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Bis vor wenigen Jahren diskutierten vor allem Energieversorger
und Umweltverbände über die Abscheidung und Lagerung von CO2. Mittlerweile ist die öffentliche Wahrnehmung von CCS gestiegen. Dabei dürfte die umstrittene Technologie für Deutschlands Kraftwerke weit weniger bedeutsam sein als für energiehungrige Schwellenländer.
CCS is discussed in a broad sense throughout Europe. In this paper a cautious, conservative estimate of CO2 storage capacity for Germany and its neighbouring countries where CO2 emissions from Germany could possibly be stored (Netherlands, France, Denmark, Norway, UK and Poland) is presented. Such a lower limit calculation is necessary for orientation purposes for potential investors and political decision-makers.
Conservative CO2 sequestration capacity in deep saline aquifers for Germany is derived by the volumetric approach where parameters such as efficiency factor, CO2 density, porosity of the geological formation are of interest. It is assumed that every geological system is closed and thus an efficiency factor of 0.1 per cent (based on maximum pressure increase and total compressibility) for saline aquifers is applied. The capacity of German depleted oil and gas fields is based on cumulative recovery data and a sweep efficiency of 75 per cent. The storage capacity in the other considered countries, adjacent to Germany, are based on a critical review and adjustment of the results of the European reports JOULE II, GESTCO and GeoCapacity.
The conservative capacities for all countries together amount to 49 Gt CO2, from which Norway and the UK provide 36 Gt, all offshore in the North Sea. Compared to the emissions from large point sources in these countries during 40 years (47.6 Gt of CO2), a virtual balance is achieved. This can only be reached, if a large scale CO2 pipeline system is installed to connect these countries, especially Germany, to the large sinks in the North Sea. If additional restrictions like source-sink matching, acceptance issues and injection rates constraints are taken into account, the available storage space gets increasingly scarce.
Carbon capture and storage (CCS) might be an important climate protection technology for coal-rich countries. This paper presents first results of a systemic and long-term analysis of a future CCS implementation in India. It focuses on potential storage formations in the geological subsurface and the geographic match of these sinks with CO2 emissions of current and future largepoint power plants. The analysis is framed by an overview on India’s position on CCS, ongoing Indian research and development projects as well as its international activities.
The geological potential for CO2 sequestration in India is subject to large uncertainty because, so far, only few studies estimated it in a vague manner. A first meta-analysis shows that there is a huge variation between 48 Gt and 572 Gt of CO2. The main differences between the evaluated studies are the assumed capacities for deep saline aquifers and basalt formations. Taking the ongoing discussion and the existing uncertainties into account, the storage potential might be provided only by aquifers (in the range of 44 to 360 Gt of CO2) and hydrocarbon fields (2 to 7 Gt of CO2).
The amount of CO2 emissions possibly available for sequestration is assessed by applying three substantially different long-term energy scenarios for India. These scenarios, indicating pathways between a "low carbon" and a "high carbon" development until 2050, result in cumulated CO2 emissions between 30 and 171 Gt if all new large-scaled power plants will be based on CCS from 2020 on. Compared with the sink capacities, only the CO2 emissions of scenario S2 (30 Gt) could theoretically be stored with high certainty. Considering the scenarios S3 and S1, their CO2 emissions (94 Gt and 171 Gt, respectively) could only be sequestered if the aquifer capacity would prove to be usable. Geological storage sites do not appear to be located close to sources in South West, Central, North and North East India. This first rough analysis means that only those CO2 emissions occurring in the Western parts of North and West India, the Eastern part of South India as well as the South part of East India might be suited for sequestration nearby.
A more detailed source-sink matching will follow in the next phase of the project, including results of expert meetings in India. Furthermore, this analysis will be complemented by an additional assessment from economic, ecological and resource-strategic points of view, which might further affect the potential for CCS.
The study presents the results of an integrated assessment of carbon capture and storage (CCS) in the power plant sector in Germany, with special emphasis on the competition with renewable energy technologies. Assessment dimensions comprise technical, economic and environmental aspects, long-term scenario analysis, the role of stakeholders and public acceptance and regulatory issues. The results lead to the overall conclusion that there might not necessarily be a need to focus additionally on CCS in the power plant sector. Even in case of ambitious climate protection targets, current energy policy priorities (expansion of renewable energies and combined heat and power plants as well as enhanced energy productivity) result in a limited demand for CCS. In case that the large energy saving potential aimed for can only partly be implemented, the rising gap in CO2 reduction could only be closed by setting up a CCS-maximum strategy. In this case, up to 22% (41 GW) of the totally installed load in 2050 could be based on CCS. Assuming a more realistic scenario variant applying CCS to only 20 GW or lower would not be sufficient to reach the envisaged climate targets in the electricity sector. Furthermore, the growing public opposition against CO2 storage projects appears as a key barrier, supplemented by major uncertainties concerning the estimation of storage potentials, the long-term cost development as well as the environmental burdens which abound when applying a life-cycle approach. However, recently, alternative applications are being increasingly considered–that is the capture of CO2 at industrial point sources and biomass based energy production (electricity, heat and fuels) where assessment studies for exploring the potentials, limits and requirements for commercial use are missing so far. Globally, CCS at power plants might be an important climate protection technology: coal-consuming countries such as China and India are increasingly moving centre stage into the debate. Here, similar investigations on the development and the integration of both, CCS and renewable energies, into the individual energy system structures of such countries would be reasonable.
If the current energy policy priorities are retained, there may be no need to focus additionally on carbon capture and storage (CCS) in the power plant sector of Germany. This applies even in the case of ambitious climate protection targets, according to the results of the presented integrated assessment study. These cover a variety of aspects: Firstly, the technology is not expected to become available on a large scale in Germany before 2025. Secondly, if renewable energies and combined heat and power are expanded further and energy productivity is enhanced, there is likely to be only a limited demand for CCS power plants, as a scenario analysis of CCS deployment in Germany shows. Thirdly, cost analysis using the learning curve approach shows that the electricity generation costs of renewable electricity approach those of CCS power plants. This leads to the consequence that, from 2020, several renewable technologies may well be in a position to offer electricity at a cheaper rate than CCS power plants. In addition, a review of new life cycle assessments for CO2 separation in the power plant sector indicates that the greenhouse gas emissions from 1 kW h of electricity generated by first-generation CCS power plants could only be reduced by 68 % to 87 % (95 % in individual cases). Finally, a cautious, conservative estimate of the effective German CO2 storage capacity of approximately 5 billion tonnes of CO2 is calculated, including a fluctuation range yielding values between 4 and 15 billion tonnes of CO2. Therefore, the total CO2 emissions caused by large point sources in Germany could be stored for 12 years (basic value) or for 8 or 33 years (sensitivity values).
The cement industry is one of the major energy consuming and CO2 emitting sectors in China. In 2010, 1,868 million tons of cement has been produced, which accounted for 56.1% of the world's total cement production. The 11th Five-Year Plan (FYP) (2006-2010) included policy measures for CO2 emission abatement in cement production. Based on the main governmental framework of CO2 mitigation policies at national level in the cement sector, key policies and technologies used during this period are identified and their effects on CO2 reduction are assessed. This paper calculates the reduction of CO2 emissions related to four main policies and technologies for efficient cement production in the 11th and the 12th FYP (2011-2015) with 2005 as a reference year. These are waste heat recovery, closing outdated facilities, substitution for clinker production and other technologies aiming to increase energy efficiency. Due to these measures, we estimate that a total CO2 emission reduction during the 11th FYP of 397 million tonnes could be saved, which is considerably different to 185.75 million tonnes estimated by Zeng (2008) and 303 million tonnes by the NDRC by using different calculation methods. Of the four technologies, the 4th group of energy efficiency increasing techniques was the most important policy and avoided the largest amount of CO2 emissions. Previous energy intensity reduction was mainly due to the outdated production closing and energy efficiency improving. Based on the assessment of technology performance, it appears that there is still a large emission reduction potential in cement production processes. The paper calculates this potential for the 12th FYP period (2011-2015) based on these four identified policy measures. The result is compared to the Chinese government targets in the 12th FYP and promising future CO2 mitigation policies and technologies are proposed, such as the use of alternative energy.