Enhanced Geothermal Systems (EGS) create a man-made reservoir in hot, low-permeability rock by drilling deep wells and hydraulically stimulating a fracture network between them. Cool water is injected down one well, heated as it circulates through the fractures, and produced hot from a second well — a closed loop that turns "hot dry rock" anywhere on Earth into a baseload power source, without needing the rare natural hot-water aquifers that limit conventional geothermal.
Drilling typically accounts for 40–60% of an EGS project's total capital cost — more than the power plant itself — which is why lateral length and depth are the two levers project economics revolve around.
A 3D cutaway of an engineered geothermal reservoir: injection and production wells drilled into hot basement rock, a stimulated fracture network carrying circulating fluid between them, and surface facilities that buffer steady rock heat into a grid-following power dispatch.
Reservoir temperature rises with depth along the geothermal gradient; drilling cost rises faster still. Fracture network size and flow rate together set the thermal power reaching the surface, and a storage tank can shift baseload heat into a peak-hour electricity dispatch.
Set reservoir depth, fracture/lateral length, and circulation flow rate to watch the temperature, power output, and drilling cost estimates update. Toggle thermal storage and switch grid demand between baseload and peak to see the storage tank charge and discharge.
Because drilling costs scale roughly with depth to a power greater than one, doubling reservoir depth for a hotter resource can more than double well cost — economics that make lateral fracture length a cheaper lever than depth for adding capacity.