Geothermal reservoirs are unique in the sense that they are the personification of a ‘unconventional reservoir’. In essence the reservoir needs to be ‘created’. Unlike hydrocarbon reservoirs which are physically present as a fluid (state of mater), the geothermal reservoir is simply a ‘hot source rock’ that contains thermal (potential-) energy that can only be extracted via heat transfer to circulating fluids. In this session, the panel will discuss challenges, solutions, current theorized concepts for determining, evaluating, and producing from a geothermal reservoir – enhanced geothermal system and closed loop system.