Analysis of economy, thermal efficiency and environmental impact of geothermal heating system based on life cycle assessments

Deep geothermal energy extraction, a review on environmental hotspots with focus on geo-technical site conditions

“…The information reported regarding the geo-technical characteristics of deep geothermal heating plants is limited (Table 14). One study compared the performance of two different borehole heat exchanger designs (butted vs coaxial) [31] and only the better-performing one was considered in this study (butted). Two studies [24,29] considered the construction of the distribution network.…”

“…Two studies [24,29] considered the construction of the distribution network. Two studies considered a lifetime of 25 years based on the expected lifetime of the real plant investigated [24] or without providing further information [31]. By contrast, [25] used a lifetime of 30 years, derived from the plant's feasibility analysis, [29] did so without providing further information and [30] did so based on the GEOENVI guidelines [13].…”

“…Of the 30 reviewed studies, 10 mention the exploration stage and assign it to the construction phase. Eight studies regard the drilling of exploratory wells [15,18,19,23,32,33,40,41], while two [24,31] consider only the fuel consumed during the seismic exploration activities, as also suggested in [13].…”

Technologies for sustainable heat generation in food processing

“…There is little published data on levelized costs of energy or heat for the use of geothermal energy and the associated costs highly depend on the region and well depth. One study reported a levelized costs of energy of around 28–31€ per MWh (31$−34$) for a coaxial borehole heat exchanger that was used for direct space heating (without heat pump) with a well depth of 2500–3000 m (Xia et al., 2021). Moreover, a recent study reported that the levelized costs of heating ranged from $13 to $350 per MWh at different locations in the United States for direct geothermal use (without heat pump), depending on the subsurface conditions, surface configurations, and cost and financing assumptions (Beckers et al., 2021).…”

Repurposing a deep geothermal exploration well for borehole thermal energy storage: Implications from statistical modelling and sensitivity analysis

“…Extraction studies have shown that increasing the borehole depth disproportionately increases the achievable heat load due to the interplay of two factors: (i) increasing temperature due to the geothermal gradient, and (ii) a greater borehole length (and surface area) for heat exchange [15,61]. Therefore, the greater overall surface areas of deeper boreholes could also increase performance during energy storage.…”