Reducing CO2 emissions by making cheaper CO2 capture technologies available

2007 ◽  
Author(s):  
Theo C. Klaver
Keyword(s):  
Author(s):  
Shuzhuang Sun ◽  
Hongman Sun ◽  
Paul T Williams ◽  
Chunfei Wu

CO2 is one of the most important greenhouse gases leading to severe environmental issues. The increase of CO2 emissions from the consumption of fossil fuels has received much research attention....


Author(s):  
Theodore Hanein ◽  
Marco Simoni ◽  
Chun Long Woo ◽  
John L Provis ◽  
Hajime Kinoshita

The calcination of calcium carbonate (CaCO3) is a major contributor to carbon dioxide (CO2) emissions that are changing our climate. Moreover, the calcination process requires high temperatures (~900°C). A novel...


Author(s):  
Hannah Chalmers ◽  
Jon Gibbins ◽  
Mathieu Lucquiaud

Carbon capture and storage (CCS) is often identified as an important technology for mitigating global carbon dioxide (CO2) emissions. For example, the IEA currently suggests that 160GW of CCS may need to be installed globally by 2030 as part of action to limit greenhouse gas concentrations to 550ppm-CO2eq, with a further 190GW CCS capacity required if a 450ppm-CO2eq target is to be achieved. Since global rollout of proven CCS technologies is not expected to commence until 2020 at the earliest this represents a very challenging build rate. In these circumstances retrofitting CO2 capture to existing plants, probably particularly post-combustion capture on pulverized coal-fired plants, could play an important role in the deployment of CCS as a global strategy for implementing CO2 emissions reductions. Retrofitting obviously reduces the construction activity required for CCS deployment, since fewer additional new power plants are required. Retrofitting CCS to an existing fleet is also an effective way to significantly reduce CO2 emissions from this sector of the electricity generation mix; it is obviously not possible to effect an absolute reduction in coal power sector CO2 emissions simply by adding new plants with CCS to the existing fleet. Although it has been proposed that plants constructed now and in the future can be ‘capture ready’, much of the existing fleet will not have been designed to be suitable for retrofit of CO2 capture. Some particular challenges that may be faced by utilities and investors considering a retrofit project are discussed. Since it is expected that post-combustion capture retrofits to pulverized coal plants will be the most widely applied option for retrofit to the existing fleet (probably regardless of whether base plants were designed to be capture ready or not), a review of the technical and potential economic performance of this option is presented. Power cycle performance penalties when capture is retrofitted need to be addressed, but satisfactory options appear to exist. It also seems likely that the economic performance of post-combustion capture retrofit could be competitive when compared to other options requiring more significant capital expenditure. Further work is, however, required both to develop a generally accepted methodology for assessing retrofit economics (including consideration of the implications of lost output after retrofit under different electricity selling price assumptions) and to apply general technical principles to case studies where site-specific constraints are considered in detail. The overall conclusion from the screening-level analysis reported in this paper is that, depending on project-specific and market-specific conditions, retrofit could be an attractive option, especially for fast track initial demonstration and deployment of CCS. Any unnecessary regulatory or funding barriers to retrofit of existing plants and to their effective operation with CCS should, therefore, be avoided.


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.


Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 361 ◽  
Author(s):  
Rubén Rodríguez-Alegre ◽  
Alba Ceballos-Escalera ◽  
Daniele Molognoni ◽  
Pau Bosch-Jimenez ◽  
David Galí ◽  
...  

Anaerobic digestion of sewage sludge produces large amounts of CO2 which contribute to global CO2 emissions. Capture and conversion of CO2 into valuable products is a novel way to reduce CO2 emissions and valorize it. Membrane contactors can be used for CO2 capture in liquid media, while bioelectrochemical systems (BES) can valorize dissolved CO2 converting it to CH4, through electromethanogenesis (EMG). At the same time, EMG process, which requires electricity to drive the conversion, can be utilized to store electrical energy (eventually coming from renewables surplus) as methane. The study aims integrating the two technologies at a laboratory scale, using for the first time real wastewater as CO2 capture medium. Five replicate EMG-BES cells were built and operated individually at 0.7 V. They were fed with both synthetic and real wastewater, saturated with CO2 by membrane contactors. In a subsequent experimental step, four EMG-BES cells were electrical stacked in series while one was kept as reference. CH4 production reached 4.6 L CH4 m−2 d−1, in line with available literature data, at a specific energy consumption of 16–18 kWh m−3 CH4 (65% energy efficiency). Organic matter was removed from wastewater at approximately 80% efficiency. CO2 conversion efficiency was limited (0.3–3.7%), depending on the amount of CO2 injected in wastewater. Even though achieved performances are not yet competitive with other mature methanation technologies, key knowledge was gained on the integrated operation of membrane contactors and EMG-BES cells, setting the base for upscaling and future implementation of the technology.


2005 ◽  
Vol 127 (3) ◽  
pp. 545-552 ◽  
Author(s):  
Alessandro Corradetti ◽  
Umberto Desideri

In the last several years greenhouse gas emissions, and, in particular, carbon dioxide emissions, have become a major concern in the power generation industry and a large amount of research work has been dedicated to this subject. Among the possible technologies to reduce CO2 emissions from power plants, the pretreatment of fossil fuels to separate carbon from hydrogen before the combustion process is one of the least energy-consuming ways to facilitate CO2 capture and removal from the power plant. In this paper several power plant schemes with reduced CO2 emissions were simulated. All the configurations were based on the following characteristics: (i) syngas production via natural gas reforming; (ii) two reactors for CO-shift; (iii) “precombustion” decarbonization of the fuel by CO2 absorption with amine solutions; (iv) combustion of hydrogen-rich fuel in a commercially available gas turbine; and (v) combined cycle with three pressure levels, to achieve a net power output in the range of 400 MW. The base reactor employed for syngas generation is the ATR (auto thermal reformer). The attention was focused on the optimization of the main parameters of this reactor and its interaction with the power section. In particular the simulation evaluated the benefits deriving from the postcombustion of exhaust gas and from the introduction of a gas-gas heat exchanger. All the components of the plants were simulated using ASPEN PLUS software, and fixing a reduction of CO2 emissions of at least 90%. The best configuration showed a thermal efficiency of approximately 48% and CO2 specific emissions of 0.04 kg/kWh.


Author(s):  
Abhishek P. Ratanpara ◽  
Alexander Shaw ◽  
Sanat Deshpande ◽  
Myeongsub Kim

Abstract As the consumption of fossil fuel resources has continuously increased to meet global fuel demands for power generation, atmospheric emissions of greenhouse gases, particularly carbon dioxide (CO2), have rapidly increased over the last century. Increased CO2 emissions have caused serious international concerns about global warming, sea-level rise, and ocean acidification. Although post-combustion carbon capture technology that separates CO2 from flue gas in fossil fuel-fired power plants has contributed to significant migration of atmospheric CO2 emissions, this approach generates considerable amounts of toxic wastewater containing a heavy chemical which is difficult to treat, raises concerns about acute corrosion of metal structures in the facility, and waste of significant amounts of freshwater. In this research, we are particularly interested in reducing the use of freshwater for CO2 capture and generating carbonate minerals, byproducts of CO2 with calcium (Ca2+) or magnesium ions (Mg2+) in ocean water which are useful building blocks for marine animals, such as seashells and coral reefs. In our experimental approach, we attempted to use ocean water with different monoethanolamine (MEA) concentrations and compared the CO2 capturing efficiency with that in DI water. We found that there are considerable benefits of the use of ocean water in CO2 dissolution, showing that a replacement of freshwater with ocean water would be a possible option. In the future, we will further enhance the dissolution of CO2 in ocean water by using nanoparticle catalysts without using MEA, which will be an environmentally friendly method for CO2 capture.


2012 ◽  
Vol 16 (3) ◽  
pp. 655-668 ◽  
Author(s):  
Filip Johnsson ◽  
Jan Kjärstad ◽  
Mikael Odenberger

The CO2 capture and storage (CCS) technology is since more than ten years considered one of the key options for the future climate change mitigation. This paper discusses the implications for the further development of CCS, particularly with respect to climate change policy in an international geopolitics context. The rationale for developing CCS should be the over-abundance of fossil fuel reserves (and resources) in a climate change context. From a geopolitical point, it can be argued that the most important outcome from the successful commercialisation of CCS will be that fossil fuel-dependent economies with large fossil fuel resources will find it easier to comply with stringent greenhouse gas (GHG) reduction targets (i.e. to attach a price to CO2 emissions). This should be of great importance since, from a geopolitical view, the curbing on GHG emissions cannot be isolated from security of supply and economic competition between regions. Thus, successful application of CCS may moderate geopolitical risks related to regional differences in the possibilities and thereby willingness to comply with large emission cuts. In Europe, application of CCS will enhance security of supply by fuel diversification from continued use of coal, especially domestic lignite. Introduction of CCS will also make possible negative emissions when using biomass as a fuel, i.e. in so called Biomass Energy CCS (BECCS). Yet, the development of BECCS relies on the successful development of fossil fuelled CCS since BECCS in itself is unlikely to be sufficient for establishing a cost efficient CCS infrastructure for transport and storage and because BECCS does not solve the problem with the abundant resources of fossil fuels. Results from research and development of capture, transport and storage of CO2 indicate that the barriers for commercialization of CCS should not be technical. Instead, the main barriers for implementation of CCS seem to be how to reach public acceptance, to reduce cost and to establish a high enough price on CO2 emissions. Failure to implement CCS will require that the global community, including Europe, agrees to almost immediately to start phasing out the use of fossil fuels, an agreement which seems rather unlikely, especially considering the abundant coal reserves in developing economies such as China and India.


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