A 3D elasto-plastic rate-dependent model for rock mechanics is formulated and implemented into a Finite Element (FE) numerical code. The model is based on the approach proposed by Vermeer and Neher (A soft soil model that accounts for creep. In: Proceedings of the International Symposium “Beyond 2000 in Computational Geotechnics,” pages 249-261, 1999). An original strain-driven algorithm with an Inexact Newton iterative scheme is used to compute the state variables for a given strain increment.The model is validated against laboratory measurements, checked on a simplified test case, and used to simulate land subsidence due to groundwater and hydrocarbon production. The numerical results prove computationally effective and robust, thus allowing for the use of the model on real complex geological settings. 相似文献
China is in the process of establishing a national emissions trading system (ETS). Evaluating the implementation effectiveness of the seven pilot ETSs in China is critical for designing this national system. This study administered a questionnaire survey to assess the behaviour of enterprises covered by the seven ETS pilots from the perspective of: the strictness of compliance measures; rules for monitoring, reporting and verification (MRV); the mitigation pressure felt by enterprises; and actual mitigation and trading activities. The results show that the pilot MRV and compliance rules have not yet been fully implemented. The main factors involved are the lack of compulsory force of the regulations and the lack of policy awareness within the affected enterprises. Most enterprises have a shortage of free allowances and thus believe that the ETSs have increased their production costs. Most enterprises have already established mitigation targets. Some of the covered enterprises are aware of their own internal emission reduction costs and most of these have used this as an important reference in trading. Many enterprises have accounted for carbon prices in their long-term investment. The proportion of enterprises that have participated in trading is fairly high; however, reluctance to sell is quite pervasive in the market, and enterprises are mostly motivated to trade simply in order to achieve compliance. Few enterprises are willing to manage their allowances in a market-oriented manner. Different free allowance allocation methods directly affect the pathways enterprises take to control emissions.
Key policy insights
In the national ETS, the compulsory force of ETS provisions should be strengthened.
A reasonable level of free allowance shortage should be ensured to promote emission reduction by enterprises.
Sufficient information should be provided to guide enterprises in their allowance management to activate the market.
To promote the implementation of mitigation technologies by enterprises, actual output-based allocation methods should be used.
The government should use market adjustment mechanisms, such as a price floor and ceiling, to ensure that carbon prices are reasonable and stable, so as to guide long-term low carbon investment.
Although agriculture could contribute substantially to European emission reductions, its mitigation potential lies untapped and dormant. Market-based instruments could be pivotal in incentivizing cost-effective abatement. However, sector specificities in transaction costs, leakage risks and distributional impacts impede its implementation. The significance of such barriers critically hinges on the dimensions of policy design. This article synthesizes the work on emissions pricing in agriculture together with the literature on the design of market-based instruments. To structure the discussion, an options space is suggested to map policy options, focusing on three key dimensions of policy design. More specifically, it examines the role of policy coverage, instruments and transfers to farmers in overcoming the barriers. First, the results show that a significant proportion of agricultural emissions and mitigation potential could be covered by a policy targeting large farms and few emission sources, thereby reducing transaction costs. Second, whether an instrument is voluntary or mandatory influences distributional outcomes and leakage. Voluntary instruments can mitigate distributional concerns and leakage risks but can lead to subsidy lock-in and carbon price distortion. Third, the impact on transfers resulting from the interaction of the Common Agricultural Policy (CAP) with emissions pricing will play a key role in shaping political feasibility and has so far been underappreciated.
POLICY RELEVANCE
Following the 2015 Paris Agreement, European climate policy is at a crossroads. Achieving cost-effectively the 2030 and 2050 European targets requires all sectors to reduce their emissions. Yet, the cornerstone of European climate policy, the European Union Emissions Trading System (EU ETS), covers only about half of European emissions. Major sectors have been so far largely exempted from carbon pricing, in particular transport and agriculture. While transport has been increasingly under the spotlight as a possible candidate for an EU ETS sectoral expansion, policy discussions on pricing agricultural emissions have been virtually absent. This article attempts to fill this gap by investigating options for market-based instruments to reduce agricultural emissions while taking barriers to implementation into account. 相似文献
The ambitious Marine Strategy Framework Directive (MSFD) has been the focus of much marine research across Europe in the pursuit of achieving Good Environmental Status in the four European Union marine regions; Baltic Sea, Black Sea, Mediterranean Sea and North-east Atlantic. This research addresses the Strengths, Weakness, Opportunities and Threats (SWOT) of the current European marine governance structures and its relationship to implement the MSFD. Results of the SWOT analysis were acquired through a combination of approaches with MSFD experts and stakeholders including: 30 face-to-face interviews, an online survey with 264 stakeholder respondents and focus groups within each European marine region. The SWOT analysis concurrently identifies common strengths and weakness and key governance issues for implementing the MSFD for European marine regions. This paper forms one assessment within the governance component of the Options for Delivering Ecosystem Based Marine Management (ODEMM) project and presents timely issues that can be of benefit to national and European Union policy makers. 相似文献