The long gestation period, high upfront costs and the risks in the development of central geothermal power plants are the main reasons for the slow rate of geothermal electricity growth and its contribution to the global electricity mix. The overall objective of this study was to make a comparison between central geothermal power plants and wellhead power plants in the delivery of geothermal electricity projects. The study showed that wellhead power plants are generally less efficient compared to central power plants because of higher specific steam consumption, but are financially attractive because of the quicker return on investment, early electricity generation and the lower financial risks. The study showed that permanent wellhead power plants are a better option for geothermal wells with too low or too high steam pressure compared to others in the steam field. Temporary use of wellhead power plants as opposed to their permanent use is preferred when only limited time is available between the commissioning of a wellhead plant and the commissioning of a central power plant in the same steam field. Technical, operational and environmental challenges, including higher specific steam consumption and lower efficiency than central power plants as well as absence of geothermal fluid reinjection system make wellhead plants less economical and less sustainable in resource use. It can thus be concluded that wellhead power plants can reduce the long wait to generate geothermal electricity and make an early return on investment for investors. Both central and wellhead power plants have relatively higher capacity factor than many other power plants and so can be used to supply base load electricity for the grid or off-grid power supply. This study is a review of the central and wellhead power plants and additionally provides policy guidelines in the execution of geothermal electricity projects either as central or wellhead power plants for grid electricity generation.

中文翻译：

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地热电网发电中的中央电厂与井口电厂

地热孕育期长，前期成本高以及中央地热发电厂发展的风险，是导致地热发电增速缓慢及其对全球电力结构的贡献的主要原因。这项研究的总体目标是对地热发电项目交付过程中的中央地热发电厂和井口发电厂进行比较。研究表明，井口发电厂通常比中央发电厂效率低，这是因为其蒸汽消耗量较高，但由于投资回报更快，早期发电和财务风险较低，因此在经济上具有吸引力。研究表明，与蒸汽场中的其他蒸汽源相比，永久性井口发电厂对于蒸汽压力过低或过高的地热井来说是更好的选择。当在同一蒸汽场中，在井口装置的调试与中央电站的调试之间只有有限的时间时，相对于永久使用，优选暂时使用井口电厂。技术，运营和环境方面的挑战，包括比中央电厂更高的单位蒸汽消耗和更低的效率，以及缺乏地热流体回注系统，使得井口装置的经济性和资源利用的可持续性降低。因此可以得出结论，井口发电厂可以减少漫长的等待时间来产生地热发电，并为投资者带来早期的投资回报。中央电厂和井口电厂都具有比许多其他电厂更高的容量系数，因此可用于为电网或离网供电提供基本负荷电力。这项研究是对中央和井口发电厂的综述，并为执行地热发电项目（作为用于电网发电的中央或井口发电厂）提供了政策指导。