Deep Decarbonization Research Articles

What Do We Know about Zero-Emission Vehicle Mandates?

Many researchers, policymakers, and stakeholders view zero-emissions vehicles (ZEVs) as playing an important role in deep decarbonization of the transport sector. Here, we bring attention to one policy that can effectively induce ZEV sales in the long term: a ZEV sales mandate. Although three decades have passed since the first mandate was implemented in California, there is surprisingly little research regarding its policy impacts. From a greenhouse gas (GHG) mitigation perspective, we argue that ZEV mandates should be framed and analyzed as complex policy-with intended impacts on industry, consumers, and institutions over the long term. We present an interdisciplinary framework to address this complexity, summarizing the limited evidence to date on policy effectiveness, efficiency, public acceptability, and transformative potential. We conclude with a critical research agenda to improve understanding of the role of a mandate in an effective policy mix.

Implications of variations in renewable cost projections for electric sector decarbonization in the United States

SummaryThe costs of wind and solar technologies have dropped rapidly, but unknowns about technological change and emissions policies create uncertainty about future deployment. We compare projections of U.S. wind and solar costs across published studies and use an energy systems model to evaluate how these reductions could alter electric sector planning decisions and costs under deep decarbonization. Model results indicate that wind and solar are the largest generation resources for many scenarios and regions, but shares depend on assumptions about costs, policy targets, and policy timeframes (spanning 14% to 67% of national generation by 2035). Renewables cost reductions lower decarbonization costs and reduce projections for nuclear and carbon-captured-equipped generation, but policy decisions have a larger influence on future trajectories. Lower wind and solar costs have more limited impacts on deployment of carbon removal technologies and the capacity of clean firm technologies in reaching net-zero emissions in the electric sector.

Deep decarbonization of the Indian economy: 2050 prospects for wind, solar, and green hydrogen

SummaryThe paper explores options for a 2050 carbon free energy future for India. Onshore wind and solar sources are projected as the dominant primary contributions to this objective. The analysis envisages an important role for so-called green hydrogen produced by electrolysis fueled by these carbon free energy sources. This hydrogen source can be used to accommodate for the intrinsic variability of wind and solar complementing opportunities for storage of power by batteries and pumped hydro. The green source of hydrogen can be used also to supplant current industrial uses of gray hydrogen produced in the Indian context largely from natural gas with important related emissions of CO2. The paper explores further options for use of green hydrogen to lower emissions from otherwise difficult to abate sectors of both industry and transport. The analysis is applied to identify the least cost options to meet India’s zero carbon future.

Assessing the implications of bioenergy deployment in the EU in deep decarbonization and climate‐neutrality context: a scenario‐based analysis

AbstractBioenergy may take up different roles in the context of greenhouse gas emission reduction in the EU by mid‐century. We discuss the implications of large‐scale bioenergy deployment in the EU within a decarbonization context using the PRIMES biomass supply model to quantify four scenarios, which explore alternative mitigation pathways based on different emission reduction targets (at least 80% emission reduction by 2050 compared to 1990, and net‐zero emissions by 2050), and different mitigation options, including electrification, behavioral changes, and synfuels. The quantitative assessment of these pathways reveals challenges and opportunities related to the development of a large‐scale bioenergy supply system in the EU. The analysis demonstrates that bioenergy provides between 14% and 17% of final energy consumption and 7–9% of electricity generation. Bioenergy commodities such as gaseous bioenergy and advanced biofuels are deployed in all pathways. The market size of solid biomass and advanced biofuels depends on the contribution of alternative mitigation options such as electricity and synfuels, and decarbonization ambitions. Large‐scale bioenergy deployment requires the supply of energy crops, and the availability of additional agricultural land. Alongside technological preparedness, it requires policies that ensure regulatory coherence and proper market design in order to address the needs of a diverse set of actors across sectors, ranging from farmers, technology investors, and distributors to final consumers; this requires market and policy coordination to unlock the bioenergy contribution to decarbonization. © 2022 Society of Chemical Industry and John Wiley & Sons, Ltd.

How price responsive is industrial demand for electricity in the United States?

We use five parametric specifications and monthly data for the lower 48 states in 2001–2019 to document that industrial demand for electricity in the United States (US) is price inelastic, with statistically significant (p-values ≤ 0.05) estimates of − 0.029 to − 0.130 for the static own-price elasticity, − 0.021 to − 0.133 for the short-run own-price elasticity, and − 0.043 to − 0.214 for the long-run own-price elasticity. Absent significant price escalation (e.g., 10% per year), the US industrial customer class’s price-induced conservation of electricity is likely modest, justifying the continued use of energy efficiency standards and demand side management programs to achieve deep decarbonization.

Getting models and modellers to inform deep decarbonization strategies

ABSTRACT An increasing number of countries issue Deep Decarbonization Strategies (DDS). While DDS contents are well analysed, the processes by which they are developed attract less attention. This paper investigates what numerical model(s) are used in these processes, how they are used, and how models, modellers and stakeholders jointly contribute to the production of DDS. It draws lessons from an in-depth analysis of the second French national low-carbon strategy, complemented with insights from the US, Swedish and Brazilian DDS production processes. While configurations differ, DDS processes typically rely on multiple, sometimes overlapping models and involve a broad range of stakeholders. Articulating models together, and through stakeholder consultations, produces both numbers and collectives that share visions of the future – and both are equally important. Setting up and coordinating such assemblages of models and stakeholders requires effort, time, anticipation and resources. The cases presented here highlight the importance of technical, institutional and relational legacies (e.g. prior experience of joint work, hybrid communities), and of political support. We conclude on the importance for policymakers to account for these dimensions when setting up DDS processes and layout avenues for further research. Key policy insights The production of Deep Decarbonization Strategies (DDS) relies on multi-model, multi-stakeholder processes and requires developing models in consultation with stakeholders. These modelling assemblages produce numbers, shared visions and also relationships – all of which are equally important when it comes to elaborating DDS. Such assemblages require time, resources, trial and error, which in turn points to the importance of institutional, relational and technical legacies (e.g. prior experience with and around modelling tools, hybrid communities), as well as of political support, in facilitating this work. DDS elaboration processes constitute a learning experiment and present opportunities for technical and institutional innovation. Policymakers should anticipate and plan for these dimensions when deciding to produce DDS.

Analysis of energy-saving and environmental benefits from power structure adjustment in China: A comparative study from 2020 to 2060

The power industry plays a major role in achieving carbon emission peak and carbon neutrality. China needs a power industry with deep decarbonization and high energy efficiency in the next 40 years. The adjustment of electric power structure mainly contains two parts: (1) The transition of thermal power generation to renewable energy power generation. (2) The transition of low-parameter thermal power generating to high-parameter thermal power generating. Here this paper predicted the total power-generating capacity in the future 40 years using multivariable linear regression and LEAP (Long-range Energy Alternatives Planning System) methods. Afterwards, based on baseline and policy-driven (China's energy and electric power development plan in 2030 and prospect in 2060) scenarios, this study projected the proportions of different power generation technologies/different parameters of thermal power plants using Origin and historical data. This research also used LCI (life cycle inventory) to obtain energy-saving and environmental benefits in the transitions of thermal energy to renewable energy power generation/low-parameter to high-parameter thermal power generating. Results showed that in policy-driven scenario, wind power and photovoltaic power generation will reach 36.5% and 36.9% of total power generation respectively by 2060. Moreover, renewable and new energy power generation will save 5780 million tons standard coal and 14,512 million tons of CO2 emissions by 2060. Super thermal power generation, however, was predicted to expand 1690 billion kWh from 2017 to 2050 for its large environmental benefits but phase out gradually from 2050 to 2060 to achieve Chinese government's “carbon neutrality” goal.

The demand-side resource opportunity for deep grid decarbonization

<h2>Summary</h2> Technological innovations are creating a larger role for demand-side resources in electric grids. The rise of demand-side resources is occurring alongside the efforts to decarbonize grids. The confluence of these two trends has motivated research on the role of demand-side resources in grid decarbonization. Here, we synthesize the demand-side resource literature to develop a coherent and realistic vision for that role. We find that demand-side resources can supplement supply-side approaches to decarbonize grids more quickly and cost effectively. The role of demand-side resources is secondary to that of supply-side resources, and a critical analysis of tradeoffs is required whenever demand-side solutions substitute for supply-side solutions. Nonetheless, our review suggests that demand-side solutions can play a meaningful role, providing around 10%–30% of the resources required for deep decarbonization in domains such as energy, peak capacity, and deployed solar capacity. However, demand-side resources remain underutilized due to several solvable barriers. The urgency imposed by climate change requires that these barriers be addressed to fully realize the demand-side resource opportunity.

Evaluation of the impact of green hydrogen blending scenarios in the Italian gas network: Optimal design and dynamic simulation of operation strategies

Blending hydrogen (H2) produced from PEM electrolysis coupled to Renewable Energy Sources (RES) in the existing Natural Gas (NG) network is a promising option for the deep decarbonization of the gas sector. However, blending H2 with NG significantly affects the thermophysical properties of the gas mixture, changing the gas supply requirements to meet the demand. In this work, different scenarios of green hydrogen blending (Blend Ratio BR equal to 5/10/15/20%vol) are analyzed at the national level with different temporal constraints (hour/day/week/month/year) based on real gas demand data in Italy, addressing both design requirements (RES and PEM electrolyzer capacity) via Linear Programming (LP) and carrying out dynamic simulations of different operational strategies (constant or variable blend). Although H2/NG blending provides a huge opportunity in terms of deployed H2 volume, higher BRs show rapidly increasing design requirements (1.3-1.5 GWe/%vol and 2.5-3 GWe/%vol for PEM electrolyzers and RES capacity, respectively) and a significative increase of the total gas mixture volume (0.83%/%vol) which hinders the CO2 reduction potential (0.37%/%vol). A variable blend operation strategy (allowing a variation of BR within the analyzed period) allows to balance a variable H2 production from RES. Wider temporal constraints imply several beneficial effects such as relaxing design constraints and avoiding the implementation of an external storage. The Levelized Cost Of Hydrogen (LCOH) is preliminarily estimated at around 7.3 $/kg for yearly scenarios (best-case), although shorter temporal constraints entail significant excess hydrogen which would increase the LCOH if not deployed for other applications.

Shedding light on the efforts into the rehabilitation of a major culprit of carbon emissions: A scientometric analysis of net-zero in the built environment sector

Recent global commitments towards net-zero 2050 have resulted in an increased interest within a number of industries. The built environment has been identified as a major culprit contributing to the ongoing complex problem of carbon emissions. In an attempt to reveal the efforts, put into alleviating this challenge, this paper aims to provide a comprehensive, quantitative analysis of the literature on net-zero (energy and GHG emissions) in the built environment over the last two decades. In this study, well-established bibliometric and scientometric techniques are deployed to map the scientific domains by developing and analysing the resulting co-citation and keyword co-occurrence network developed from the bibliometric data from 1934 peer-reviewed articles retrieved from the SCOPUS database.The most significant contributions in net-zero research have originated primarily from UK, USA, and China. The results of the network analysis identified seven foundational themes of research - greenhouse gas emission, deep decarbonisation, earth material, residential building, high-rise building, displacement, ventilation, and walling element. The burst analysis revealed how a number of emerging digital technologies in the sector present opportunities to optimise future developments towards the attainment of a net-zero emission-built environment. To address the complexity associated with emissions caused by the built environment, the findings suggest that there is a need to expand the current LCA assessments to a broader, industry-wide scale, beyond the predominant ‘single building case study’ as the unit of reference. Moreover, the national net-zero pathway studies should aim to extend beyond the operational emission scenarios, and into assessing the impacts on materials and embedded emissions, which has grown exponentially.

Addressing Knowledge Gaps for Global Climate Justice

The Conference of Parties (COP) 26 highlighted the need for global-level deep decarbonization and provided financial instruments to aid climate mitigation in the global south, as well as compensation avenues for loss and damage. This narrative reiterated the urgency of addressing climate change, as well as aiding advances in green products and green solutions whilst shifting a portion of responsibility upon the global south. While this is much needed, we argue that the science rhetoric driving this initiative continues to be advantageous to the global north due to their capacity to control consumption gaps and to access human knowledge and resource extraction. If not addressed, this will reinforce a continuing unjust north/south narrative, highlighting neo-climate colonialism precepts.

Multiscale simulation of integrated energy system and electricity market interactions

Accelerating the deep decarbonization of the world’s electric grids requires the coordination of complex energy systems and infrastructures across timescales from seconds to decades. In this paper, we present a new multiscale simulation framework that integrates process- and grid-centric modeling paradigms to better design, operate, and control integrated energy systems (IESs), which combine multiple technologies, in wholesale energy markets. Traditionally, IESs are analyzed with a process-centric paradigm such as levelized cost of electricity (LCOE) or annualized net revenue, ignoring important interactions with electricity markets. This framework explicitly models the complex interactions between an IES’s bidding, scheduling, and control decisions and the energy market’s clearing and settlement processes, while incorporating operational uncertainties. Through two case studies, we show the importance of understanding and quantifying complex resource-grid interactions. In case study 1, we demonstrate that optimized bidding from one resource shifts the profit distribution for all energy systems in the market. This result suggests new and more flexible IES technologies can disrupt the economics of all market participants, possibly leading to accelerated retirements of less flexible resources. Interestingly, the optimized bidding has little impact on grid-level aggregate statistics, such as total generation costs and renewable penetration rate. While aggregate modeling strategies may remain valid under some IES adoption scenarios for analysis focused on regional outcomes, direct comparisons of IES technologies at specific locations without considering these interactions may lead to misleading or incorrect conclusions. In case study 2, we consider the design and flexible operation of IESs that hybridize conventional generators with energy storage. Through a sensitivity analysis, we find that as the size of the storage system increases, the total number of start-ups for coal- and natural gas-based IESs reduced by 25% and 33.6%, and the total thermal generator ramping (i.e., mileage) reduced by 86.5% and 62.5%, respectively. This shows the primary benefit of storage may not be reduced operational costs (which do not change significantly) but fewer start-ups and less ramping, which may greatly simplify the design, operation, and control of carbon capture systems. The new modeling and optimization capabilities from this work enable the coupling of rigorous, dynamic process models with grid-level production cost models to quantitatively identify the nuanced interdependencies across these vast timescales that must be addressed to realize clean, safe, and secure energy production. Moreover, the proposed general multiscale simulation framework is applicable to all IES technologies and can be easily extended to consider other energy carriers (e.g., hydrogen, ammonia) and energy infrastructures (e.g., natural gas pipelines).

Luminescence imaging of solar modules in full sunlight using ultranarrow bandpass filters

AbstractPhotovoltaic (PV) electricity generation is the fastest growing energy source globally and also humanity's best opportunity to achieve the urgently required deep decarbonisation of the energy sector. As PV enters the terawatt scale, with millions of modules in a single PV power plant, quality testing of installed PV modules becomes indispensable to guarantee PV as a reliable long‐term source of electricity. We present a method that extends the use of photoluminescence (PL) imaging to field‐deployed solar modules in full sunlight. The method takes advantage of sunlight absorption in the Earth's atmosphere in a narrow spectral range around 1,135‐nm wavelength and recent developments in ultranarrow bandpass optical filter technology. The technical principles and experimental data are provided. This method lays the foundations for PL imaging, a powerful inspection method for the PV industry and research, to be applied to routine high‐volume inspection of fielded PV modules on large‐scale solar power plants.

Life‐cycle greenhouse gas emissions reduction potential for corn ethanol refining in the USA

AbstractThis study evaluates how low‐carbon production technologies applicable to ethanol plants may reduce the life‐cycle greenhouse gas emission (GHG) intensities of corn ethanol production in the USA. Results indicate that options focusing on incremental energy efficiency (e.g., combined heat and power) and yield improvements have a limited impact on GHG reductions. To achieve deep decarbonization (&gt;50% GHG reduction compared to current corn ethanol production), a fuel switch from natural gas (NG) to alternative low‐carbon fuels is needed. Replacing 50% of NG demand at ethanol plants with syngas from biomass through gasification or renewable natural gas from animal waste could achieve significant GHG reductions (11.7–23.5 g CO2e/MJ ethanol). Adding multiple technologies, including carbon capture and storage, to existing ethanol plants may further reduce GHG emissions to −18.4 g CO2e MJ−1 ethanol (including land‐use change emissions), which is 120% lower than the carbon intensity of pure gasoline. These results could inform how the ethanol industry could move toward net‐zero ethanol production. © 2022 UChicago Argonne, LLC, Operation of Argonne National Laboratory. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley &amp; Sons Ltd.

Exploring pathways to deep de-carbonization and the associated environmental impact in China’s ammonia industry

China is the largest producer of synthetic ammonia, accounting for one-third of the world’s total production. Ammonia is mainly used to produce fertilizer and is also considered as a potential fuel and new energy carrier for the future. Concomitantly, the ammonia industry is the largest energy consumer and CO2 emitter in China’s chemical industry. In this study, we developed the MESSAGEix-ammonia model with detailed process descriptions to evaluate the energy-saving and emission reduction potential that can be generated by energy efficiency (EE) improvement, as well as the transition path and emission characteristics in the context of deep emission reduction. Results show that the cost-effective EE measures implemented under the EE scenario could reduce fresh water, fuel coal, and electricity consumptions by 7%, 25%, and 16%, as well as reduce CO2, PM2.5, SO2, and NOx emissions by 33%, 24%, 24%, and 24%, respectively, by 2060. Regarding the exploration of the deep de-carbonization path, carbon capture and storage technology (CCS) increases the CO2 reduction potential to 62%, but it requires additional electricity. Meanwhile, electrolysis technology not only saves additional fresh water and fuel coal, but also reduces CO2, PM2.5, SO2, and NOx by 80%, 84%, 86%, and 84%, respectively. Furthermore, the integration of electrolysis technology and CCS can bring 98% carbon emission reduction, which is close to net-zero emission status. With the development of renewable electricity, sufficient, clean, and affordable electricity can be provided for electrolysis devices. Our recommendation to policy makers is that electrolysis of water to produce ammonia using renewable electricity is a feasible deep de-carbonization pathway.

Research on hydrogen energy storage capacity model based on Genetic Algorithm in new power system

In order to promote China’s energy revolution and realize China’s energy transformation, green and low-carbon energy development and comprehensive green transformation of economic and social development are the keys. Among them, the development of hydrogen energy has great influence and significance on energy saving, emission reduction, deep decarbonization and improvement of utilization efficiency. For the power industry, it is necessary to build a new power system with new energy as the main body. Under this system, this paper establishes a hydrogen energy storage planning model by studying the application scenarios of new energy sources, and uses genetic algorithm to solve it. Finally, a case study proves the rationality of this planning model for hydrogen energy storage planning research, and provides theoretical support and decision-making basis for large-scale investment and operation of similar systems in the future.

Life cycle greenhouse gas emissions and energy footprints of utility-scale solar energy systems

Grid-connected utility-scale solar PV has emerged as a potential pathway to ensure deep decarbonization of electricity in regions with fossil fuel-dominated energy mixes. Research on utility-scale solar PV projects mainly focuses on assessing technical or economic feasibility. Environmental performance assessments of large-scale solar applications are scarce. There is limited information on the greenhouse gas (GHG) emissions and energy footprints of utility-scale solar energy systems. Earlier studies conducted on small-scale solar systems have limited application in the grid system. We developed a comprehensive bottom-up life cycle assessment model to evaluate the life cycle GHG emissions and energy profiles of utility-scale solar photovoltaic (PV) system with lithium-ion battery storage to provide a consistent electricity supply to the grid with peak load options. We conducted a case study for a fossil fuel-based energy jurisdiction, Alberta (a western province in Canada). The results of the energy assessment show that raw material extraction, production, and assembly of solar panels are the key drivers, accounting for 53% of the total consumption. Energy consumed during battery manufacturing is responsible for 28%. The system shows a net energy production with a mean net energy ratio as high as 6.6 for two-axis sun tracking orientation. The life cycle GHG emissions range from 98.3 to 149.3 g CO2 eq /kWh with a mean value of 123.8 g CO2 eq /kWh. The largest emissions contribution is due to the manufacturing of batteries, 54% of the total emissions. The solar PV system offers a mean energy payback time of 3.8 years (with a range of 3.3 to 4.2 years). The results are highly sensitive to the expected lifetime of the system, the panel’s peak wattage, and process energy consumption at various life cycle stages.

The economic competitiveness of flexibility options: A model study of the European energy transition

The European energy transition towards renewable energy is increasingly ambitious and climate targets have been reinforced. Options to increase the flexibility of the energy system are expected to become more valuable with higher shares of variable renewable energy. This paper analyzes the economic benefits of key flexibility options in the Northern, Western and Central European energy system under six increasingly ambitious climate targets towards 2030. The value of and competition between flexibility options is investigated by comparing total system costs and profits. The BALMOREL energy system modeling framework is applied, minimizing system costs. The study results show the increasing value of all flexibility measures with increasingly ambitious climate targets. Demand side management has a large impact on system costs when climate targets are low, while sector coupling with the district heat sector and interconnector investments have an increasing impact with more ambitious climate targets. Biomass is essential for achieving deep decarbonization.

Electricity systems in the limit of free solar photovoltaics and continent-scale transmission

SummarySolar photovoltaics, with sufficient power generation potential, low-carbon footprint, and rapidly declining costs, could supplant fossil fuels and help produce lower-cost net-zero emissions energy systems. Here we used an idealized linear optimization model, including free lossless transmission, to study the response of electricity systems to increasing prescribed amounts of solar power. Our results show that there are initially great benefits when providing solar power to the system, especially under deep decarbonization scenarios. The marginal value of additional solar power decreases substantially with increasing cumulative solar capacities. At costs near today’s levels, the modeled zero-emission electricity system with free solar generation equaling twice the annual mean demand is more costly than a carbon-emitting natural-gas-based system supplying the same electricity demand with no solar. Taking full advantage of low-cost solar will depend on developing and deploying low-cost approaches to temporally shift either energy supply (e.g., storage) or electricity loads (e.g., load-shifting).

Technology, technology, technology: An integrated assessment of deep decarbonization pathways for the Canadian oil sands

As a party to the Paris Agreement, Canada has an ambitious climate target of net-zero emissions by 2050. The country also holds the world's third largest oil reserves in the Alberta oil sands. Given increasing emissions from the oil sands sector, achieving Canada's net-zero target requires significant oil sands decarbonization. If, while phasing out fossil fuels, there is still a demand for Canadian oil sands, then the decarbonization of the resource production process becomes crucial. In this study, we use an enhanced version of the Global Change Analysis Model (GCAM) with a detailed unconventional oil sector for Canada, including mining and in situ resources. We ask, what is the future of the oil sands sector in deeply decarbonized global and Canadian economies? We address this question under four mitigation scenarios with varying global net-zero GHG emissions constraints, three additional representative lower carbon extraction technologies available for the oil sands sector, as well as global direct air capture (DAC) deployment. We find that lower carbon technology deployment allows a 20%–44% increase in oil sands production by 2050 for scenarios with net-zero GHG emissions in 2100 or 2075. DAC helps maintain oil sands production in the most ambitious global decarbonization scenario (net-zero GHG by 2050), without which low international oil demand makes Canadian oil sands production uncompetitive. Canadian oil sands production thus depends highly on the availability of lower carbon extraction technologies and international oil demand, which to a certain extent relies on the availability and global deployment of negative emissions technologies.