WorldWide Drilling Rescource

47 WorldWide Drilling Resource ® OCTOBER 2019 A Clean, Cost-Effective, Reliable Energy Solution for Australia Adapted from Information by the Australian Geothermal Association The Australian Geothermal Association (AGA) conducted a census of the geothermal projects in Australia to highlight the rel- evance and positive impacts of the geothermal energy industry. The AGA hopes the census can be used as a database to calculate the life cycle cost of energy for geothermal applications, allowing them to be easily compared to other alternative energy sources inAustralia. The installed thermal capacity reported for all operating geo- thermal installations in 2018 was 85 megawatts (MWs). By 2020- 2025, this total is estimated to grow to 146 MWs. AGA estimated the produced thermal energy from the installed systems in 2018 to be about 156 gigawatt-hours per year. Direct-use and commercial hot spring in- stallations accounted for much of the thermal energy total because these typically operate 40-60% of the year, taking full advantage of the baseload nature of geothermal energy to produce large sustainable quantities of energy from relatively small capacities. In 2018, ground source heat pumps (GSHPs) represented 66% of the installed geothermal energy capacity. GSHP installations accounted for 19% (heating) and 10% (cooling) of the produced ther- mal energy with most systems designed to provide both heating in winter and cooling in summer. While their use was mostly for heating, ventilation, and air conditioning (HVAC) applications, there were some reported applications for residential pool heating. GSHPs were installed primarily in residential properties (65%), with 20% installed in public buildings, and the remaining 15% in commercial premises. GSHPs rely on stable shallow ground / aquifer temperatures typically in the range of 60-77ºF (15-25ºC). Direct-use of geothermal heat represented about 26% of the total installed capacity, but 48% of the produced thermal energy. In many of these applications, geothermal water is used, generally via a heat exchanger, to heat pools in large leisure centers. Other applications include aquaculture, meat pro- cessing, and cooling of supercomputers. Since energy input is limited to electricity supplied to the submersible pumps in the geothermal bores, direct-use systems oper- ate very efficiently. Conventional heating sys- tems often rely on gas boilers for heat, which are only 80% as efficient. Hundreds of hot springs, artesian bores, and spas were reported. In addition to these often remotely located hot springs, new de- velopments are proposed near tourist des- tinations. These commercial operations represent the remaining 8% of the installed capacity identified by the census, but makes up 23% of the thermal energy because the facilities are often used year-round for up to 14 hours a day. This segment of the industry is primed to grow quickly in coming years. AGA’s census revealed the geothermal industry inAustralia has undergone a decade of quiet growth, particularly for space heating and cooling, as well as pool heating. Com- pared to conventional technologies, the growth in geothermal energy has been driven by lower life cycle costs, with an added advantage of lowering carbon dioxide emissions. With better education and com- munication about the benefits of geothermal energy, AGA believes the future of the geo- thermal sector in Australia will involve more GSHP and direct-use projects. This could include applications in the manufacturing industry and agriculture, as well as other contributions to the energy mix, taking full advantage of the characteristics of geo- thermal energy. GEO