The Effect of Fossil Fuel Prices on Flexible CO2 Capture Operation

Author(s):  
Stuart M. Cohen ◽  
John Fyffe ◽  
Gary T. Rochelle ◽  
Michael E. Webber

Coal consumption for electricity generation produces over 30% of U.S. carbon dioxide (CO2) emissions, but coal is also an available, secure, and low cost fuel that is currently utilized to meet roughly half of America’s electricity demand. While the world transitions from the existing fossil fuel-based energy infrastructure to a sustainable energy system, carbon dioxide capture and sequestration (CCS) will be a critical technology that will allow continued use of coal in an environmentally acceptable manner. Techno-economic analyses are useful in understanding the costs and benefits of CCS. However, typical techno-economic analyses of post-combustion CO2 capture systems assume continuous operation at a high CO2 removal, which could use 30% of pre-capture electricity output and require new capacity installation to replace the output lost to CO2 capture energy requirements. This study, however, considers the inherent flexibility in post-combustion CO2 capture systems by modeling power plants that vary CO2 capture energy requirements in order to increase electricity output when economical under electricity market conditions. A first-order model of electricity dispatch and a competitive electricity market is used to investigate flexible CO2 capture in response to hourly electricity demand variations. The Electric Reliability Council of Texas (ERCOT) electric grid is used as a case study to compare plant and grid performance, economics, and CO2 emissions in scenarios without CO2 capture to those with flexible or inflexible CO2 capture systems. Flexible CO2 capture systems can choose how much CO2 to capture based on the competition between CO2 and electricity prices and a desire to either minimize operating costs or maximize operating profits. Coal and natural gas prices have varying degrees of predictability and volatility, and the relative prices of these fuels have a major impact on power plant operating costs and the resulting plant dispatch sequence. Because the chosen operating point in a flexible CO2 capture system affects net power plant efficiency, fuel prices also influence which CO2 capture operating point may be the most economical and the resulting dispatch of power plants with CO2 capture. Several coal and natural gas price combinations are investigated to determine their impact on flexible CO2 capture operation and the resulting economic and environmental impacts at the power plant and electric grid levels. This study investigates the costs and benefits of flexible CO2 capture in a framework of a carbon-constrained future where the effects of major energy infrastructure changes on fuel prices are not entirely clear.

Author(s):  
Ana R. Diaz

The tendency in the world energy demand seems clear: it can only grow. The energetic industry will satisfy this demand-despite all its dialectic about new technologies-at least medium term mostly with current fossil fuel technologies. In this picture from an engineer’s point of view, one of the primary criterions for mitigating the effects of increasing atmospheric concentration of CO2 is to restrict the CO2 fossil fuel emissions into the atmosphere. This paper is focused on the analysis of different CO2 capture technologies for power plants. Indeed, one of the most important goal to concentrate on is the CO2 capture energy requirements, as it dictates the net size of the power plant and, hence, the net cost of power generation with CO2 avoidance technologies. Here, the Author presents a critical review of different CO2 absorption capture technologies. These technologies have been widely analyzed in the literature under chemical and economic points of view, leaving their impact on the energy power plant performance in a second plan. Thus, the central question examined in this paper is the connection between abatement capability and its energetic requirements, which seriously decrease power generation efficiency. Evidencing that the CO2 capture needs additional technical effort and establishing that further developments in this area must be constrained by reducing its energy requirements. After a comprehensive literature revision, six different chemical absorption methods are analyzed based on a simplified energetic model, in order to account for its energetic costs. Furthermore, an application case study is provided where the different CO2 capture systems studied are coupled to a natural gas cogeneration power plant.


2006 ◽  
Vol 10 (3) ◽  
pp. 71-80
Author(s):  
Nikolaos Koukouzas ◽  
Paraskevas Klimantos ◽  
Prokopis Stogiannis ◽  
Emmanouel Kakaras

The aim of this paper is to examine the possibilities for the abatement of CO2 emissions in the Greek fossil fuel power generation sector. An overview of CO2 capture, transportation, and storage concepts, on which the R&D community is focused, is presented. The implementation of post-combustion CO2 capture options in an existing fossil fuel power plant is then examined and the consequences on the overall plant performance are determined. Finally, the possibilities of transportation and then underground storage of the pure CO2 stream are analyzed taking into account both technical and economical factors. The results of this analysis show that CO2 sequestration is technically feasible for existing fossil fuel fired power plants in Greece. However, substantial reduction in plant efficiency is observed due to increased energy demand of the technologies used as well as in electricity production cost due to capital and operation costs of capture, transport, and storage of CO2. .


2019 ◽  
Vol 8 (4) ◽  
pp. 9449-9456

This paper proposes the reliability index of wind-solar hybrid power plants using the expected energy not supplied method. The location of this research is wind-solar hybrid power plants Pantai Baru, Bantul, Special Region of Yogyakarta, Indonesia. The method to determine the reliability of the power plant is the expected energy not supplied (EENS) method. This analysis used hybrid plant operational data in 2018. The results of the analysis have been done on the Pantai Baru hybrid power plant about reliability for electric power systems with EENS. The results of this study can be concluded that based on the load duration curve, loads have a load more than the operating kW of the system that is 99 kW. In contrast, the total power contained in the Pantai Baru hybrid power plant is 90 kW. This fact makes the system forced to release the load. The reliability index of the power system in the initial conditions, it produces an EENS value in 2018, resulting in a total value of 2,512% or 449 kW. The EENS value still does not meet the standards set by the National Electricity Market (NEM), which is <0.002% per year. Based on this data, it can be said that the reliability of the New Coast hybrid power generation system in 2018 is in the unreliable category.


2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Bilal Hassan ◽  
Oghare Victor Ogidiama ◽  
Mohammed N. Khan ◽  
Tariq Shamim

A thermodynamic model and parametric analysis of a natural gas-fired power plant with carbon dioxide (CO2) capture using multistage chemical looping combustion (CLC) are presented. CLC is an innovative concept and an attractive option to capture CO2 with a significantly lower energy penalty than other carbon-capture technologies. The principal idea behind CLC is to split the combustion process into two separate steps (redox reactions) carried out in two separate reactors: an oxidation reaction and a reduction reaction, by introducing a suitable metal oxide which acts as an oxygen carrier (OC) that circulates between the two reactors. In this study, an Aspen Plus model was developed by employing the conservation of mass and energy for all components of the CLC system. In the analysis, equilibrium-based thermodynamic reactions with no OC deactivation were considered. The model was employed to investigate the effect of various key operating parameters such as air, fuel, and OC mass flow rates, operating pressure, and waste heat recovery on the performance of a natural gas-fired power plant with multistage CLC. The results of these parameters on the plant's thermal and exergetic efficiencies are presented. Based on the lower heating value, the analysis shows a thermal efficiency gain of more than 6 percentage points for CLC-integrated natural gas power plants compared to similar power plants with pre- or post-combustion CO2 capture technologies.


Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
Joa˜o Roberto Barbosa

In the Ecuadorian electrical market, several sugar plants, which significantly participate in the local electricity market, are producing their own energy and commercializing the surplus to the electrical market. This study evaluates the integral use of the sugar cane bagasse for productive process on a Cogeneration Power Plant in an Ecuadorian Sugar Company [8]. The electrical generation based on biomass requires a great initial investment. The cost is around US$ 800/kW installed, twice the US$ 400/kW initial investment of conventional thermoelectric power plant and almost equal to the US$ 1,000/kW initial cost of hydroelectric power plant [5]. A thermoeconomic study was carried out on the production of electricity and the sales of the surplus of 27 MWe average produced by the power plant. An operational analysis was made using instantaneous values from the estimated curves of demand and generation of electricity. From the results, it was concluded that the generated electricity costs are 0.0443 US$/kWh, while the costs of the electricity from Fossil Power Plants (burning fuel oil, diesel fuel and natural gas) are in the range 0.03–0.15 US$/kWh and from Hydroelectric Plants are about 0.02 US$/kWh. Cogeneration power plants burning sugar cane bagasse could contribute to the mitigation of climatic change. This specific case study shows the reduction of the prospective emissions of greenhouse gases, around 55,188 ton of CO2 equivalent yearly for this cogeneration power plant.


2011 ◽  
Vol 4 (4) ◽  
pp. 5147-5182
Author(s):  
V. A. Velazco ◽  
M. Buchwitz ◽  
H. Bovensmann ◽  
M. Reuter ◽  
O. Schneising ◽  
...  

Abstract. Carbon dioxide (CO2) is the most important man-made greenhouse gas (GHG) that cause global warming. With electricity generation through fossil-fuel power plants now as the economic sector with the largest source of CO2, power plant emissions monitoring has become more important than ever in the fight against global warming. In a previous study done by Bovensmann et al. (2010), random and systematic errors of power plant CO2 emissions have been quantified using a single overpass from a proposed CarbonSat instrument. In this study, we quantify errors of power plant annual emission estimates from a hypothetical CarbonSat and constellations of several CarbonSats while taking into account that power plant CO2 emissions are time-dependent. Our focus is on estimating systematic errors arising from the sparse temporal sampling as well as random errors that are primarily dependent on wind speeds. We used hourly emissions data from the US Environmental Protection Agency (EPA) combined with assimilated and re-analyzed meteorological fields from the National Centers of Environmental Prediction (NCEP). CarbonSat orbits were simulated as a sun-synchronous low-earth orbiting satellite (LEO) with an 828-km orbit height, local time ascending node (LTAN) of 13:30 (01:30 p.m.) and achieves global coverage after 5 days. We show, that despite the variability of the power plant emissions and the limited satellite overpasses, one CarbonSat can verify reported US annual CO2 emissions from large power plants (≥5 Mt CO2 yr−1) with a systematic error of less than ~4.9 % for 50 % of all the power plants. For 90 % of all the power plants, the systematic error was less than ~12.4 %. We additionally investigated two different satellite configurations using a combination of 5 CarbonSats. One achieves global coverage everyday but only samples the targets at fixed local times. The other configuration samples the targets five times at two-hour intervals approximately every 6th day but only achieves global coverage after 5 days. From the statistical analyses, we found, as expected, that the random errors improve by approximately a factor of two if 5 satellites are used. On the other hand, more satellites do not result in a large reduction of the systematic error. The systematic error is somewhat smaller for the CarbonSat constellation configuration achieving global coverage everyday. Finally, we recommend the CarbonSat constellation configuration that achieves daily global coverage.


Author(s):  
Moritz Hübel ◽  
Jens Hinrich Prause ◽  
Conrad Gierow ◽  
Egon Hassel ◽  
Raphael Wittenburg ◽  
...  

The increasing share of fluctuating renewable energy sources leads to changing requirements for conventional power plants. The changing characteristics of the residual load requires the conventional fleet to operate with higher load gradients, lower minimum load at improved efficiency levels as well as faster start-ups and provision of ancillary services. Despite the requirements from the electricity market, the value of improving those flexibility parameters is hard to evaluate for power plant operators. In order to quantify the additional benefit that can be achieved by improving flexibility parameters on a certain power plant in a changing market environment, an adjustable load dispatch model has developed for that purpose. Using past electricity market data, the model is validated for typical coal and a typical gas fired power plants by reproducing their operational schedule. In the next step, the model is used to apply parameter changes to the power plants specifications and economic effects are demonstrated. General statements are derived on which flexibility parameter needs to be improved on each power plant type. Furthermore, specific economic evaluations are shown for the reference power plants in order to present the ability of the developed tool to support investment decisions for modernization projects of existing power plants.


Author(s):  
John R. Fyffe ◽  
Stuart M. Cohen ◽  
Michael E. Webber

Coal-fired power plants are a source of inexpensive, reliable electricity for many countries. Unfortunately, their high carbon dioxide (CO2) emissions rates contribute significantly to global climate change. With the likelihood of future policies limiting CO2 emissions, CO2 capture and sequestration (CCS) could allow for the continued use of coal while low- and zero-emission generation sources are developed and implemented. This work compares the potential impact of flexibly operating CO2 capture systems on the economic viability of using CCS in gas- and coal-dominated electricity markets. The comparison is made using a previously developed modeling framework to analyze two different markets: 1) a natural-gas dominated market (the Electric Reliability Council of Texas, or ERCOT) and 2) a coal-dominated market (the National Electricity Market, or NEM in Australia). The model uses performance and economic parameters for each power plant to determine the annual generation, CO2 emissions, and operating profits for each plant for specified input fuel prices and CO2 emissions costs. Previous studies of ERCOT found that flexible CO2 capture operation could improve the economic viability of coal-fired power plants with CO2 capture when there are opportunities to reduce CO2 capture load and increase electrical output when electricity prices are high. The model was used to compare the implications of using CO2 capture systems in the two electricity systems under CO2 emissions penalties from 0–100 US dollars per metric ton of CO2. Half the coal-fired power plants in each grid were selected to be considered for a CO2 capture retrofit based on plant efficiency, whether or not SO2 scrubbers are already installed on the plant, and the plant’s proximity to viable sequestration sites. Plants considered for CO2 capture systems are compared with and without inflexible CO2 capture as well as with two different flexible operation strategies. With more coal-fired power plants being dispatched as the marginal generator and setting the electricity price in the NEM, electricity prices increase faster due to CO2 prices than in ERCOT where natural gas-plants typically set the electricity price. The model showed moderate CO2 emissions reductions in ERCOT with CO2 capture and no CO2 price because increased costs at coal-fired power plants led to reduced generation. Without CO2 prices, installing CO2 capture on coal-fired power plants resulted in moderately reduced CO2 emissions in ERCOT as the coal-fired power plants became more expensive and were replaced with less expensive natural gas-fired generators. Without changing the makeup of the plant fleet in NEM, a CO2 price would not currently promote significant replacement of coal-fired power plants because there is minimal excess capacity with low CO2 emissions rates that can displace existing coal-fired power plants. Additionally, retrofitting CO2 capture onto half of the coal-based fleet in NEM did not reduce CO2 emissions significantly without CO2 costs being implemented because the plants with capture become more expensive and were replaced by the coal-fired power plants without CO2 capture. Operating profits at NEM capture plants increased as CO2 price increased much faster than capture plants in ERCOT. The higher rate of increasing profits for plants in NEM is due to the marginal generators in NEM being coal-based facilities with higher CO2 emissions penalties than the natural gas-fired facilities that set electricity prices in ERCOT. Overall, coal-fired power plants were more profitable with CO2 capture systems than without in both ERCOT and NEM when CO2 prices were higher than USD25/ton.


2011 ◽  
Vol 1 (1) ◽  
pp. 72-82 ◽  
Author(s):  
Luis M. Romeo ◽  
David Catalina ◽  
Pilar Lisbona ◽  
Yolanda Lara ◽  
Ana Martínez

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