Emission Reduction Opportunities Research Articles

Assessment of the carbon footprint of total hip arthroplasty and opportunities for emission reduction in a UK hospital setting.

This study aimed to assess the carbon footprint associated with total hip arthroplasty (THA) in a UK hospital setting, considering various components within the operating theatre. The primary objective was to identify actionable areas for reducing carbon emissions and promoting sustainable orthopaedic practices. Using a life-cycle assessment approach, we conducted a prospective study on ten cemented and ten hybrid THA cases, evaluating carbon emissions from anaesthetic room to recovery. Scope 1 and scope 2 emissions were considered, focusing on direct emissions and energy consumption. Data included detailed assessments of consumables, waste generation, and energy use during surgeries. The carbon footprint of an uncemented THA was estimated at 100.02 kg CO2e, with a marginal increase to 104.89 kg CO2e for hybrid THA. Key contributors were consumables in the operating theatre (21%), waste generation (22%), and scope 2 emissions (38%). The study identified opportunities for reducing emissions, including instrument rationalization, transitioning to LED lighting, and improving waste-recycling practices. This study sheds light on the substantial carbon footprint associated with THA. Actionable strategies for reducing emissions were identified, emphasizing the need for sustainable practices in orthopaedic surgery. The findings prompt a critical discussion on the environmental impact of single-use versus reusable items in the operating theatre, challenging traditional norms to make more environmentally responsible choices.

From expansion to efficiency: Machine learning-based forecasting of Japan's building material stocks under demographic declines

Japan's unique demographic trajectory, marked by population decline and aging, coupled with continued urbanization, presents distinct challenges for aligning built environment capacity with resource efficiency. This study aims to investigate the historical evolution and project future scenarios of building material stock (MS) and their spatial distribution across Japan's three major metropolitan areas. Through a comprehensive material flow and stock analysis, the historical accumulation of building materials from 2009 to 2020 was quantified, revealing a dominance of concrete and an increasing overall stock. The contributions of various driving factors to changes in construction areas were explored, identifying population dynamics as the predominant influence. Leveraging shared socioeconomic pathway scenarios (SSPs), this research forecasted building floor area and MS until 2050 under five distinct SSPs. The results indicated an overall reduction across all scenarios, yet with a continued concentration in high-density urban cores. The substantial gap between the highest and lowest projected MS scenarios highlighted opportunities for material conservation and emission reductions through sustainable practices. Sustainable urban development in densely populated regions necessitates a balance between infrastructure provision and environmental conservation, while in sparsely populated areas, the focus shifts to the efficient management and utilization of vacant properties and materials to cope with the impacts of significant population declines. By offering insights into the building floor area and MS implications of Japan's demographic changes, this study underscores the necessity of sustainable urban planning and resource management strategies to navigate the challenges posed by demographic shifts, ultimately contributing to sustainable development and environmental conservation goals.

Landscape Architecture Carbon Emission Lifecycle Management Tool Based on Artificial Intelligence

In the contemporary discourse, carbon emissions have emerged as a focal point of global concern due to their role in inducing climate warming and precipitating ecological collapse. The establishment of a comprehensive carbon emission management system, coupled with effective measures, holds the potential to mitigate climate change, safeguard ecological integrity, improve health conditions, and promote global sustainable development. The Carbon Lifecycle AI Project Management Tool (CLA) proposed in this paper makes use of Large Language Model (LLM) and image processing model to intelligently analyze and manage the carbon emission of landscape architecture throughout its life cycle, and focuses on solving the carbon emission problem in landscape architecture. By gathering, integrating, and analyzing data related to landscape architecture, including information on material selection, plant configuration, and energy utilization, comprehensive monitoring and management of carbon emissions from landscape architecture are achieved. CLA not only offers real-time monitoring and analytical capabilities for carbon emissions but also identifies emission reduction opportunities and provides corresponding optimization recommendations, thus offering crucial support for the sustainable development of the landscape architecture industry.

Renewable Energy Technical Potential Performance for Zero Carbon Emissions.

Global 2021 energy flows indicate sectors with the greatest opportunities for efficiency improvements and emissions reduction. Analysis of the International Energy Agency's 2050 Net Zero Emissions (NZE) Scenario with respect to the 2021 energy profile as a reference point provides a model for changes in energy efficiency, emissions reduction, cost, and land use resulting from substitutions of fossil fuels with renewable options at the levels required for net zero emissions by 2050. Even with optimized outcomes, the probability of such widespread changes occurring over the next 30 years is reduced by the need for large investments, infrastructure changes, and the successful deployment of technologies still under development. Achievement of the technical potential outcomes for alternative solar energy to fuels conversion technologies, including cultivated microalgae biomass and biofuels and photocatalytic and photobiological hydrogen, would reduce reliance on mature renewable technologies and provide increase in net energy ("power to wheels") to help meet the demands of a growing population while reducing cost and CO2 emissions compared to the baseline 2050 NZE scenario. Such technical potential performance along with those for solar and wind represents 4 billion tons of CO2 removal (a 28% increase) over the baseline 2050 NZE Scenario but still requires another 9.5 billion tons of carbon capture and removal (CCR) to achieve NZE.

Charting a path to low-carbon leadership: unlocking up to 90% emissions reductions in greenfield LNG

The liquefied natural gas (LNG) industry stands at the cusp of a transformation driven by the climate imperative. Focussing on the Middle Arm Industrial Precinct, this paper shows how carbon dioxide (CO2) emissions are being reduced in a proposed world-class LNG project by assessing, screening and selecting known technologies using a Marginal Abatement philosophy linked to key emissions drivers. (1) We propose a new breed of electrified LNG facilities that could deliver an up to 90% reduction in CO2 intensity. (2) We show that through developing strategic partnerships in upstream renewable power, hydrogen supply, and enabled downstream carbon capture and storage (CCS), the significant low carbon energy requirements of an LNG facility can be delivered. (3) We discuss a Marginal Abatement assessment strategy which ensures a pathway to viable lowest cost opportunities selected in an ‘Avoid & Mitigate’ first approach. This proposed strategy ensures that CO2 emission reduction opportunities are assessed and selected consistently to determine both a lifecycle cost ($) and volume (tons CO2e) of emission reduction. These innovative strategies collectively articulate a roadmap for a low carbon future for LNG and other heavy industrial industries, underlining Australia’s potential to become a leading provider of low-carbon natural resources.

Carbon Footprint Drivers in China’s Municipal Wastewater Treatment Plants and Mitigation Opportunities through Electricity and Chemical Efficiency

Reducing greenhouse gas (GHG) emissions to address climate change is a global consensus, and municipal wastewater treatment plants (MWWTPs) should lead the way in low-carbon sustainable development. However, achieving effluent discharge standards often requires considerable energy and chemical consumption during operation, resulting in significant carbon footprints. In this study, GHG emissions are systematically accounted for, and the driving factors of carbon footprint growth in China’s MWWTPs are explored. In 2020, a total of 41.9 million tons (Mt) of carbon dioxide equivalent (CO2-eq) were released by the sector, with nearly two-thirds being indirect emissions resulting from energy and material usage. The intensity of electricity, carbon source, and phosphorus removing agent consumption increasingly influence carbon footprint growth over time. Through statistical inference, benchmarks for electricity and chemical consumption intensity are established across all MWWTPs under various operational conditions, and the potential for mitigation through more efficient energy and material utilization is calculated. The results suggest that many MWWTPs offer significant opportunities for emission reduction. Consequently, empirical decarbonization measures, including intelligent device control, optimization of aeration equipment, energy recovery initiatives, and other enhancements to improve operational and carbon efficiency, are recommended.

Carbon-negative heat-stored limestone calcined clay cement mortar containing form-stable phase change materials

Heat-stored cement-based materials (HSCMs) with form-stable phase change materials (PCMs) have exhibited tremendous opportunities for energy conservation and emission reduction in buildings. In this study, a novel HSCM system was designed by incorporating form-stable PCMs into limestone calcined clay cement (LC3) mortar, in which a highly compatible form-stable PCM was constructed by the three-step method including the synthesis of red mud-based geopolymer hollow microsphere (RMHM), the impregnation of n-Octadecane (ODE) into RMHM and the surface precipitation of CaCO3. The microstructures, phase transition properties, chemical compatibility and thermal stability of the two resulting form-stable PCMs (namely ODE/RMHM and ODE/RMHM@CaCO3) were evaluated. A comparative analysis was conducted to reveal the influence mechanism of ODE/RMHM and ODE/RMHM@CaCO3 on the microstructural evolution, hydration reaction, mechanical and thermal properties of LC3 mortar. Moreover, the numerical model method confirmed the significant role of the prepared LC3-based in temperature control and energy conservation in building. In addition, the obtained LC3-based HSCM could achieve a short dynamic payback period and sequestered huge of carbon emissions for service life. In overall, this work opened up a novel path of economically feasible carbon-negative building materials with form-stable PCM.

Development of an open-source carbon footprint calculator of the UK craft brewing value chain

Craft breweries may fall behind large brewing companies in reducing the carbon footprints of their value chains due to limited resources, financial constraints, and a lack of technical knowledge to fully understand their emissions. However, by increasing their awareness of the impact of their entire value chains, craft breweries can accelerate the decarbonisation of the industry by creating competition among breweries to appeal to environmentally conscious consumers. This work developed a freely available carbon calculator (10.6084/m9.figshare.22758692) using transparent, open-source data which may be used for benchmarking and identifying opportunities for emission reductions in UK craft breweries as well as providing a reference point for future carbon footprint analyses of global brewing value chains. The carbon footprint for craft brewing was calculated for a wide range of packaging types across three realistic scenarios (low, medium, and high carbon footprints) based on collected data and addresses the discrepancies between values reported in previous literature. Overall, the calculated carbon footprints ranged between 205 (20 L steel kegs, low carbon footprint scenario) and 1483 (single-use, 0.33 L glass bottles, high carbon footprint scenario) gCO2e per litre of beer. Novel hotspots (including wort boiling, the packaging process in a brewery, and the contribution of secondary and tertiary packaging) were identified. The overwhelming contribution of Scope 3 emissions (contributing between 57 and 95 % of the total carbon footprint) further emphasised the need to provide increased knowledge to craft breweries.

Greenhouse gas emission reduction opportunities for the Norwegian salmon farming sector - can they outweigh growth?

Norwegian farmed Atlantic salmon is a nutritious type of food in increasing demand and although production has stagnated and is faced by various challenges, it is likely to continue to expand in the future. We present results from a detailed greenhouse gas emission assessment of the most important Norwegian farmed salmon export products along with improvement measures. By scaling up both baseline results and reduction opportunities, based on growth projections, we estimate current and future emissions of the sector as a whole. We show that export of gutted salmon to Europe by truck dominates Norwegian salmon exports, not only in volume and value, but also in emissions, followed by export of fresh gutted salmon and fillets to Asia and fillets to the US by air. The cumulative greenhouse gas emissions are dominated by feed production followed by emissions from overseas airfreighting of fresh products. The five most important emission reduction measures, based only on existing technology and without particular order were 1) slightly increased feed efficiency, 2) increased utilization of side streams occurring in secondary processing after export, 3) seafreight to market instead of road and air, 4) higher energy efficiency and cleaner energy sources, and 5) changed feed composition. Collectively, they have the potential to reduce greenhouse gas emissions of current production by 60%, from 5.2 to 2.1 million tonnes of CO2e, assuming the same relative importance of each supply chain.This implies that a medium growth-scenario, representing more than a doubling of the volume of salmon farmed to 3.3 million tonnes, would be possible while reducing total sector emissions by 16% if the improvement measures were fully implemented. For larger reductions, either lower growth or more ambitious implementation of improvement measures is needed. Although greenhouse gas emissions are often linked to resource efficiency and wider sustainability, this is not always the case, and it is important to avoid shifting burdens from climate to e.g. eutrophication or biodiversity impacts. However, many environmental impacts of salmon farming are centered around feed efficiency, and even problems with welfare, escapees, and in part eutrophication are reflected in lower feed efficiency resulting in higher greenhouse gas emissions. In addition to the systematic collection of robust data for more continuous monitoring of greenhouse gas emission performance over time, we therefore recommend identifying additional indicators to monitor to ensure the sector develops not only towards climate neutrality but also towards broader sustainability.

Impacts of different hydrogen demand levels and climate policy scenarios on the Chilean integrated hydrogen–electricity network

As countries continue to update their climate ambitions, they are seeking cost-effective solutions for decarbonizing energy use. In this context, low-carbon hydrogen production and use presents relevant opportunities for emissions reductions and economic development, and recent studies show important potential benefits from integrating electricity and hydrogen networks. Based on a novel mathematical optimization model, we conduct a case study for Chile in 2020–2050 to assess the least-cost evolution of the integrated hydrogen–electricity system, testing different carbon prices, 100% renewable mandates, and incorporating domestic and international hydrogen demand. By optimizing over various scenarios, we find that, due to the country’s significant renewable potential and the flexibility that electrolyzers can provide, adding hydrogen exports to domestic hydrogen use may enhance renewable integration, while not necessarily increasing average wholesale electricity prices for typical end-users (relative to our baseline scenario), but also make battery deployment unattractive. Further, we conclude that climate policies such as a high carbon price or a 100% renewable mandate may be crucial to achieve a fully renewable system by 2050 and reduce cumulative emissions, resulting in 3%–14% higher net present system costs. Finally, we discuss that various concerns such as water and land use must be addressed by policymakers.

Willingness to pay for climate change mitigation measures in households: Bundling up renewable energy, energy efficiency, and renovation

AbstractThrough their consumption behavior, households are responsible for more than 70% of total global greenhouse gas emissions. Therefore, the GHG emission reduction potential due to the household behavior is very high. Energy consumption is the main source of the GHG emission in households. There are two main ways to reduce GHG emissions in households: use of renewable energy, energy efficiency improvement, and energy conservation due to changes in the energy use patterns. The highest energy saving potential in households is linked with building renovation, followed by the use of energy efficient appliances (including lighting). Renewable energy microgeneration technologies in households also provide opportunities for GHG emission reduction. Although there have been many policies developed to reduce GHG emissions from energy consumption in households, they still need to be more effective. This paper aims to assess willingness of Lithuanian households to reduce GHG emissions from energy consumption in households by embarking on energy renovation of buildings, use of energy efficient appliances and use of renewable energy technologies. The willingness to pay for these GHG emission reduction measures allows to compare household preferences with respect to available support measures and assess the adequacy of such measures. The paper also discusses household attitudes toward the main policies and measures for GHG emission reduction. The results show the highest willingness to pay for energy efficient appliances, followed by renewable energy technologies. The willingness to pay for energy renovation is the lowest one and such s measure requires significant state support.

High-Resolution Mapping of Material Stocks in Belgian Road Infrastructure: Material Efficiency Patterns, Material Recycling Potentials, and Greenhouse Gas Emissions Reduction Opportunities.

Road infrastructure is an integral part of built environment stocks, as it delivers essential social and economic services. While previous work has assessed material stocks, flows, and embodied emissions, spatially refined mapping of materials accumulated in road infrastructure can highlight hitherto underappreciated synergies between improved spatial planning, material stock efficiency, and urban mining. In this study, we mapped the materials stocked in road infrastructure across Belgium, explored the patterns of material stock efficiency and the recyclability of end-of-life road materials, and examined the greenhouse gas (GHG) emissions reductions of improving stock efficiency and recycling. We assembled data scattered across various governmental sources and crowdsourced platforms and developed a comprehensive database to warehouse locational information on road typology, layer geometry and thickness, material characteristics, traffic volume, climatic conditions, and soil conditions. Our results reveal a strong but nonlinear correlation between material stock efficiency and population density, indicating that spatial planning can reduce the required road stocks and associated GHG emissions. Urban mining potentials in road infrastructure hinge on multiple factors, such as the proximity to recycling facilities and the degradation of pavements during use. Our counterfactual analysis shows that urban road planning and reusing recycled asphalt can cut GHG emissions by up to 53 and 70%, respectively. Therefore, material-efficient road planning and improved material recycling can help realize circular economy potentials and mitigate GHG emissions moving forward.

Il sistema verde: soluzioni per la tutela dell’ambiente e la riduzione delle emissioni di CO2. L’esempio di una scuola esistente.

The public school building sector offers great opportunities for energy efficiency and CO2 emissions reduction. In this research a method for the energy evaluation of school buildings is proposed. It implements simple input information connected to dynamic simulations. The main objective is to evaluate the energy, environmental and economic impact of different regeneration proposals, combining a green system integration. The building chosen as a case study, which presents serial and widespread constructive and thermo-physical characteristics, allows to extend the validity of obtained results to similar cases and conditions. Findings highlighted the importance of developing site-specific strategies and green energy solutions, to optimally adapt any intervention to the architectural, typological and plant characteristics of the school. The proposed example is a prototype case so that the Municipalities and Public Administrations, owned by most of the schools in Italy, can use it as basic knowledge for future projects oriented towards the energy transition, but also for specific tailored training.

Global trade networks bring targeted opportunity for energy-related CH4 emission mitigation.

Recent literature highlights the contributions the global energy sector has made to anthropogenic CH4 emissions, calling for immediate action. However, extant studies have failed to reveal the energy-related CH4 emissions induced by global trades of intermediate and final commodities or services. This paper traces fugitive CH4 emissions via global trade networks using the multi-regional input-output and complex network models. Results show that approximately four-fifths of global fugitive CH4 emissions in 2014 were associated with international trade, of which 83.07% and 16.93% were embodied in the intermediate and final trades, respectively. Japan, India, the USA, South Korea, and Germany were the world's five largest net importers of embodied fugitive CH4 emissions, while Indonesia, Russia, Nigeria, Qatar, and Iran were the five largest net exporters. Gas-related embodied emission transfers were the largest in both the intermediate and the final trade networks. The fugitive CH4 emissions embodied within the intermediate and final trade networks were all characterized by five trading communities. The virtual fugitive CH4 emission transfers via intermediate trade were largely determined by global energy trade patterns, especially the trade in regionally integrated crude oil and natural gas. Significant heterogeneity was revealed by the coexistence of numerous loosely linked economies and several hub economies (e.g., China, Germany, the USA, and South Africa). Interventions on the demand side of interregional and intraregional trade partners in different communities and hub economies will bring targeted opportunities for global energy-related CH4 emission reduction.

IoT-enabled user agency for building sustainability

Buildings are a significant source of greenhouse gas emissions, and many organizations recognize that reducing commercial building-related emissions is crucial to achieving a carbon-neutral future. However, leveraging state-of-the-art building energy-efficiency techniques can be expensive and require installing new equipment, resulting in only a small percentage of energy-efficient commercial buildings. To address this challenge, our paper focuses on empowering building occupants to become informed change-makers that drive building efficiency through an IoT-based solution. By leveraging the data collected from low-cost sensors, we envision creating personalized dashboards and interventions for individuals, fostering energy transparency and empowering people to optimize their space usage while reducing emissions. Moreover, we can leverage human flexibility and flexible environments to further improve space usage and realize energy and emissions reduction opportunities. Thus, by enabling human-building interaction, our approach will be more effective in achieving the full potential of reducing energy and emissions in existing buildings.

Towards 2030: transforming asset emissions in Australian production operations

Operators are building roadmaps to reduce emissions at an increasing rate because of initiatives such as the Australian Government’s Safeguard Mechanism and global draft proposals to make emissions from plants auditable. There are three main levers for integrated gas operators: (1) Optimising existing operations to improve efficiency. (2) Designing sustainable developments and modifications. (3) Rebalancing portfolios to lower carbon equivalent intensity assets. Large capital projects are typically proposed as responses to the second lever – such as carbon capture and electrification. However, operating assets hold pressing challenges to reduce ~10–20% of emissions and need to develop viable roadmaps. Through our work in Australian integrated gas industry, we found that the majority of CO2-e operational emissions reduction opportunities can be addressed by discrete improvement programmes on rotating reliability, process optimisation and methane leak reduction. We discuss how asset operators can drive their Operations, Energy Transition and Digital Functions to realise these significant CO2-e benefits on a scale of months by: (1) Developing a value-driven decarbonisation strategy for operations, identifying benefits in production, cost and emissions, front-loaded with high impact, rapid 20–30% reduction initiatives that can be realised in the next 1–2 years. (2) Implementing effective and auditable real-time monitoring of plant emissions direct from existing control systems, sensors and imaging techniques. (3) Deriving a programme of tech-enabled optimisation levers and bringing this into new designs for carbon capture, utilisation and storage (CCUS), hydrogen and electrification projects for maximum benefits.

Identifying Emissions Reduction Opportunities in International Bilateral Emissions Trading Systems to Achieve China's Energy Sector NDCs.

Exploring more emissions reduction opportunities for China's energy sector and lowering China's decarbonisation costs are essential to fulfilling China's nationally determined contributions (NDCs) and making China's sustainable development more feasible. This study explored emissions reduction opportunities for China's energy sector in international bilateral emissions trading systems (ETSs) using a CGE (computable general equilibrium) model. This study revealed that linking China's ETS to those of regions with lower decarbonisation responsibilities, which tend to be developing regions, could lower China's carbon prices, thus increasing China's domestic energy supply and lowering energy prices (and vice versa). Meanwhile, the volume of emissions from regions linked to China also significantly affected the degree of the change in China's carbon prices. Among these, ETS links to India and Russia could reduce China's carbon price from 7.80 USD/ton under domestic ETS to 2.16 USD/ton and 6.79 USD/ton, allowing the energy sector and energy-intensive sectors to increase greenhouse gas emissions by 1.14% and 7.05%, respectively, without falling short of meeting its NDC targets. In contrast, as a consequence of links with the United States and the European Union, China's carbon price could increase to 5.37 USD/ton and 1.79 USD/ton, respectively, which would limit China's energy and energy-intensive sectors to emitting 5.45% and 2.24% fewer greenhouse gases in order to meet its NDC targets.

Understanding variability in petroleum jet fuel life cycle greenhouse gas emissions to inform aviation decarbonization

A pressing challenge facing the aviation industry is to aggressively reduce greenhouse gas emissions in the face of increasing demand for aviation fuels. Climate goals such as carbon-neutral growth from 2020 onwards require continuous improvements in technology, operations, infrastructure, and most importantly, reductions in aviation fuel life cycle emissions. The Carbon Offsetting Scheme for International Aviation of the International Civil Aviation Organization provides a global market-based measure to group all possible emissions reduction measures into a joint program. Using a bottom-up, engineering-based modeling approach, this study provides the first estimates of life cycle greenhouse gas emissions from petroleum jet fuel on regional and global scales. Here we show that not all petroleum jet fuels are the same as the country-level life cycle emissions of petroleum jet fuels range from 81.1 to 94.8 gCO2e MJ−1, with a global volume-weighted average of 88.7 gCO2e MJ−1. These findings provide a high-resolution baseline against which sustainable aviation fuel and other emissions reduction opportunities can be prioritized to achieve greater emissions reductions faster.

Technological avenues and market mechanisms to accelerate methane and nitrous oxide emissions reductions.

Strategies targeting methane (CH4) and nitrous oxide (N2O) emissions are critical to meeting global climate targets. Existing literature estimates the emissions of these gases from specific sectors, but this knowledge must be synthesized to prioritize and incentivize CH4 and N2O mitigation. Accordingly, we review emissions sources and mitigation strategies in all key sectors (fuel extraction and combustion, landfilling, agriculture, wastewater treatment, and chemical industry) and the role of carbon markets in reducing emissions. The most accessible reduction opportunities are in the hydrocarbon extraction and waste sectors, where half (>3 Gt-CO2e/year) of the emissions in these sectors could be mitigated at no net cost. In total, 60% of CH4 emissions can be mitigated at less than $50/t-CO2. Expanding the scope of carbon markets to include these emissions could provide cost-effective decarbonization through 2050. We provide recommendations for carbon markets to improve emissions reductions and set prices to appropriately incentivize mitigation.

Effect of CO2 tax on energy use in oil production: waterflooding optimization under different emission costs

Tackling emissions from hydrocarbon production is a necessity because hydrocarbon production will last for a prolonged time. As a popular hydrocarbon production method, waterflooding operation is energy-intensive and accounts for significant CO2 emissions. This article investigates the effect of CO2 tax level on recovery process of already producing fields with waterflooding. Our methodology is waterflooding optimization in reservoir simulation models, specifically optimizing well-controls. Unlike traditional studies, our optimization objective comprises two components: the profitability of hydrocarbon production and an additional tax proportional to CO2 emissions. The associated CO2 emissions is estimated using a scheme developed upon an integrated model of reservoir, surface network, and topside facility. We examine our methodology on two cases with heterogeneous reservoir models. In each case, we optimize multi-scenarios enforcing different CO2 tax rates. The solutions indicate that imposing a higher CO2 tax rate reduces both emissions and hydrocarbon production. The fractional reduction of oil produced is however smaller than the emission reduction. While an increased tax rate drives the topside equipment to operate at higher efficiencies, the main effects of a higher tax rate are reduced water injection and more efficient subsurface drainage. There is a non-linear relationship between the reduced production and emissions. For increasing tax levels there are diminishing returns on lower emissions, reflecting reduced opportunities for emission reduction by changes in the drainage strategy. Some increments on the tax rate will therefore have negligible impacts on the optimal drainage strategy, and hence an adverse effect on the profitability with negligible emission reduction.