Gas Fueled Power Plant Research Articles

Experimental implementation of extremum-seeking control: Gas fuel efficiency at electrical generation under power requirements

A current challenge stands for operating the emergency power system (EPS) that involves the challenge of supplying sufficient electrical energy at same time the fuel consumption is minimum. A complication arises as power requirements change during the EPS operation which can be seen as uncertain load disturbances. In such a context, the extremum-seeking (ES) is alternative towards the efficient energy conversion when control goal involves fuel optimization along the time operation. Here, the dynamical response of a gas fueled power plant is identified via Hammerstein model. The model is realized such that an ES control is designed for automatically reaching an extreme in face to distinct (unmeasured and uncertain) power requirements. The ES control is designed and experimentally tested at an electrical generator at distinct power requirements. The results show the minimum gas fuel consumption remains in face to distinct power requirements.

Small-scale Bio Gas Combined Heat and Power Plant with Biochar Catalyst

Alternative energy sources allows to replace traditional fossil fuels and firewood. However the most widely used wind and solar power plants can not provide constant power generation due to multiple factors that makes necessary to develop new types of power sources and to to improve efficiency of already existing ones. One of such energy sources are bio gas-fueled power plants which allow to combine the power generation and organic waste disposal functions. Efficiency and quality of bio gas production in such facilities can be significantly increased by using different catalysts such as biochar. A brief analysis of biochar production usage perspectives was held which showed that it can be used in different applications and can significantly increase efficiency of different technological processes. The influence of biochar on the biogas production processes was studied. The structure of bio gas-fueled heat and power plant with local bio gas generation was proposed.

Retrofit of a standard split-type air conditioner into an air-to-water heat pump

In the context of the rising prices of energy and especially of natural gas, the interest in heat pumps has grown steadily over the last period, as they are a very convenient alternative to low and medium power thermal plants. Although the price of heat pumps has dropped a lot recently, these systems are still very expensive compared to the wall-mounted natural gas fuelled power plants found in the vast majority of residential buildings in Romania. In this context, the authors proposed the conversion of an inverter type air conditioner into an air-water heat pump with minimal costs, maintaining and even improving the global performance of the system. The newly made heat pump was tested at variable regimes in the Cogeneration Trigeneration Laboratory of the Faculty of Mechanical Engineering of Iasi. The external unit was inserted into a climatic chamber capable of simulating variable climatic conditions for any region in Europe. Later, the same heat pump was tested in real operating conditions, being inserted in the heating circuit of a medium-sized house in the Iasi area. Its operation was then monitored during an entire winter season, being instrumented to measure the energetic balance and determine the coefficient of performance (COP) continuously throughout the season, in accordance with the weather conditions and also to measure the seasonal coefficient of performance (SCOP).

Multi-objective optimisation of a power generation system integrating solid oxide fuel cell and recuperated supercritical carbon dioxide cycle

This article presents an advanced power generation system that integrates a solid oxide fuel cell (SOFC) module with a recuperated supercritical CO2 (s-CO2) cycle. The waste heat generated by the exhaust of the SOFC module is utilised to drive the s-CO2 cycle, resulting in enhanced energy efficiency. The performance of the system was investigated through thermodynamic and economic analyses and optimised using response surface methodology. The optimisation process focused on two objectives: maximising the energy efficiency of the integrated system and minimising the levelised cost of electricity. The study meticulously analysed the effects of important variables such as current density, fuel utilisation factor, and operating temperature of the fuel cell. The optimisation efforts yielded impressive results, achieving an energy efficiency of 64% and a levelised cost of electricity (LCOE) of 0.18£/kWh. The proposed system surpassed traditional natural gas-fuelled power plants in terms of efficiency and specific emissions. Furthermore, the system's performance was evaluated when operated with green hydrogen fuel, which led to a substantial improvement in efficiency, estimated at 73.37%. However, it was found that the LCOE of the system is relatively higher and approximately 15% higher than the methane-based alternative.

Developing Coal Bed Methane Gas Utilization Pilot Project To Produce Residential Electricity

Coal Bed Methane pilot project has produced around 80 m3 CBM gas containing around 14,66% volume of CO2 and 85,34% volume of CH4. CO2 has to be removed, the methane gas can be utilized to produce residential electricity applying the lattest technology. Some equipment need to be installed in place at proposed CBM gas site plant to produce the electricity of around 150 KWe per day or 51,75 MWe per annum from which the pilot project can be scaled up to 1 x 55 MW gas fuelled power plant.

Solid Oxide Cell Technology for Supply, Recovery, and Storage Energy

Fuel Cell Energy, Inc. (FCE) is advancing the current state of Solid Oxide Fuel Cell (SOFC) technology towards commercial deployment for efficient and nonpolluting generation of electric power from natural gas and biomass derived fuels. Additionally, FCE is utilizing the same solid oxide cell and stack technology in electrolysis of steam for production of hydrogen from renewable sources and other electric power sources, such as nuclear power plants during the curtailment periods. Additionally, FCE’s SOFC technology has shown to be a viable technology for storage of energy by cyclic charge and discharge operation.FCE’s SOFC technology is based on anode supported thin electrolyte planar cell platform chosen for its higher power density at reduced operating temperature (700-800°C). Traditional materials, such as Ni/YSZ anodes, YSZ electrolytes and perovskite cathodes have been utilized in a basic cell structure. Research and development focus has been placed on developing better electrochemical functional areas at both cathode/electrolyte and anode/electrolyte interfaces. This was achieved through material advancements, microstructure optimization, and manufacturing process integration.The solid oxide stack is comprised of planar solid oxide fuel cells with glass ceramic seals and sheet metal, bipolar plate interconnects; and has a mix of internal and external gas manifolds. Each cell is a 0.30 mm thick annular (donut shaped), cell with 81 cm2 active area made in a process consisting of tape casting, screen printing, and firing cell components. The full height stack consists of 350 repeat units and a set of non-repeat parts. A repeat unit includes one ceramic cell, inner and outer seals, and a metallic interconnect which incorporates flow fields for both fuel and oxidant. Non-repeat parts include the end plates, manifolds, and compression components. The stack is capable of producing 7kW power when fueled with natural gas, biogas, hydrogen, or other fuels. The same stack is capable of operating at higher power density in electrolysis mode, producing 25 kg/day hydrogen with 36 kW power input.FCE’s SOFC system design philosophy is based on using factory-assembled stack building blocks, which in turn may be used to fabricate larger multi-stack modules for applications in centralized natural gas and coal fueled power plants. An attractive pathway to deployment of SOFC systems is through near-term market opportunities in natural gas fueled distributed generation (DG) applications. FCE is planning to take the advantage of the scalability, modularity, and fuel flexibility of the SOFC technology to transition the technology from small (sub-MW) systems to megawatt class power plants for distributed generation, and ultimately (through aggregation of fuel cell modules) to large stationary power plants for base-load utility applications using coal and/or natural gas fuel.FCE has recently designed, fabricated, and tested a 200kW natural gas fueled packaged system. This autonomous unit is an outdoor rated power system with capabilities for both grid-connection as well as island operation.Electricity storage is a growing need given the increasing penetration of intermittent renewable sources of solar and wind. Traditional battery storage technology uses rare materials that could pose sourcing challenges and depletion with widespread adoption. Hydrogen based energy storage is the only practical way to store the GWh of energy that will need to be stored to enable significant penetration of intermittent renewable energy on the electricity grid. Another advantage of hydrogen based energy storage is that once hydrogen is stored it can be used to make power, or exported for another use such as vehicle fueling or industrial uses.

CO2 quota attribution effects on the European electricity system comprised of self-centred actors

Abstract We propose to rethink collaboration between the European countries to robustly materialise the electricity system of the near future. The European countries all agree that carbon dioxide ( CO 2 ) emissions need to be decreased. The dividing question is who must contribute by how much. Three aspects of collaboration are investigated and set into relation to one another. First, the individual countries can be attributed a CO 2 emission quota in different ways. Second, they can collaborate by relaxing their need for autonomy, e.g. becoming less self-sufficient by placing generation capacity in countries with better prerequisites. Third, collaboration can also be strengthened by extending the cross-border transmission grid. We investigate a near future European electricity system where the primary source of emission-neutral electricity is coming from different variable renewable energy sources, but which also includes current and planned nuclear, coal, lignite and gas-fuelled power plants. We show that different CO 2 emission quota attributions have an immense effect on the required local CO 2 prices. Furthermore, we investigate how this influences the technology mix in the individual countries. We conclude that it is significantly easier for certain countries to decarbonise their electricity production than for others. The difficulty in the specific country depends strongly on how emission allowances are allocated in Europe. Deep collaboration between the countries leads both to a lowered total system cost and, perhaps even more importantly, to CO 2 emissions and required CO 2 prices that are much more equal between the European partners.

Improving the Business Case for CCS in the Electric Power Generation Industry

Supporting new, high impact energy and environmentally friendly initiatives has been a regular and important component of US tax policy. A production tax credit (PTC) of up to 2.3 cents per kWh (now reduced) was available for electricity generated by wind. Solar photovoltaic projects receive a 30% investment tax credit (ITC). These tax credits, along with state-level renewable performance standards, have significantly increased investments in renewables and supported their growth in the electricity generation sector. A similar opportunity now exists for supporting accelerated installation of large-scale Carbon Capture and Storage (CCS) in the US electric power generation industry. Section 45Q of the US tax code represents a first, but still insufficient, step for covering the costs of using CCS with electric power generation. It provides a $50 per metric ton (mt) tax credit for captured CO2 stored in geological formations and a $35 per mt tax credit for captured CO2 used and stored with enhanced oil recovery. However, the 45Q tax credits contain limitations, including-- a rapidly approaching “commence construction” deadline, limited years for claiming the tax credit, a tax credit level insufficient for economically viable installation of CCS by natural gas-fueled power plants, and little support for first-of-a-kind (FOAK), higher CO2 capture rate facilities. In a previous paper (Esposito, et al., 2019), the authors illustrated the basic arithmetic for assessing the economic viability of CCS in the electric power generation industry with availability of the Section 45Q tax credits, including an extensive look at the business case for installing CCS by coal-fueled power plants. This paper discusses a series of modifications to the Section 45Q tax credit, as well as additional steps, that would improve the business case for installing CCS on natural gas-fueled power plants. The paper addresses the following topics: • Extending the Commence Construction Date for the Section 45Q Tax Credit. Given a fast-approaching deadline, the paper provides a series of arguments for extending the “commence construction” date for eligibility for the Section 45Q tax credit. • Increasing the Time Period for Eligibility for the Section 45Q Tax Credit. The paper examines how the business case for CCS would be improved by increasing the time of eligibility for the Section 45Q tax credit to 20 years from the current 12 years. • Increasing the Value of the Tax Credit for Natural Gas-Fueled Power Generation. The overall CO2 capture costs at a natural gas-fueled plant are about 60% as much as at an equivalent generation capacity coal-fueled power plant. However, the volume of CO2 produced from a natural gas-fueled power plant is about 40% as much as from a coal-fueled plant. As such, the per-ton costs of capturing CO2 at a natural gas power plant are 1.5 times higher than the per-ton costs of capturing CO2 at a coal-fueled power plant. Since the Section 45Q tax credit rate was designed to approximately cover the cost of CO2 capture at a coal-fueled power plant, it needs to be increased by about 50% to cover the cost of CO2 capture at a natural gas-fueled power plant. • Providing Incentives for Higher Capture Rate, FOAK Plants. The paper also examines how a more robust set of incentives, including modified Section 45Q tax credits and other options, could help overcome the barriers facing first-of-a-kind (FOAK), high (95%+) CO2 capture rate plants. • Providing Section 48A Investment Tax Credits for Natural Gas-Fueled Power Plants. The paper examines how expansion of the eligibility for the Section 48A investment tax credit could support installation of CCS at natural gas-fueled power plants.

Risk Analysis of Associated Gas Utilization in Power Plants

This study presents the analysis of associated gas fueled gas turbine power plant with a view to harnessing associated gas. GASTURB performance simulation software was employed to model and simulate the design and off design performance of the various engines that made up the power plant investigated. Monte Carlo Simulation using Palisade’s @RISK software was employed to conduct the risk analysis of associated fueled gas turbine by incorporating different variables. A decline rate of -13% was applied over the 20-year period of power plant life, beginning from Year 2015. When the distribution curves for the clean and degraded conditions of DS25 engine set were compared, the plots show that the clean condition generates higher profit than the degraded condition. Also, when the clean condition for DS25 and LM6K engine sets were compared, the distribution curve plots show that the cluster of DS25 engine set generates a higher profit than the LM6K engine set.

Risk Analysis of Associated Gas Utilization in Power Plants

This study presents the analysis of associated gas fueled gas turbine power plant with a view to harnessing associated gas. GASTURB performance simulation software was employed to model and simulate the design and off design performance of the various engines that made up the power plant investigated. Monte Carlo Simulation using Palisade’s @RISK software was employed to conduct the risk analysis of associated fueled gas turbine by incorporating different variables. A decline rate of -13% was applied over the 20-year period of power plant life, beginning from Year 2015. When the distribution curves for the clean and degraded conditions of DS25 engine set were compared, the plots show that the clean condition generates higher profit than the degraded condition. Also, when the clean condition for DS25 and LM6K engine sets were compared, the distribution curve plots show that the cluster of DS25 engine set generates a higher profit than the LM6K engine set.

Unit Commitment With Gas Network Awareness

Recent changes in the fuel mix for electricity generation and, in particular, the increase in Gas-Fueled Power Plants (GFPP), have created significant interdependencies between the electrical power and natural gas transmission systems. However, despite their physical and economic couplings, these networks are still operated independently, with asynchronous market mechanisms. This mode of operation may lead to significant economic and reliability risks in congested environments as revealed by the 2014 polar vortex event experienced by the northeastern United States. To mitigate these risks, while preserving the current structure of the markets, this paper explores the idea of introducing gas network awareness into the standard unit commitment model. Under the assumption that the power system operator has some (or full) knowledge of gas demand forecast and the gas network, the paper proposes a tri-level mathematical program where natural gas zonal prices are given by the dual solutions of natural-gas flux conservation constraints and commitment decisions are subject to bid-validity constraints that ensure the economic viability of the committed GFPPs. This tri-level program can be reformulated as a single-level Mixed-Integer Second-Order Cone program which can then be solved using a dedicated Benders decomposition. The approach is validated on a case study for the Northeastern United States [1] that can reproduce the gas and electricity price spikes experienced during the early winter of 2014. The results on the case study demonstrate that gas awareness in unit commitment is instrumental in avoiding the peaks in electricity prices while keeping the gas prices to reasonable levels.

Life cycle assessment of natural gas fuelled power plants based on chemical looping combustion technology

Among the different Carbon Capture and Storage (CCS) technologies being developed in the last decades, Chemical Looping Combustion (CLC) stands out since it allows inherent CO2 capture. In the CLC process, there is a solid oxygen carrier circulating between two reactors in a cycle that allows providing the oxygen needed for combustion. In one of the reactors, named as fuel reactor, the fuel is introduced and combusted while the oxygen carrier reduction takes place. In the second reactor, named air reactor, the oxygen carrier is reoxidized in air. Different materials based on copper, nickel and iron oxides have been proposed as oxygen carriers for the CLC process. This work presents an environmental evaluation of the CLC process for natural gas based on Life Cycle Assessment (LCA). Five different oxygen carrier materials already tested in pilot plants were considered and the results compared to the conventional natural gas combustion in a gas turbine in a combined cycle without and with CO2 capture using postcombustion capture with amines. In view of the results, lower impact of the CLC process compared to the base case is expected without and with CO2 capture. The influence of several variables on the results was considered, such as temperature in the air reactor, lifetime of the oxygen carrier and possibility of recuperation of the depleted oxygen carrier. The nickel-based oxygen carriers were identified as the most adequate to be used in natural gas combustion. However, due to their toxicity, several analyses were also performed in order to identify improvements in the known oxygen carriers that can qualify them to replace nickel-based materials.

Selection and design of post-combustion CO2 capture process for 600 MW natural gas fueled thermal power plant based on operability

Post-combustion CO2 capture (PCC) plant for a typical 600 MW natural gas fueled thermal power plant was designed as a trade-off between operability and mitigation of the efficiency penalty. Two modified PCC plant configurations with low efficiency penalty were selected. The methodology for designing PCC plants was adapted by incorporating design constraints based on operability and the construction of absorbers. This was applied in sizing the equipment of the plants. Two configurations of absorbers were analyzed based on flue gas flow rate at full-load condition and at time-average of an assumed load variation of a power plant operating flexibly. It was found that the absorber designed at time-average load provided a reduction of approximately 4% in the purchased cost of absorbers. The performance of the designed plants under power plant load variation, flow maldistribution and variable capture ratio was analyzed using off-design condition simulations. The absorber designed at full-load condition was found to lead to lower reboiler duty in order to maintain a similar capture rate to that of the other absorber during part-load operation. Dynamic simulations of the plants with the existing control structure were performed under similar power plant load variations to confirm their operability, and suggestions for selecting one of them were presented.

Degenerate optimization problems and competitiveness of NPPs

Optimization of large systems in economy and power generation produces multi-dimensional degenerate solutions [1,2]. This implies the need to deal with very serious mathematical complications. On the other hand, it allows regarding future development of power generation as combined operation of nuclear power plants (NPPs), power plants (PPs) fueled with coal and gas-fueled power plants. Systems optimization of NPP parameters is necessary in order to accomplish this goal.If PP of certain type fails to be included in the optimal plan of development of electric power generation system it means that by definition is it not optimal and, hence, it is not competitive.NPP can succeed to be included in the optimal plan of development of electric power generation system. In such case, if in locally-optimal plans of development of electric power generation system the nuclear power units (NPPs) put into operation earlier interrupt after operation under load during certain period generation of power (power supply) to “zero” for the time interval exceeding the time period required for implementation of scheduled maintenance operations it signifies that the chosen parameters and operation modes are not optimal. Such NPPs will demonstrate competitiveness only during time intervals when the electric power system allows them to be operated under load.If nuclear power units (NPPs) put into operation during earlier stages stop their work (are removed from operation) before expiration of the design service life for any reasons which are not associated with “moral” ageing of equipment it also signifies that the chosen parameters and operation modes are not optimal. It signifies as well the failure of these NPPs to demonstrate their competitiveness.NPP which is included in the optimal plan of development of electric power generation system and was operated without interruptions under load during the design service life can be regarded as competitive.Since, as it was demonstrated by the performed systems optimization calculations of power generation in Russia, the examined options of NPPs with fast reactors (SVBR-100, BN-1200 (three-circuit), BREST-1200) appeared to be included not into all optimal plans, there is a place for certain doubts that the chosen parameters of the NPPs and the associated nuclear fuel cycles (NFCs) are not competitive although strenuous multi-parameter research in this direction is ongoing during already several decades.

Cost-analysis of health impacts associated with emissions from combined cycle power plant

The economic assessment of expected air pollution levels and its associated health impact requires different investigational stages, including an analysis of specific air pollutants and their emission rates, calculations of air shed concentrations, measurements of exposure, correlations with human health risk responses to air pollutants' exposure changes, and a monetization of human health risks. The study aims to assess the monetary value of pollutant concentrations and the expected risks of those pollutants on human mortality and morbidity as path of a cost analysis. The pollutants carbon monoxide (CO), nitrogen dioxide (NO2), fine particles (PM2.5), and sulfur dioxide (SO2) from a sample natural gas fueled combined cycle power plant were chosen based on their emission rates and their severity on the health impacts with which they are associated. The SCREEN3 dispersion model was used to obtain pollutant concentration estimates, and an air pollutant health impact matrix was established based on health data pooled throughout the study period. To lessen the health impact from natural gas fuel, hydrogen-enriched natural gas (HENG) was used to fuel the combined cycle power plant. The desired hydrogen was collected from renewable energy sources through the electrolysis process in an energy hub system. The Health Canada's Air Quality Benefits Assessment Tool was used for monetizing the impacts of pollutants on health by taking into account a range of morbidity and mortality outcomes as well as their dollar value, when the natural gas and the hydrogen enriched natural gas fuels were used. The total hidden costs of health impacts associated with producing electricity averaged CAD$33.50 per megawatt hour based on the selected area and year in which the scenario was run. It was found that fuelling combined cycle power plant with hydrogen-enriched natural gas up to 5% hydrogen concentrations could save CAD$1.15 per megawatt hour in terms of health impact costs. The health impact cost of PM2.5 had the highest value followed by NO2, SO2, and CO.

APPLICATION OF MOSS AS BIO-MONITOR FOR HEAVY METALS DEPOSITION IN PORT DICKSON, MALAYSIA

Port Dickson in Malaysia is a sea-side township of mixed activities within the area, comprising of a coal-fired power plant, a petroleum refinery, a gas-fuelled power plant, and tourism with the visit of many road vehicles, especially during weekends and public holidays. The impact of emission from these activities to the environment has becomes a matter of concern to the authorities as well as local residents. The present study embarked on the use of mosses (Octoblepharum sp. & Isopterygium sp.) as long terms monitor of heavy metals emission from such activities. Mosses samples were collected on land area within 30 km radius from the town centre. Prepared samples were analysed for the concentration of As, U, Th, Fe, Cr and Zn using Neutron Activation Analysis (NAA) technique. These metals are related to various industries, fuel combustion and refineries emissions. Although the results show no elevated concentration of the elements studied, except for Cr, the spatial pattern of heavy metal distributions observed reflected the energy-related activities and vehicular emissions in the study area. Enrichment Factor values of each element also in agreement with the distribution pattern. The research finding suggests that ‘moss-method’ is applicable for deposition measurement in vicinity of stationary as well as non-point sources.

Modelling the Weekly Electricity Demand Caused by Electric Cars

As transport is one of the big sources of carbon dioxide emissions, it is natural to seek for solutions reducing the carbon dioxide emissions in transport as well. Replacing cars powered by a combustion engine by battery electric vehicles may be one measure to achieve this goal, at least as long as the electricity consumed by these cars is produced carbon neutral or in a low-carbon manner. In Germany, the Federal Government aims at a stock of one million electric vehicles in the year 2020. This goal is very ambitious, since customers are reluctant to buy battery electric cars, probably most of all due to their limited range. A possible solution to the limited range problem is the use of Plug-in Hybrid Electric Vehicles or Extended Range Electric Vehicles (EREV), combining an electric battery with a combustion engine or a generator. These solutions overcome the range limitations while at the same time allowing driving on electric power for the majority of the total mileage.In this paper, we analyse the effects of an increased use of EREVs and battery electric vehicles using the travel demand model mobiTopp. For three scenarios with different rates of market penetration of electric vehicles, the travel demand and car usage is simulated over a simulation period of one week. The results show, that for 65 up to 70 percent of the mileage, EREVs can be driven in battery-only mode, demonstrating the usefulness of the EREV concept and indicating a substantial potential for the reduction of carbon dioxide emissions. The results, however, also show that with an uncontrolled charging strategy, i. e. every car recharges immediately after accessing a charging location, the peaks of electricity demand for charging the electric cars occurs when the general electricity demand is already high. During these periods, additional electricity demand is typically covered by gas-fuelled power plants, thus using fossil fuels. Therefore, the concept of introducing electric vehicles in order to reduce total carbon dioxide emissions can only succeed if combined with intelligent charging strategies.

Full Chain Analysis and Comparison of Gas-Fired Power Plants with Co2 Capture and Storage with Clean Coal Alternatives

This paper presents the new models developed for the natural gas fuelled power generation chain, involving various natural gas production methods, gas processing routes, gas transport options, and alternative gas based power generation with/without CO2 capture. The comprehensive and quantitative Life Cycle Inventory (LCI) database developed models inputs/outputs of processes at high level of detail, allowing to account for technical and geographic differences in the power generation value chain scenarios analysed. With the advantage of LCI models developed at unit process level, this work successfully identified the key operational parameters for alternative gas-fuelled power plants and the key component processes that emit the majority of GHGs across the gas supply chains.

Emergency visits and hospital admissions in aged people living close to a gas-fired power plant

BackgroundCombustion of natural gas for energy generation produces less pollutants than coke/oil. However, little is known about the short-term effect of pollution generated by gas-fired power plants on the health of elderly people. MethodsDuring three months, daily emergency visits/hospital admissions of subjects living within 3km from a gas-fueled power plant were counted and related to ambient concentrations of nitrogen dioxide (NO2) and particulate matter of median aerometric diameter <10μm (PM10). A generalized additive model served to correlate visits/hospital admissions to pollutants, controlling for meteorological confounders. ResultsMean air concentrations of PM10 and NO2 were higher after-than before the start of operation of the plant, with the highest concentrations recorded within 1km. Although pollutants were below the limits set by the European legislation, in elderly people there was a positive correlation between the number of emergency visits and daily air concentrations of PM10 and NO2, as measured at 1 and 3km from the plant. In subjects aged 70years or more, the number of hospital admissions was positively correlated with PM10 levels measured within 3km from the power plant, whereas in older subjects (≥80year) it was also significantly linked with the lowest air concentration of PM10 (measured at 6km from the plant). DiscussionCombustion of natural gas for energy generation produces a rise in air concentration of PM10 and NO2 close to the plant, with a concentration-dependent increment of daily emergency visits and hospital admissions in elderly people, and with an age-dependent susceptibility.

COOLCEP (cool clean efficient power): A novel CO2-capturing oxy-fuel power system with LNG (liquefied natural gas) coldness energy utilization☆

A novel liquefied natural gas (LNG) fueled power plant is proposed, which has virtually zero CO 2 and other emissions and a high efficiency. The plant operates as a subcritical CO 2 Rankine-like cycle. Beside the power generation, the system provides refrigeration in the CO 2 subcritical evaporation process, thus it is a cogeneration system with two valued products. By coupling with the LNG evaporation system as the cycle cold sink, the cycle condensation process can be achieved at a temperature much lower than ambient, and high-pressure liquid CO 2 can be withdrawn from the cycle without consuming additional power. Two system variants are analyzed and compared, COOLCEP-S and COOLCEP-C. In the COOLCEP-S cycle configuration, the working fluid in the main turbine expands only to the CO 2 condensation pressure ; in the COOLCEP-C cycle configuration, the turbine working fluid expands to a much lower pressure (near-ambient) to produce more power. The effects of some key parameters, the turbine inlet temperature and the backpressure, on the systems' performance are investigated. It was found that at the turbine inlet temperature of 900 °C, the energy efficiency of the COOLCEP-S system reaches 59%, which is higher than the 52% of the COOLCEP-C one. The capital investment cost of the economically optimized plant is estimated to be about 750 EUR/kWe and the payback period is about 8-9 years including the construction period, and the cost of electricity is estimated to be 0.031-0.034 EUR/kWh.