Geothermal aquifers offer green potential but quality checks required
Aquifer Thermal Energy Storage (ATES) systems utilize geothermal energy as a renewable energy source and are one solution for reducing fuel consumption and CO2 emissions. This system uses groundwater as the thermal medium, storing heat in underground aquifers. The heat is then extracted based on seasonal needs to efficiently heat and cool the building.
Its use is expanding mainly in Europe and is expected to be widely promoted in Japan. However, regular inspections are required for trouble-free use of these systems.
This fact became apparent when a research team led by Harue Masuda, Distinguished Professor at the Urban Resilience Research Center at Osaka Metropolitan University, discovered that a pipe in an ATES well at an Osaka facility had become clogged.
Among their findings, iron oxyhydroxide precipitation occurred after a vent accidentally opened and air flowed through a pipe into the geothermal well. In turn, an oxygen-rich environment forms and the iron oxyhydroxide diffuses through the pipes, causing blockages, leaks, and subsequent mixing of groundwater between the two aquifers at different depths in each well. Fortunately, natural microbial activity resolved the blockage and restored the groundwater.
Observation of this series of events demonstrates the critical importance of assessing water quality before a well is put into operation and continuing to monitor the long-term use of ATES systems.
Professor Masuda said: “The results of this study show that groundwater geochemical analysis is effective and essential for the stable and widespread use of ATES systems, and so far, groundwater geochemical analysis has not received attention in the engineering field. ” ” We believe that by proposing a water quality monitoring method as a guide, we can establish the ATES system as a technology that can be used in the long term.”
The research results were published in geothermal science.
2024-12-20 18:32:14