高温地热高效开发钻井关键技术

地热能是来自地球深部的热能,是一种清洁、低碳、环保的可再生资源,高效开发地热资源对调整我国能源结构具有重要意义。目前高温地热开发的钻井技术都是采用油气开发的技术,由于高温地热储层的特殊性质,使得常规油气钻井技术作业效率低,成本较高。针对目前高温地热资源开发的工程需求,介绍了高温地热储层的类型,分析了高温地热储层特性和高效开发的钻井关键技术,包括高效破岩技术,防漏堵漏技术、抗高温井下工具和仪器、抗高温钻井液、抗高温水泥浆和高效低成本钻井技术,并对未来高温地热高效开发的钻井技术攻关方向提出了建议。     

华北地下水超采区冬小麦退耕的生态补偿问题探讨

压减冬小麦种植面积是有效减少华北平原地下水用量最为有效的方法。近期,国家和地方政府均出台了土地休耕政策,拟在华北地下水超采区退耕冬小麦,实现“一季休耕、一季雨养”。然而,华北平原已经出现农户主动退耕冬小麦的现象。在此背景下,明确冬小麦退耕的瞄准目标、制订合理适度的补偿标准是土地休耕政策有效实施所面对的核心问题。本文利用农户问卷数据,构建多层次logit模型分析农户种植制度决策的影响因素,并计算冬小麦退耕的机会成本,旨在确定华北平原地下水超采区土地休耕政策的瞄准目标,并为农户补偿标准的制订提供建议。结果表明：① 地块层次的土地质量和灌溉条件是解释农户种植制度差异的关键因素,近70%的四等耕地和90%以上的旱地已退出冬小麦耕作,土地休耕政策应瞄准一、二、三等土地质量的水浇地;② 相似耕作条件的地块种植春、夏玉米的净收益大致相同,土地休耕的机会成本等于种植冬小麦的净收益;③ 仅考虑冬小麦对地下水资源的影响,土地休耕政策初期以地下水回升和地下水环境恢复为主要目标时,建议以350元/亩作为补偿标准参考值,后期目标转为维持地下水资源采补平衡时,可调整至280元/亩左右。     

煤炭生产和消费环境天花板之探究

煤炭生产和消费的过程必然对大气、水、土造成污染和消耗,环境天花板是煤炭生产和消费数量的约束边界。我国煤炭生产的环境天花板约为41~43亿t,消费约为34~38亿t。随着经济结构和能源结构的调整以及生态环境的约束,预测煤炭需求总量大约在2020~2025年达到40亿t左右的峰值。生态文明战略是新阶段社会经济发展对煤炭生产和消费的必然要求,其包含"生态优先"原则、煤炭"三清洁"发展策略、生产和消费生态环境成本内部化措施、后找煤时期煤田地质勘查工作的结构调整。煤可以清洁利用,但不能低碳化利用。煤炭的低速增长或负增长已经成为煤炭工业发展的新常态。     

Value of information analysis in rock engineering: a case study of a tunnel project in Äspö Hard Rock Laboratory

Geoengineering prognoses are often based on data from a limited number of investigations of soil and rock mass. There is generally a desire to reduce the uncertainty in the prognoses while minimising the investigation costs. Value of Information Analysis (VOIA) is a support for decisions regarding investigation strategies and the aim of this paper is to present methodology for VOIA that takes into account four decision alternatives where the input data could be provided by experts. The methodology will be applied in a case study where the value of information related to an investigation borehole will be calculated. The results indicate that the value of information of the borehole is low compared with the realisation costs of the investigation. It was found that models for VOIA in underground construction projects are complex but that the analysis can be simplified with extensive use of expert knowledge and calculations of the value of perfect information as a benchmark for investigation strategies.     

Pricing carbon consumption: synthesizing an emerging trend

Nearly every carbon price regulates the production of carbon emissions, typically at midstream points of compliance such as power plants, consistent with typical advice from the literature. Since the early 2010s however, policymakers in Australia, California, China, Japan and Korea have implemented carbon prices that regulate the consumption of carbon emissions, where points of compliance are further downstream, such as distributors or final consumers. This article identifies the pivot towards placing the point of compliance for carbon prices further downstream as an emerging international trend, describes the designs of different prices on carbon consumption around the world, and explains the various motivations of the policymakers implementing them. Findings reveal that policymakers tend to layer prices on carbon consumption on top of prices on carbon production in an effort to improve economic outcomes by addressing incomplete pass-through of the carbon price from producer to consumer, thereby facilitating more cost-effective abatement. Policymakers also use prices on carbon consumption to reduce emissions leakage or because large producers of carbon are not within their jurisdiction. The prevalence of prices on carbon consumption will likely increase as evidenced by proposals in China and Europe.

Key policy insights

• The recent surge in the number of jurisdictions implementing prices on carbon consumption represents an emerging international trend.

• Policymakers use prices on carbon consumption in an effort to improve economic outcomes and capture environmental benefits.

• While this article offers insights that detail initial challenges and successes, whether these prices on carbon consumption actually achieve their intended goals is an academically rich topic that requires further research on individual policies.

     

The levelized cost of carbon: a practical,if imperfect,method to compare CO2 abatement projects*

Calculating the cost effectiveness of projects and policies with respect to reducing carbon emissions provides a simple way for local government agencies to consider the climate impacts of their actions. Yet, defining a metric for cost-effectiveness in relation to climate change is not straightforward for several reasons. In this paper, we focus primarily on dynamics, reflecting the time value of money and how the benefits of reducing carbon emissions may change over time. We define a cost-effectiveness metric called Levelized Cost of Carbon (LCC) that carefully accounts for these dynamics. We also investigate the theoretical and practical implications and limitations of using a cost-effectiveness metric as an approach to rank projects. We apply our metric to a set of transportation projects to illustrate the insights that can be gained by such a process.

Key policy insights:

• Levelized Cost of Carbon (LCC) provides a simple way for local governments to consider climate change mitigation in decision making.

• LCC is a cost-effectiveness metric that carefully accounts for the time value of money and possible changes in the value of reducing emissions through time, thus helping local governments to make better decisions.

• LCC can be used to rank projects, with some caveats, even in the absence of a specific value for the benefits of reducing GHG emissions, thus providing flexibility in the face of uncertainty and political constraints.

     

Climate change may impair electricity generation and economic viability of future Amazon hydropower

Numerous hydropower facilities are under construction or planned in tropical and subtropical rivers worldwide. While dams are typically designed considering historic river discharge regimes, climate change is likely to induce large-scale alterations in river hydrology. Here we analyze how future climate change will affect river hydrology, electricity generation, and economic viability of > 350 potential hydropower dams across the Amazon, Earth’s largest river basin and a global hotspot for future hydropower development. Midcentury projections for the RCP 4.5 and 8.5 climate change scenarios show basin-wide reductions of river discharge (means, 13 and 16%, respectively) and hydropower generation (19 and 27%). Declines are sharper for dams in Brazil, which harbors 60% of the proposed projects. Climate change will cause more frequent low-discharge interruption of hydropower generation and less frequent full-capacity operation. Consequently, the minimum electricity sale price for projects to break even more than doubles at many proposed dams, rendering much of future Amazon hydropower less competitive than increasingly lower cost renewable sources such as wind and solar. Climate-smart power systems will be fundamental to support environmentally and financially sustainable energy development in hydropower-dependent regions.     

基于学习曲线的中国未来制氢成本趋势研究

氢能是中国能源系统低碳转型和实现2060年前碳中和目标的重要技术选择之一。根据原料来源可以将氢分为绿氢、蓝氢和灰氢,其制备成本和碳排放强度存在较大差异。文中以中国氢能生产现状为基础,建立基于学习曲线的平准化制氢成本（LCOH）模型,测算不同制氢技术从2020年到2060年的成本变化趋势。结果表明：现阶段灰氢成本最低,绿氢成本最高;到2030年绿氢成本将下降至20~25元/kg;2050年后,绿氢将成为成本最低的制氢方式（含碳排放成本),而且PEM（质子交换膜）电解水制氢的成本将低于AE（碱性）电解水制氢,光伏+PEM电解水制氢成本将下降至12元/kg。电解槽和电力成本下降是未来绿氢成本下降的主要驱动因素。敏感性分析表明,运营维护成本和关键技术学习率是影响绿氢成本下降速度的重要参数。     

基于Revit的基坑工程造价计算插件开发与应用研究

针对目前Revit软件对基坑工程造价计算功能的缺失,提出将基坑工程建筑信息模型（BIM）全过程构件族类化,并利用Revit API二次开发技术实现基坑工程造价自动化计算。首先,利用Revit平台建立基坑工程BIM模型构建族类库,实现基坑工程支护结构族类参数化;然后,对基坑工程造价计算流程进行分析,利用Revit API二次开发技术自动获取基坑工程项目BIM模型中各类构件参数,并结合基坑工程造价计算公式,实现实际工程量计算、定额套用、数据的显示与输出等功能;最后,以长沙市某基坑工程为例,开展实际工程项目的自动化造价计算,验证上述基于Revit的基坑工程造价计算插件的可行性。结果表明,本文开发的Revit造价计算插件可以基于导入的基坑工程BIM模型实现自动化造价计算,且与人工计算结果吻合良好。这一技术的实现,弥补了Revit软件在基坑工程造价计算以及基坑工程造价方面功能的不足,提高设计人员的工作效率,为进一步扩展BIM技术在基坑工程中的应用打下良好基础。     

第一性原理思维法在页岩气革命中的实践与启示

我国油气对外依存度不断攀升,通过传统意义上的创新难以满足油气勘探开发大幅增产降本的要求,必须通过革命性、颠覆性的创新来破困突围。在页岩气革命中,基于第一性原理思维法,围绕提高控制储量和降低开发成本两大目标,创新了井工厂钻井、一趟钻钻井、超长水平段水平井钻井等颠覆性创新技术,使钻井周期和作业成本大幅降低,实现了我国首个大型页岩气田——涪陵页岩气田的高效开发。最后,笔者展望了第一性原理思维法在缝洞型碳酸盐岩油气藏和干热岩地热资源开发领域的创新应用,并指出运用第一性原理思维法是未来石油工程技术实现颠覆性创新的重要途径和方法。