Page 270 - Geothermal Energy Renewable Energy and The Environment

260 Geothermal Energy: Renewable Energy and the Environment

determined. Heavy investment in equipment and materials is required and careful execution of the
effort is needed to assure that the well will be robust enough to have a lifetime that will meet the
needs of the project. Casing and cementing materials must be selected to match the chemical and
environmental rigors of the emplacement environment. Temperature measurements must be made
periodically to determine the thermal structure of the reservoir. Flow testing must be done to estab-
lish the hydrological properties of the reservoir.
Once these data have been collected, a feasibility study can be completed that provides the final
refinement of the resource assessment. If flow rates, temperatures, and other conditions are ade-
quate to meet the project goals, financing can be obtained to complete the last two phases of project
development, which are drilling of production and injection wells and construction of the facility.
Historically, the overall duration of project development has been between five and seven years.
however, it is anticipated that the time needed to complete these steps may decrease significantly
if geothermal applications become more common. As experience grows, industry and regulatory
agencies gain knowledge regarding the best practices to employ to reduce development time while
assuring compliance with necessary requirements for safe and sustainable project development.

synopsIs

The factors that affect the economics of geothermal power production make it a competitive energy
conversion technology. The capacity factor, which reflects the proportion of time a conversion tech-
nology is available to generate power, is the highest of all other technologies, exceeding 90%. The
levelized cost of power, which accounts for the balance of expenses that a generation technology must
absorb in order to generate power, are among the lowest of competing power generation technologies.
Combined, these factors indicate that geothermal power production is currently a competitive energy
conversion technology. When considered in terms of its maturity with regard to R&D investment and
improvement in performance, geothermal power falls at the early stages of an S-curve technology
analysis. This indicates that significant improvement may be possible in performance for a relatively
small investment, compared to historical trends. If the trend in cost reduction for geothermal power
generation continues, there is an indication that geothermal energy production will be less expensive
than production from fossil fuels. The crossover point for this may occur within 10 years. To be
economically viable, a geothermal project must address the necessary steps to successfully be com-
pleted in a timely fashion. A number of sequenced actions are required that, under normal circum-
stances, take about five to seven years to complete. These include acquiring the rights to explore and
use geothermal heat from the subsurface, an adequate assessment of the resource, and a feasibility
study to demonstrate the resource is suitable for the targeted project goals.

Problems
13.1 What are capacity factors, what determines their magnitude, and how do they vary
among power generating technologies?
13.2 How is levelized cost computed? Is it constant through time? What can influence it?
13.3 Describe the economic and output evolution of a technology as it goes from its initial
state of innovation to a mature industry. What factors influence this process? What can
change the evolutionary path?
13.4 What is a technology S-curve? Where does geothermal energy sit in the technology
S-curve analytical approach?
13.5 What are the projected costs of geothermal power, compared to power generated from
fossil fuels? What can influence these projections?
13.6 What are the key steps that are usually required to successfully develop a geothermal
project?
13.7 How might the amount of time required to accomplish the steps in Problem 13.6 be
reduced without jeopardizing sound project development?