Carbon Emission Savings Research Articles

Estimating carbon emission and cost savings from virtual dermatology residency interviews

To the Editor: COVID-19 has transformed dermatology residency recruitment into a largely virtual process. Benefits include increased environmental and cost sustainability, whereas drawbacks include fewer in-person opportunities to determine program fit. In light of stakeholders soon deciding how best to move forward, we provide an estimate of carbon emission and applicant cost savings associated with maintaining virtual residency recruitment.

Role of On-Site Generation in Carbon Emissions and Utility Bill Savings under Different Electric Grid Scenarios

Energy-efficient and sustainable technologies are necessary to lower energy and carbon footprints. Many technologies are being pursued to meet the increasing energy demand in buildings. An attractive option is efficient utilization of available energy resources, including renewables, to support current and future building energy needs while targeting grid resiliency, energy, and environmental security at an affordable cost via on-site cogeneration-based approaches. This must include energy-efficient technologies with lower greenhouse gas emissions and optimized cost, performance, and reliability. This paper presents the economic and environmental benefits associated with power technologies such as thermionics and solid oxide fuel cells. Hybrid configurations consisting of heat pumps, power systems, and renewable photovoltaics in cogeneration and trigeneration modes of operation are presented. The role of such technologies in lowering CO2 emissions while improving energy resiliency and serving the needs of underprivileged communities is discussed. The key barriers of affordability and potential solutions for large-scale implementation of these promising technologies are reviewed. Case studies demonstrating the influence of power rating, electrical efficiency, design configuration, carbon dioxide intensity of the grid, and fuel on annual greenhouse gas emissions are presented for residential and commercial buildings.

Technical design and environmental analysis of 100-kWp on-grid photovoltaic power plant in north-western Iran

Abstract Due to the fuel security and environmental concerns of traditional energy resources like fossil fuels, grid operators are tending to use renewable energies as the primary energy supply. This paper presents the study of designing, simulation and analysis of a 100-kWp on-grid photovoltaic power plant (PV-PP) in north-western Iran. Accurate meteorological data, satellite images and local knowledge from this region have narrowed down the options to three highly irradiated cities of Maragheh, Mahabad and Khalkhal in this region. PVsyst and MATLAB software are used in this paper to obtain the performance results. Environmental effects and carbon-emission savings from the execution of the proposed PV-PP are also available in this paper. The result of this study shows that PV-PP installation in Maragheh will have higher energy output than the two other cities. This study is insightful for the academics and the grid stakeholders in finding optimal spots in north-western Iran to construct a PV-PP. Also, recommendations are available for future studies. A 100-kWp on-grid photovoltaic power plant is designed in north-western Iran. Accurate meteorological data, satellite images, and local knowledge are used in a simulation to select the best location from among three cities.

Ambient loop district heating and cooling networks with integrated mobility, power and interseasonal storage

This paper describes a heat pump investigation for GreenSCIES (GS), a fifth Generation district heating and cooling (5DHC) network in Islington, London. The paper describes the GreenSCIES concept integrating Mobility, Power and Heat into a Smart Local Energy System (SLES). At the heart of the system is an ultra-low temperature ambient loop network, which permits bi-directional flow within the pipes to allow energy exchange between heating and cooling customers at different times and in different locations, depending on where demand is at any given time. An existing data centre provides the primary source of waste heat for the scheme. Heat pumps in distributed energy centres are utilised to amplify the temperature of the ambient loop to deliver heat in connected buildings. The energy centres integrate heat pumps with building-mounted solar photovoltaic (PV) systems and electric vehicle (EV) charging points. The paper provides an overview of the integrated SLES concept, focussing on the heat pump selection and the short and long-term thermal storage options designed for the scheme. The results show that even the smaller constructible ‘New River’ scheme will save 5,000 tons of CO2e annually. This will tend to 100% as the grid decarbonise further. Therefore, the GS SLES concept applied to urban areas could deliver significant carbon emission savings in the UK and elsewhere. Practical application: Project GreenSCIES, is a detailed design study to develop a Smart, Local Energy System (SLES) for a large community in the London Borough of Islington. Our consortium have developed an innovative SLES concept, centred around a fifth generation district heating and cooling network. The GS ambient loop systems have negligible losses and much greater efficiencies than traditional district heat networks. As recognised by the UK Government’s Heat and Buildings Strategy, ambient loop systems should be considered where large-scale neighbourhood regeneration occurs. The proposed SLES concept applied to wider urban areas could deliver significant carbon emission savings in the UK.

Transitioning to sustainable freight transportation by integrating fleet replacement and charging infrastructure decisions

The transportation sector is the largest contributor to global greenhouse gas emissions. Disruptive technological changes in this sector, such as alternative fuel vehicles, are crucial for emission reduction. We show how a cost-minimizing strategic transition plan to adopt electric trucks over time can be developed for a firm that owns and operates a fleet of diesel trucks. We consider the case in which the firm decides to invest in the charging infrastructure required to support this transition, either because the public charging infrastructure is currently inadequate or for strategic reasons. The congestion effect at the charging stations, the charging times, and the potential loss of productive driving time due to detours to reach charging stations are explicitly considered. By developing an independence property, we are able to model this problem as a linear integer program without specifying origins and destinations. We illustrate the resulting transition plan with realistic parameter configurations. Our results indicate that a firm with high transportation demand density over a given service region significantly benefits from adoption of electric trucks, while also enjoying substantial carbon emissions savings. High demand density also favors smaller battery capacity with shorter ranges under the optimized charging network capacity, even though larger battery capacity would increase productivity with extended ranges. Our analysis also offers insights for governments and regulators regarding the impact of several influential factors such as carbon cost, content of renewable energy in electricity mix, diesel engine efficiency, and subsidizing the charging infrastructure. Additionally, we present an extension to the model that allows for different modalities of partnership in the infrastructure investment; notably public-private and private-private partnerships. While in general our results suggest that such partnerships are beneficial to all involved, the amount and relative distribution of the potential gains depend on the topography and on the density of charging infrastructure.

Prescribed burning as a cost-effective way to address climate change and forest management in Mediterranean countries

As climate change and forest management become the focus of various development agendas and the price of carbon rises in the market, the need for improving carbon sequestration and avoiding wildfires emissions increases. Prescribed burning interventions might play an important role in this context, as in some situations, it has been suggested that it can reduce overall fire emissions. In this study, the potential economic benefits associated with the practice are analyzed for five Mediterranean countries. Despite the uncertainty in the estimates, the results suggest that under some circumstances these interventions can be cost-effective from a carbon management perspective. Wildland fires are becoming a major concern for many European countries and are expected to become more prevalent due to climate change, affecting societies, ecosystems, and various ecosystem services provided by forests that are not valued by traditional markets, such as carbon sequestration. The objective of this study is to evaluate the possibility of using carbon taxation to fund fire management measures in Mediterranean countries. The analysis is done by converting prescribed burning savings in carbon emissions into their economic value. This is performed for France, Greece, Italy, Spain, and Portugal, which is studied in more detail, since the country has a National Prescribed Burning Program (NPBP) and a specific tax on carbon in place. The results indicate that most countries could potentially have benefits in the order of millions of euros from employing prescribed burning measures. In Portugal, NPBP has the potential to be a relevant policy instrument to reduce wildfire emissions, as well as economically since the carbon emissions savings can outweigh the prescribed burning costs in some circumstances. Also, the revenue from the country’s Addition Tax on Carbon Emissions would be able to accommodate the foreseen prescribed burning costs. There are still many uncertainties regarding the benefits of prescribed burning in terms of overall emission reductions, and more studies should be conducted on this topic. However, as the price of carbon rises in the markets and climate change becomes a more pressing concern, even small emissions reductions might be economically interesting. The analysis framework used in this study has the potential to be useful for other countries, especially in Mediterranean-type ecosystems.

Towards Net Zero Energy Factory: A multi-objective approach to optimally size and operate industrial flexibility solutions

This study proposes a methodology for sizing and operating new flexibility options within a German carpentry, targeting to be operated as Net Zero Energy Factory (NZEF). A key element of this system is the maximization of the integration of the electric power locally generated by a photovoltaic plant and the electric demand for driving the manufacturing processes. This aim is achieved with a proper integration between design choices in terms flexibility options and optimal control of energy fluxes. In this work, benefits and criticalities arising from the integration of different flexibility options, such as stationary and mobile Energy Storage Systems, are identified and analyzed.A double step optimization process is implemented. First, a Model Predictive Control strategy is used to schedule the manufacturing machines and the energy storage systems (stationary and mobile). Then, a multi-objective optimization aiming at the minimization of annual energy grid exchange and the optimal exploitation of battery capacity is carried out with the Genetic Algorithm. Such a methodology allows the factory operators to optimally size the flexibility capacity (the battery energy storage in this application) needed to operate their industrial facility as a net-zero energy factory.Results show that an optimally controlled stationary energy storage system allows a reduction of energy exchange with the grid up to 53%. The further introduction of electric vehicles increases of about 5% and 67% the renewable energy self-consumption and carbon emissions savings, respectively, ensuring also a significant increase in the yearly annual savings (up to 406%).

Carbon-Negative Hydrogen Production (HyBECCS) from Organic Waste Materials in Germany: How to Estimate Bioenergy and Greenhouse Gas Mitigation Potential

Hydrogen derived from biomass feedstock (biohydrogen) can play a significant role in Germany’s hydrogen economy. However, the bioenergy potential and environmental benefits of biohydrogen production are still largely unknown. Additionally, there are no uniform evaluation methods present for these emerging technologies. Therefore, this paper presents a methodological approach for the evaluation of bioenergy potentials and the attainable environmental impacts of these processes in terms of their carbon footprints. A procedure for determining bioenergy potentials is presented, which provides information on the amount of usable energy after conversion when applied. Therefore, it elaborates a four-step methodical conduct, dealing with available waste materials, uncertainties of early-stage processes, and calculation aspects. The bioenergy to be generated can result in carbon emission savings by substituting fossil energy carriers as well as in negative emissions by applying biohydrogen production with carbon capture and storage (HyBECCS). Hence, a procedure for determining the negative emissions potential is also presented. Moreover, the developed approach can also serve as a guideline for decision makers in research, industry, and politics and might also serve as a basis for further investigations such as implementation strategies or quantification of the benefits of biohydrogen production from organic waste material in Germany.

Evaluation of criteria for site selection of solar photovoltaic (PV) projects using fuzzy logarithmic additive estimation of weight coefficients

The aim of this study is to determine the degree of importance of criteria affecting site selection of solar photovoltaic (PV) projects using a decision-making model. This study consists of four consecutive stages, as follows: criteria identification, questionnaire (survey), statistical analyses, and degree of importance of criteria. In the first stage, the criteria are determined by reviewing the scientific literature on solar PV projects. Secondly, we conduct a questionnaire to identify the importance of the criteria for solar PV project site selection. We received responses from 33 internationally renowned experts from 22 countries, including academia and industry, using an international evaluation method. Thirdly, statistical analysis is performed in SPSS regarding each criterion, comparing the averages between the groups who filled out the questionnaire. Finally, a novel logarithmic additive estimation of weight coefficients (LAAW) under fuzzy environment is proposed to determine the degree of importance of each criterion for solar PV site selection. The results show that the most important criteria for solar PV site selection are solar radiation, economic performance indicators (net present value (NPV), internal rate of return (IRR), and return on investment (ROI)), carbon emission savings, and policy support.

Domestic Retrofit Assessment of the Heat Pump System Considering the Impact of Heat Supply Temperature and Operating Mode of Control—A Case Study

In this study, performance assessment of the variable speed compressor-based air source heat pump (ASHP) system as a domestic retrofit technology instead of fossil fuel-based heating technologies for the 1900s Mid terraced house is investigated. The assessment was conducted considering operating mode of control and heat supply temperature impact of the system. In the literature, ASHP system experimental development with variable speed mode (VSM) of control in comparison to fixed speed mode (FSM) of control at low to medium and high heat supply temperature in the context of UK was found with very limited number of studies, but without considering retrofit application. The focus of the earlier studies was on the individual components and performance improvement. The designed heat pump (HP), developed, and tested at constant heat load, simulating the real domestic heat demand under the controlled laboratory conditions and numerical modeling is utilized for the analysis purposes. The HP performance, energy demand, carbon emissions, and cost varies significantly due to changing heat supply temperature (35 °C, 45 °C, and 55 °C), control mode and accordingly the carbon emission and cost savings are achieved. The oil and gas boilers ranges from conventional to highly efficient type and evaluated in terms of annual running cost, energy consumptions, and carbon emissions in comparison with the HP system. Additionally, a comparative study with the existing retrofitted very high temperature ASHP inside the house is conducted. The developed HP at 55 °C could not defeat the very high heat supply temperature HP system (75 °C supply temperature) in performance and cost savings but become attractive at low supply temperature (35 °C). The HP system in VSM at low heat supply temperature instead of gas boiler (90% efficiency) could cut the annual carbon emissions by 59% but with additional 6% running cost for the Mid terraced test house in Belfast climatic conditions.

Managing a sustainable integrated inventory model for imperfect production process with type one and type two errors

Unlike previous research, this study develops an integrated inventory model for controllable lead time with defective items, errors in inspection, and variable lead time considering sustainability. The research investigates the effect of controlling lead time and capital investment in the setup cost. We assume that the buyer receives a lot size that may contain some defective items with a known defective probability. The buyer’s inspector conducts a 100% quality inspection and may incorrectly classify a non-defective item as a defective item (type one (I) error) or incorrectly classify a defective item as a non-defective item (type two (II) error). The mathematical inventory model considering carbon emission cost is developed, and the solution procedure is designed using the heuristic algorithm to derive the optimal or near optimal solution. Finally, numerical examples and sensitivity analysis are given to illustrate the results. The results show that the defective rate, and type I type II inspection errors, have a significant impact on the shipment lot. This leads to the changes in the total cost, lead time, and the carbon emissions. Our study provides cost savings of 4.39% and carbon emission savings of 28.44%.Graphic abstract

Analysis of global energy savings in the frozen food industry made possible by transitioning from conventional isobaric freezing to isochoric freezing

An efficient global cold food chain is critical to the sustainability of the growing world population, and it is anticipated that the global frozen food market will reach $404.8 billion by 2027. Frozen foods are typically stored under conventional industry-standard isobaric (constant-pressure) conditions at sub-freezing temperatures, however, which can degrade the textural and nutritional quality of the food and comes at high energetic and carbon costs. While efforts to reduce this energetic toll have traditionally targeted the devices used to generate refrigeration, we herein identify that significant energy savings may be attainable by altering the fundamental thermodynamics of the freezing process itself. Here we show that preserving frozen food under isochoric (constant-volume) thermodynamic conditions, as opposed to conventional isobaric conditions, may theoretically reduce annual global energy consumption by as much as 6.49 billion kWh, with accompanying carbon emission savings of 4.59 billion kg. Importantly, these savings can be achieved rapidly and inexpensively, without any costly changes to the current global refrigeration infrastructure. Furthermore, early studies demonstrate that isochoric freezing results in substantially improved food quality, extends the preservable lifetime of fresh and otherwise delicate food products, and has cross-cutting biopreservation applications in domains as diverse as medicine, biology, and pharmaceuticals.

Carbon emission savings and short‐term health care impacts from telemedicine: An evaluation in epilepsy

Health systems make a sizeable contribution to national emissions of greenhouse gases that contribute to global climate change. The UK National Health Service is committed to being a net zero emitter by 2040, and a potential contribution to this target could come from reductions in patient travel. Achieving this will require actions at many levels. We sought to determine potential savings and risks over the short term from telemedicine through virtual clinics. During the severe acute respiratory syndrome coronavirus 2 (SARS-2-CoV) pandemic, scheduled face-to-face epilepsy clinics at a specialist site were replaced by remote teleclinics. We used a standard methodology applying conversion factors to calculate emissions based on the total saved travel distance. A further conversion factor was used to derive emissions associated with electricity consumption to deliver remote clinics from which net savings could be calculated. Patients' records and clinicians were interrogated to identify any adverse clinical outcomes. We found that enforced telemedicine delivery for over 1200 patients resulted in the saving of ~224000km of travel with likely avoided emissions in the range of 35000-40000kg carbon dioxide equivalent (CO2 e) over a six and half month period. Emissions arising directly from remote delivery were calculated to be <200kg CO2 e (~0.5% of those for travel), representing a significant net reduction of greenhouse gas emissions. Only one direct adverse outcome was identified, with some additional benefits identified anecdotally. The use of telemedicine can make a contribution toward reduced emissions in the health care sector and, in the delivery of specialized epilepsy services, had minimal adverse clinical outcomes over the short term. However, these outcomes will likely vary with clinic locations, medical specialties and conditions.

Advanced optimal planning for microgrid technologies including hydrogen and mobility at a real microgrid testbed

This paper investigates the optimal planning of microgrids including the hydrogen energy system through mixed-integer linear programming model. A real case study is analyzed by extending the only microgrid lab facility in Austria. The case study considers the hydrogen production via electrolysis, seasonal storage and fueling station for meeting the hydrogen fuel demand of fuel cell vehicles, busses and trucks. The optimization is performed relative to two different reference cases which satisfy the mobility demand by diesel fuel and utility electricity based hydrogen fuel production respectively. The key results indicate that the low emission hydrogen mobility framework is achieved by high share of renewable energy sources and seasonal hydrogen storage in the microgrid. The investment optimization scenarios provide at least 66% and at most 99% carbon emission savings at increased costs of 30% and 100% respectively relative to the costs of the diesel reference case (current situation).

Energy efficiency improvement in farming equipment, for agricultural holdings

The use of depreciated and outdated agricultural equipment reflects both, on the increased cost of production (due to the higher energy component), and the greater amount of emissions produced during the operation of that equipment. The presented paper deals with energy and emission analysis of the replacement of existing farming equipment in a holding, with a new one. The analysis considers the baseline tractor and harvester and their specific agricultural operations, related to the processing of the soil and the harvesting of the production. The analysis is based on the existing energy consumption of the old machines and accounting information on the operation of the new equipment, one year after its commissioning. The study shows that the estimated energy savings from the measures of 17.2%, with a similar carbon footprint reduction. Based on the technical characteristics, CO, HC, HC + NOx and NOx emissions were also analyzed. The percentage of estimated carbon emission savings is higher than 43.5%.

PV Energy Performance in a Sustainable Campus

The challenge of photovoltaic integration as the basis of an energy generation system has been achieved and carried out by the University Autónoma de Cali, Colombia, using an avant-garde energy technology model. This innovative sustainable campus not only fulfills its purpose as an advanced model of a renewable energy integration system, it also aims at environmental research, e-mobility, and energy efficiency. This paper describes how the university implements the technological innovation of integrating the photovoltaic system installation in a university campus, showing its relevant contribution to the electricity generation in the campus buildings by analyzing the different electrical parameters together with the system performance indicators. The implementation of technological solutions has allowed the generation of a quantity of renewable energy within the campus, supplying a sustainable energy response based on energy efficiency and carbon emissions savings. This innovation has been applied following the international standards for the evaluation of the energy performance of photovoltaic systems (IEC 61724), reaching very optimal values for this type of renewable solution. In this paper, the dynamic monitoring of several parameters has been carried out in order to analyze the energy performance, and an energy simulation has been used to achieve optimal solutions and to obtain the perfect modeling of the system. This study shows how to evaluate the performance of an integration of a photovoltaic system in a smart university campus, according to international standards. It achieves complete viability due to its economic savings, energy efficiency and reduction of carbon emission.

The effects of fuel variability on the electrical performance and durability of a solid oxide fuel cell operating on biohythane

Biohythane is typically composed of 60/30/10 vol% CH4/CO2/H2 and can be produced via two-stage anaerobic digestion of renewable and low carbon biomass with much greater efficiency compared with CH4/CO2 biogas. This work investigates the effects of fuel variability on the electrical performance and fuel processing of a commercially available anode supported solid oxide fuel cell (SOFC) operating on biohythane mixtures at 750 °C. Cell electrical performance was characterised using current-voltage curves and electrochemical impedance spectroscopy. Fuel processing was characterised using quadrupole mass spectroscopy. It is shown that when H2/CO2 is blended with CH4 to make biohythane, the SOFC efficiency is significantly increased, high SOFC durability is achieved, and there are considerable savings in CH4 consumption. Enhanced electrical performance was due to the additional presence of H2 and promotion of CH4 dry reforming, the reverse Boudouard and reverse water-gas shift reactions. These processes alleviated carbon deposition and promoted electrochemical oxidation of H2 as the primary power production pathway. Substituting 50 vol% CH4 with 25/75 vol% H2/CO2 was shown to increase cell power output by 81.6% at 0.8 V compared with pure CH4. This corresponded to a 3.4-fold increase in the overall energy conversion efficiency and a 72% decrease in CH4 consumption. A 260 h durability test demonstrated very high cell durability when operating on a typical 60/30/10 vol% CH4/CO2/H2 biohythane mixture under high fuel utilisation due to inhibition of carbon deposition. Overall, this work suggests that decarbonising gas grids by substituting natural gas with renewably produced H2/CO2 mixtures (rather than pure H2 derived from fossil fuels), and utilising in SOFC technology, gives considerable gains in energy conversion efficiency and carbon emissions savings.

Contribution of Roof Refurbishment to Urban Sustainability

Achieving sustainable urban environments is a challenging goal—especially in existing cities with high percentages of old and obsolete buildings. This work analyzes the contribution of roof refurbishment to sustainability, considering that most roofs are currently underused. Many potential benefits of refurbishment can be achieved, such as the improvement of the energy performance of the buildings and the use of a wasted space for increasing green areas or for social purposes. In order to estimate the degree of the improvement, a vulnerable area in Castellón (east Spain) was selected as a case study. A thorough analysis of the residential building stock was undertaken. Using georeferenced information from the Cadastral Office we classified them according to typology, year of construction and roof type. Some refurbishment solutions were proposed and their applicability to the actual buildings was analyzed under different criteria. The theoretical benefits obtained in the neighborhood such as energy and carbon emissions savings were evaluated, together with the increase of green areas. Moreover, other social uses were suggested for neglected urban spaces in the area. Finally, a more accurate analysis was performed combining different solutions in a specific building, according to its particular characteristics.

Development of a data driven FDD approach for building water networks: Water distribution system performance assessment rules

While fault detection and diagnosis is a popular tool in the process industry, its application in building water distribution systems is however still largely absent. In this study, a new set of Water Distribution System Performance Assessment Rules (WDSPARs) were developed to identify common faults in a building water distribution system. The WDSPARs comprise a three-phase process which can be applied using flow and pressure sensor signals obtained in real-time and/or via analysis of historic data in conjunction with knowledge of water distribution system layouts. The performance assessment rules originated from analysis of behaviour in water consumption at two non-residential pilot sites over a 6 month trial. Implementation of WDSPAR at the two pilot studies revealed a number of faults and cases of non-optimal performance which were diagnosed and costed accordingly. The WDSPAR approach is intuitive and can be easily integrated into existing building management systems using sensor data. This study serves as the first practical guide for the implementation of the WDSPAR approach for adoption by large non-residential building end-users. Using the WDSPARs, the case studies outlined in this paper demonstrate 62% savings in water consumption which resulted in energy and carbon emission savings of the order of 50 kW h and 29.9 kg.CO2 per day respectively.

Optimal design and operation of an urban energy system applied to the Fiera Del Levante exhibition centre

To move from centralised fossil fuel-based energy systems, synergies between distributed renewable generation, storage and demand-side strategies can be exploited to lower environmental impact and costs. This paper proposes an optimisation model for the techno-economic assessment of energy management strategies with a short-term investment horizon aimed at business managers and decision-makers in the commercial sector. The main novelty is the selection of a combination of on-site technologies and peak shaving strategies to minimise energy costs under time-of-use electricity tariffs, and the adaptation of a general methodology for a specific socio-technical context under seasonal loads. The “Fiera del Levante” exhibition centre in the city of Bari is selected due to the high seasonality of its electricity demand. The optimal solution uses a combined system with photovoltaics, diesel-fired and gas-fired combined-heat-and-power, including part-load operation and electric storage. The cost minimisation scenario reports up to 20% cost savings and 35% carbon emission savings with a 1MWp photovoltaic plant, compared to the baseline. This presents a five-year return on investment of 75%, and levelized cost of energy of €0.14 kWh−1. When coupled with a lithium-ion battery, solar energy brings up to 60% carbon emission savings through load shifting strategies, though this reduces the five-year return on investment by 9%. This hybrid setup is not financially competitive in the Italian retail market, but a hypothetical 25% rise of the grid import prices would make it economically viable. The proposed model is flexible and can be adapted to commercial end-users, providing decision-support in urban energy systems under local conditions.