Gas-fired Generation Research Articles

The early retirement challenge for fossil fuel power plants in deep decarbonisation scenarios

Rapid decarbonisation of the global energy sector will likely have a multitude of economic consequences, including the premature decommissioning of most fossil fuel power plants. In this analysis, we examine the impact of early retirements for oil, coal, and natural gas-fired generators required to follow a given 2 °C emissions trajectory (the IEA 2DS) and explore the policy implications surrounding this challenge. Modelling the period up to 2060, the drop in retirement age required to meet this scenario potentially creates $541 billion worth of stranded power plant assets across the US, EU, China, and India alone. In some cases, coal plants built within the past 5 years will need to be retired after only half the nominal operating lifetime. Regional analysis exposed disproportionate impacts in China and India, shouldering the vast majority of the costs and amplifying concerns over energy access and affordability. Policies such as burden-sharing for equitable mitigation, investment into CCS technology, and international financial compensation are discussed as potential avenues for mitigating this impact. However, limitations in all avenues highlight the need for further consideration of the inferred requirement to force early retirements, in order to avoid exacerbating regional imbalances and improve the feasibility of imposed targets.

Coordinated Expansion Planning of Natural Gas and Electric Power Systems

The interdependence between natural gas and electric power systems is becoming increasingly tight, as the share of natural gas-fired units increases. Within this context, this paper addresses the coordinated expansion planning of natural gas and power systems. We analyze the tradeoff of building natural gas-related facilities (e.g., natural gas pipelines and natural gas-fired generation units) versus electric-power-related facilities (e.g., transmission lines and other generation units). We use a two-stage stochastic optimization model that provides an appropriate balance between accuracy and computational tractability and represents uncertainty pertaining to electricity and natural gas demands. We show the importance of representing uncertainty by computing the value of stochastic solution, which is significant. We analyze the functioning of the model through a small example and a case study based on the IEEE 118-bus system. Computational results confirm the need for detailed representation of both the natural gas and power systems to achieve investment decisions that are well coordinated and optimal.

Gas-Constrained Secure Reserve Allocation With Large Renewable Penetration

Gas-fired generation provides flexibility to the power system for peak-load shaving and reserve allocation. Large penetration of renewables strengthens the gas-electric coupling. Consequently, constraints to the operations of the high-pressure gas transmission system may endanger the security of power supply. To address this issue, we assess the impact of gas constraints on the day-ahead electric power and reserve scheduling. Furthermore, we investigate the effect of unforeseen, large negative ramps of wind power generation on the gas network operations. The day-ahead scheduling of electric generator dispatch and reserves is determined via a stochastic, N-1 secure optimization. Minimum-pressure constraints update the scheduling of electric generators and reserves. The simplified energy infrastructure of Great Britain in the 2030 Gone Green scenario is investigated for diverse gas load and wind availability conditions. Results show that large gas demands decrease linepack and cause gas-fired units to shut down due to minimum pressure violations. In scarce-wind conditions, gas network limitations largely affect reserve scheduling and nonelectric gas curtailments are needed to comply with pressure safety margins. Conversely, reserve planning including gas constraints prevents pressure violations caused by unexpected wind fluctuations. These results support operators and regulators by providing a technoeconomical evaluation of the gas-electric interdependencies.

The heterogeneous impacts of low natural gas prices on consumers and the environment

We show that low natural gas prices increase gas-fired electricity generation, reduce coal-fired electricity generation, and reduce wholesale electricity prices. However, not all regions experience the same degree of coal-to-gas generation switching or electricity price declines. Specifically, regions experiencing more coal-to-gas switching experience smaller electricity price drops. We provide intuition that may explain this pattern. This finding also has environmental and welfare consequences: coal-fired plants emit more pollutants, and therefore regions that benefit more from greater emissions reductions experience lower benefits from declining electricity prices. The finding highlights a mechanism through which a carbon price would have heterogeneous impacts across regions.

Fuel prices, restructuring, and natural gas plant operations

Switching from coal-fired to natural gas-fired generation and increasing the thermal efficiency (energy generated per unit of energy burned) of fossil fuel fired electricity generation plants have been identified as ways of achieving meaningful emission reductions. In this study, we examine the fuel-price responsiveness across gas plant technologies and across the market structures in which the plants operate. We find that there are significant differences in the generation and efficiency responses of gas plants to fuel prices across generation technologies and market structures. Specifically, our results indicate that, regardless of market structure, generation from natural gas combined cycle (NGCC) plants is responsive to both coal and gas prices, but that generation from simple cycle (NGSC) plants only respond to gas prices. On the other hand, with respect to efficiency, we generally find that only NGCC plants operating in deregulated regions show statistically significant efficiency improvements in response to coal price increases and that, generally, neither NGCC or NGSC plants, regardless of market structure, respond in any significant way to gas prices. Finally, using these parameter estimates, we calculate emissions savings from efficiency improvements and fuel-switching possibilities.

Design, Evaluation and Implementation of an Islanding Detection Method for a Micro-grid

Correct and fast detection of a micro-grid (MG) islanding is essential to the MG since operation, control, and protection of the MG depend on its operating mode i.e., an interconnected mode or islanding mode. This study describes the design, evaluation and implementation of an islanding detection method for an MG, which includes a natural gas-fired generator, a doubly fed induction generator type wind generator, a photovoltaic generator, and some associated local loads. The proposed method is based on the instantaneous active and reactive powers at the point of common coupling (PCC) of the MG. During the islanding mode, the instantaneous active and reactive powers at the PCC are constants, which depend on the voltage of the PCC and the impedance of the dedicated line. The performance of the proposed method is verified under various scenarios including islanding conditions for the different outputs of the MG, and fault conditions by varying the position, type, inception angle and resistance of the fault, using the PSCAD/EMTDC simulator. This paper also concludes by implementing proposed method into a TMS320C6701 digital signal processor. The results indicate that the proposed method successfully detects islanding for the MG in islanding conditions, and remains stable in fault conditions.

Optimising energy sourcing and consumption in the oil and gas sector

Oil and gas companies are fairly large users of electricity, and the rising cost of electricity has become a major issue for the sector. Oil and gas producers often develop their own gas-fired generation plants and consume their own gas as generation fuel. An increasing price of gas in the domestic market has resulted in a corresponding increase in the opportunity cost of utilising gas for power generation. Declining costs of renewable energy and battery storage open opportunities for oil and gas companies to reduce the consumption of their own gas and source electricity at a lower cost, as well as achieve their sustainability objectives. Gas-fired generation is expected to continue to play a key role in ensuring the reliability of electricity supply. However, the percentage of renewable energy in the supply mix can be increased significantly without compromising the reliability. This paper will focus on the opportunities that exist for oil and gas companies to reduce their overall energy supply costs through a differentiated approach considering renewable energy sources and batteries, competitive tendering of energy supply requirements, and attracting capital from independent power producers and institutional investors. The paper will draw on lessons learnt from other energy intensive businesses in Australia.

Carbon dioxide emissions effects of grid-scale electricity storage in a decarbonizing power system

While grid-scale electricity storage (hereafter ‘storage’) could be crucial for deeply decarbonizing the electric power system, it would increase carbon dioxide (CO2) emissions in current systems across the United States. To better understand how storage transitions from increasing to decreasing system CO2 emissions, we quantify the effect of storage on operational CO2 emissions as a power system decarbonizes under a moderate and strong CO2 emission reduction target through 2045. Under each target, we compare the effect of storage on CO2 emissions when storage participates in only energy, only reserve, and energy and reserve markets. We conduct our study in the Electricity Reliability Council of Texas (ERCOT) system and use a capacity expansion model to forecast generator fleet changes and a unit commitment and economic dispatch model to quantify system CO2 emissions with and without storage. We find that storage would increase CO2 emissions in the current ERCOT system, but would decrease CO2 emissions in 2025 through 2045 under both decarbonization targets. Storage reduces CO2 emissions primarily by enabling gas-fired generation to displace coal-fired generation, but also by reducing wind and solar curtailment. We further find that the market in which storage participates drives large differences in the magnitude, but not the direction, of the effect of storage on CO2 emissions.

Impact of “ultra low emission” technology of coal-fired power on PM2.5 pollution in the Jing-Jin-Ji Region

In response to severe haze pollution, the Chinese government has announced a series of policies focusing on controlling emissions from coal consumption. “Ultra-low emission” (ULE) technologies have the potential to dramatically reduce emissions from coalfired power plants, and have been deployed at some facilities in recent years. This paper estimated the potential environmental benefits of the widespread adoption of ULE in the Jing-Jin-Ji Region. Atmospheric modeling scenarios were analyzed for three cases: a “standard” scenario assuming no ULE deployment, a “best case” scenario assuming complete adoption of ULE across all power plants in the region, and a “natural gas” scenario, assuming emissions factors consistent with natural gas-fired power generation. The simulations show that the widespread adoption of ULE technologies can be an effective and economically competitive option for reducing the impacts of coal-fired power generation on air quality.

Managing Your Carbon Footprint: Impacts and Opportunities Arising From Alberta’s Climate Change Legislation

This article explores Alberta’s climate change policies and laws in conjunction with parallel federal climate change measures. The authors provide an overview of the existing regulatory structure applicable to industrial carbon emissions, and an evaluation of the recent evolution of the regulatory structure. The comprehensive regulatory structure as a whole is then analyzed for its practical impacts across industries, and the authors identify a number of strategies for oil and gas producers, natural gas-fired electricity generators, renewable power project developers, and public entities to manage their performance within the new Alberta governance model for climate change management.

Market equilibrium analysis with high penetration of renewables and gas-fired generation: An empirical case of the Beijing-Tianjin-Tangshan power system

Facing stricter energy policies, the power mix in China is experiencing significant changes. First, the proportion of renewables, which have intermittent and stochastic generation, is assumed to be rapidly increasing. Thus, there is an increasing requirement to install more flexible generation capacity in the power system. According to the Chinese government’s energy planning, in the near future, the proportion of gas-fired units will be greatly promoted to add flexibility to the power system. The impacts incurred by developing a high proportion of both renewables and gas-fired generation on the power market should be formulated and analyzed. In this study, a modified Nash-Cournot equilibrium model is proposed, considering renewable curtailment situations during valley times. Then, a large-scale and multi-period unit commitment model that considers the combined heat and power characteristics is presented to simulate market behaviors. On this basis, an empirical analysis of the Beijing-Tianjin-Tangshan power system equilibrium is illustrated as numerical examples, presenting the influences of the changing power mix on electricity prices, renewable energy integration, carbon emissions and air pollutant emissions. Finally, some suggestions on future electrical and environmental policies are presented.

Valuation of power plants

In this paper we develop continuous-time stochastic control models for valuation and operation of three stylised types of power plants in an electricity market: a renewable plant, a conventional plant and a storage plant. Examples of these types of power plants are respectively wind turbines, gas-fired generation units and hydroelectric facilities. We demonstrate how to derive analytical or quasi-analytical solutions in spite of many details in modeling. In particular, we model uncertainty in electricity prices and in production input/output when it is relevant for the technology considered. Input/output is assumed to follow a diffusion process, whereas the price process may include jumps. Our models account for special characteristics of the technologies, including a non-Normal distribution of wind speeds as well as start-up and shut-down costs of thermal units. We use our models to assess the impact of conjectured future market conditions such as increasing average price level, price volatility and correlation between renewable production and electricity prices.

Investment optimization path of NG power generation in China based on carbon value realization and market linkage

Basedonrealoptionstheory, this paper builds a model for analysing Chinese NG (Natural gas) power generation costs, cost reduced due to the substitution of original thermal power generation with NG power generation and the carbon value in this process. This study presents a mathematical representation of the cost savings of NG. It is the first model to introduce market linkage mechanism in order to discuss the problems with the analyses of the costs of China’s NG power generation. On the basis of considering many uncertain factors, this article attempts to unravel the market linkage effect based on the model analyses with and without the consideration of market linkage mechanism, as well as the impact analyses of the cost-savings in NG power generation project. From the perspective of power generation businesses, the paper model and analyse cost reduced brought by the substitution of original thermal power generation with NG power generation and the carbon value. Government subsidies and carbon values are added to the simulation section. The article provides the change curves of NG power generation, thermal power generation and carbon prices under random paths through path simulation and compares multiple uncertain factors under a single path. Five scenarios are proposed with different assumptions and the results indicate that the market linkage of nature gas price can help to decrease the cost of nature gas-fired power generation. Furthermore, it addresses the scenario of obtaining government subsidies to reduce the cost of NG power generation when carbon value exists. The conclusions of the study will help power companies assess the value of natural gas power generation projects and help them decide whether to invest in the project.

An Equivalent Model of Gas Networks for Dynamic Analysis of Gas-Electricity Systems

The increasing coupling between natural gas and electricity systems by gas-fired generation units brings new challenges to system analysis, such as pressure variations due to consumption perturbations of generation units. The emerging issues require revolutionary modeling and analysis techniques. This paper proposes a novel model to quantify gas pressure variations due to gas-fired power unit ramping and the impact of constraints from natural gas pressure change on ramp rates of gas-fired plants. By utilizing Laplace transform to resolve the governing equations of gas networks, the proposed model can significantly reduce modeling complexity and computational burden. The dynamic behaviors in time scale in s-domain and spatial partial differential equations are transformed into finite difference equations. By introducing the concept of transfer matrices, the relation between states at each node of gas systems can be expressed by transfer parameter matrices. Additionally, a simplified model is introduced to simply the analysis. The explicit expressions of nodal pressure variations in response to demand change are very convenient for analyzing system dynamic performance under disturbances, identifying the most influential factors. The new models are extensively demonstrated on three natural gas networks and benchmarked with traditional simulation approaches. Results illustrate that they produce very close results with the simulation approach, particularly when gas pipelines are long and enter steady states.

A real option assessment of flexibilities in the integrated planning of natural gas distribution network and distributed natural gas-fired power generations

There is an increasing integration of distributed natural gas-fired electric power generations across the globe. The natural gas-fired power generators are dependent on the availability of reliable natural gas distribution systems. This interdependency coupled with the scalability of the natural gas-fired distributed power generators presents the management of an energy utility with real options to execute, delay or abandon long-term expansion plans based on new realities of electric power demand. A real options analysis of these flexibilities is carried out in this paper. The assessment of these options includes the identification and valuation of the identified options. The value of flexibilities and options is illustrated by assessing the options to implement, delay or abandon expansion plans in the presence of uncertain electric power demand on 9 and 33 bus electricity distribution systems.

Modeling constraints to distributed generation solar photovoltaic capacity installation in the US Midwest

This paper presents a model for estimating the amount of distributed generation solar photovoltaics (DGPV) that can be accommodated by an electrical system, limited by the ability of existing generation infrastructure to change output. The model is applied to a region of seven states in the U.S. Midwest, showing the potential for temporary curtailment of installed DGPV to mitigate those constraints, and the associated reductions in coal- and natural gas-fired electricity generation. Scenarios considered are those under which 100%, 99.5%, and 95% of available solar can be utilized, and the point at which DGPV curtailment can no longer mitigate constraints because of the inability of conventional generation to keep pace as solar output declines in the late afternoon.The model is developed using historical hourly fuel use data for electricity generation, hourly solar capacity factor, and carbon emissions factors. The model includes a generalized linear model, constructed by regression analysis, used to allocate potential reductions in conventional generation in response to demand changes caused by DGPV. Limits on output and ramping of conventional generation are considered and initially mitigated, where possible, by changes in hydroelectric generation.Results indicate that a substantial amount of DGPV can be accommodated without any changes to current generation infrastructure, and that small amounts of curtailment enable greater DGPV capacity and generation. In a scenario without curtailment, DGPV could provide about 6% of total generation in the modeled region. With just 0.5% curtailment at DGPV installations, roughly 9% of generation could be provided by DGPV. Ultimately, up to 14% of generation could be achieved through DGPV installation before technological limitations would diminish the ability to meet all demand with further increased DGPV.

Air quality impacts of projections of natural gas-fired distributed generation

This study assesses the potential impacts on emissions and air quality from the increased adoption of natural gas-fired distributed generation of electricity (DG), including displacement of power from central power generation, in the contiguous United States. The study includes four major tasks: (1) modeling of distributed generation market penetration; (2) modeling of central power generation systems; (3) modeling of spatially and temporally resolved emissions; and (4) photochemical grid modeling to evaluate the potential air quality impacts of increased DG penetration, which includes both power-only DG and combined heat and power (CHP) units, for 2030. Low and high DG penetration scenarios estimate the largest penetration of future DG units in three regions – New England, New York, and California. Projections of DG penetration in the contiguous United States estimate 6.3 GW and 24 GW of market adoption in 2030 for the low DG penetration and high DG penetration scenarios, respectively. High DG penetration (all of which is natural gas-fired) serves to offset 8 GW of new natural gas combined cycle (NGCC) units, and 19 GW of solar photovoltaic (PV) installations by 2030. In all scenarios, air quality in the central United States and the northwest remains unaffected as there is little to no DG penetration in those states. California and several states in the northeast are the most impacted by emissions from DG units. Peak increases in maximum daily 8-h average ozone concentrations exceed 5 ppb, which may impede attainment of ambient air quality standards. Overall, air quality impacts from DG vary greatly based on meteorological conditions, proximity to emissions sources, the number and type of DG installations, and the emissions factors used for DG units.

Implications of Gas Infrastructure in Integrated Community Energy Systems

Integrated community energy systems have attracted considerable attention due to their capabilities in supporting distributed generation integration and providing various energy services to customers. However, the rising use of gas-fired generations at the community level is pushing the gas distribution network to its operational boundaries and preventing its further applications. This paper investigates the dynamic interactions and mutual dependence between community energy systems and the gas network through an integrated energy system model. The model incorporates the dynamic behaviors of the gas network, distributed generations and the relevant energy management system. Based on this model, disturbance propagations between the gas network and communities are analyzed from the viewpoint of energy exchanges. Numerical results demonstrate that the change of loads and solar panel outputs can cause large pressure drops of the gas network when microturbines are set to compensate for these variations, and the pressure drop can affect the operation of other gas-fired equipment in surrounding areas. The results also show that different communities can influence each other through the gas network, which indicates some coordination is required in order to restrain adverse interactions as well as their impacts on the gas network.

The effects of variable renewable electricity on energy efficiency and full load hours of fossil-fired power plants in the European Union

This study focused on the effects of variable renewable electricity (VRE) on full load hours and energy efficiency of fossil-fired power generation in the European Union from 1990-2014. Member states were aggregated into three groups based on the level of VRE penetration. Average full load hours are found to be decreasing since 2006 for all groups. The decrease is most in the group with the highest VRE penetration level with a 53% decline from 2005 to 2014 (while VRE penetration increased from 8% to 25%). For VRE-medium the decrease was 34% from 2007 to 2014 (while VRE increased from 3% to 13%) and for VRE-low 32% (with 1% to 5% VRE penetration increase). Both the financial crisis and the share of VRE show strong correlations with full load hours. Both can explain the developments for VRE-high. For VRE-medium no significant relation with the recession was found and for VRE-low both factors were not significant. For energy efficiency, the commissioning year shows a strong correlation for natural gas and less for coal. Significant impacts are found for average commissioning year and full load hours on the energy efficiency of natural gas-fired power generation but not for coal.

A chance constrained programming approach to integrated planning of distributed power generation and natural gas network

The growing integration of distributed electric power generators means the reliability of electricity distribution systems will increasingly depend on the reliability of primary energy resources such as natural gas supply for natural gas-fired distributed power generation. This, therefore, necessitates an integrated approach for planning both the electricity and natural gas distribution systems for the purpose of ensuring reliable natural gas supply for electricity generation. We propose a probabilistic planning approach based on the chance constrained programming method for planning these two systems in the presence of uncertain real and reactive power demand. The proposed model minimizes the investment cost of gas-fired generators, natural gas pipeline and the operation cost of the natural gas-fired distributed generators over a long-term planning horizon. The proposed integrated planning approach is used to develop a 10 years long-term plan for 9 and 33 bus distribution systems. The result shows that the integrated planning approach results in a cheaper and more reliable system in comparison with a traditional sequential planning approach.