世界地热能发电新进展

 简要回顾了国际地热发电的历史,介绍了过去5年全球地热能开发的理论、技术和设备等方面的巨大变化。2005年开始的高油价以及减少温室气体排放的全球性需求使各国开始把注意力聚焦在可再生能源方面。地热能的开发在全世界范围内发展迅速,既有像新西兰、印度尼西亚和美国这样长久以来热衷于开发地热能的国家,也有像澳大利亚和德国这样过去对地热能不太感兴趣的国家。分析表明,一些新的地热开发项目依旧遵循传统思路在火山活动区域使用常规水热资源,而另一些则选择在非火山活动区采用增强地热系统(EGS)技术开发干热岩地热能。目前,部分国家已经建立一些EGS项目,比如美国,有6个建设中的EGS项目,试图在不同的技术层面进行探索和研究。现代地热开采和发电技术使得人们可以在缺少冷却水以及交通不便的情况下对温度较低的常规地热资源进行开发。根据目前情况来看,预计未来地热工业的发展在发现新的地热田以及提高现有地热田开发程度方面将面临较大的技术挑战,主要可能有以下两个关键问题：(1) 在开发过程中的“生产盲区”问题,这主要针对那些温度不高也不低的地热田,温度不太高但又高到无法下泵,温度不太低但又不能采用闪蒸方法发电;(2) 可靠的EGS开发方案和技术研发,要求可以确保有可持续、足够高的产能(温度与流量),并能向公众,特别是项目附近的居民保证不会诱发地震灾害。

New Progress in the World Geothermal Power Generation

The history of geothermal power generation in the world has been briefly reviewed. In the past five years, considerable changes in the geothermal development have been brought. Historically high oil prices since 2005, supporting by a global ambition to address greenhouse gas reduction have impelled every country in the world paying attention to the renewable energy. Geothermal developments have accelerated in many parts of the world, either in the countries, such as New Zealand, Indonesia, and the USA having a traditional interest in conventional geothermal resources, or in the countries having no historical interest in geothermal energy, such as Australia and Germany. The analysis conducted indicates that some new developments have followed well-worn paths using conventional hydrothermal resources in volcanic regions, while others have struck out in new directions involving Enhanced Geothermal System (EGS) projects in non-volcanic regions. Technology advance has allowed to developing conventional resources with lower temperature, restricted water access, and constrained surface utilization. EGS projects have launched in a variety of different directions and places, currently the USA keeps six EGS projects in operation. Based on current status, the future for the operation expansion of geothermal developments depends on new fields exploration and technical challenges overcoming in known but not-yet-exploited fields. Two issues are currently being addressed by the world geothermal community, they are (1) the productivity gap in the exploitation of fields, namely, temperature is too high for down-hole pumps, however it is too low for flash production; (2) the reliable EGS development procedures are able to ensure sustainable flow rates and assure the public that seismologic disasters will not be induced.