Enabling Unconventional Geothermal Energy Development

Conventional geothermal systems currently provide approximately 16 gigawatts (GW) of power and are limited geographically to areas that have very unique geological conditions such as the western USA, Iceland, East Africa and the Pacific Ring of Fire which includes California. Next generation geothermal systems do not rely on these unique conditions and simply target hot rock. To optimise the economics, hotter is better, and the goal is to drill wells into rock with temperatures in excess of 400ºC. These so-called “Super Hot Rock” systems have the potential to provide electricity that is cost-competitive with existing renewable energy sources, providing up to 800 GW of power by 2050, according to the International Energy Agency (IEA). One of the challenges associated with these wells is that highly accurate well positioning is required – and this in turn relies on directional drilling equipment from the oil & gas industry, which is currently limited to 200ºC. To upgrade this equipment, electronics that can operate at 300°C ambient environment is going to be required. In order to achieve 300°C ambient operation, every facet of electronics design and manufacturing needs to be addressed. One key area that cannot be overlooked: how do we keep the core of the electronic components as close to ambient as possible? The margin for self-heating will be ultra slim. Without minimizing the self-heating, the environmental requirement could mean electronics that will work closer to 350°C. This paper presents the challenges associated with developing a truly high temperature Geothermal Electronics system.