Conventional Fossil Fuel Power Plants Research Articles

Evaluation of MEA 5 M performance at different CO2 concentrations of flue gas tested at a CO2 capture lab-scale plant

Chemical absorption is the most effective and mature post-combustion alternative that might be applied for carbon capture in fossil-fuel power plants and other energy-intensive industries such as cement production, refineries and iron and steel manufacturing. In respect to the cement production, inherent CO2 emissions produced during the calcination of limestone contributes around 60% of the total CO2 emissions and they can be only reduced using CCS. A test campaign was carried out in a 0.48 kg CO2/h lab-scale CO2 capture plant using a synthetic flue gas derived from both a conventional fossil-fuel power plant (15%v/v CO2) and a cement plant (20%v/v). The use of a higher CO2 concentrated flue gas enhanced the CO2 absorption and hence the overall CO2 capture process. Higher CO2 concentrations also increased the solvent cyclic capacity which was displaced to higher values as CO2 concentration shifted from 15%v/v CO2 to 20%v/v CO2. A 29% reduction of the energy consumption per ton of CO2 was achieved in the stripper as flue gas shifted from 15%v/v CO2 to 20%v/v, showing post-combustion capture based on chemical absorption as a potential approach to mitigate CO2 emissions originating from cement production.

Fuzzified multi-objective particle swarm optimisation for the solution of economic and emission dispatch problem

Conventional economic dispatch (ED) problem deals with minimising the generation cost while satisfying a set of equality and inequality constraints. The conventional fossil fuel power plants pollutes environment by emitting some toxic gases. Hence, conventional minimum cost operation cannot be the only basis for generation dispatch, however emission minimisation can also be considered. The objective of reactive power optimisation problem can be seen as the minimisation of real power loss over the transmission lines. Large integrated power systems are being operated under heavily stressed conditions, which imposes the threat to voltage stability. The objectives economic dispatch, emission dispatch, loss minimisation and voltage stability are to be met for efficient operation and control. The simulation results of all 4 objectives, considering one objective at a time are conflicting and non-commensurable. Therefore, an efficient control scheme which meets all the specified objectives is required. Initially each objective is optimised independently using particle swarm optimisation (PSO) and then all the four objectives are optimised simultaneously using fuzzified PSO. The effectiveness of the proposed approach is tested on IEEE 30 and IEEE 57 bus test systems.

Impact of Battery Cost on the Economics of Hybrid Photovoltaic Power Plants

In recent years, photovoltaic (PV) technology has experienced a rapid cost reduction. This trend is expected to continue, which in many countries drives interest in utility-scale PV power plants. The main disadvantage of such plants is that they operate only when the sun is shining. The installation of PV modules together with energy storage and/or fossil fuel backup is a way to solve that issue, but consequently increases the costs. In the last few years, however, lithium-ion batteries as well have shown a promising price reduction. This paper studies the competitiveness of a hybrid power plant that combines a PV system, lithium-ion battery and gas turbine (GT) compared to conventional fossil-fuel power plants (coal and natural gas-fired) with focus on the battery cost. To fulfil the demand an auxiliary GT is used in the hybrid PV plant, but its annual generation is limited to 20% of the total output. The metric for the comparison of the different technologies is the levelized cost of energy (LCOE). The installation of the plants is showcased in Morocco, a country with excellent solar resources. Future market scenarios for 2020 and 2030 are considered. A sensitivity analysis is performed to identify the key parameters that influence LCOE.

Pro-Ecological Exergy Tax of Electricity

The concept of the pro-ecological tax or support is proposed in this article. It could replace the existing subsidy mechanisms for renewable power technology or could represent the ecological taxes burdening the fabrication of consumer products based on nonrenewable resources, e.g., electricity from the conventional fossil fuel power plants. Moreover, the proposed concept for renewable power technologies could represent a new system of subsidy based on physical laws. The proposed pro-ecological tax or support is defined as proportional to the thermo-ecological cost (TEC). TEC expresses the cumulative consumption of nonrenewable exergy burdening the fabrication of the considered consumption of the product with the additional inclusion of necessity of compensating adverse environmental effects due to harmful waste products rejection. It is assumed that calculating new exergy tax or subsidy for electricity, the total cost burdening the final consumer remains the same. This principle determines the coefficient of proportionality between the cumulative consumption of nonrenewable exergy (TEC) and the value of the tax or subsidy. In the case of nonrenewable electricity generation, the TAX causes the largest price growth. The higher is the efficiency of power technology, and the lower is the TEC of fuel, the lower tax is provided. In this paper, the prices of electricity produced from renewable and nonrenewable resources are calculated, taking into account the unavoidable consumption of resources. The unavoidable exergy consumption is caused due to the power plant construction, which is distributed through the whole life cycle of the plant. Results of calculation of proposed subsidies are compared with the current Polish system for supporting renewable power technologies.

Sustainable Reserve Power From Demand Response and Fluctuating Production—Two Danish Demonstrations

The Danish grid is moving from a system based on centralized fossil-fueled power plants to a system based on renewable energy where wind is a major energy source. This raises a number of challenges. A main challenge is that the centralized power plants currently are the main providers of reserve power. Alternative sources of flexibility are consequently needed as the conventional power plants are being replaced with fluctuating renewable energy sources. In this paper, we present results from two key demonstrations which illustrate that alternative sources of flexibility exist and that this flexibility can be utilized for reserve power. In the first demonstration, a portfolio of inhabited households heated with heat pumps are remotely monitored and controlled such that the aggregate consumption follows a power reference. This experiment is conducted over a full week where an hourly power reference is tracked while the comfort of the inhabitants is ensured. In the second demonstration, an operational wind power plant is regulated to provide a system-stabilizing response. This experiment is conduced over a 2-h period where the wind power plant follows a 5-min power reference. Together, the two demonstrations illustrate that both consumption and fluctuating production can contribute as sources of reserve power and a sustainable alternative to conventional fossil-fueled power plants in the future grid.

The Research of High Voltage Auxiliary Power System Neutral Point Grounding Modes between the Nuclear Power Plant and Conventional Fossil Fuel Power Plant

<p>Currently, in power plants, the application of the extinction coil in high voltage auxiliary power system neutral point is less experienced. A research done on nuclear power plant and conventional fossil fuel power plant proved that using an auxiliary power system’s different characteristics was leading to different demands of the grounding modes. Thus, this research was done by selecting the grounding mode of high voltage auxiliary power system neutral point on the main nuclear power plants and the partial fossil fuel power plants together with the calculation of practical engineering, and optimal design schemes. The high voltage auxiliary power system neutral point grounding modes have been induced in the large-scale into the nuclear power plant and the conventional fossil fuel power plant. Methods in determining the neutral point grounding modes are used by analyzing the principles commonly used grounding modes and requirements of related codes. First, choose the suitable grounding mode according to the calculation result of capacitive current. Then, choose more conducive grounding mode to the operation of power plant according to the operation of technology equipment. The power is required from the configuration, connection of auxiliary power and the cut from the accident of auxiliary power. As some power plants which are under-construction will be putting into operation one after another, the whole set of perfect security arrangements and operating experiences will also be accumulated inevitably. As a conclusion, high voltage auxiliary power system neutral point grounding modes directly affect the running of the auxiliary power system and even affect the security of the nuclear safety and the operation of the power plant. I hope this article can play a role for reference on the selection of the auxiliary power system grounding modes.</p>

The Research of High Voltage Auxiliary Power System Neutral Point Grounding Modes between the Nuclear Power Plant and Conventional Fossil Fuel Power Plant

<p>Currently, in power plants, the application of the extinction coil in high voltage auxiliary power system neutral point is less experienced. A research done on nuclear power plant and conventional fossil fuel power plant proved that using an auxiliary power system’s different characteristics was leading to different demands of the grounding modes. Thus, this research was done by selecting the grounding mode of high voltage auxiliary power system neutral point on the main nuclear power plants and the partial fossil fuel power plants together with the calculation of practical engineering, and optimal design schemes. The high voltage auxiliary power system neutral point grounding modes have been induced in the large-scale into the nuclear power plant and the conventional fossil fuel power plant. Methods in determining the neutral point grounding modes are used by analyzing the principles commonly used grounding modes and requirements of related codes. First, choose the suitable grounding mode according to the calculation result of capacitive current. Then, choose more conducive grounding mode to the operation of power plant according to the operation of technology equipment. The power is required from the configuration, connection of auxiliary power and the cut from the accident of auxiliary power. As some power plants which are under-construction will be putting into operation one after another, the whole set of perfect security arrangements and operating experiences will also be accumulated inevitably. As a conclusion, high voltage auxiliary power system neutral point grounding modes directly affect the running of the auxiliary power system and even affect the security of the nuclear safety and the operation of the power plant. I hope this article can play a role for reference on the selection of the auxiliary power system grounding modes.</p>

Sulfur dioxide emission reduction of power plants in China: current policies and implications

Electricity generation by conventional fossil fuel power plants have caused severe environmental problems worldwide. Besides greenhouse gas emissions which has global impacts on the climate, there are also pollutant emissions like sulfur dioxide which endanger the local environment. In particular, for developing countries who often highly rely on coal for power generation due to their resource endowment and the competitive costs of coal, the issue of environment pollution caused by coal-fired power plants is getting increasingly severe. Therefore, various solutions should be combined and implemented to address the issue, including environmental regulation, and economic and financial incentives. This study conducted an industry survey in 7 coal-fired power plants in China to collect detailed data in the field to examine the costs and benefits of flue gas desulfurization. Currently, coal-fired power plants in China which install and properly operate flue gas desulfurization equipment can receive 15 Yuan/MWh premium tariff on top of their on-grid tariffs. However, this study shows that this incentive is insufficient to cover the flue gas desulfurization costs of most of the sample plants. More solutions, both regulatory and market-based, should be considered to address this issue. Firstly, under China's current regulated power plants dispatch scheme, allocating generation hour based on the pollutant emission would provide strong incentive for sulfur dioxide mitigation. Secondly, it is suggested to provide more supportive financial environment for flue gas desulfurization industry by fiscal supports, diverse financing accesses, and innovation financial and business models. Thirdly, more environmental regulation tools such as emission cap and emission discharge fees should be set properly and examined carefully, to optimize their impacts on economy, society and environment. Finally, the analysis and results of this study can also be applied in other fields such as denitration and dedusting of coal-fired power plants.

Geothermal power plants: Evolution and performance assessments

This paper traces the technical development of geothermal plants from the very beginning, focusing on the efficiency of the geothermal-to-electrical energy conversion. The plants at Larderello (Italy) and Wairakei (New Zealand) are examined in some detail. Included are discussions and analyses of little-known plants in Africa and on the Italian island of Ischia that pioneered the development of geothermal energy conversion systems beyond the dry steam plants in Tuscany. Presented are important milestones in geothermal power plant development that opened the way to worldwide expansion of the use of geothermal resources for electricity generation. It is shown that while there has been a slight trend toward higher efficiency over the years, the improvement is less than has occurred in conventional fossil-fueled power plants. The efficiency gains result mainly from more elaborate conversion systems whose extra capital costs may not be justified in all cases. Nevertheless, the data show that geothermal power plants can be designed and built to achieve high efficiencies, comparable to or even greater than conventional plants when appropriate economic conditions and incentives exist.

Optimized Multi-pollutant Control in Oxy-fuel Combustion Systems Using CO2 Capture and Compression Process

In conventional fossil fuel power plants, SOx and NOx are removed via flue gas desulfurization units (FGDs) and selective catalytic or non-catalytic reduction units (SCRs and NSCRs) or by other processes, which increase CAPEX and OPEX of the plant. Oxy-fuel combustion with CO2 capture and compression provides new means for efficient removal of these pollutants. This is done within the compression and cooling inter-stages of the CO2 capture unit, hence eliminating the need for upstream FGDs and SCRs. This paper provides the preliminary results from a test campaign carried out at CanmetENERGY's 0.3MWthermal integrated oxy-fuel research facility. Results show significant removal rates for SOx (>90%) and NOx (∼50%) and provide insight for maximizing the removal of these pollutants with simple modifications to the unit.

Exergy and economic analyses of advanced IGCC–CCS and IGFC–CCS power plants

We present exergy and economic analyses of two advanced fossil fuel power plants configurations: an integrated gasification combined cycle with advanced H2 and O2 membrane separation including CO2 sequestration (Adv. IGCC–CCS) and an integrated gasification fuel cell cycle with a catalytic gasifier and a pressurized solid oxide fuel cell including CO2 sequestration (Adv. IGFC–CCS). The goal of the exergy analysis was to evaluate the power generation and the exergy destruction of each of the major components. We estimated the capital, labor, and fuel costs of these power plants, and then calculated the internal rate of return on investment (IRR) and the levelized cost of electricity (LCOE). In the Adv. IGFC–CCS case, we chose a configuration with anode gas recycle back to the gasifier, and then varied the SOFC pressure to find the optimal pressure under this particular configuration. Using a base load generation price of electricity of $50/MWh, the IRR of the Adv. IGFC–CCS configuration was 4±3%/yr if the CO2 can be used for EOR and 1±3%/yr if the CO2 can only be sequestered in a saline aquifer. The IRR of the Adv. IGCC–CCS configuration with H2 and O2 membrane separation was 8±4%/yr if the CO2 can be used for enhanced oil recovery (EOR) and 3±3%/yr if the CO2 must be sequestered in a saline aquifer. The uncertainty here reflects the uncertainty in capital costs, operation & maintenance (O&M) costs, and CO2 sequestration costs.One goal of the economic analysis was to compare the IRR and LCOE of these configurations with the IRR and LCOE of other fossil fuel power plant configurations. For example, using capital/labor/maintenance cost estimates from the literature, we calculated the IRR and LCOE of conventional fossil fuel power plant configurations, including scenarios with CCS and scenarios with varying costs to emit CO2. We also present results on which power plant configuration yields the lowest value of LCOE as a function of the price of CO2 emissions and a function of the price of natural gas, holding all other variables constant. An Adv. IGCC–CCS–EOR configuration yields the lowest value of LCOE when the price of natural gas and the price of CO2 emissions are above the line between ($5/GJ, $10/tCO2) and ($2.5/GJ, $50/tCO2).

Life Cycle Costs and Life Cycle Assessment for the Harvesting, Conversion, and the Use of Switchgrass to Produce Electricity

This paper considers both LCA and LCC of the pyrolysis of switchgrass to use as an energy source in a conventional power plant. The process consists of cultivation, harvesting, transportation, storage, pyrolysis, transportation, and power generation. Here pyrolysis oil is converted to electric power through cocombustion in conventional fossil fuel power plants. Several scenarios are conducted to determine the effect of selected design variables on the production of pyrolysis oil and type of conventional power plants. The set of design variables consist of land fraction, land shape, the distance needed to transport switchgrass to the pyrolysis plant, the distance needed to transport pyrolysis oil to electric generation plant, and the pyrolysis plant capacity. Using an average agriculture land fraction of the United States at 0.4, the estimated cost of electricity from pyrolysis of 5000 tons of switchgrass is the lowest at $0.12 per kwh. Using natural gas turbine power plant for electricity generation, the price of electricity can go as low as 7.70 cent/kwh. The main advantage in using a pyrolysis plant is the negative GHG emission from the process which can define that the process is environmentally friendly.

Biomass co-firing options on the emission reduction and electricity generation costs in coal-fired power plants

Co-firing offers a near-term solution for reducing CO 2 emissions from conventional fossil fuel power plants. Viable alternatives to long-term CO 2 reduction technologies such as CO 2 sequestration, oxy-firing and carbon loop combustion are being discussed, but all of them remain in the early to mid stages of development. Co-firing, on the other hand, is a well-proven technology and is in regular use though does not eliminate CO 2 emissions entirely. An incremental gain in CO 2 reduction can be achieved by immediate implementation of biomass co-firing in nearly all coal-fired power plants with minimum modifications and moderate investment, making co-firing a near-term solution for the greenhouse gas emission problem. If a majority of coal-fired boilers operating around the world adopt co-firing systems, the total reduction in CO 2 emissions would be substantial. It is the most efficient means of power generation from biomass, and it thus offers CO 2 avoidance cost lower than that for CO 2 sequestration from existing power plants. The present analysis examines several co-firing options including a novel option external (indirect) firing using combustion or gasification in an existing coal or oil fired plant. Capital and operating costs of such external units are calculated to determine the return on investment. Two of these indirect co-firing options are analyzed along with the option of direct co-firing of biomass in pulverizing mills to compare their operational merits and cost advantages with the gasification option.

Comparative simulation of hydrogen production derived from gasification system with CO2 reduction by various feedstocks

Integrated gasification combined cycle (IGCC) technology is recognized as an alternative to conventional fossil fuel power plants for cleaner electricity generation. As well as electricity, chemical energy is also produced in the form of syngas that can be further converted into valuable chemicals such as hydrogen, dimethyl ether and synthetic fuel. This study focuses on 300 MWe scale gasification system for poly-generation of both H2 and electricity by utilizing various feedstocks while achieving CO2 capture using monoethanolamine absorption. The investigated feedstocks are pulverized dry coal and coal water slurry from Illinois ♯6 coal, bunker-C, naphtha and bitumen. A simulation model of the gasification system is prepared with the following sub-processes: fuel preparing, gasification, ash removal, acid gas removal, water gas shift, H2 purification process and combined cycle model simulated by ASPEN plus. The performance of the developed model is compared for each feedstock in terms of poly-generation and CO2 capture, according to the following evaluation parameters: cold gas efficiency and carbon conversion of the gasifier, production rate of H2, plant net efficiency and CO2 avoidance. Finally, sensitivity analysis is conducted on the following operating parameters of the shifted reactors for H2 production: divergence fraction, temperature and reactor pressure. Copyright © 2009 John Wiley & Sons, Ltd.

6.6.1 An Integrated Engineering and Economic Model Proposal for Ocean Thermal Energy Conversion Technology

AbstractOcean Thermal Energy Conversion (OTEC) techniques represent a unique opportunity to exploit solar energy from a source available 24 hours a day 365 days a year, can compete economically with conventional fossil fuel power plants, use minimal consumables, and produce virtually no harmful emissions. Large‐scale commercial and industrial adoption of OTEC will be realized only if a clear economic advantage can be demonstrated based on accurate and complete economic modeling. Determination of optimal system designs require application of multivariate system optimization techniques to define the “best” OTEC plant including non‐traditional economic activities that an OTEC plant supports with minor or no additional capitalization or operational costs. Non‐traditional activates that must be considered include sale of cold water effluent to agriculture/aquaculture users, industrial facilities for cooling, and fresh water production. OTEC's low/no emissions also allows sale of emission credits. This paper presents a proposal for modeling OTEC technology using system optimization techniques to define appropriate OTEC plant capacity combined with integrated non‐traditional economic activities to better understand the benefits and costs of OTEC power plants.

Life Cycle Assessment of electricity production from poplar energy crops compared with conventional fossil fuels

The environmental impact of electric power production through an Integrated Gasification Combined Cycle (IGCC) fired by dedicated energy crops (poplar Short Rotation Forestry (SRF)) is analysed by a Life Cycle Assessment approach. The results are compared with the alternative option of producing power by conventional fossil fueled power plants. The energy and raw materials consumption and polluting emissions data both come from experimental cases. Thermodynamic models are applied for simulation of the energy conversion system. The results establish relative proportions for both consumption and emissions of the two energy systems, in detail. Considerable differences emerge about the environmental impact caused by the different gasification conditions. The evaluation of the environmental effects of residues of the pesticides in ground/surface water and in the soil required a particular care, as well as the characterisation of all chemicals (herbicides, fungicides and insecticides) used for the crops.

Reduction of Combustion Irreversibility in a Gas Turbine Power Plant Through Off-Gas Recycling

Combustion in conventional fossil-fueled power plants is highly irreversible, resulting in poor overall energy conversion efficiency values (less than 40 percent in many cases). The objective of this paper is to discuss means by which this combustion irreversibility might be reduced in gas turbine power cycles, and the conversion efficiency thus improved upon. One such means is thermochemical recuperation of exhaust heat. The proposed cycle recycles part of the exhaust gases, then mixes them with fuel prior to injection into a reformer. The heat required for the endothermic reforming reactions is provided by the hot turbine exhaust gases. Assuming state-of-the-art technology, and making a number of simplifying assumptions, an overall efficiency of 65.4 percent was attained for the cycle, based on the lower heating value (LHV) of the methane fuel. The proposed cycle is compared to a Humid Air Turbine (HAT) cycle with similar features that achieves an overall efficiency of 64.0 percent. The gain in cycle efficiency that can be attributed to the improved fuel oxidation process is 1.4 percentage points. Compared to current high-efficiency gas turbine cycles, the high efficiency of both cycles studied therefore results mainly from the use of staged compression and expansion with intermediate cooling and reheating, respectively.