Figure I Generalized map of the Wilbur Mining ... - University of Utah

.PUMP
CONTDOl.
CEOTHERMAL Pnoa MJECTION WELL
WELLS
a rupture); or a drop in supply temperature (caused
by a closed valve or stopped pump).
When the project is expanded to Phase III, a
computerized control center will replace all chart
recorders and provide BTU calculations for remote
building as well as temperature and pressure of
heating water supplied and used.
PART IV
LIFE CYCLE AND COST ANALYSIS
For the Klamath Falls district, heating of
the central business core Phase.II (the elevenblock
district) was evaluated due to the fact that
this phase will be completed in the very near
future.
Cost benefit analysis was based on the annual
heat load using geothermal energy.as opposed to natural
gas. The economic analysis was based on the
following assumptions:
1) The economic inflation rate was forecast
at 7%. As of this writing, 9% would be more
accurate.
2) Inflation rates for conventional energy
were obtained from the Oregon Department of Energy
as follows:
a. natural gas--5.2% above the economic inflation
rate through 1986 and 1.5% above
the economic inflation rate thereafter.
b. electric power—2.5% above the economic
inflation rate through 1986 and 1.5% above
the economic inflation rate thereafter.
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FIGURE 9. Distribution Network Control
393
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MEAT EKCHAMGEH/COWTROL BUILOtwC
Lund, et. al.
3) Cost of capital 6.5% as indicated by the
City of Klamath Falls.
4) Current cost of natural gas $0.34394 per
therm (rate paid in February, 1979).
5) 85% efficiency for natural gas.
These inflation rates have proven to be very conservative.
During the past 3 years, the City has
experienced a 26.5% per year increase in the cost
of natural gas as compared to 12.2% in our evaluation.
The fact that actual inflation rates exceed
those used in the study further supports the arguraent
for the geothermal system.
Tables I and II of the report show capital investment
for 16 combinations of primary and secondary
piping systems.
Life cycle costs were calculated on these
piping systems for a 10-year period and appear in
Tables III and IV.
A fifty-year life cycle cost analysis was completed
on four piping systems and the results are
illustrated graphically on the chart following.
Although steel pipe installed in concrete tunnels
requires the highest capital investment, the
annual maintenance costs were estimated to be considerably
lower. Such a system provides easy access,
room for future expansion at minimal cost,
and reduces maintenance time and cost particularly
in conjested business districts.