NESC0711 GEOCOST-BC

1. NAME OR DESIGNATION OF PROGRAM:  GEOCOST-BC

3. DESCRIPTION OF PROBLEM OR FUNCTION

GEOCOST calculates the cost of  generating electricity from geothermal energy. The version of GEOCOST in this release, GEOCOST-BC, simulates the production of electricity using a binary fluid cycle based upon a hydrothermal resource.

4. METHOD OF SOLUTION

GEOCOST is a simulation model which combines both technical processes and economic factors into one systematic framework. The simulation is composed of two principal parts: a reservoir model which simulates the exploration, development, and operation of a geothermal reservoir, and a power plant model which simulates the design, construction, and operation of the power plant. Each of these parts is composed of several submodels which treat fluid transmission and disposal, geothermal fluid/working fluid heat exchangers, turbine, generators, working fluid condenser, pumps, heat rejection, and calculation of thermodynamic state points in basic subcritical and supercritical Rankine cycles for a variety  of working fluids. Working fluids which are now in the model include isobutane, n-butane, R-ll, R-12, R-22, R-113, R-114, and ammonia. Thermodynamic properties of the working fluids at the state points are calculated using empirical equations of state. The Starling equation of state is used for hydrocarbons and the Martin-  Hou equation of state is used for fluorocarbons and ammonia. A wide  variety of financial and tax structures can be simulated through varying the rates of return on equity and debt, the debt-equity ratio, and tax rates. Using discounted cash flow analyses, GEOCOST calculates the cost of energy by equating the present worth of the revenues and expenses over the economic life of the reservoir and plant.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

Current array dimensions provide for a maximum well field size of 625 wells and maximum operating period of 50 years from reservoir exploration through the economic life of the power plant.

6. TYPICAL RUNNING TIME

From 15 seconds to 2 minutes are required for the majority of simulation cases.

7. UNUSUAL FEATURES OF THE PROGRAM:

8. RELATED AND AUXILIARY PROGRAMS:

10. REFERENCES

- C.H. Bloomster et al,
  GEOCOST: A Computer Program for Geothermal Cost Analysis,
  BNWL-1888, February 1975.
- C. H. Bloomster,
  An Economic Model for Geothermal Cost Analysis,
  BNWL-SA-5378, May 1975.
- P.D. Cohn, and C.H. Bloomster,
  Capital Cost Models for Geothermal Power Plants,
  BNWL-1990, July 1976.
- R.A. Walter, C.H. Bloomster, and S.E. Wise,
  Thermodynamic Modeling of Geothermal Power Plants,
  BNWL-1911, May 1975.

- H.D. Huber, R.A. Walter, and C.H. Bloomster:
  User Manual for GEOCOST: A Computer Model for Geothermal Cost
  Analysis, Volume 2, Binary Cycle Version
  BNWL-1931-V2 (March 1976).
- CYBER Control Information for GEOCOST
  BNWL Note (Sept. 13, 1976).

11. MACHINE REQUIREMENTS:  At least 55K (decimal) memory.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:   SCOPE 3.4.3.

14. OTHER PROGRAMMING OR OPERATING INFORMATION OR RESTRICTIONS

  Users
without access to the CDC Math Sciences Library will have to supply  a replacement for the subroutine RQNWT used to solve systems of nonlinear equations. The GEOCOST-BC source includes the 1967 ASME Steam Table data.

15. NAME AND ESTABLISHMENT OF AUTHORS

                 H. D. Huber, C. H. Bloomster, and R. A. Walter
                 Pacific Northwest Laboratories
                 Battelle
                 Battelle Boulevard
                 Richland, Washington  99352

File name	File description	Records
NESC0711_01.002	INFORMATION FILE	20
NESC0711_01.003	GEOCOST SOURCE	15283
NESC0711_01.004	RQNWT SOURCE	14
NESC0711_01.005	MINPACK SOURCE	4771
NESC0711_01.006	SPMPAR SOURCE	139
NESC0711_01.007	GEOCOST INPUT	4
NESC0711_01.008	GEOCOST OUTPUT	3723
NESC0711_01.009	GEOCOST UPDATE FORM	15445