Zero-carbon Sources Research Articles

A study of the benefits of including thermal energy stores in district heating networks

A model to simulate district heating networks (DHN) was applied to a hypothetical DHN in Loughborough, UK. The model includes different thermal energy storage (TES) systems: i) short-term water-based stores and phase-change material-based stores and ii) a seasonal thermal energy storage (STES) system. Heat pumps (HP) and evacuated-tube solar thermal collectors (ETSTC) are considered to both provide heat for dwellings and charge the TES systems. The model assumes that the HPs can only be used to charge TES at those times when the electricity is produced by zero-carbon sources. To assess this real CO2 emissions data per kWh of electricity produced in UK was used. The effect of both 1) the STES volume and 2) the half-hourly maximum amount of zero-emissions electricity available to charge TES on a) cost, b) efficiency and c) CO2 emissions was studied. The results showed that CO2 emissions and electricity cost can be reduced to 83.4 % and 12.3 %, respectively, using TES, when comparing with the scenario with no TES. Savings of 41.7 % can be achieved when comparing the cost of electricity used in the proposed DHN with TES with the current cost of the gas.

Modeling and forecasting carbon dioxide emission in Pakistan using a hybrid combination of regression and time series models

Carbon dioxide (CO2) emissions continue to rise globally despite efforts to combat climate change. Energy industry emissions are a pressing global issue, causing devastating impacts. Hence, it is vital to accurately and efficiently forecast CO2 emissions. Thus, this study comprehensively analyzes forecasting CO2 emissions by comparing various hybrid combinations of regression and time series methods to explore the CO2 emissions in Pakistan. First, divide the yearly time series of CO2 emissions into the long-run curve trend series and the residual subseries. The long-run curve trend subseries is modeled using parametric and nonparametric regression methods, while various standard time series models are used to forecast the residual subseries. However, the forecasts of each subseries will be combined to obtain the final forecast of CO2 emissions. This work used four different accuracy mean errors, a statistical test, and a graphical analysis as performance measures to evaluate the proposed hybrid forecasting technique. The findings confirmed that the proposed hybrid combination forecasting technique is highly accurate and efficient in forecasting CO2 emissions. Likewise, according to the proposed final optimal hybrid combination forecasting model, Pakistan's per capita CO2 emissions will be 1.130215 metric tons in 2030. Pakistan's escalating emission trend signals that creative solutions must be implemented to curb it. Thus, the government must price carbon footprints, regulate electricity from zero-carbon sources, reduce population, encourage afforestation in densely populated areas, adopt clean technology, and fund research.

The Analysis of The Impossible Triangle in Hydrogen Production Technologies

In the current global context, the transformation of the world's energy structure is of utmost importance. Hydrogen energy, being a zero-carbon source, serves as a crucial catalyst for achieving green and low-carbon transition. Despite China being the largest producer of hydrogen energy worldwide, it still heavily relies on coal-based energy systems and consumption patterns. It is essential to acknowledge that an inherent attribute of any single form of energy is its impossibility to fulfill all three aspects simultaneously: economy, cleanliness, and security. By delving into the theoretical connotation of this "energy impossible triangle" and considering factors such as energy security, economic viability, and environmental sustainability associated with various hydrogen production methods; we can analyze a feasible pathway for transforming China's hydrogen energy structure. This transformation necessitates gradually integrating advantages from existing coal-based systems while tailoring production structures according to local conditions. The development of hydrogen energy should be guided by both resource allocation capabilities and actual demand for sustainable growth. Additionally, establishing a comprehensive energy system will greatly facilitate the transition toward more efficient hydrogen production structures.

Utilizing high-resolution genetic markers to track population-level exposure of migratory birds to renewable energy development

With new motivation to increase the proportion of energy demands met by zero-carbon sources, there is a greater focus on efforts to assess and mitigate the impacts of renewable energy development on sensitive ecosystems and wildlife, of which birds are of particular interest. One challenge for researchers, due in part to a lack of appropriate tools, has been estimating the effects from such development on individual breeding populations of migratory birds. To help address this, we utilize a newly developed, high-resolution genetic tagging method to rapidly identify the breeding population of origin of carcasses recovered from renewable energy facilities and combine them with maps of genetic variation across geographic space (called ‘genoscapes’) for five species of migratory birds known to be exposed to energy development, to assess the extent of population-level effects on migratory birds. We demonstrate that most avian remains collected were from the largest populations of a given species. In contrast, those remains from smaller, declining populations made up a smaller percentage of the total number of birds assayed. Results suggest that application of this genetic tagging method can successfully define population-level exposure to renewable energy development and may be a powerful tool to inform future siting and mitigation activities associated with renewable energy programs.

The role of biomass in energy transition to net zero carbon emissions due to climate change: the Apulia case

Biomass is a net zero carbon source of energy. On the way to reduce carbon emissions, although a few part of biomass is already used and energetically valorised, a large untapped potential remains. If high energy production comes from intermittent sources like solar panels and wind turbines, it becomes challenging to balance energy supply and demand. Therefore, the role of biomass is important for two main aspects: the full valorisation of this source of energy itself, and its stabilization role in new renewable energy scenario. The path towards a net zero carbon scenario cannot overlook the following three key factors. The first factor is the realization that energy demand is continuously rising. The second factor is the urgent need for immediate CO2 reduction. The third factor is the importance of maintaining the electric grid stable. Guided by these fundamental principles, this paper aims to analyse the role of full biomass valorisation in stabilizing the energy system and reducing CO2 emissions. As a part of a much wider work, this analysis encompasses the role of biomass in both a more ambitious scenario with a great amount of photovoltaics, as well as the current energy landscape. The methodology used is numerical simulation of the Apulia case through EnergyPLAN software, and the main findings reveal a significant reduction in CO2 emissions while keeping energy systems stable.

Extracellular electron transfer for aerobic denitrification mediated by the bioelectric catalytic system with zero-carbon source

The slow rate of electron transfer and the large consumption of carbon sources are technical bottlenecks in the biological treatment of wastewater. Here, we first proposed to domesticate aerobic denitrifying bacteria (ADB) from heterotrophic to autotrophic by electricity (0.6 V) under zero organic carbon source conditions, to accelerate electron transfer and shorten hydraulic retention time (HRT) while increasing the biodegradation rate. Then we investigated the extracellular electron transfer (EET) mechanism mediated by this process, and additionally examined the integrated nitrogen removal efficiency of this system with composite pollution. It was demonstrated that compared with the traditional membrane bioreactor (MBR), the BEC displayed higher nitrogen removal efficiency. Especially at C/N = 0, the BEC exhibited a NO3--N removal rate of 95.42 ± 2.71 % for 4 h, which was about 6.5 times higher than that of the MBR. Under the compound pollution condition, the BEC still maintained high NO3--N and tetracycline removal (94.52 ± 2.01 % and 91.50 ± 0.001 %), greatly superior to the MBR (10.64 ± 2.01 % and 12.00 ± 0.019 %). In addition, in-situ electrochemical tests showed that the nitrate in the BEC could be directly converted to N2 by reduction using electrons from the cathode, which was successfully demonstrated as a terminal electron acceptor.

Managing reservoir dynamics when converting natural gas fields to underground hydrogen storage

On the path to a net-zero-carbon economy, large-scale energy storage will be an essential part of a renewable energy system. Hydrogen generated from renewable or zero-carbon sources has significant potential as an energy storage medium, by allowing for long-duration and high-capacity energy storage. At the volumes anticipated, however, underground storage systems will likely be essential. Much like the current natural gas system, underground hydrogen storage would provide a safe and cost-effective complement to smaller surface storage infrastructure. Recently, there has been significant interest in the possibility of converting existing gas storage systems to hydrogen storage, though many uncertainties exist in such a process. This paper explores the reservoir dynamics of natural gas/hydrogen gas mixtures and the resulting impacts on storage conversion and gas deliverability. Two specific topics are addressed. First, a novel viscosity model for hydrogen-containing gas mixtures is developed, which shows better agreement with experimental measurements than the widely-used Lohrenz-Bray-Clark model. Second, detailed reservoir simulations are used to investigate cost-effective injection/withdrawal strategies for converting a natural gas storage system to one that stores hydrogen/natural-gas blends. The critical role of buoyancy and gravity override is described, and recommendations are made regarding key reservoir characteristics and injection strategies for managing this behavior.

Techno-economic analysis of waste-heat conversion

<h2>Summary</h2> With more than 50% of the primary energy consumed worldwide currently lost as waste heat, waste-heat conversion (WHC) should be considered a promising zero-carbon source of electricity. Despite significant research on WHC, the market penetration of such technologies remains limited, in large part because the R&D community has primarily focused on the development of new WHC heat engines with limited attention given to the techno-economic aspects. As different types of WHC heat engines vary significantly in their physical origins, there is a critical need to develop a system-level techno-economic model that is relatively independent of the detailed physics and design of the engine. In this perspective, we develop a techno-economic model for WHC technologies based on the well-known endoreversible thermodynamics formulations, which results in a fairly universal model. Our results indicate that regardless of the type or efficiency, WHC heat engines are not economically viable below 100°C, which has been the focus of significant research in the literature in recent years. Under highly optimistic assumptions, such as the cost of the WHC heat engines being the same as gas turbines (∼$0.25/W) and the capacity factor of the waste heat source being 0.9, for relative device Carnot efficiency <0.2, which is typical of various WHC heat engines, WHC is economical only for temperatures above 150°C and power output in the range of 100 kW to 1 MW. We conclude this perspective by providing a future outlook on the research needed in the field of WHC heat engines for it to be techno-economically viable. We also propose that along with the temperature and amount of waste heat available from various sources, the capacity factor of the waste-heat sources must be documented.

Does financial development influence renewable energy consumption to achieve carbon neutrality in the USA?

In order to achieve the goal of carbon neutrality, as defined in the Paris climate agreement, the United States, the second-largest greenhouse gas emitter, must intensify its use of zero-carbon sources such as renewable energy. In this paper, we use the nonlinear autoregressive distributed lags (NARDL) model to investigate the influence of financial development on renewable energy consumption in the U.S. from 1975Q1 to 2019Q4. More precisely, three measures of financial development are considered: the overall financial development, bank-based financial development, and stock-based financial development indices. The model is augmented to control for the effects of real oil prices, real GDP, and trade openness. The empirical results show evidence of a long-run asymmetric effect of overall and stock-based financial development measures. Positive and negative changes in financial development measures dictate renewable energy consumption. In the short run, only negative changes of overall and stock-based financial development measures significantly impact renewable energy consumption. The latter impact is contemporaneously positive and negative at the one-lagged period. Renewable energy consumption does not react to a short-run change in bank-based financial development. Our empirical findings possess important policy implications.

Using Impedance to Quantify Transport Losses in Alkaline Water Electrolysis Electrode Catalyst Layers

Anthropogenic climate change has brought on a global climate crisis and emergency. Increased levels of atmospheric carbon dioxide levels has brought with it undesirable changes to the world’s climate. To halt and eventually stop this trend the world needs to move to zero-carbon sources of electricity, transport and chemical production.To offset the variability in zero-carbon electricity sources storage or usage of the excess energy is necessary. One of several technologies to achieve this is water electrolysis. A promising candidate of this field of study is Alkaline Water ElectrolysisThe field of alkaline electrolysis have recently moved from a gap-based macro-material approach to a nanomaterials based membrane cell architecture.Due to recent advances in membrane technology both ion-conduction and electrolyte solvating membranes allow for a zero-gap cell architecture. With this approach comes new engineering challenges. Bubble formation, -diffusion, -suppresion, and –transport are all phenomena that are relatively unexplored in the context of nanopowder-based electrodes in fully flooded aqeous KOH systems.One of the ways of exploring this is the use of Galvanostactic Electrochemical Impedance Spectroscopy (GEIS).Through GEIS investigations and Distribution of Relaxation Times of the electrochemical response of nano-powder based cathodes a Gerischer-like response can be observed indicating transport issues and a way of quantifying this.

Using Impedance to Quantify Transport Losses in Alkaline Water Electrolysis Electrode Catalyst Layers

Anthropogenic climate change has brought on a global climate crisis and emergency. Increased levels of atmospheric carbon dioxide levels has brought with it undesirable changes to the world’s climate. To halt and eventually stop this trend the world needs to move to zero-carbon sources of electricity, transport and chemical production.To offset the variability in zero-carbon electricity sources storage or usage of the excess energy is necessary. One of several technologies to achieve this is water electrolysis. A promising candidate of this field of study is Alkaline Water ElectrolysisThe field of alkaline electrolysis have recently moved from a gap-based macro-material approach to a nanomaterials based membrane cell architecture.Due to recent advances in membrane technology both ion-conduction and electrolyte solvating membranes allow for a zero-gap architecture. With this approach comes new engineering challenges. Bubble formation, -diffusion, -suppresion, and –transport are all phenomena that are recently unexplored in the context of nanopowder-based electrode in flooded KOH systems. One of the ways of exploring this is the use of Galvanostactic Electrochemical Impedance Spectroscopy (GEIS)..Through GEIS investigations and Distribution of Relaxation Times of the electrochemical response of nano-powder based cathodes a Gerischer-like response indicating transport issues and a way of quantifying this.

Effects of alternate nutrient medium on microalgae biomass and lipid production as a bioenergy source for fuel production

Over last three decades, worldwide researchers are researching on biomass feedstock, as it is a promising renewable and zero-carbon source of energy. Fuels produced from biomass are called as biofuels; biofuels can play an important role in meeting the energy demand and can help to reduce global warming. As compared to other biomass feed stocks (terrestrial plants) microalgae is considered as a promising source due to its high potential to produce lipids by absorbing nutrients from the wastewater, without affecting the usage of arable land and fresh water resources. Among the different microalgae strains, green microalgae have higher growth rate with more lipid content. Biomass production and lipid accumulation of microalgae are limited by various factors, such as CO2 supply, temperature, aeration, salinity and concentration of nutrients in the medium. Nutrient concentration and its limitation is one of the effective limiting factor to increase the lipid accumulation in microalgae.During the present study, three various alternate nutrient concentration experiments viz. higher strength, full strength and half strength, and one standard Bold’s Basal Medium (BBM) with full strength have been prepared to investigate the effects of alternate nutrient medium and different nutrient concentrations on biomass and oil productivity of green microalgae Chlorella Sorokiniana-5673. The cultivation was carried in a semi-controlled open pond environment and all experiments were conducted in duplicate. The alternate nutrient medium was prepared by using agriculture fertilizers, as source of major nutrients and tap water as a substrate. The growth performance of microalgae was observed by UV–visible spectrophotometer and the oil extraction was carried by Bligh–Dyer Method. The growth performance, biomass productivity and oil productivity of all experiments were observed. These findings indicate that alternate nutrient medium gives better performance than the standard BBM and low nutrients concentration medium showed high oil productivity. Thus the open pond cultivation of microalgae with alternate nutrient medium viz. agriculture fertilizer medium is an efficient cultivation method to produce more biomass and oil.

Analyzing Energy Technologies and Policies Using DOSCOE

Low-carbon electricity technologies are often evaluated by their Levelized Cost of Energy (LCOE). However, LCOE cannot model the impact of one electricity source on the value of others. In previous work, System LCOE was proposed to estimate the costs of integrating an intermittent source into a grid consisting of multiple dispatchable electricity sources. Using a new DOSCOE (Dispatch-optimized system cost of electricity) model, we generalize System LCOE. DOSCOE can handle any mixture of dispatchable and non-dispatchable sources. It can analyze systems which contain storage, have legacy infrastructure, or have imposed policies. DOSCOE thus updates System LCOE to be applicable to more realistic electricity grid models. DOSCOE uses a linear program to find the capacity and generation mix which yields minimum LCOE. Running this linear program multiple times yields System LCOE curves. DOSCOE shows that to cost-effectively remove the last 10-20% of fossil fuels requires a moderate price on carbon and either low-cost nuclear power or carbon capture and sequestration. Alternatively, a hypothetical zero-carbon source needs to have a net present cost less than $2200/kW (with a 100% capacity factor) to displace existing fossil-fuel plants.

Multienergy vector modelling of a Scottish Energy System: Transitions and technology implications

The Scottish Government’s commitment for 100% of electricity consumed in Scotland to be from renewable, zero-carbon sources by 2020 continues to drive change in the energy system alongside European and UK targets. The growth of renewables in Scotland is being seen at many scales including industrial, domestic and community generation. In these latter two cases, a transition from the current ‘top down’ energy distribution system to a newer approach is emerging. The work of this paper will look at a ‘bottom up’ view that sees community led distributed energy at its centre. This paper uses the modelling tool HESA to investigate high penetrations of distributed generation in the Angus Region of Scotland. Installations of distributed generation will follow Thousand Flowers transition pathway trajectory, which sees more than 50% of electricity demand being supplied by distributed generation by 2050. From this, insights around the technological and socio-political feasibility, consequences and implications of high penetrations of distributed generation in the UK energy system are presented. Results demonstrate the influence that system change will have on regional and local emission levels under four separate scenarios. It is shown that the penetration of distributed generation requires supplementary installations of reliable and long-term storage alongside utilisation of transmission and transportation infrastructures to maximise the potential of distributed generation and maximise whole system benefits. Importantly, there must be a level of co-ordination and support to realise a shift to a highly distributed energy future to ensure there is a strong economic case with a reliable policy backing.

Modelling the potential to achieve deep carbon emission cuts in existing UK social housing: The case of Peabody

As part of the UK’s effort to combat climate change, deep cuts in carbon emissions will be required from existing housing over the coming decades. The viability of achieving such emission cuts for the UK social housing sector has been explored through a case study of Peabody, a housing association operating in London. Various approaches to stock refurbishment were modelled for Peabody’s existing stock up to the year 2030, incorporating insulation, communal heating and micro-generation technologies. Outputs were evaluated under four future socio-economic scenarios. The results indicate that the Greater London Authority’s target of a 60% carbon emission cut by 2025 can be achieved if extensive stock refurbishment is coupled with a background of wider societal efforts to reduce carbon emissions. The two key external requirements identified are a significant reduction in the carbon intensity of grid electricity and a stabilisation or reduction in householder demand for energy. A target of achieving zero net carbon emissions across Peabody stock by 2030 can only be achieved if grid electricity becomes available from entirely zero-carbon sources. These results imply that stronger action is needed from both social landlords and Government to enable deep emission cuts to be achieved in UK social housing.

Greenhouse gas reduction benefits and costs of a large-scale transition to hydrogen in the USA

Hydrogen is an energy carrier able to be produced from domestic, zero-carbon sources and consumed by zero-pollution devices. A transition to a hydrogen-based economy could therefore potentially respond to climate, air quality, and energy security concerns. In a hydrogen economy, both mobile and stationary energy needs could be met through the reaction of hydrogen (H 2) with oxygen (O 2). This study applies a full fuel cycle approach to quantify the energy, greenhouse gas emissions (GHGs), and cost implications associated with a large transition to hydrogen in the United States. It explores a national and four metropolitan area transitions in two contrasting policy contexts: a “business-as-usual” (BAU) context with continued reliance on fossil fuels, and a “GHG-constrained” context with policies aimed at reducing greenhouse gas emissions. A transition in either policy context faces serious challenges, foremost among them from the highly inertial investments over the past century or so in technology and infrastructure based on petroleum, natural gas, and coal. A hydrogen transition in the USA could contribute to an effective response to climate change by helping to achieve deep reductions in GHG emissions by mid-century across all sectors of the economy; however, these reductions depend on the use of hydrogen to exploit clean, zero-carbon energy supply options.

Climate Change Policy and Its Effect on Market Power in the Gas Market

The European Emissions Trading Scheme (ETS) limits CO2 emissions from covered sectors, especially electricity (accounting for about 56%). At 44 billion per annum. the ETS is the largestemissionstradingsystemever,40timeslargerthanUSprogrammes.Thearticledemonstrates that fixing the quantity rather than the price of carbon reduces the price elasticity of demand for gas appreciably, amplifying the market power of gas suppliers, and amplifying the impact of gas price increases on the electricity price. A rough estimate using British data suggests that this could increase the Lerner Index by 50%. (JEL: Q54, Q58, L94) The European Union has agreed upon the European Emissions Trading Scheme (ETS) as its principle means of reducing emissions of the main greenhouse gas (GHG), carbon dioxide, CO2. The ETS fixes the quantity of CO2 that can be emitted from the covered sector, and can be contrasted with the alternative (and as argued herein, preferable) policy of taxing or setting a charge for the release of CO2. More than half (56%) of emissions from the covered sector come from the electricity supply industry (ESI; i.e., electricity generation), and in the EU in 2004, 31% of electricity was generated from coal, and 19% from gas. Nuclear, hydro, and renewables—all zero-carbon sources—accounted for 46% of total generation (IEA 2006, p. 507). For the EU-15 the share of gas is higher (at 21%) and of coal lower (at 27%). The zero carbon generation is inelastically supplied over the course of the year, as it has very low variable costs, but coal, which is very carbon-intensive, competes with gas-fired generation, which has half or less of coal’s carbon intensity.