Description:
In planning the development of a geothermal field, there is a
trade-off between plant capacity and the cost of make-up
drilling. A larger plant benefits from economies of scale in
the construction and operation of surface facilities. On the
other hand, a larger plant also places a greater load on the
geothermal reservoir, which causes higher rates of decline in
well productivity. Greater decline rates for existing wells
require a larger number of make-up wells. Because the cost
of make-up wells occurs later in the project life, this cost has
relatively less impact on project economics than the up-front
cost of plant construction. Similarly, the loss of revenue from
a decline in output late in a project's life is much less
significant than revenue foregone at the start of a project due
to limited plant capacity.
