High Efficiency Low Emissions Research Articles

Power sector decarbonisation in developing and coal-producing countries: A case study of Indonesia

Global efforts to transition away from coal within a decade encounter significant challenges, particularly in developing and coal-producing countries, e.g. Indonesia. Most current studies do not discuss the impact of coal phase-out on the upstream sector, which is important for coal-producing countries. This study aims to analyse Indonesia's power sector decarbonisation impact on the power and fossil upstream sectors. This analysis used VEDA-TIMES energy system optimisation using three scenarios: least-cost system (BAU), decarbonisation without coal phase-out (PA 1.5), and decarbonisation with coal phase-out (PA 1.5 PO). In all cases, decarbonisation will reduce the amount of coal used in energy systems. However, in a technology-agnostic transition, coal still constitutes 16% of total capacity in 2060. By this time, the coal-fired power generating assets have also transitioned to high efficiency, low emissions (HELE) technologies. CCS plays an important role in Indonesia's decarbonisation. A key implication of the coal phase-out scenario is the stranding of $9 bn worth of existing assets and an increased role for renewable energy and imported natural gas in 2035–2050, posing a notable threat to gas security within the industrial sector. In addition, the potential loss due to untapped coal reserves is estimated at $63 bn, while the cumulative net loss in the coal upstream sector amounts to $799 bn (0.26% of Indonesia's GDP and 3.7% of the coal-producing GDRP). Nevertheless, the total investment and electricity production costs exhibit negligible differences in the rapid VRE expansion, but it will reduce total investment by 24% in the low VRE buildrate.

Impact of Cylinder Deactivation Strategies on Three-way Catalyst Performance in High Efficiency Low Emissions Engines

Reduction of CO2 emissions is a prevalent subject in the transportation sector. Cylinder deactivation (CDA) provides a method to reduce CO2 emissions at part load. However, there is little consideration of how these strategies affect catalyst performance.Effects of two CDA strategies on catalyst performance were studied. The first strategy of open-loop lambda control CDA improved catalyst CO conversion to 100 % and prevented NH3 formation over the catalyst. There was a NOX penalty if the duration exceeded 5 seconds. The closed-loop CDA strategy increased catalyst temperature by 300°C for durations of 60 seconds.Open-loop CDA can prevent NH3 formation and improve CO conversion. Closed-loop CDA strategy has potential to increase catalyst temperature and be effective at reducing light-off during cold starts without additional hardware. This gives the strategy an advantage over more complex heating options. Both strategies provide opportunities to help meet current and future emission regulations.

Long‐term optimal power generation pathways for Pakistan

AbstractPakistan has faced an electricity shortfall for over two decades despite various efforts taken at different levels. Though electricity supply in recent times has crossed the demand, the supply‐side stresses and deciding optimal power generation pathways have always been a challenge for policymakers and researchers. In this study using a LEAP energy model, following the sectoral electricity demand forecast, four supply‐side scenarios have been developed and analyzed for the study period 2017‐2055. In each scenario, referred to as Business as Usual (BAU), Renewable Energy Technologies (RET), Coal Power Penetration (CPP), and High‐Efficiency Low‐Emission (HELE) scenario, electricity generation, installed generation capacity, cost of production, and GHG emissions are estimated and compared for seeking long‐term optimal energy pathways for Pakistan. The study results reveal that for the end year (2055), RET is an environmentally sustainable scenario with an estimated electricity generation of 2421 TWh, which is enough to meet the electricity demand of 2374TWh. The GHG emissions under the RET scenario are estimated to be 857 million metric Tons, which are around 50% less than CPP and 40% less than the BAU scenario. However, the cost of generation is higher than BAU and CPP scenarios. The CPP scenario emerges to be cost‐competitive, however with the highest GHG emissions. This study thus suggests that convergence of RET with the CPP scenario could be an appealing option for Pakistan to meet increasing demand with energy security and environmental sustainability.

Experimental Investigation on Nonlinear Response of a Low-Swirl Flame to Acoustic Excitation With Large Amplitude

Abstract Thermoacoustic instability is a major issue in developing high-efficiency low emission gas turbine combustors. In order to predict the amplitude of limit cycle oscillation, an understanding of the amplitude-dependent response of the flame, i.e., the nonlinear response, to large acoustic excitation is needed. In the present study, the nonlinear response of a low-swirl CH4/air premixed flame to acoustic excitation is experimentally studied. Amplitude dependences of flame dynamic at 75 Hz and 195 Hz are discussed in detail over a wide range of excitation levels. Experimental results show the gain of flame describing function of the low-swirl flame has a peak value at 65 Hz and a local minimum at 105 Hz which is caused by the destructive (out of phase) and constructive (in-phase) of the axial and azimuthal velocity fluctuation. At low perturbation level, flame heat release fluctuation is in linear relationship with the normalized velocity driving level. Heat release fluctuation begins to saturate at a certain level which depends on the driving frequency. The low-swirl flame oscillates mainly in the axial direction at 75 Hz while it is in the radial direction at 195 Hz. The nonlinear flame heat release response is a result of combination effect of flame rollup process and harmonic responses.

Research and development of high efficiency low emission combined cycle power plant arrangements

Coal-fired steam turbine thermal power plants produce a large part of electricity. These power plants usually have low efficiency and high carbon dioxide emission. An application of combined cycle power plants with coal gasification equipped with carbon capture and storage systems may increase the efficiency and decrease the harmful emission. This paper describes investigation of the oxidizer type in the integrated gasification combined cycle combustion chamber and its influence upon the energy and environmental performance. The integrated gasification combined cycle and oxy-fuel combustion technology allow the carbon dioxide capture and storage losses 58% smaller than the traditional air combustion one. The IGCC with air combustion without and with carbon dioxide capture and storage has 53.54 and 46.61% and with oxy-fuel combustion has 34.94 and 32.67% net efficiency. Together with this the CO2 emission drops down from 89.9 to 10.6 gm/kWh. The integrated coal gasification combined cycle with air oxidizer has the best net efficiency.

Comprehensive technical review of the high-efficiency low-emission technology in advanced coal-fired power plants

Abstract Advancements in supercritical (SC), ultrasupercritical (USC), and advanced USC coal-fired power plants have been achieved through the development of enhanced materials utilized in advanced steam cycles and through the deployment of advanced emission control systems. These are referred to as high-efficiency low-emission (HELE) technologies, which may solve numerous issues associated with coal-based power generation. There is a clear global transition from subcritical to advanced power plant types and significant R&D work on HELE technologies. Therefore, this comprehensive review covers the latest HELE technology deployment in major coal-consuming countries and their R&D roadmaps to advance HELE technologies. In spite of the various advantages of HELE technologies, there have been numerous technical challenges relevant to achieving the HELE steam conditions and deploying low emission control technologies in the HELE systems. Hence, this review covers the technical challenges and the relevant recent research by using various coal combustion test facilities. The current focus for the progression from USC boilers to advanced USC boilers is a successful demonstration of the developed high-performance alloys under the advanced steam conditions. This review covers the current status of research and development of advanced USC (A-USC) materials and challenges based on the major material research programs.

A Review of the Numerical Modeling of Pulverized Coal Combustion for High-Efficiency, Low-Emissions (HELE) Power Generation

High-efficiency, low-emissions (HELE) coal-fired power plant technologies operate with a higher thermal efficiency of the steam cycle for coal-fired power generation, reducing CO2 emissions per unit energy generation. They represent some of the primary and intermediate solutions to the world’s energy security. Extensive numerical modeling efforts have been undertaken over the past several decades, which have increased our understanding of the technical problems in HELE boilers, including combustion and boiler performance optimization, ash deposition, and material problems at higher operating temperatures and pressures. Overall, the differences in the physical and chemical models, boiler performance, and ash deposition of oxy-fuel combustion in HELE boilers that recirculate CO2 and H2O in the boilers are also discussed in comparison with the combustion of coal in the air. This Review comprehensively summarizes the current research on numerical modeling to offer a better understanding of the technical aspects and provides future research requirements of HELE coal-fired boilers, including boiler performance optimization, ash deposition, and material problems. The effects of changes in the configuration and operating conditions are discussed, focusing on the optimization of boiler performance in aspects such as unburnt carbon and NOx emissions. The paper also reviews the retrofit and optimization of operating conditions and the burner geometry with the low-NOx coal combustion technologies necessary to operate the HELE power plants. In terms of ash deposition, the development of submodels, including particle sticking and impacting behaviors and their effects on the deposit growth predictions under different temperatures, are discussed. Numerical models of the material oxidation and creep in the austenitic and nickel-based alloys generally used in HELE conditions have been developed using the finite element method to predict the availability of advanced alloys and creep life in the actual service time of the boiler parts. The predictions of oxide scale growth and exfoliation on the steam-side and fire-side and the creep strength are analyzed. The review also identifies some further research requirements in numerical modeling to achieve the optimization of coal combustion processes and address the technical problems in advanced HELE power plant operations.

Cost–Benefit Analysis of HELE and Subcritical Coal-Fired Electricity Generation Technologies in Southeast Asia

A large potential exists in the Southeast Asia region for deployment of high-efficiency, low-emission (HELE) electricity generation technologies. A cost–benefit analysis of HELE technologies compared to the less efficient subcritical electricity generation plants is thus carried out to find a persuasive scenario supporting quicker transition from subcritical stations towards HELE technologies in the region. A levelized cost of electricity (LCOE) analysis is carried out for both technologies under four potential policy scenarios. Scenario 1 does not take into consideration any carbon pricing or costs associated with the desulphurization (deSOx) and denitrification (deNOx) facilities. Scenario 2 (Scenario 3) incorporates carbon pricing (costs associated with the deSOx and deNOx facilities), and Scenario 4 includes both carbon pricing and costs associated with the deSOx and deNOx facilities. Under each scenario, a sensitivity analysis is performed to evaluate the uncertainty affecting the future coal prices. This study demonstrates that HELE technologies are competitive against the subcritical plants under all four scenarios and both the technologies derive benefit from lifetime extensions and low coal prices. It is revealed that future deployments of HELE technologies can be best expedited by factoring in carbon pricing in LCOE costs of coal-fired power plants under Scenario 2.

Investment Decision Making for Carbon Capture and Storage Technology in High Efficiency, Low-Emission Coal-fired Power Plant via Dynamic Techno-Economic-Policy Evaluation Framework: Case Study in China

There are significant uncertainties pertaining to the future of coal power generation across the globe and especially for China. Being one of the largest coal consumers and CO2 emitters, China aims at addressing its national energy security while ensuring to achieve sustainable operations. In following its commitments to the Paris Agreement and in pursuit of near-zero emissions from power plants, China has actively moved towards high efficiency, low emission (HELE) coal-fired power plants. However, HELE technology alone cannot completely cut carbon emissions, and will require a mature CO2 emissions reduction technology such as carbon capture and storage (CCS) to significantly reduce the CO2 emissions within short to medium term. This paper conducts a preliminary evaluation for investment in HELE coal-fired power plant with CCS (HELE-CCS) in China, under the context of the Shenzhen emissions trading scheme. We carry out this preliminary analysis through mixed-integer non-linear programming (MINLP) framework, and by using publicly available power generation and carbon pricing data. Based on hypothetical scenarios, a HELE coal-fired power plant is found to contribute 55 % profit by selling the electricity. However, a substantial CO2 emissions cost is incurred due to the installation of CCS, leading to a high caution on investment. A more detailed analysis is warranted using real power plant data to confirm real business feasibility of HELE-CCS, including an expansive set of scenarios that also assess relevant appropriate government incentives and subsidies as well as variant financial models.

IS COAL POWER GENERATION A SUSTAINABLE SOLUTION FOR ENERGY NEEDS OF PAKISTAN: A DELPHI-SWOT PARADIGM?

This paper aims to apply tools like Delphi and SWOT as a reference theme that diagnosis the sustainability of current status and future road map to develop coal based power generation in Pakistan. The SWOT analysis is performed on the themes of energy security, energy efficiency and environmental sustainability. Within this analytical framework, the coal power generation has been discussed in the context of Pakistan’s energy scenario through categorical analysis of strengths, weaknesses, opportunities and threats. The paper explores the strength of coal based power production as indigenous coal reserves, internal weaknesses appears to be quality of coal (high moisture content), unavailability of water for power generation at site of coal mines and lack of coherence between coal exploitation and climate change policy. The conversion of coal to gaseous products and liquid fuels offers an opportunity alongside employing advanced technologies of High Efficiency Low Emission (HELE) to cut CO 2 emissions. Threats to coal power are its adverse environmental impacts on land, soil and air. Furthermore, to enhance energy security and sustainability, strategic planning based on measures such as cleaner use of coal, promotion of renewables and energy efficiency with flexibility are suggested. Each of these actions require concrete steps from all stakeholders and policy makers to develop coherence between coal exploitation and climate change policy of Pakistan. Keywords : SWOT analysis, Delphi, Coal based power generation of Pakistan, Energy security, Environmental sustainability. JEL Classifications: P4, Q4 DOI: https://doi.org/10.32479/ijeep.10598

Oxy-CFB combustion technology for use in power-generation applications

Implementation of circulating fluidized bed (CFB) boilers in the energy sector has witnessed a steady increase owing to their afforded advantages of operational flexibility in terms of compliance with several low-grade fuels and in-situ DeSOx and DeNOx capabilities. In recent years, the rise in global warming and development of intermittent power-generation technologies have stressed the need for development of techniques to afford high-efficiency low-emission (HELE) power-generation, effective carbon capture and storage, and flexible operation of thermal power plants. To meet these demands, the Future Energy Plant Convergence Research Center (FEP CRC) has investigated oxy-combustion technologies for CFB boilers that use low-grade fuels with calorific values <5000 kcal/kg while maintaining high operational efficiency and low pollutant emission. Of key interest in this study is the operation of the proposed system under rapid load variations over a wide operating range, including an oxy-combustion test with high oxygen concentration more than 40% within oxidants. Efforts in this regard are underway through pilot experiments performed using demonstration-scale facilities and multidimensional numerical simulations. Additionally, studies have been performed to identify materials for use in the said high-efficiency boilers and develop techniques for exhaust-system water recovery. In this paper, the current conclusions from the research activities of FEP CRC will be presented.

Enabling a gasification and carbon capture economy in India: An integrated techno-economic analysis

India emits over 2.4 gigatons of CO2[1,2] today and will continue to see the biggest increase in fossil fuel CO2 emissions. This is partly due to rapid economic growth, industrialization, and efforts to bring electricity to rural communities. Apart from restructuring the power sector through progressive adoption of high efficiency low emission (HELE) power plants with potential carbon capture, pre-combustion carbon capture along with syngas based industrial production and petrochemical feedstock substitution can lay the foundations for an economically viable, less carbon emission intense industrial future for India. One of the biggest opportunities for carbon dioxide abatement through clean coal technology lies in using India’s abundant low rank coal reserves through coal gasification and carbon capture to enable and expand a carbon neutral industrial economy, which today emits close to 25% [1–3] of the total greenhouse gases (GHG).A practical and holistic macro and micro-level techno-economic analysis is an essential pre-requisite for enabling a clean coal-based industrial economy in a cost-sensitive developing country like India. Through this study, the key sectors that can be enabled using coal gasification and carbon capture are identified and the viable techno-economic options, macro-economic and trade impact, policy support options and a carbon capture finance model for India are analyzed.

Progress of Osaki CoolGen Project of Oxygen-blown IGCC Demonstration

Coal-fired power plants, which provide stable power at low cost, will continue to serve as base load supporting the world's increasing power demands. However, the amount of CO2 emitted by coal utilization is larger than that of other fossil fuels. Therefore the Osaki CoolGen Project has been launched to realize innovative HELE (High Efficiency, Low Emissions) coal-fired power generation which combines an Integrated coal Gasification Combined Cycle (IGCC) / Integrated coal Gasification Fuel Cell combined cycle (IGFC) with CO2 capture. This project is subsidized by the Ministry of Economy, Trade and Industry (until 2015 FY) and New Energy and Industrial Technology Development Organization (from 2016 FY). The oxygen-blown IGCC demonstration test, which is the base technology for IGFC, commenced in March 2017. We've achieved world-class net efficiency, environmental performance, plant reliability and flexibility. Construction of CO2 capture unit started in April 2018 and is underway to start demonstration test.

Cleaning up coal power

Currently, the average efficiency of coal-fired power plants is 33 per cent, which is a lot lower than the 45 per cent achieved by state-of-the-art plants and still significantly below the 40 per cent efficiency that `off-theshelf technologies can deliver. Every one per cent increase of in coal-fired power plant efficiencies can reduce CO2 emissions by between two and three per cent.Cleaner coal technologies such as high efficiency low emission (HELE) coal-fired power generation and carbon capture, use and storage (CCS) are already commercially available and WCA says that if they are deployed now they can reduce greenhouse gas emissions from the entire power sector by around 20 per cent.

Analysis of a High-Efficiency Low-Emissions "Chemical Gas Turbine" System

This paper analyzes the energy, exergy, emissions, and heat exchanger sizes ofa novel gas-turbine/steam-turbine combined cycle based on the chemical gas turbine system (ChGT). The system consists of a series arrangement of a fuel-rich and fuel-lean combustor with their gas turbines, recuperators, and a steam bottoming cycle. The fuel-rich combustion in the first stage creates a reducing atmosphere in the first turbine, which allows higher temperature operation (here 1773-2073 K) with carbon-fiber-reinforced·carbon (C/C) composites blades, and produces low NOx emissions. The second·stage fuel-lean turbine operates at a lower temperature compatible with more conventional blade materials, and completes the fuel combustion. The results show that, compared with conventional combined cycles, the ChGT has distinct advantages, rising with the first-stage TIT: the efficiency is up to 5% higher, the exergy losses are up to 18% lower, the NOx emissions are up to 40% lower, and the required heat exchanger area

99/00774 Analysis of the chemical gas turbine system, a novel high-efficiency low-emissions power cycle

The integrated CO2/sludge gasification using the waste heat in hot slags, was explored with the aim of syngas production, waste heat recovery and sewage sludge disposal. The results demonstrated that hot slags presented multiple roles on sludge gasification, i.e., not only a good heat carrier (500–950 °C) but also an effective desulfurizer (800–900 °C). The total gas yields increased from 0.022 kg/kgsludge at 500 °C to 0.422 kg/kgsludge at 900 °C; meanwhile, the SO2 concentration at 900 °C remarkably reduced from 164 ppm to 114 ppm by blast furnace slags (BFS) and 93 ppm by steel slags (SS), respectively. A three-stage reaction was clarified including volatile release, char transformation and fixed carbon using Gaussian fittings and the kinetic model was analyzed. Accordingly, a decline process using the integrated method was designed and the optimum slag/sludge ratio was deduced. These deciphered results appealed potential ways of reasonable disposal of sewage sludge and efficient recovery of waste heat from hot slags.