March 24, 2022
The latest British Drilling Association (BDA) Webinar took place 23 March 2022 and discussed the interesting topic of “Drilling for Ground Sourced Heat Pumps in the Nordic Countries”.
The webinar, divided into two parts, was co-presented by Stefan Swarting, LKAB Wassara AB and Professor Göran Hellström, CEO NeoEnergy AB.
Stefan opened his presentation ‘Drilling Techniques – With particular emphasis on Down the Hole (DTH) Water Hammer’, by outlining the geological conditions of the Nordic region, before moving onto the geothermal market in Europe and the Nordics. Stefan then detailed the procedure for installing a GSHP in typical single-family house and the standard equipment deployed. He then detailed the differing requirements for projects that vary in size and location, before looking at the various drilling technologies – rotary; top hammer; and down-the-hole.
From comparing penetration rates for the different drilling methods to performance (Wassara W100 4” vs Air DTH 4”), Stefan then discussed DTH drilling in water rich formations, as well as how to safely drill in sensitive formations and better borehole accuracy. Geothermal hard rock drilling was also explained.
Fuel consumption and CO2 emissions for its own Wassara W120 (5”) with water DTH hammer was compared to a competitive air DTH hammer too.
Stefan concluded his section of the presentation looking at LCA system boundaries for stages; GSHP system and how drilling technologies and systems are likely to develop in the future.
Professor Göran Hellström’s section of the presentation was titled “Underground Thermal Energy Storage (UTES) – How it may be used to save CAPEX and /or OPEX”. He began his presentation looking in detail at geothermal and geoenergy, before examining the specifics of Scandinavian thermogeology. Göran then looked at underground thermal energy storage, including ATES – Aquifer Thermal Energy Storage; BTES – Borehole Thermal Energy Storage; and CTES – Cavern Thermal Energy Storage. Using real-world example projects, Göran explained the various MWh/K storage capacities of each method and the bored infrastructure used.
The basic types of borehole heat exchangers (BHE) were also discussed and how they are typically not grouted in the Nordic region compared to other countries unless environmental conditions dictate. Heat transfer characteristics of BHE was outlined, as well as U-type BHE, High Temperature BHE, and Open Coaxial BHE (Deep Geothermal Probes).
Göran concluded taking a look at HT-BTES research and development, with many examples from across the Nordics.
A video of the webinar is available for those that missed it or those that wish to refresh some of the key topics discussed. The video can be found here: BDA Webinar – March 2022 – Drilling for Ground Sourced Heat Pumps in the Nordic Countries – British Drilling Association
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