Natural Gas Power Research Articles

CCUS: Solving the conundrum of decoupling sustainable economic growth and CO2 emissions

COP-24 left us with the important legacy of a rulebook for putting the Paris Agreement into practice, particularly in terms of measuring and reporting CO2 emissions. However, countries failed to agree voluntary market mechanisms, and more importantly, the imperative of staying below the 1.5°C of the IPCC report. Globally, in 2017 renewable power contributed to 70% of net additions to power generating capacity with estimated 178 gigawatts added.1 New additions to solar capacity were greater than combined additions in coal, natural gas and nuclear power. However, CO2 energy-related emissions increased 1.4%, primarily due to global economic growth of 3.7%. The UK has successfully managed to curb CO2 emissions by 43% compared to 1990 levels, and therefore, making good progress towards the 80% reduction target by 2050.2 This is especially significant considering that during the same period the UK economy grew by over 70% (above the G7 average). So, have we solved the conundrum of decoupling economic growth and CO2 emissions? Decarbonisation of the power sector with a shift from coal to gas is largely responsible for the UK emissions reduction, with 75% reductions since 2012 coming from the power sector. It is clear, though, that further reductions require decarbonisation of other sectors, particularly heat, industry and transport. The UK Spring Statement 2019 introduced the Future Homes Standard, mandating the end of fossil-fuel heating systems in all new houses from 2025, and this has been met with disbelief in the construction sector. There is consensus that meeting the global climate ambitions of the Paris Agreement without jeopardising economic growth requires that we take a holistic approach to decarbonisation, particularly to incentivise decarbonisation of energy intensive industries.3 For example, existing 45Q tax legislation in the United States provides incentives in reducing CO2 emissions to power plants and industrial facilities and offering tax credits of $50 per tonne of CO2 stored and $35 per tonne for CO2 utilised. It is clear also that policy parity is needed across energy technologies.4 The UK has recently set up the Clean Growth Strategy aiming to grow national income, while cutting CO2 emissions.5 The UK CCUS Cost Challenge Taskforce reported that CCUS can play a critical role in reducing emissions across electricity, as well as heating, industry and transport.3 In addition, CCUS can also improve productivity and competitiveness in a future low carbon economy. It is also clear that a ‘no CCS pathway’ would result in a more costly option to achieve the required targets. For example, for the UK to decarbonise electricity without CCS, it would require low-carbon generation to be more than quadrupled between now and 2050. The deployment of CCUS in industrial clusters can help drive lower costs. These clusters are areas with a number of industrial sites (e.g. chemicals, iron/steel, food/drink, cement, refineries etc) and will benefit from sharing infrastructure as well as knowledge. Industrial decarbonisation is key to achieve the 80% reduction target as around 25% of UK emissions come from industry. The UK Industrial Strategy has set out Grand Challenges to maximise the advantages for UK industry from the global shift to clean growth. This includes establishing at least one low-carbon cluster by 2030 and a net-zero carbon industrial cluster by 2040.6 King Coal's abdication is only a partial fix for decarbonisation of the power sector. It will not solve the conundrum of decoupling sustainable economic growth and CO2 emissions. CCUS does! Prof M. Mercedes Maroto-Valer, FRSE, FIChemE, FRSC, FRSA R. Buchan Chair in Sustainable Energy Engineering Director Research Centre for Carbon Solutions (RCCS) Assistant Deputy Principal (Research & Innovation) Heriot-Watt University

Design and operations optimization of membrane-based flexible carbon capture

We develop a modeling and optimization framework to investigate membrane-based carbon capture from a natural gas power plant with flexible electricity output. The model jointly optimizes the design and time-varying operations of the power generation and membrane capture system to maximize net present value. We apply the optimization framework to a 400 MW natural gas combined cycle and a two-stage membrane cascade. The power plant responds to varying electricity prices under a set of constant CO2 prices. We found that the optimal design (membrane and equipment sizes) is a result of balancing capital and operating costs, and that the optimal operating schedule (electricity output, membrane operating pressure, CO2 capture rate) depends on the carbon price relative to the electricity price. A variety of exogenous input variables determine the optimal design of the membrane system and overall system cost. The model is sensitive to market conditions such as demand, electricity price, and carbon regulation, with both optimal design and operations affected by these external factors.

Resilient operational strategies for power systems considering the interactions with natural gas systems

Threatened by natural disasters and man-made attacks, the resilient operation of power systems has drawn increased attention, which gives rise to a greater demand for power generation assets with high operational flexibility, such as natural gas power plants (NGPPs). This, in turn, results in a greater proportion of NGPPs and greater interdependence between power and gas systems. As a consequence, the modeling of the interactions between power systems and natural gas systems to achieve operational resilience in power systems becomes extremely vital. This topic has been discussed by quite a few researchers; however, previous studies suffered from two major drawbacks, namely (1) they assumed the existence of only one utility that has full control authority over the power system and gas system; (2) the economic interactions between power systems and gas systems have been neglected, which goes against current industrial practice. In this study, the power system and gas system are regarded as two individual utilities and their physical and economic interactions are modeled by considering the fuel consumption of the NGPPs and gas contracts and by guaranteeing the fuel availability of NGPPs in the pre- and post-contingency stages, respectively. The proposed model is developed based on a two-stage robust decision-making framework to optimize the operational performances of power systems under the worst-case N-k contingencies. To deal with the binary variables introduced by the linearization of the Weymouth equation and the on/off grid operation of generators, the nested column-and-constraint generation (NC&CG) algorithm is adopted. The necessity of considering economic and physical interactions between power systems and natural gas systems and the effectiveness of the proposed model and algorithm are verified by numerical simulations of two test systems.

Layered Double Hydroxide Sorbents for Removal of Selenium from Power Plant Wastewaters

Selenium is an essential trace element but is increasingly becoming a contaminant of concern in the electric power industry due to the challenges of removing solubilized selenate anions, particularly in the presence of sulfate. In this work, we evaluate granulated layered double hydroxide (LDH) materials as sorbents for selenium removal from wastewaters obtained from a natural gas power plant with the aim to elucidate the effect of competing ions on the sorption capacities for selenium removal. We first present jar test data, followed by small-scale column testing in 0.43 inch (1.1 cm) and 2 inch (5.08 cm) diameter testbed columns for the treatment of as-obtained cooling tower blowdown waters and plant wastewaters. Finally, we present field results from a pilot-scale study evaluating the LDH media for treatment of cooling tower blowdown water. We find that despite the high levels of total dissolved solids and competing sulfate ions, the selenium oxoanions and other regulated metals such as chromium and arsenic are successfully removed using LDH media without needing any pre-treatment or pH adjustment of the wastewater.

A convex decentralized optimization for environmental-economic power and gas system considering diversified emission control

To mitigate two major environmental concerns of global warming and air pollution, natural gas power generation is growing in power supply, which makes power and natural gas system increasingly integrated. In this work, an environmental-economic dispatch incorporating diversified emission control is established for integrated power and gas system (IPGS). The traditional emission amount control for carbon emissions is adopted in IPGS, while a novel spatial and temporal diffusion control concerning ground concentration and spatial environmental protection requirements is proposed for air pollutant emissions. Furthermore, in view of information sharing difficulties between power and gas system, this paper proposes a novel two-layer convex decentralized optimization for the issue. The upper layer handles the nonconvex gas flow transmission with penalty convex-concave procedure based convexification. The lower layer solves each step of upper layer convexification with alternating direction method of multipliers based decentralized optimization, such that the information privacy of these two sub-systems is protected. Finally, simulation studies on two test systems validate the superiority of spatial and temporal diffusion control in reducing the air pollutant concentration, as well as the nearly global optimality and convergence efficiency of the two-layer method.

Regional Integrated Energy System Planning considering Energy Price Uncertainties: A Two-stage Stochastic Programming Approach

Abstract The implementation of regional Integrated Energy System (IES) in urban areas enable the integration of multiple energy systems including electric, cooling and heating power systems. In this paper, we propose a stochastic programming planning method for IES based on Energy Hub model, in which energy price uncertainties from bulk energy systems are considered. In terms of investment planning for IES, the considered candidate options are combined cooling, heating and power (CCHP), gas boiler, centralized air conditioner with different sizes, which are described by several generalized constraints. Moreover, the operation cost of importing natural gas and electric power are considered, where several typical days based on annual load profile are included so that the cost can be simulated more accurately. The price uncertainties are described as normal distribution and simulated by multi-scene, thus a two-stage stochastic programming model is formulated with investment planning as first-stage problem and IES operation as second-stage problem. Case studies demonstrated the effectiveness of proposed model, in which the benefits of IES resulted from complementary and coordination between multi energy systems are illustrated.

Implications of hydropower variability from climate change for a future, highly-renewable electric grid in California

This study investigates how hydropower generation under climate change affects the ability of the electric grid to integrate high wind and solar capacities. Using California as an example, water reservoir releases are modeled as a function of hydrologic conditions in the context of a highly-renewable electric grid in the year 2050. The system is perturbed using different climate models under the Representative Concentration Pathway 8.5 climate scenario. The findings reveal that climate change impact on hydropower can increase greenhouse gas emissions up to 8.1% due to increased spillage of reservoir inflow reducing hydropower generation, but with minimal effects (<1%) on renewable utilization and levelized cost of electricity. However, increases in dispatchable power plant capacity of +2.1 to +6.3% and decreases in the number of start-up events per power plant unit up to 3.1%, indicate that the majority of dispatchable natural gas power plant capacity is offline for most of the climate change scenarios. While system-wide performance metrics experience small impacts, climate change effects on hydropower generation increase both the need for dispatchable generation and the costs of electricity from these power plants to support large-scale wind and solar integration on the electric grid.

The value of bulk energy storage for reducing CO2 emissions and water requirements from regional electricity systems

The implementation of bulk energy storage (BES) technologies can help to achieve higher penetration and utilization of variable renewable energy technologies (e.g., wind and solar), but it can also alter the dispatch order in regional electricity systems in other ways. These changes to the dispatch order affect the total amount of carbon dioxide (CO2) that is emitted to the atmosphere and the amount of total water that is required by the electricity generating facilities. In a case study of the Electricity Reliability Council of Texas system, we separately investigated the value that three BES technologies (CO2-Geothermal Bulk Energy Storage, Compressed Air Energy Storage, Pumped Hydro Energy Storage) could have for reducing system-wide CO2 emissions and water requirements. In addition to increasing the utilization of wind power capacity, the dispatch of BES also led to an increase in the utilization of natural gas power capacity and of coal power capacity, and a decrease in the utilization of nuclear power capacity, depending on the character of the net load, the CO2 price, the water price, and the BES technology. These changes to the dispatch order provided positive value (e.g., increase in natural gas generally reduced CO2 emissions; decrease in nuclear utilization always decreased water requirements) or negative value (e.g., increase in coal sometimes increased CO2 emissions; increase in natural gas sometimes increased water requirements) to the regional electricity system. We also found that these values to the system can be greater than the cost of operating the BES facility. At present, there are mechanisms to compensate BES facilities for ancillary grid services, and our results suggest that similar mechanisms could be enacted to compensate BES facilities for their contribution to the environmental sustainability of the system.

Switching on an Environmentally Friendly and Affordable Light in Africa: Evaluation of the Role of Natural Gas

The purpose of this article is to review the dynamics of natural gas resources in Africa and evaluate how it can help solve the power challenges of the continent. This article develops from a descriptive analysis and desk review on natural gas and power. The key finding is that despite the increased discovery of natural gas in Africa, it has had minimal impact on power production. This study provides a descriptive overview and is limited to only natural gas. It does not consider how other energy sources can contribute to solving Africa’s power challenges. This article draws the attention of both policymakers and the investment community to the opportunities in the ‘natural gas-power’ value chain and the need to invest in gas infrastructure. An overview of the power challenges and natural gas potential of Africa is provided.

Development status and suggestions of Natural Gas Power Generation Industry in China

At present, the development speed of natural gas power generation in China lags far behind the world average level, and there are many problems in the gas electricity industry, including the high gas price of natural gas is difficult to dredge the electricity price, the online electricity quantity is difficult to guarantee, the natural gas supply has the bottleneck, the power plant lacks the bargaining right and so on, which seriously restricts the healthy and sustainable development of the natural power generation industry. On the basis of combing and investigating the existing problems of natural gas power generation in China, this paper expounds the orientation and goal of the development of China's natural gas power generation industry, and puts forward some concrete suggestions for promoting the development of China's natural gas power generation industry.

Optimization of Fixed-Bed Design for Natural Gas Mercury Removal by Sulfur Doped into Porous Activated Carbon

The present work reports the synthesis and application of sulfur doped into porous activated carbon for removing elemental mercury from natural gas using a bench-scale fixed-bed reactor. A series of experiments were carried out to investigate the optimization of Hg0 capture. Furthermore, our experimental results about optimum conditions to remove Hg0 were 1:10 of sulfur to activated carbon impregnation ratio, 350°C of impregnation temperature, and 3 hours of impregnation time. This research showed that the prepared adsorbents were capable to remove remarkable amount of Hg0 (23.615 mg/g) at high adsorption efficiency. This study may serve as reference on natural gas power plants for the removal of Hg0 using the same conditions.

ANALISIS PROTEKSI KEBAKARAN PADA PERUSAHAAN PRODUKSI GAS DAN PEMBANGKIT LISTRIK

PT. Gresik Gases Indonesia and PT. Gresik Power Indonesia is a company engaged in the production of gas and power plants with natural gas and diesel power. This production site has a potential fire hazard so it must be implemented active and passive fire protection system. This research held to determine the suitability of active fire protection systems, passive in the workplace based on with several standards such as the SNI 03-3985-2000, NFPA 13, Permenaker no. 04/1980, Permen PU no. 26/PRT/M/2008, SNI 03-1745-2000. Observational data collection used regulated checklists, with cross-sectional research design. This production site was the potential for serious hazards to cause large area fire and in a short time. Classification of fire in this production of type A, B, C were derive from fuel oil storage tanks, T 80 C, T 80 D, MCC 20 KV, SHEQ and admin office, ware house, gas compressor area, gas engines, combustion turbine, control room, centrifuge pump, and regent heater. Active fire protection was several assessments such as alarm, detector, sprinkler, exhaust, and hydrant. On passive fire protection, the assessment was based on buildings. Field observations obtained the following results active protection system such as alarm with enough categories, detector with enough categories, sprinkler with enough categories, a fire extinguisher with a good category, hydrants with good categories and on passive fire protection systems with sufficient category.Keywords: fire protection, gas production, power plant

The integration of long-term marginal electricity supply mixes in the ecoinvent consequential database version 3.4 and examination of modeling choices

PurposeThe long-term marginal electricity supply mixes of 40 countries were generated and integrated into version 3.4 of the ecoinvent consequential database. The total electricity production originating from these countries accounts for 77% of the current global electricity generation. The goal of this article is to provide an overview of the methodology used to calculate the marginal mixes and to evaluate the influence of key parameters and methodological choices on the results.MethodsThe marginal mixes are based on public energy projections from national and international authorities and reflect the accumulated effect of changes in demand for electricity on the installation and operation of new-generation capacities. These newly generated marginal mixes are first examined in terms of their compositions and environmental impacts. They are then compared to several sets of alternative electricity supply mixes calculated using different methodological choices or data sources.Results and discussionRenewable energy sources (RES) as well as natural gas power plants show the highest growth rates and usually dominate the marginal mixes. Nevertheless, important variations may exist between the marginal mixes of the different countries in terms of their technological compositions and environmental impacts. The examination of the modeling choices reveals substantial variations between the marginal mixes integrated into the ecoinvent consequential database version 3.4 and marginal mixes generated using alternative modeling options. These different modeling possibilities include changes in the methodology, temporal parameters, and the underlying energy scenarios. Furthermore, in most of the impact categories, average (i.e., attributional) mixes cause higher impact scores than marginal mixes due to higher shares of RES in marginal mixes.ConclusionsAccurate and consistent data for electricity supply is integrated into a consequential database providing a strong basis for the development of consequential Life Cycle Assessments. The methodology adopted in this version of the database eliminates several shortcomings from the previous approach which led to unrealistic marginal mixes in several countries. The use of energy scenarios allows the evolution of the electricity system to be considered within the definition of the marginal mixes. The modeling choices behind the electricity marginal mix should be adjusted to the goal and scope of individual studies and their influence on the results evaluated.

Two-stage distributionally robust coordinated scheduling for gas-electricity integrated energy system considering wind power uncertainty and reserve capacity configuration

As the interdependency between natural gas system and power system is significantly close and the integration of renewable energy with uncertainty and volatility greatly increased in the last decades, the operation security and economics of the gas-electricity integrated energy system has attracted growing concerns. A two-stage distributionally robust optimization (DRO) model is proposed to study the coordination optimization scheduling for this multi-energy coupled system considering wind power uncertainty. Integrating the advantages of stochastic programming and traditional adjustable robust optimization (ARO), DRO aims to minimize the expectation of the operation cost under the worst-case distribution over an ambiguity set. The operation constraints of the above two energy subsystems are fully considered, moreover, the feasibility check subproblem for the reserve capacity configuration by gas-fired units is built. As a result, the DRO model is solved in a master-subproblem framework. A case study is implemented on a 6-bus power system with a 7-node natural gas system to demonstrate the superiority of the proposed DRO model compared to the existing ARO and data-driven DRO models. Furthermore, the modified IEEE 24-bus system with a 10-node gas system is used to verify the effectiveness and practicability of the proposed model.

Placing hubs in CO2 pipelines: An application to industrial CO2 emissions in the Iberian Peninsula

Carbon capture and geological storage (CCS) is a key technology for the World deep decarbonization. However, several challenges remain, such as the optimization of the carbon transportation infrastructures. This study proposes a methodology that applies the Kernel Density function in a geographic information system software and uses as input, CO2 emission sources data to identify emission clusters and emission high-density hotspots. The main goal of the proposed methodology is to perform a preliminary screening to identify areas of interest to install hubs when designing an optimized CO2 pipeline network. The methodology includes an estimation of capturable CO2 emissions and a density analysis that was based on Kernel Density function from the ArcGIS Desktop 10. The methodology was applied to the Iberian Peninsula CO2 industrial emission sources such as refineries, coal and natural gas power plants and cement factories (case study) and the results showed that in Portugal, CO2 industrial emissions reduction can reach up to 68% and, in Spain, up to 74% of CO2 industrial emissions, could be avoided. These are called capturable CO2 emissions which means that they are the portion of the total emissions that can be captured from industrial processes before they reach the atmosphere. Moreover, hubs were shown to be more viable when Portugal and Spain are considered together, therefore, carbon routes (pipeline network) in the future may consider an integrated route for the Iberian Peninsula.

Energy, exergy, environmental and economic analysis of hybrid waste-to-energy plants

Recently, studies have been evaluating the thermodynamic performance of new configurations of integrated waste-to-energy/gas turbine cycles, but a question still remains: “Instead of building new natural gas power plants or installing conventional waste-to-energy facilities, should one be investing in flexible efficient hybrid plants?” This article aims at presenting a novel comprehensive approach to help answering this question. The strategy intends to demonstrate how to integrate four known key procedures (energy, exergy, economic and environmental analysis) in an original manner in order to evaluate the feasibility of such systems. The technique consists of a conventional Energy-Exergy analysis followed by a new Environmental-Economic approach. The novelties are in the economic and environmental parts, namely: (i) the use of multiple cost equations for estimating the plant’s initial investment range and (ii) the indirect estimate of the pollution abatement system cost through an energy-ecological efficiency indicator. A case study configuration (similar to the existing plant of Bilbao) is used as exercise to demonstrate the method and its comparability potential, as well as to allow discussion using tangible results. The case-studied plant has a power output capacity of 107 MWe, thermal efficiency of 36%, ecological efficiency of 89%, thermal waste input capacity of 155 MWt and levelized cost of electricity production of US$ 64–89 per MWh. It is compared to several existing single-fueled waste-to-energy facilities and other energy sources, including renewable and non-renewable. As unique findings of this research, it is shown that the proposed economic method allows to predict costs quite accurately and that the specific investment costs of such technology are very attractive compared to existing single-fueled waste-to-energy facilities in Europe and other electricity sources in the Brazilian context. The proposed method proved to be a comprehensive procedure to analytically evaluate the feasibility of hybrid waste-to-energy power plants, which present good potential in the Energy conversion field.

Bridges beyond renewable energy: Decarbonizing the global electricity sector under uncertainty

Mitigating global climate change requires decarbonizing the electricity sector, but the optimal strategy for doing so is not obvious. As power plants fueled by coal and petroleum are phased out, other generation technologies must fill the gap. While technically feasible, many low-carbon technologies are currently expensive – though costs may fall with experience. As an alternative, natural gas-fired power plants provide lower-carbon electricity – and cheaply if gas is abundant. The least-cost portfolio of generation technologies depends on several uncertain parameters. This paper presents a stylized model of the global electricity sector and evaluates several decarbonization strategies focused on three bridge technologies – natural gas, carbon capture and storage (CCS), and nuclear – over the period 2015–2050. With constraints on total demand for electricity and penetration of renewables, I find that the results are sensitive to the learning curve for CCS, the cost of natural gas, and the social cost of carbon. Depending on the true state of the world, decision-makers may find either natural gas power plants or CCS to be least-cost options for decarbonization portfolios. The expected value of information from resolving uncertainty is hundreds of billions of dollars, indicating high social benefits from investments into scientific research.

Using Electrical Energy Storage to Mitigate Natural Gas-Supply Shortages

The recent leak of the Aliso Canyon natural gas storage facility calls for coordinated planning of natural gas and electric power systems with specific consideration of electrical energy storage. This paper proposes a coordinated planning model that fills this need. The model is formulated as a two-stage stochastic optimization problem, in which electricity- and natural gas-demand growth and natural gas-supply uncertainties are represented. We analyze the tradeoff between building electrical, natural gas, and electrical energy storage infrastructure. The sensitivity of electrical energy storage investment to the modeling of the operating conditions is also studied. The model is tested using a California-based case study.

The LCOE of Chinese coal-fired power plants with CCS technology: a comparison with natural gas power plants

In the process of energy transformation in China, the potential competitiveness of natural gas power plants and coal-fired power plants equipped with carbon capture and storage (CCS) technology should be considered. In this study, the levelized cost of electricity (LCOE) method is used to compare the competitiveness of these two types of power plants. The results show that regardless of whether a carbon pricing mechanism is included, the LCOE is lower for coal-fired power plants with CCS than for natural gas power plants if the coal-fired power plants have the same level of emission reduction as the natural gas power plants or ensure deep emission reductions. When the coal price reaches 750 CNY/t, the coal-fired power plants with the CCS technology lose their competitive advantage when the carbon price is less than 158 CNY/t. In Shanxi province, the coal-fired power plants with CCS technology have a greater competitive advantage than the natural gas power plants.

Low-Concentration CO2 Capture from Natural Gas Power Plants Using a Rotating Packed Bed Reactor

A rotating packed bed (RPB) was employed as a highly effective reactor to intensify CO2 capture in a green and natural amino acid salt absorbent, potassium sarcosine (KSAR), from the flue gas containing a low CO2 concentration. Experimental results show that a good CO2 capture performance, presented in terms of CO2 capture efficiency and overall volumetric mass transfer coefficient (KGa), can be obtained at a low CO2 concentration of 2–6%. CO2 capture efficiency could reach higher than 80% at a relatively high gas–liquid ratio, with CO2 loading up to 0.17 mol of CO2/mol of KSAR. Comparison results with a packed column show that a RPB can obtain higher CO2 capture performance with a smaller device size. Moreover, a mathematical model was developed to describe the mass transfer process in a RPB. Calculated values of KGa agreed well with experimental data, with a deviation within ±25%, and the tendency of the CO2 concentration at the outlet of the RPB can be well-predicted under a high liquid flow rate and h...