Power Sector Emissions Research Articles

Effectiveness of climate policies: Carbon pricing vs. subsidizing renewables

Most but not all economists view carbon pricing as most effective to combat carbon emissions, whereas other policies are widely applied and highly debated. We quantify the effectiveness of climate policies in the form of pricing carbon and subsidizing renewable energies for Germany's and Britain's power sectors. While Germany relies on heavy subsidies for renewables but on a weak price for carbon certificates (EUA) from the EU Emission Trading System (ETS), its emissions hardly declined. To underpin the low EUA price, Britain introduced a unilateral tax on power sector emissions, the Carbon Price Support (CPS). Within only five years, carbon emissions declined by 55%. Our results demonstrate that in the power sector, even a modest carbon price (∼€30/tCO2) can induce significant abatement at low costs within a short period as long as “cleaner” gas plants exist to replace “dirty” coal plants. We also find that carbon pricing is superior to subsidizing wind or solar power in these two countries.

Regional disparities in emissions reduction and net trade from renewables

Operational constraints of the power system and inter-regional trade of electricity make it challenging to predetermine the reduction in emissions from the integration of solar and wind power. Using spatially resolved historical data for solar and wind generation, fossil fuel-based generation, emissions and exports, we isolate the impacts of renewable integration for multiple regions spanning the United States. Here we show regional differences for the reduction of carbon dioxide, sulfur dioxide and nitrogen oxides emissions, with a wider range of outcomes for regional wind power. Given the heterogeneity in transmission infrastructure, some regions have limited capacity to increase electricity exports to neighbouring regions. For both solar and wind generation, we identify the regions that retain nearly all of the emissions reductions locally and those that increase net exports, reducing emissions in neighbouring regions. Our results show lower rates of emissions mitigation than previous studies that relied on less-contemporary data or utilized simulated renewable generation. These differences may reflect the longer-term trends in power-sector emissions reductions and the importance of utilizing observed renewable generation data. An analysis of spatially explicit historical data shows notable regional differences in the benefits in reduced emissions from integrating renewable energy across the United States.

Reducing power sector emissions under the 1990 Clean Air Act Amendments: A retrospective on 30 years of program development and implementation

The 1990 Clean Air Act Amendments (CAAA) launched a new era in environmental protection. New provisions created the innovative Acid Rain Program to curtail acid-rain-causing emissions from the electric power sector through an allowance trading program. Success implementing this new type of program led to its expanded use to achieve additional power plant emission reductions in support of the CAAA "Good Neighbor" requirements. As a result, air pollution and its environmental effects have decreased dramatically in the last 30 years. Implementation of power plant regulations under the acid rain and Good Neighbor provisions of the CAAA provides insights into the efficacy of legislative versus regulatory policy and holds valuable lessons for future environmental policy.

The role of shale gas in shaping the U.S. long-run CO2 emissions

The shale gas boom in the U.S. has lowered the U.S. CO2 emissions in recent years mainly through substitution of gas for coal in power generation. Will the shale gas boom reduce the emissions in the long-run as well? To study this, we consider a counterfactual without the shale gas boom based on a general equilibrium modeling for the 2011 U.S. economy. To enhance the power sector modeling, the supply responses of coal-fired and gas-fired generations are calibrated to existing research. We find that if gas prices remain at 2007 levels in 2011, only a model setting that allows very little reduction in electricity demand, reflecting a short-run demand response, generates an increase in economy-wide emissions. For all other cases, the higher gas price under the counterfactual will have a dampening effect on economic activities and consequently lowers economy-wide emissions, even though the power sector emissions may increase due to the gas-to-coal switch. In other words, without any policy intervention, although the shale gas boom could reduce emissions in the short run, it may lead to higher emissions in the long run if the low gas prices persist. Our finding suggests that extrapolating the current decline in emissions due to the shale gas boom to the distant future could be misleading. Instead, if curbing emissions is the goal, rather than depending upon the cheap gas, policies and measures for cutting emissions remain imperative.

Adaptive mechanisms to refund emissions payments

Carbon pricing is often discussed as a means by which to reduce power sector emissions, but typically faces opposition on the grounds that such schemes will increase wholesale electricity prices and have adverse impacts on the wider economy. Consequently, there is renewed focus on emissions pricing initiatives that have muted price impacts, with a Refunded Emissions Payments Scheme one such example. Under this mechanism, collected emissions payments are refunded to generators in proportion to energy output, with the net effect of the scheme resulting in each generator being subject to a net liability per MWh that is proportional to the difference between it’s own emissions intensity and the average emissions intensity of energy produced by regulated plant. A limitation of the scheme is the average emissions intensity of energy produced by regulated plant is only known after energy has been delivered, therefore there is some uncertainty with respect to each generator’s short-run marginal cost at the time of production. The presented framework addresses this issue by developing adaptive recalibration strategies that seek to make these net liabilities explicit. A rule-based updating strategy is developed, along with a highly generalisable model predictive control framework for updating scheme parameters. A case study using an agent-based framework is used to evaluate these mechanisms in the context of Australia’s National Electricity Market, and demonstrates how a policymaker could use such an approach to transparently update scheme parameters, and also accomplish auxiliary economic objectives.

Analyzing California’s framework for estimating greenhouse gas emissions associated with retail electricity sales

Accurately attributing greenhouse gas (GHG) emissions in the electric power sector is critical to measuring progress towards climate policy goals. We evaluate a new methodology adopted by the California Energy Commission to calculate the GHG emissions intensity of retail electricity providers. In the long run, the new regulations better align with the physical nature of grid operation than did past practices, but policymakers should monitor a set of potential challenges as market structures evolve.

Estimating Power Sector Leakage Risks and Provincial Impacts of Canadian Carbon Pricing

Carbon pricing systems have emerged in Canada at provincial and federal levels to reduce CO2 emissions. However, cross-border electricity trade with the U.S. is already extensive, and although Canada is currently a net exporter, policy changes could alter these trade dynamics. Since CO2 emissions are currently unregulated in many U.S. states, there is a concern that this incomplete regulatory coverage will lead to emissions leakage, as electric generation and emissions shift toward these unregulated regions. This paper examines potential power sector emissions leakage and distributional implications across provinces from Canadian carbon pricing. Using an integrated model of electric sector investments and operations with detailed spatial and temporal resolutions, the analysis demonstrates how emissions leakage through trade adjustments can be non-trivial fractions of the intended emissions reductions even in the presence of leakage containment measures. Magnitudes of long-run leakage rates from Canadian carbon pricing depend on market and policy assumptions (e.g., natural gas prices, projected load growth, long-run demand elasticities, timing of future U.S. CO2 policy), ranging from 13% (high gas price scenario with border carbon adjustments) to 76% (lower gas price scenario without antileakage measures), which are higher than reported literature values for national policies. When leakage containment measures are implemented, net emissions and leakage rates decrease, but gross emissions in Canada and policy costs increase. Leakage persists in alternate scenarios with constrained transmission expansion, higher natural gas prices, lower load growth, higher price elasticities of demand, and U.S. adoption of carbon pricing, but leakage rates decrease under these conditions.

A framework for analyzing trade-offs in cost and emissions in power sector

Current electricity markets operate on a cost minimizing objective for power supply. However, countries across the world need to decarbonize their power systems in line with their policy objectives to mitigate climate change. In this context, this paper presents a framework to analyze synergies and trade-offs in cost and emission minimization strategies in the power sector. Emission minimizing objective can reduce emissions from existing fleets having flexibility in electricity supply, regardless of renewable energy capacity additions. This framework can also provide us with win-win strategies for reducing emissions while keeping costs low.An optimization model is developed for case study of India with data of 568 coal and 199 gas thermal units to analyze alternative real time dispatch and operating strategies. The cost and emission optimal supply strategies are compared in terms of power plant operations, emission reductions, and resulting cost of carbon abatement. The results show that 9.8% of carbon dioxide emissions can be reduced with 19% increment in the cost of electricity in emission minimizing strategy with respect to cost minimization. The operations in emission optimal supply strategy require additional 28 million dollars per day. The cost of carbon abatement is 99–129 dollars per tonne.

Numerical modelling of the interaction between geothermal injectate-non condensable gas solutions and greywacke

In response to global warming, it is important to explore alternative disposal technologies for greenhouse gas emissions in the geothermal power sector. One alternative which has received widespread focus is co-injection of non-condensable gases with the waste fluids from geothermal operations.Passarella et al. (2015) simulated the interaction between brine with dissolved CO2 and H2S, and a sample of greywacke in their laboratory. The present work aimed to numerically model the results from the experiment using TOUGHREACT. The goal of this study was to develop numerical simulation techniques to investigate the effects of the reinjection of brine with dissolved NCG. The resulting model provided insights into the geochemical interaction of greywacke with brine-NCG solutions under simulated reservoir conditions. The numerical simulations show that mineral dissolution occurred to a greater degree than precipitation, leading to increased permeability and porosity. It was also observed that the mineral reactive surface areas evolved as mineral dissolution progressed, through etch pit formation. Additionally, flow rate had an impact on the overall reaction rates such that a decrease in injection rate led to a corresponding decrease in reaction rates. Lastly, both experimental data and model outputs indicated that CO2 was minimally sequestered in the simulation, while H2S was clearly captured as pyrite.A similar numerical investigation was conducted on the co-injection of NCG with steam condensates subsequently. The modelling results indicate predominant mineral dissolution, CO2 is expected to be captured as magnesite within the reactor, while H2S is still captured as pyrite.

Linking permit markets multilaterally

We formally study the determinants, magnitude and distribution of efficiency gains generated in multilateral linkages between permit markets. We provide two novel decomposition results for these gains, characterize individual preferences over linking groups and show that our results are largely unaltered with strategic domestic emissions cap selection or when banking and borrowing are allowed. Using the Paris Agreement pledges and power sector emissions data of five countries which all use or considered using both emissions trading and linking, we quantify the efficiency gains. We find that the computed gains can be sizable and are split roughly equally between effort and risk sharing.

Effects of air pollution control measures on air quality improvement in Guangzhou, China

The ambient air quality of Guangzhou in 2016 has significantly improved since Guangzhou and its surrounding cities implemented a series of air pollution control measures from 2014 to 2016. This study not only estimated the effects of meteorology and emission control measures on air quality improvement in Guangzhou but also assessed the contributions of emissions reduction from various sources through the combination of observation data and simulation results from Weather Research and Forecasting - Community Multiscale Air Quality (WRF-CMAQ) modeling system. Results showed that the favorable meteorological conditions in 2016 alleviated the air pollution. Compared to change in meteorology, implementing emission control measures in Guangzhou and surrounding cities was more beneficial for air quality improvement, and it could reduce the concentrations of SO2, NO2, PM2.5, PM10, and O3 by 9.7 μg m−3 (48.4%), 9.2 μg m−3 (17.7%), 7.7 μg m−3 (14.6%), 9.7 μg m−3 (13.4%), and 12.0 μg m−3 (7.7%), respectively. Furthermore, emission control measures that implemented in Guangzhou contributed most to the concentration reduction of SO2, NO2, PM2.5, and PM10 (46.0% for SO2, 15.2% for NO2, 9.4% for PM2.5, and 9.1% for PM10), and it increased O3 concentration by 2.4%. With respect to the individual contributions of source emissions reduction, power sector emissions reduction showed the greatest contribution in reducing the concentrations of SO2, NO2, PM2.5, and PM10 due to the implementation of Ultra-Clean control technology. As for O3 mitigation, VOCs product-related source emissions reduction was most effective, and followed by transportation source emissions reduction, while the reductions of power sector, industrial boiler, and industrial process source might not be as effective. Our findings provide scientific advice for the Guangzhou government to formulate air pollution prevention and control policies in the future.

Study on the biomass-based integrated gasification combined cycle with negative CO2 emissions under different temperatures and pressures

To reduce the carbon emissions in power sector, a biomass-based integrated gasification combined cycle (BIGCC) with oxy-fuel combustion is proposed. The syngas generated from biomass gasification is burned under oxy-fuel atmosphere for power generation, and CO2 in the flue gas is captured by merely cooling. Thus, the negative CO2 emissions are realized considering the carbon neutral character of biomass. The effects of gasification temperature and pressure on syngas composition and system performance are investigated. The results show that rising pressure and temperature lead to lower H2 and CO production, while CO2 and CH4 generation are enhanced with higher pressure and lower temperature. The system efficiency increases with the pressure rise, while it fluctuates with the temperature variation. The optimum temperature and pressure of gasification is 1000 °C and 3.5 MPa. The corresponding energy and exergy efficiency is 35.41% and 31.21%. The thermodynamic analysis is carried out for each subsystem. The energy loss and exergy destruction is 76.2% and 55.4% for gasifier and 21.8% and 31.3% for HRSG. Considering the unavoidable energy and exergy consumption in gasification, the system optimization can be concentrated on HRSG. The efficient power generation and significant carbon emissions reduction are achieved in the proposed system.

Air Quality-Related Health Benefits of Energy Efficiency in the United States.

While it is known that energy efficiency (EE) lowers power sector demand and emissions, study of the air quality and public health impacts of EE has been limited. Here, we quantify the air quality and mortality impacts of a 12% summertime (June, July, and August) reduction in baseload electricity demand. We use the AVoided Emissions and geneRation Tool (AVERT) to simulate plant-level generation and emissions, the Community Multiscale Air Quality (CMAQ) model to simulate air quality, and the Environmental Benefits Mapping and Analysis Program (BenMAP) to quantify mortality impacts. We find EE reduces emissions of NO x by 13.2%, SO2 by 12.6%, and CO2 by 11.6%. On a nationwide, summer average basis, ambient PM2.5 is reduced 0.55% and O3 is reduced 0.45%. Reduced exposure to PM2.5 avoids 300 premature deaths annually (95% CI: 60 to 580) valued at $2.8 billion ($0.13 billion to $9.3 billion), and reduced exposure to O3 averts 175 deaths (101 to 244) valued at $1.6 billion ($0.15 billion to $4.5 billion). This translates into a health savings rate of $0.049/kWh ($0.031/kWh for PM2.5 and $0.018/kWh for O3). These results illustrate the importance of capturing the health benefits of EE and its potential as a strategy to achieve air standards.

Driving forces of provincial-level CO2 emissions in China’s power sector based on LMDI method

As the major energy consumer and carbon emitter, the power sector accounts for 40% of total carbon emissions in China in 2011. Understanding provincial-level driving mechanisms of CO2 emissions in power sector is vital for achieving China’s national carbon emissions reduction targets in 2030. To understand the critical provinces and driving forces of CO2 emissions in power sector, this paper firstly derives seven different driving factors based on the logarithmic mean Divisia index (LMDI) decomposition model. The provincial-level CO2 emissions in thermal power sectors are calculated from 2004 to 2014. Then, we analyze the CO2 emissions growth ratio of each province, provincial-level change rate of contribution and positive or negative contributions of the emission dynamics for each driving force. The main results show that the power sector of Inner Mongolia and Jiangsu contribute a lot to national CO2 emissions. The change of CO2 emissions of power sector is bigger in developing provinces compared to that in developed provinces. Based on provincial the CO2 emissions changes and total amounts, more carbon emission reduction policy should be implanted in Inner Mongolia, Xinjiang, Anhui, Jiangsu and Ningxia. In addition, the economic scale, industrial intensity and energy intensity are the critical driving forces for total carbon emission. By investigating the critical driving forces and their contributions in critical provinces, this paper aims to provide theoretical foundations for decarbonizing power sector.

Support for Emissions Reductions Based on Immediate and Long-term Pollution Exposure in China

Reducing power sector emissions in China is a critical step toward mitigating climate change and lowering health damages from air pollution. We conduct a discrete choice survey (N = 1060) among urban residents from 10 Chinese cities, assessing how individuals compare electricity source, cost, and reduction of emissions related to climate change or air pollution. Using observed air quality data, we also evaluate how pollution levels affect respondents' support for different types of emissions reductions. We find that reductions targeting both climate change and human health benefits have stronger support than those which address only one of the two. Furthermore, respondents in cities with the highest annual concentrations of particulate matter are willing to pay 30% more to clean up the air when compared to individuals living in less polluted cities. The analysis suggests that the public values co-optimizing mitigation policy across climate and health objectives, and that making available information on long-term air quality may encourage sustained support for cleaner energy.

Response of electricity sector air pollution emissions to drought conditions in the western United States

Water is needed for hydroelectric generation and to cool thermoelectric power plants. This dependence on water makes electricity generation vulnerable to droughts. Furthermore, because power sector CO2 emissions amount to approximately one third of total US emissions, droughts could influence the inter-annual variability of state- and national-scale emissions. However, the magnitude of drought-induced changes in power sector emissions is not well understood, especially in the context of climate mitigation policies. Using multivariate linear regressions, we find that droughts are positively correlated to increases in electricity generation from natural gas in California, Idaho, Oregon, and Washington; and from coal in Colorado, Montana, Oregon, Utah, Washington, and Wyoming. Using a statistical model, we estimate that this shift in generation sources led to total increases in regional emissions of 100 Mt of CO2, 45 kt of SO2, and 57 kt of NOx from 2001 to 2015, most of which originated in California, Oregon, Washington, and Wyoming. The CO2 emissions induced by droughts in California, Idaho, Oregon, and Washington amounted to 7%–12% of the total CO2 emissions from their respective power sectors, and the yearly rates were 8%–15% of their respective 2030 yearly targets outlined in the Clean Power Plan (CPP). Although there is uncertainty surrounding the CPP, its targets provide appropriate reference points for climate mitigation goals for the power sector. Given the global importance of hydroelectric and thermoelectric power, our results represent a critical step in quantifying the impact of drought on pollutant emissions from the power sector—and thus on mitigation targets—in other regions of the world.

Getting to Zero Carbon Emissions in the Electric Power Sector

Jesse D. Jenkins is a postdoctoral Environmental Fellow at the Harvard Kennedy School and the Harvard University Center for the Environment. His research harnesses methods from operations research, power systems engineering, and applied economics to improve regulation, policy, and practice in the rapidly evolving electricity sector. He earned a PhD in Engineering Systems (2018) and an SM in Technology & Policy (2014) at the Massachusetts Institute of Technology, where he was also a researcher at the MIT Energy Initiative and a lead author of the Utility of the Future study. Max Luke is a consultant in the energy practice at NERA Economic Consulting where he specializes in economic, regulatory, and legal implications of emerging trends in the electric power sector. He has worked on projects related to network regulation, electricity tariff design, electricity market design, and the impact of emerging technologies on utility business models. He earned an SM in Technology & Policy (2016) at the Massachusetts Institute of Technology, where he was also a researcher at the MIT Energy Initiative and a contributor to the Utility of the Future study. Samuel Thernstrom is Executive Director of the Energy Innovation Reform Project, a nonprofit organization that promotes the development of advanced energy technologies and practices that will improve the affordability, reliability, safety, and security of American energy supplies and our energy economy. He is also a senior fellow at the Center for the National Interest.

A Comparative Analysis of Deep Decarbonisation Scenarios for the European Power System

Emerging literature highlights the essential role played by decarbonised electricity generation in future energy systems consistent with the Paris climate agreement. This analysis is the first to examine the impacts of high levels of renewable energy and negative emissions technologies on exploratory visions of the future EU power system in 2050 in terms of emissions reduction, technical operation and total system costs. In the absence of negative emission technologies significant emission reductions are observed, however, converting 2% of Europe’s installed generation capacity to bioenergy with carbon capture technology enables net-negative power sector emissions while remaining cost-comparable to a counterfactual scenario. Direct air capture increases this further but with associated higher costs. We show for the scenarios examined that net negative emissions technology contribute to power system operations and may be realized without breaching regional sustainable biomass potentials and national CO2 geological storage limits.

Decarbonizing power and transportation at the urban scale: An analysis of the Austin, Texas Community Climate Plan

Despite the growing importance of cities in climate change mitigation, there remains a dearth of rigorous analysis to inform municipal climate policies and mitigation strategies. Our study addresses this gap in the literature. We develop an energy system optimization model for urban-scale decarbonization, and use it to analyze the Community Climate Plan adopted by Austin, Texas. Austin is a valuable testbed for analysis because it is a member of the C40 Cities Climate Leadership Group and its goal of net-zero greenhouse gas emissions by 2050 is particularly ambitious. We find that this policy objective can be achieved at a modest 2.7% increase in net present power and transportation costs relative to business-as-usual. The optimal decarbonization pathway proceeds through two distinct stages, first reducing power sector emissions, then electrifying transportation. Solar PV expands in the long run with or without the climate plan based on favorable cost projections, but the policy causes wind to replace natural gas as a complement to solar PV. Results also highlight the substantial value of intelligently scheduled battery storage operations and electric vehicle charging.

Air-quality-related health impacts from climate change and from adaptation of cooling demand for buildings in the eastern United States: An interdisciplinary modeling study.

BackgroundClimate change negatively impacts human health through heat stress and exposure to worsened air pollution, amongst other pathways. Indoor use of air conditioning can be an effective strategy to reduce heat exposure. However, increased air conditioning use increases emissions of air pollutants from power plants, in turn worsening air quality and human health impacts. We used an interdisciplinary linked model system to quantify the impacts of heat-driven adaptation through building cooling demand on air-quality-related health outcomes in a representative mid-century climate scenario.Methods and findingsWe used a modeling system that included downscaling historical and future climate data with the Weather Research and Forecasting (WRF) model, simulating building electricity demand using the Regional Building Energy Simulation System (RBESS), simulating power sector production and emissions using MyPower, simulating ambient air quality using the Community Multiscale Air Quality (CMAQ) model, and calculating the incidence of adverse health outcomes using the Environmental Benefits Mapping and Analysis Program (BenMAP). We performed simulations for a representative present-day climate scenario and 2 representative mid-century climate scenarios, with and without exacerbated power sector emissions from adaptation in building energy use. We find that by mid-century, climate change alone can increase fine particulate matter (PM2.5) concentrations by 58.6% (2.50 μg/m3) and ozone (O3) by 14.9% (8.06 parts per billion by volume [ppbv]) for the month of July. A larger change is found when comparing the present day to the combined impact of climate change and increased building energy use, where PM2.5 increases 61.1% (2.60 μg/m3) and O3 increases 15.9% (8.64 ppbv). Therefore, 3.8% of the total increase in PM2.5 and 6.7% of the total increase in O3 is attributable to adaptive behavior (extra air conditioning use). Health impacts assessment finds that for a mid-century climate change scenario (with adaptation), annual PM2.5-related adult mortality increases by 13,547 deaths (14 concentration–response functions with mean incidence range of 1,320 to 26,481, approximately US$126 billion cost) and annual O3-related adult mortality increases by 3,514 deaths (3 functions with mean incidence range of 2,175 to 4,920, approximately US$32.5 billion cost), calculated as a 3-month summer estimate based on July modeling. Air conditioning adaptation accounts for 654 (range of 87 to 1,245) of the PM2.5-related deaths (approximately US$6 billion cost, a 4.8% increase above climate change impacts alone) and 315 (range of 198 to 438) of the O3-related deaths (approximately US$3 billion cost, an 8.7% increase above climate change impacts alone). Limitations of this study include modeling only a single month, based on 1 model-year of future climate simulations. As a result, we do not project the future, but rather describe the potential damages from interactions arising between climate, energy use, and air quality.ConclusionsThis study examines the contribution of future air-pollution-related health damages that are caused by the power sector through heat-driven air conditioning adaptation in buildings. Results show that without intervention, approximately 5%–9% of exacerbated air-pollution-related mortality will be due to increases in power sector emissions from heat-driven building electricity demand. This analysis highlights the need for cleaner energy sources, energy efficiency, and energy conservation to meet our growing dependence on building cooling systems and simultaneously mitigate climate change.