy Technologies and Assessments, Vol: 54, Pages: 1-22, ISSN: 2213-1388

Concerns about climate changes are urging the decarbonisation of the energy sector and heat pumps are evaluated for this purpose here. About half of total energy consumption is caused by heating, and the use of heat pumps for this aim is gaining the attention of the research community.This work shows a comprehensive overview of air-source heat pumps used for water heating at a high temperature, with a particular aim to add the supplied heat into the air capture cycle. Air-source heat pumps use different cycles. The literature analysis shows that high temperatures (up to 90 °C) can be easily achieved by trans-critical cycles, while innovative schemes based on heat recuperative solutions might provide hot water up to 99 °C. Very few studies have been conducted about absorption cycles, although these can potentially ensure higher temperatures for the supplied water (up to 115 °C).Although real industrial air source heat pumps achieve a water temperatures lower than those reported above, their utilization is encouraged because, even at high temperatures (up to 100 °C), there are primary energy consumption, cost and carbon dioxide emission savings compared to a traditional boiler, especially when the renewable electricity is used.

Journal article

Al-Mufachi NA, Shah N, 2022, The role of hydrogen and fuel cell technology in providing security for the UK energy system, Energy Policy, Vol: 171, Pages: 1-13, ISSN: 0301-4215

It is not yet well understood how hydrogen and fuel cell technology could perform in the UK energy system (ES) and what influence it may have in contributing towards its security. This article aims to discuss the potential of a hydrogen economy examining its ability to reduce dependency on fossil fuels sourced both domestically and internationally. A snapshot of the hydrogen economy is presented introducing the latest development in hydrogen production technologies and distribution infrastructure. It has been postulated that with the introduction of a CO2 tax, integrating carbon capture and sequestration (CCS) systems with commercial hydrogen production technologies such as steam methane reforming (SMR), coal gasification (CG) and biomass gasification could significantly reduce the levelised cost of hydrogen (LCOH) production. The role of hydrogen and fuel cell technology in coupling the building, transport and industrial sectors has been demonstrated. Decarbonisation of heat in the UK is expected to incur a large cost for transitioning the incumbent network and it is expected that government assistance will be necessary to lessen the burden on consumers. Deployment of fuel cell combined heat and power (CHP) systems and integration into the UK ES could make great strides towards improving its security.

Journal article

Triantafyllou N, Bernardi A, Lakelin M, Shah N, Papathanasiou Met al., 2022, A digital platform for the design of patient-centric supply chains, Scientific Reports, Vol: 12, ISSN: 2045-2322

Chimeric Antigen Receptor (CAR) T cell therapies have received increasing attention, showing promising results in the treatment of acute lymphoblastic leukaemia and aggressive B cell lymphoma. Unlike typical cancer treatments, autologous CAR T cell therapies are patient-specific; this makes them a unique therapeutic to manufacture and distribute. In this work, we focus on the development of a computer modelling tool to assist the design and assessment of supply chain structures that can reliably and cost-efficiently deliver autologous CAR T cell therapies. We focus on four demand scales (200, 500, 1000 and 2000 patients annually) and we assess the tool’s capabilities with respect to the design of responsive supply chain candidate solutions while minimising cost.

Journal article

Daniel S, Kis Z, Kontoravdi K, Shah Net al., 2022, Quality by design for enabling RNA platform production processes, Trends in Biotechnology, Vol: 40, Pages: 1213-1228, ISSN: 0167-7799

RNA-based products have emerged as one of the most promising and strategic technologies for global vaccination, infectious disease control and future therapy development. The assessment of critical quality attributes, product-process interactions, relevant process analytical technologies, and process modeling capabilities can feed into a robust Quality by Design (QbD) framework for future development, design and control of manufacturing processes. Its implementation will help the RNA technology to reach its full potential and will be central in the development, pre-qualification and regulatory approval of rapid response, disease-agnostic RNA platform production processes.

Journal article

Leonzio G, Fennell PS, Shah N, 2022, Modelling and analysis of direct air capture systems in different locations, Chemical Engineering Transactions, Vol: 96, Pages: 1-6, ISSN: 1974-9791

Direct air capture is an important negative emission technology with the aim to reduce carbon dioxide emissions in the atmosphere and to face the current environmental problems such as global warming and climate change. This emerging technology can be based on an adsorption system affected by the used sorbent (physisorbents or chemisorbents). Efficiencies can be measured through the use of key performance indicators that allow a comparison among different processes. An independent analysis was conducted in our previous research to evaluate key performance indicators (total cost, energy consumption, environmental impact and capture capacity) for a direct air capture system based on adsorption using different sorbents (three metal organic frameworks and two amine functionalized sorbents). In this research, the same analysis was extended to several Countries around the world, changing the ambient air temperature according to the yearly average value of the location. Results show that by increasing the air temperature, the adsorption capacity decreases, in a more significant way for metal organic frameworks compared to amine functionalized sorbents. An opposite effect is for energy consumption. Moreover, by increasing the ambient air temperature, a higher environmental impact (in terms of climate change) is present. A trend with the air temperature was not found for total costs. Overall, locations with lower ambient air temperatures are preferred due to a lower environmental impact and energy consumption.

Journal article

Acha Izquierdo S, vieira G, Bird M, Shah Net al., 2022, Modelling UK electricity regional costs for commercial buildings, Energy and Buildings, Vol: 271, Pages: 1-15, ISSN: 0378-7788

Motivated by rising electricity prices UK non-domestic consumers are being required to develop smart energy management practices. However, most of these consumers lack awareness of the spatial-temporal dynamics of electricity prices and their tariff components. To help overcome these barriers and contribute to energy prices digitalisation, this paper presents a Modelling UK Electricity Regional Costs (MUKERC) framework. A bottom-up methodology that defines all the tariff components and then aggregates them to quantify the cost of a kWh across each half-hour of the day. The framework not only facilitates understanding which tariffs components have a higher impact during different time periods but also depicts how they vary spatially across regions. This model was used to estimate and analyse the evolution of electricity costs from 2017 to 2024. Case studies from buildings in the education sector are showcased depicting their energy costs derived from their load profiles. Results show that the London area has the lowest average prices, while the Northern Wales & Merseyside is the most expensive. From the case studies conducted, peak period charges account for 17% of annual electricity costs (occurring between 4 to 7 p.m.). Winter period charges represented about 53% of the charges. The MUKERC framework showcases the valuable insights data-driven costing models offer as it allows to understand the dynamics of electricity charges and identifies “when” and “where” the cost of electricity is more expensive; thus, supporting the development of bespoke cost-effective energy measures that improve resource efficiency and smart energy management initiatives.

Journal article

Bird M, Daveau C, O'Dwyer E, Acha S, Shah Net al., 2022, Real-world implementation and cost of a cloud-based MPC retrofit for HVAC control systems in commercial buildings, Energy and Buildings, Vol: 270, Pages: 1-13, ISSN: 0378-7788

Many businesses are looking for ways to improve the energy and carbon usage of their buildings, particularly through enhanced data collection and control schemes. In this context, this paper presents a case study of a food-retail building in the UK, detailing the design, installation and cost of a generalisable model predictive control (MPC) framework for its Heating, Ventilation and Air Conditioning (HVAC) system. The hardware/software solution to collect relevant data, as well as the formulation of the MPC scheme, is presented. By utilising cloud-based microservices, this approach can be applied to all modern building management systems with little upfront capital, and an ongoing monthly cost as low as $6.39/month. The MPC scheme calculates the optimal temperature setpoint required for each Air-Handling Unit (AHU) to minimise its overall cost or carbon usage, while ensuring thermal comfort of occupants. Its performance is then compared to the existing legacy controller using a simulation the building’s thermal behaviour. When simulated across two months the MPC approach performed better, able to achieve the same thermal comfort for a lower overall cost. The economic optimisation resulted in an energy saving of 650 kWh, with an associated cost savings of $240 (1.7% compared to the baseline), while the carbon optimisation gave negligible CO2 savings due to the inability of the building to shift heating to low-carbon periods. Findings from this study indicate the potential for improving building performance via MPC strategies but impact will depend on specific building attributes.

Journal article

Broukos P, Fragkogios A, Shah N, 2022, A Linearized Mathematical Formulation for Combined Centralized and Distributed Waste Water Treatment Network Design, Operations Research Forum, Vol: 3

Waste water treatment (WWT) is a very important issue affecting both the environment and public health in the twenty-first century. The increasing earth’s population together with the growing urbanism leads to the need of redesigning effective WWT. In this paper, the problem of optimal Waste Water Treatment Network Design (WWTND) is addressed. To this end, various parameters affecting the problem have been taken into consideration, such as the distance between the residential areas and the treatment plants, estimations for future population of towns and costs of expanding existing network or building a new one. The last parameter of cost has a lot of components (pipeline cost, treatment plant cost, etc.), all of which are non-linear functions depending on the amount of waste water produced and treated within the network. The authors have developed a mathematical model for the solution of WWTND problem and have applied piecewise linearization in order to deal with the non-linear terms. The developed model has been implemented on an area in Luxemburg, for which data were collected. The results prove the model’s validity and usefulness, while its solution is computationally affordable.

Journal article

Li K, Acha Izquierdo S, Sunny N, Shah Net al., 2022, Strategic transport fleet analysis of heavy goods vehicle technology for net-zero targets, Energy Policy, Vol: 168, ISSN: 0301-4215

This paper addresses the decarbonisation of the heavy-duty transport sector and develops a strategy towards net-zero greenhouse gas (GHG) emissions in heavy-goods vehicles (HGVs) by 2040. By conducting a literature review and a case study on the vehicle fleet of a large UK food and consumer goods retailer, the feasibilities of four alternative vehicle technologies are evaluated from environmental, economic, and technical perspectives. Socio-political factors and commercial readiness are also examined to capture non-technical criteria that influences decision-makers. Strategic analysis frameworks such as PEST-SWOT models were developed for liquefied natural gas, biomethane, electricity and hydrogen to allow a holistic comparison and identify their long-term deployment potential. Fossil and renewable natural gas are found to be effective transitional solutions. Technology innovation is needed to address range and payload limitations of electric trucks, whereas government and industry support are essential for a material deployment of hydrogen in the 2030s. Given the UK government’s plan to phase out new diesel HGVs by 2040, fleet operators should commence new vehicle trials by 2025 and replace a considerable amount of their lighter diesel trucks with zero-emission vehicles by 2030, and the remaining heavier truck fleet by 2035.

Journal article

Hoseinpoori P, Olympios AV, Markides CN, Woods J, Shah Net al., 2022, A whole-system approach for quantifying the value of smart electrification for decarbonising heating in buildings, Energy Conversion and Management, Vol: 268, Pages: 1-24, ISSN: 0196-8904

This paper uses a whole system approach to examine system design and planning strategies that enhance the system value of electrifying heating and identify trade-offs between consumers’ investment and infrastructure requirements for decarbonising heating in buildings. We present a novel integrated model of heat, electricity and gas systems, HEGIT, to investigate different heat electrification strategies using the UK as the case study from two perspectives: (i) a system planning perspective regarding the scope and timing of electrification; and (ii) a demand-side perspective regarding the operational and investment schemes on the consumer side. Our results indicate that complete electrification of heating increases peak electricity demand by 170%, resulting in a 160% increase in the required installed capacity in the electricity grid. However, this effect can be moderated by implementing smart demand-side schemes. Grid integration of heat pumps combined with thermal storage at the consumer-end was shown to unlock significant potential for diurnal load shifting, thereby reducing the electricity grid reinforcement requirements. For example, our results show that a 5 b£ investment in such demand-side flexibility schemes can reduce the total system transition cost by about 22 b£ compared to the case of relying solely on supply-side flexibility. In such a case, it is also possible to reduce consumer investment by lowering the output temperature of heat pumps from 55 °C to 45 °C and sharing the heating duty with electric resistance heaters. Furthermore, our results suggest that, when used at a domestic scale, ground-source heat pumps offer limited system value since their advantages (lower peak demand and reduced variations in electric heating loads) can instead be provided by grid-integration of air-source heat pumps and increased thermal storage capacity at a lower cost to consumers and with additional flexibility benefits for the electricity gr

Journal article

Ordonez DF, Halfdanarson T, Ganzer C, Shah N, Mac Dowell N, Guillen-Gosalbez Get al., 2022, Evaluation of the potential use of e-fuels in the European aviation sector: a comprehensive economic and environmental assessment including externalities, SUSTAINABLE ENERGY & FUELS, Vol: 6, Pages: 4749-4764, ISSN: 2398-4902

Journal article

Leonzio G, Shah N, 2022, Innovative process integrating air source heat pumps and direct air capture processes, Industrial and Engineering Chemistry Research, Vol: 61, Pages: 13221-13230, ISSN: 0888-5885

Most integrated assessment models indicate a need for technological carbon dioxide removal from the atmosphere to achieve climate mitigation targets. Currently, direct air capture (DAC) appears to be one the “backstop” technologies suitable to provide this service. These technologies usually require low-carbon heat as part of their operation cycle. Here, we consider a way of providing this heat when no local heat source is available. Air source heat pump (ASHP) water heaters are a well-known technology that takes heat from the air to supply hot water. Variations on their operating conditions could provide water at 100 °C, when a trans-critical cycle is used. This level of temperature is required by several DAC adsorption processes as the thermal energy for the regeneration stage. For this reason, an innovative process integrating an ASHP and a DAC adsorption system is proposed here. The heat pump provides not only heating but also cooling, while three separate stages (adsorption, cooling, and regeneration) are considered for the DAC. In the integrated process, the air is sent to the adsorbent bed at first and after that to the evaporator of the heat pump and then used for the cooling stage. The hot water supplied by the heat pump is used for the desorption. Different working fluids (CO2, CO2-ethane, CO2-R41), with low ozone depletion and global warming potentials, are investigated. The results show that a high level of efficiency is possible for heat pumps supplying hot water at 100 °C. Moreover, energetic advantages are present with reference to the base case, where heat is provided by a municipal water incinerator and cooling by a cooling tower. Savings in the energy consumption of 55, 60, and 53% for the integrated process using CO2, CO2/R41, and CO2/ethane, respectively, are possible. Economic benefits are present when economic incentives are provided, ensuring lower costs up to 39 $/tonCO2, and the technology benefits from location flexibili

Journal article

Leonzio G, Fennell PS, Shah N, 2022, Analysis of technologies for carbon dioxide capture from the air, Applied Sciences-Basel, Vol: 12, ISSN: 2076-3417

Journal article

Gonzalez-Garay A, Heuberger-Austin C, Fu X, Klokkenburg M, Zhang D, van der Made A, Shah Net al., 2022, Unravelling the potential of sustainable aviation fuels to decarbonise the aviation sector, Energy and Environmental Science, Vol: 15, Pages: 3291-3309, ISSN: 1754-5692

The aviation industry is responsible for approximately 2% of the total anthropogenic greenhouse gas emissions. With an expected four to six-fold growth by 2050, increased attention has been paid to reduce its carbon footprint. In this study, we analyse the requirements to promote Sustainable Aviation Fuels (SAFs) from solar energy to reduce the emissions of the sector. Using a discrete spatio-temporal mathematical description of the region of Spain, we present the key elements required to produce jet fuel via Fischer–Tropsch (FT) and Methanol to fuels (MtF). We have found that solar PV, electricity storage, and alkaline water electrolysis are the key drivers for the performance of solar SAFs while the optimal location of the facilities is driven by the availability of solar radiation, underground H2 storage, and high jet fuel demand. We show that the constant supply of H2 requires an over sizing of technologies, which in turn decreases the utilisation of solar panels and electrolysers. While higher usage rates could be attained by a constant supply of electricity (e.g., via the electricity grid), the use of renewable sources is essential to guarantee a reduction in CO2 emissions compared to fossil-based jet fuel. We found that production costs in 2020 per kgfuel in Spain varied from 3.90 € (MtF) to 4.95 € (FT) using solar radiation as a sole source of energy and a point source of CO2, cutting CO2 life cycle emissions by ∼25% compared to their fossil-based counterpart (2.5–2.7 kgCO2eq per kgfuel). Potential technological improvements could reduce jet fuel production costs to 2.5–3.3 € per kgfuel for CO2 point sources while emissions could reach ∼1.0 kgCO2eq per kgfuel. Ultimately, the impact of these routes in the cost of a flight ticket would result in a minimum increase of 100–150% at present and 40–80% by 2050, accounting for current projections on technologies and carbon prices. This shows that future minimum c

Journal article

Kusumo K, Kuriyan K, Vaidyaraman S, Garcia Munoz S, Shah N, Chachuat Bet al., 2022, Probabilistic framework for optimal experimental campaigns in the presence of operational constraints, Reaction Chemistry and Engineering, Vol: 7, Pages: 2359-2374, ISSN: 2058-9883

The predictive capability of any mathematical model is intertwined with the quality of experimentaldata collected for its calibration. Model-based design of experiments helps compute maximallyinformative campaigns for model calibration. But in early stages of model development it is crucial toaccount for model uncertainties to mitigate the risk of uninformative or infeasible experiments. Thisarticle presents a new method to design optimal experimental campaigns subject to hard constraintsunder uncertainty, alongside a tractable computational framework. This computational frameworkinvolves two stages, whereby the feasible experimental space is sampled using a probabilistic approachin the first stage, and a continuous-effort optimal experiment design is determined by searching overthe sampled feasible space in the second stage. The tractability of this methodology is demonstratedon a case study involving the exothermic esterification of priopionic anhydride with significant risk ofthermal runaway during experimentation. An implementation is made freely available based on thePython packages DEUS and Pydex.

Journal article

Palmieri E, Kis Z, Ozanne J, Di Benedetto R, Ricchetti B, Massai L, Carducci M, Oldrini D, Gasperini G, Aruta MG, Rossi O, Kontoravdi C, Shah N, Mawas F, Micoli Fet al., 2022, GMMA as an alternative carrier for a glycoconjugate vaccine against Group A streptococcus, Vaccines, Vol: 10, Pages: 1-17, ISSN: 2076-393X

Group A Streptococcus (GAS) causes about 500,000 annual deaths globally, and no vaccines are currently available. The Group A Carbohydrate (GAC), conserved across all GAS serotypes, conjugated to an appropriate carrier protein, represents a promising vaccine candidate. Here, we explored the possibility to use Generalized Modules for Membrane Antigens (GMMA) as an alternative carrier system for GAC, exploiting their intrinsic adjuvant properties. Immunogenicity of GAC-GMMA conjugate was evaluated in different animal species in comparison to GAC-CRM197; and the two conjugates were also compared from a techno-economic point of view. GMMA proved to be a good alternative carrier for GAC, resulting in a higher immune response compared to CRM197 in different mice strains, as verified by ELISA and FACS analyses. Differently from CRM197, GMMA induced significant levels of anti-GAC IgG titers in mice also in the absence of Alhydrogel. In rabbits, a difference in the immune response could not be appreciated; however, antibodies from GAC-GMMA-immunized animals showed higher affinity toward purified GAC antigen compared to those elicited by GAC-CRM197. In addition, the GAC-GMMA production process proved to be more cost-effective, making this conjugate particularly attractive for low- and middle-income countries, where this pathogen has a huge burden.

Journal article

Baharudin L, Rahmat N, Othman NH, Shah N, Syed-Hassan SSAet al., 2022, Formation, control, and elimination of carbon on Ni-based catalyst during CO<inf>2</inf>and CH<inf>4</inf>conversion via dry reforming process: A review, Journal of CO2 Utilization, Vol: 61, ISSN: 2212-9820

Dry reforming of methane (DRM) promises to reduce greenhouse gas emission by converting CO2 and CH4 (produced e.g. in anaerobic digestion processes) into syngas with an almost equimolar H2/CO ratio suitable for use in Fischer-Tropsch (FT) synthesis for the production of varieties of high value chemicals and liquid fuels. Ni-based catalyst is the most viable catalyst to catalyse the reaction, but its use faces a great challenge due to its propensity to form and accumulate carbonaceous materials on its active surface. In this article, the mechanisms involved in the deactivation of Ni-based catalyst in DRM reaction by carbon deposition and other carbon-induced deactivation mechanisms, which understanding is vital for the improvement of the process, are reviewed. Based on a thorough assessment of literature, perspectives are given on ways to control and mitigate carbon deposition problems related to the use of Ni-based catalysts in DRM by means of manipulating reaction conditions and process parameters as well as through designing and developing highly active coke-resistant Ni-based catalysts.

Journal article

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