The attention and investment towards reducing carbon emissions is growing significantly both in Australia and worldwide. Consequently, the use of renewable energy sources has increased, but several reports indicate that the pace of change needs to rise for the carbon emission reduction targets to be met. Geothermal energy is a recognised source of clean renewable energy, and shallow geothermal direct systems are among the most versatile applications. In these systems, underground heat exchangers are built to transfer heat energy from the underground (i.e., soil and/or rock material) at relatively shallow depths to a Ground Source Heat Pump (GSHP), which upgrades this heat to provide thermal comfort to buildings. The heat transfer within the soil is achieved by circulating a heat exchanger fluid within buried pipes. The structures that hold these pipes are underground heat exchangers. While a GSHP system is considered an economic and reliable thermal comfort system, the capital investment involved in building the underground heat exchangers is often high, hence the investment payout time is typically long. Energy geostructures are an alternative to the traditional underground heat exchangers that can reduce the implementations costs. While in traditional GSHP settings structures are built for the single purpose of holding the heat exchanger pipes, energy geostructures are geotechnical structures that provide structural support while encasing heat exchanger pipes within them. The dimensions and geometry of the geostructure(s) are defined by the geotechnical engineering design; hence, the excavation and concrete costs can be excluded from the GSHP implementation share. Different structures can be utilised as energy geostructures (e.g., piles, retaining walls, tunnel linings), this doctoral thesis will focus on energy piles. Energy piles are arguably the most researched energy geostructure among the presented alternatives. However, industry did not embrace its wide usag