Low-carbon Systems Research Articles

Application of pyritic sludge with an anaerobic granule consortium for nitrate removal in low carbon systems

Granules recovered from a highly reduced anaerobic digester were capable of active nitrogen removal in the absence of exogenous electron donors, averaging 0.25 mg mgNO3−-N /gVSS/d over 546 days of operation. Electron mass balance indicated that about half the influent nitrate was converted to ammonia via DNRA and another half denitrified. This capacity was associated with an onion-like structure of multiple layers enriched in reduced iron and sulfur, and a complex microbial community shown by metagenomic sequencing to consist of multiple physiological groups and associated activities, including methanogenesis, denitrification, dissimilatory nitrate reduction to ammonia (DNRA), iron oxidation and reduction, and sulfur reduction and oxidation. Nitrate reduction was supported by both entrained organic material and reduced iron and sulfur species, corresponding to 2.13 mg COD/gVSS/d. Batch incubations showed that approximately 15% of denitrified nitrate was coupled to the oxidation of sulfur derived from both sulfate respiration and granular material enriched in iron-sulfide. Inhibition of sulfate reduction resulted in redirection of electron flow to methanogenesis and, in combination with other batch tests, showed that these granules supported a complex microbial community in which cryptic redox cycles linked carbon, sulfur, and iron oxidation with nitrate, sulfate, iron, and carbon dioxide reduction. This system shows promise for treatment of nitrate contaminated ground water without addition of an external organic carbon source as well as wastewater treatment in combination with (granular) sludge elimination leading in a net reduction of solid treatment costs.

Challenges of Low Carbon Public Transport Systems in the Arabian Gulf City: Case of Muscat, Oman

The Arabian Gulf cities are growing. The gulf cooperation council states (GCCs) are among the richest and most urbanized in the world. As a major focus on sustainable development of cities, sustainable transportation acts to diminish the city’s energy consumption by providing a public transport system that has greater ecological obligation and societal justice. The study’s significance is to figure out the challenges in the sector of public transport in the city of Muscat. The wide spread of mass transportation plays a significant role in reducing the exhaustion of energy. Also, it contributes to make a better living experience. Provision of sustainable public transport will prevent the increasing number of motor cars and equally accompanied environmental pollution and traffic congestion. The study is based on an in-depth quantitative and qualitative research method to explore the hindrances that are encountered in the way of building sustainable infrastructure of public transport. The findings of the study revealed that public transport system face real challenges in Gulf region, particularly in Muscat. It indicated that for the well-being of Gulf society, the use of public transportation was encouraged and most of the population have their own cars. In addition to it, cultural and social preservations are raised, mainly by the people that act against the operation of public transport system. Due to the substantial effect of clean and sustainable transportation on energy consumption levels, recent years have been marked with a notable trend towards sustainable and low carbon systems, particularly the mass transportation ones.

Optimal Integration of Renewable Sources and Latent Heat Storages for Residential Application

Given the large amount of energy required in the building sector, an interesting opportunity to reach future sustainable energy systems is the path towards low energy buildings. This work proposes an approach for optimally integrating building-scale energy technologies (both traditional and renewable) to enhance the transformation of the existing buildings (often energetically inefficient) in low-carbon systems. The approach promotes a transition sustainable from both the economic and environmental perspectives. Both operation and design optimization are considered with the aim of suggesting the best set of capacity of the technologies to be installed taking into account the expected operations. The building-scale technologies are integrated with proper storage units: Li-ion batteries and thermal storage (latent heat, that requires low installation space). As a dispatchable renewable technology, a biogas small-scale combined heat and power unit is included in the system. Once the key role played by this component in meeting the loads is proved, an analysis of the impact of the cost of the primary energy carrier of this technology on the system design is carried out. Two optimization approaches have been adopted (both based on non-linear programming). Results show that operation costs can be reduced by up to 29%. The adoption of a combined approach that takes into account both operation and design optimization lead to a reduction in installation and operating costs by up to 27%. In the analyzed cases, the use of the combined optimization confirms that latent heat storage is more suitable to be installed than electric storage (about −4.5% cost).

Clearing a Path to Commercialization of Marine Renewable Energy Technologies Through Public–Private Collaboration

Governments are increasingly turning toward public–private partnerships to bring industry support to improving public assets or services. Here, we describe a unique public–private collaboration where a government entity has developed mechanisms to support public and private sector advancement and commercialization of monitoring technologies for marine renewable energy. These support mechanisms include access to a range of skilled personnel and test facilities that promote rapid innovation, prove reliability, and inspire creativity in technology development as innovations move from concept to practice. The ability to iteratively test hardware and software components, sensors, and systems can accelerate adoption of new methods and instrumentation designs. As a case study, we present the development of passive acoustic monitoring technologies customized for operation in energetic waves and currents. We discuss the value of testing different systems together, under the same conditions, as well as the progression through different test locations. The outcome is multiple, complementary monitoring technologies that are well suited to addressing an area of high environmental uncertainty and reducing barriers to responsible deployment of low-carbon energy conversion systems, creating solutions for the future.

Transitioning to Low Carbon Systems - Financial Institutions as Enablers

Transitioning to Low Carbon Systems - Financial Institutions as Enablers

Effectiveness of demand response in achieving supply-demand matching in a renewables dominated electricity system: A modelling approach

Globally, electricity systems are undergoing transitions from robust, carbon-intensive, and firm power conventional systems to uncertain, intermittent, and variable renewable energy integrated low carbon systems. These transitioning electricity systems have moved from a situation of “matching available supply with dynamic demand” to “matching dynamic supply with dynamic demand.” These transformations have led to several new challenges - significant mismatch in periods of high supply and high demand, the shift in the method of accessing energy resources for electricity generation from “procure, store and generate when needed” to “generate when available,” continuous struggle to match variable supply with variable demand, and installed capacity redundancy, temporal as well as permanent leading to low plant load factors. Actions on the supply-side alone will not be enough to address these challenges and achieve optimal functioning of the electricity system. We need effective demand-side solutions, too, to manage variations in both supply and demand. In this paper, it is proposed to study the effectiveness of demand-side interventions as potential solutions for managing the variabilities introduced by renewable energy mainstreaming. Towards this, we develop a mixed-integer linear programming model to implement and validate emergency and economic demand response (DR) programs. DR options like load curtailment, short-, medium- and long-term load shifting are considered with both incentive-based and penalty-based pricing strategies to influence consumer participation. The Karnataka electricity system is used as a case study for model implementation and validation. The findings suggest that DR interventions are very effective in moderating variability in electricity demand by chopping the peak loads and topping the valleys. Further, benefits include postponement of installed capacity additions, enhanced utilization of available capacity, and minimization of demand variability.

Comparing CO2 emissions impacts of electricity storage across applications and energy systems

Summary Electricity storage systems can support the decarbonization of energy systems. However, the effect of electricity storage use on greenhouse gas emissions is complex because of roundtrip efficiency losses of the storage and its effects on the dispatch of different electricity-generation technologies. The limited literature examining this issue focus on individual electricity storage applications and the geographies where they are applied. Here, we systematically compare the effects of electricity storage on CO2 emissions across four applications in electricity systems resembling seven European countries. Our findings reveal large emission impact differences between applications and countries. Among other findings, we find that when compared with wholesale arbitrage, storing electricity in other applications exhibits much lower effects on CO2 emissions. We also investigate different policy options to reduce CO2 emissions from storing electricity. We find that although a higher carbon price can have a substantial effect on reducing the CO2 emissions from wholesale arbitrage, other applications require alternative approaches.

Fast Frequency Response From Utility-Scale Hydrogen Electrolyzers

This paper introduces the modelling foundations to study the fast frequency response (FFR) from utility-scale hydrogen electrolyzers (HEs). Specifically, we propose a dynamic model of the HE electrolysis stack, power-electronics interface, and downstream hydrogen process operational constraints, which is suitable for system-level frequency dynamics studies. We then model and study HE FFR dependency on pre-contingency operating point, size, converter's overloading capability, network location, and active power-frequency controller. Different case studies are run on the Australian multi-area test system via dynamic simulations of a 2030 scenario with 50% renewables and in the context of the August 2018 separation event. Our modelling and results illustrate how grid-scale HEs could support a more secure and resilient operation of low-carbon systems for both credible and extreme outages and the role of different design setups and operating conditions and constraints.

Ancillary services in Great Britain during the COVID-19 lockdown: A glimpse of the carbon-free future

The COVID-19 pandemic led to partial or total lockdowns in several countries during the first half of 2020, which in turn caused a depressed electricity demand. In Great Britain (GB), this low demand combined with large renewable output at times, created conditions that were not expected until renewable capacity increases to meet emissions targets in coming years. The GB system experienced periods of very high instantaneous penetration of non-synchronous renewables, compromising system stability due to the lack of inertia in the grid. In this paper, a detailed analysis of the consequences of the lockdown on the GB electricity system is provided, focusing on the ancillary services procured to guarantee stability. Ancillary-services costs increased by £200m in the months of May to July 2020 compared to the same period in 2019 (a threefold increase), highlighting the importance of ancillary services in low-carbon systems. Furthermore, a frequency-secured scheduling model is used in the present paper to showcase the future trends that GB is expected to experience, as penetration of renewables increases on the road to net-zero emissions by 2050. Several sensitivities are considered, demonstrating that the share of total operating costs represented by ancillary services could reach 35%.

Sustainable Soil-Compacted Blocks Containing Blast Furnace Slag (BFS) Activated with Olive Stone BIOMASS Ash (OBA)

Soil stabilization using cementing materials is a well-known procedure for earth-based building blocks preparation. For the selected binding materials, innovation usually focuses on low carbon systems, many of which are based on alkaline activation. In the present paper, blast furnace slag (BFS) is used as a mineral precursor, and the innovative alkali activator was olive stone biomass ash (OBA). This means that the most important component in CO2 emissions terms, which is the alkali activator, has been replaced with a greener alternative: OBA. The OBA/BFS mixture was used to prepare compacted dolomitic soil blocks. These specimens were mechanically characterized by compression, and water strength coefficient and water absorption were assessed. The microstructure of blocks and the formation of cementing hydrates were analyzed by field emission scanning electron microscopy and thermogravimetry, respectively. The final compressive strength of the 120-day cured blocks was 27.8 MPa. It was concluded that OBA is a sustainable alkali activator alternative for producing BFS-stabilized soil-compacted blocks: CO2 emissions were 3.3 kgCO2/ton of stabilized soil, which is 96% less than that for ordinary Portland cement (OPC) stabilization.

Carbon Lock-In and Sustainable Growth Challenges : Evidence from Sub-Saharan Africa

This research seeks to investigate the risks of carbon lock-in by examining the potential factors influencing carbon dioxide emissions levels in Sub-Saharan Africa. Given this, we employed a panel Sub-Saharan Africa comprised of 35 countries in the sub-region, from 2000 to 2014 with cross-sectional dependence among variables. We used the Two-step robust System Generalized Method of Moments to estimate the influencing factors of carbon emissions level that create path dependency. The main findings are: (1) income per capita, urbanization, and financial resources contribute to the increase of carbon emissions level in the Sub-Saharan Africa countries, in the short-run; (2) we noticed that in the short-run, the impacts of fossil fuels per capita, energy intensity and total energy consumption are insignificant; (3) in the long-run, income per capita, urbanization and financial resources increase carbon emissions level; (4) from various factors that increase carbon emissions level, these factors form a path dependency that slow the introduction of low-carbon systems, thus, creating carbon lock-in in the Sub-Saharan Africa countries. Considering this, policymakers and governments should ensure the strict compliance of environmental regulations by financial institutions and organizations, promote low-carbon cities during economic transformation, and encourage investments in low-carbon projects. The government should also educate and build awareness on the effects of environmental pollution on population health, provide incentives for energy conservation and promote the use of clean products to avoid future risks of lock-in in the sub-region.

Sociotechnical imaginaries of low-carbon waste-energy futures: UK techno-market fixes displacing public accountability.

To implement EU climate policy, the UK’s New Labour government (1997–2010) elaborated an ecomodernist policy framework. It promoted technological innovation to provide low-carbon renewable energy, especially by treating waste as a resource. This framework discursively accommodated rival sociotechnical imaginaries, understood as visions of feasible and desirable futures available through technoscientific development. According to the dominant imaginary, techno-market fixes stimulate low-carbon technologies by making current centralized systems more resource-efficient (as promoted by industry incumbents). According to the alternative eco-localization imaginary, a shift to low-carbon systems should instead localize resource flows, output uses and institutional responsibility (as promoted by civil society groups). The UK government policy framework gained political authority by accommodating both imaginaries. As we show by drawing on three case studies, the realization of both imaginaries depended on institutional changes and material-economic resources of distinctive kinds. In practice, financial incentives drove technological design towards trajectories that favour the dominant sociotechnical imaginary, while marginalizing the eco-localization imaginary and its environmental benefits. The ecomodernist policy framework relegates responsibility to anonymous markets, thus displacing public accountability of the state and industry. These dynamics indicate the need for STS research on how alternative sociotechnical imaginaries mobilize support for their realization, rather than be absorbed into the dominant imaginary.

Processes of elite power and low-carbon pathways: Experimentation, financialisation, and dispossession

What is a low-carbon pathway? To many, it is a way of mitigating climate change. To others, it is about addressing market failure or capturing the co-benefits attached to low-carbon systems, such as jobs or improved health. To still others, it represents building adaptive capacity and resilience in the face of climate change. However, these interpretations can fail to acknowledge how pathways of low-carbon transitions can also become intertwined with processes and structures of inequality, exclusion and injustice. Using a critical lens that draws from a variety of disciplines, this article explores three ways through which responses to climate change can entrench, exacerbate or reconfigure the power of elites. As society attempts to create a low-carbon society, including for example via coastal protection efforts, disaster recovery, or climate change mitigation and renewable energy, these efforts intersect with at least three processes of elite power: experimentation, financialisation, and dispossession. Experimentation is when elites use the world as a laboratory to test or pilot low-carbon technologies or policy models, transferring risks yet not always sharing benefits. Financialisation refers to the expansion and proliferation of finance, capital, and financial markets in the global economy and many national economies, processes of which have recently extended to renewable energy. Dispossession is when elites use decarbonisation as a process through which to appropriate land, wealth, or other assets (and in the process make society more majoritarian and/or unequal). We explore these three themes using a variety of evidence across illustrative case studies, including hard and soft coastal protection measures (Bangladesh, Netherlands), climate risk insurance (Malawi), and renewable energy auctions and associated mechanisms of finance and investment (South Africa and Mexico).

The whole systems energy injustice of four European low-carbon transitions

The need for multi-scalar analysis of energy and low-carbon systems is becoming more apparent as a way to assess the holistic socioeconomic and environmental impacts of energy transitions across a variety of scales and lifecycle stages. This paper conducts a whole systems energy justice analysis of four European low-carbon transitions—nuclear power in France, smart meters in Great Britain, electric vehicles in Norway, and solar photovoltaic panels in Germany. It asks: in what ways may each of these transitions result in injustices that extend beyond communities and countries, i.e., across the whole system? It utilizes a mixed-methods research design based on 64 semi-structured research interviews with experts across all four transitions, five public focus groups, and the collection of 58 comments from twelve public internet forums to answer this question. Drawing inductively from these data, the paper identifies and analyzes 44 injustices spread across three spatial scales. Micro scale injustices concern immediate local impacts on family livelihood, community health and the environment. Meso scale injustices include national-scale issues such as rising prices for electricity and gas or unequal access to low-carbon technology. Macro scale injustices include global issues such as the extraction of minerals and metals and the circulation of waste flows. The paper then discusses these collective injustices in terms of their spatiality and temporality, before offering conclusions for energy and climate research and policy.

Integrated evaluation of energy and emission reduction potential and management strategies for urban road systems

Solving the problems of high energy consumption and high emissions generated by the urban road systems is of great importance for the construction of low-carbon cities. Several tools have been developed to establish a method to evaluate the carbon emission related to the life cycle of road pavements. However, the lack of key basic data such as energy consumption, pollutants and carbon emissions, and accurate management policies have hindered the transition of urban roads to clean, low-carbon systems. The HERMES project aims to compile long-term dynamic inventory of urban road energy consumption and environmental emissions and build a life cycle model. The Data Envelopment Analysis model will be used to predict the energy saving and emission reduction potential of urban roads depending on the technological solution, establish a multi-criteria evaluation system that includes energy, environment, and economic parameters, identify the best available technological solution in different cities, and propose a more targeted and effective clean low-carbon management policies. The study will provide an accurate understanding of the environmental impact of urban roads in China and Europe, evaluate the potential for energy saving and emission reduction, and provide theoretical data and decision-making reference for a clean, low-carbon transition.

Low-carbon tourism system in an urban destination

ABSTRACT The current kind of isolated or reductionism research is incompetent to systematically manage the development of low-carbon tourism destination. This research takes Lhasa, a high-altitude tourist city, as the case study. In this study, we seek to establish a system dynamics model to explore the evolution characteristics of urban low-carbon tourism systems under different scenarios. Our results indicate that some decision parameters (such as the proportion of low-carbon investment, CO2 emissions per tourist, carbon intensity of other industries, CO2 emissions per resident, and travelling time) have the most significant impacts on the performance of low-carbon tourism system. Under the economic priority scenario, the environmental risks to low-carbon tourism system are controllable in the long run. The contribution of tourism development to the pollution levels is continuously increasing. The research process presented in this study could be applied to the systematic management of other low-carbon tourism cities and even larger-scale destinations.

Envisioning future travel: Moving from high to low carbon systems

Comprehensive measures for reducing transport emissions were absent from the 2015 Paris Agreement yet without radical transformations in mobility systems and travel behaviour, transport emissions will continue to grow rapidly. This study investigated perceptions of travel in the year 2050 to see whether expectations of future travel align with lower carbon mobility systems. Data were collected through an international, online survey in 2016, targeting young adults with high levels of climate change concern. Thematic content analysis of responses (N = 401) revealed that 48% (n = 192) of participants described travel in 2050 as using low carbon mobility systems. This transition was predominantly attributed to improved technology (26%), rather than a shift in transportation mode (17%) or trip avoidance (12%). Expectations of future travel that could perpetuate high carbon mobility systems were mentioned by 53% (n = 212) of participants while only 23% (n = 94) mentioned factors that could reinforce low carbon mobility systems. These results show that even amongst people with high levels of concern about climate change, anticipated travel patterns have the potential to lock in high carbon transport and undermine progress. To achieve low carbon mobility transitions, strong international commitment must be supported by coordinated efforts of both governments and individuals.

Reducing Working Hours as a Means to Foster Low(er)-Carbon Lifestyles? An Exploratory Study on Swiss Employees

In the ongoing discussions on the transition to low-carbon systems a reduction of working hours has gained increased interest. A shift to lower incomes coupled with more discretionary time might promote low(er) individual carbon lifestyles without impairing individual well-being. Lower carbon emissions have been linked to shorter working hours on a macroeconomic level and to lower income, and thus less carbon-intensive activities on an individual level. However, little empirical research has been done on the effects of a self-determined reduction of working time on an intra-individual level. The aim of this paper was to explore whether and how a reduction of working hours facilitates low(er)-carbon lifestyles. We do this by means of 17 qualitative guideline interviews with Swiss employees that had recently reduced their working hours. Our results suggest that the underlying motives behind the employees’ decisions to reduce their working hours are crucial. A beneficial climate-saving effect arose only for those employees who dedicated their newly gained time to binding activities, that require a certain degree of commitment, such as parenting and further education. In contrast, those who reduced their working hours due to a desire for more recreational time risked increasing the carbon intensity of their lifestyles due to carbon-intensive leisure activities.

The role of values in analyzing energy systems: Insights from moral philosophy, institutional economics, and sociology

In efforts to mitigate climate change, energy systems are undergoing a profound transition towards low-carbon systems. This transition does not only involve changes in energy technologies but importantly it is shaped and incentivized by changes in the rules and regulations that govern energy markets. It is a normative transition, focused at achieving secure, affordable, and sustainable energy provision. In a multidisciplinary approach, this paper proposes a framework that highlights the role of normative principles – i.e. values – in socio-technical systems. Building on the Institutional Analysis and Development (IAD) framework, the analysis explicates how values relate to institutional change in the case of the energy transition.

Processes of Elite Power and Low-Carbon Pathways: Experimentation, Financialisation, and Dispossession

What is a low-carbon pathway? To many, it is a way of mitigating climate change. To others, it is about addressing market failure or capturing the co-benefits attached to low-carbon systems, such as jobs or improved health. To still others, it represents building adaptive capacity and resilience in the face of climate change. However, these interpretations can fail to acknowledge how pathways of low-carbon transitions can also become intertwined with processes and structures of inequality, exclusion and injustice. Using a critical lens that draws from a variety of disciplines, this article explores three ways through which responses to climate change can entrench, exacerbate or reconfigure the power of elites. As society attempts to create a low-carbon society, including for example via coastal protection efforts, disaster recovery, or climate change mitigation and renewable energy, these efforts intersect with at least three processes of elite power: experimentation, financialisation, and dispossession. Experimentation is when elites use the world as a laboratory to test or pilot low-carbon technologies or policy models, transferring risks yet not always sharing benefits. Financialisation refers to the expansion and proliferation of finance, capital, and financial markets in the global economy and many national economies, processes of which have recently extended to renewable energy. Dispossession is when elites use decarbonisation as a process through which to appropriate land, wealth, or other assets (and in the process make society more majoritarian and/or unequal). We explore these three themes using a variety of evidence across illustrative case studies, including hard and soft coastal protection measures (Bangladesh, Netherlands), climate risk insurance (Malawi), and renewable energy auctions and associated processes of finance and investment (South Africa and Mexico).