Description:
Based on a review of the Enhanced Geothermal Systems (EGS)
developed to date worldwide, numerical simulation of idealized
EGS reservoirs, economic sensitivity analysis, and practical
considerations of some site characteristics, this paper shows that
certain steps can be taken towards minimizing the levelized cost
of electric power from EGS systems; these steps are as follows:
(a) choosing the site with the highest possible vertical temperature
gradient and for the thickest possible sedimentary cover on the
basement; (b) choosing the drilling depth that maximizes a well’s
power capacity per unit drilling cost rather than reaches the hottest
resource; (c) creating the largest possible stimulated volume per
well; (d) increasing per well productivity by stimulating multiple,
“vertically stacked” zones and/or increasing the pumping rate of
production wells taking advantage of the evolving advances in
pump technology; (e) improving stimulation effectiveness, and
particularly, reducing the fracture spacing and heterogeneity in
the hydraulic characteristics of the stimulated volume; (f) through
reservoir modeling, optimizing well spacing and injection rates
that minimize the rate of decline in net generation with time (g)
reducing the power plant cost; (h) developing multiple, contiguous
EGS units to benefit from the economy of scale; and (i) reducing
the operations and maintenance cost. The basis for these conclusions
is presented in the paper.