Technology Status - NET Nowak Energie & Technologie AG

An example of a large scale power plant is described in more detail below,
showing the different phases and their related costs. Costs may vary from
USD 50 to 150 million for a 50-MW plant.
Exploration and leasing: This phase is normally divided into site assessment,
leasing and land acquisition, exploratory drilling, and well testing. In general, site
assessment as well as leasing and land acquisition are low-risk activities with
relatively low costs, ranging from USD 50,000 to USD 500,000. Exploratory
drilling and reservoir assessment, as in the oil and gas field, are high-risk
activities: if an adequate resource is not found, the entire project is cancelled. A
wide range of issues must be addressed: geological data, geophysical surveys,
approval process for drilling, road building, mobilising a drilling rig, well testing,
and physical and chemical data collection. The cost can easily range from USD
0.75 to USD 2.5 million per exploration well. The entire programme can cost from
USD 3 to USD 6 million.
Project development and feasibility studies: If the previous phase gives
satisfactory results, a further series of activities can be carried out:
compilation of a reservoir assessment report; negotiation of a power sales
contract; approval of construction of wells, steam and water lines and power
plant; and finalisation of design and cost/revenue estimation. The cost range
is from USD 0.25 to USD 2.3 million, with the highest expenses for preconstruction
permits and environmental approval.
Well-field development and project finance, construction, start-up: This
phase is rather complicated and time consuming. Activities like drilling and
power plant construction can overlap and require careful scheduling.
Construction time is only 12-16 months for the power generating plant, but
well drilling (depending on the number of drilling rigs operating in parallel)
can take several years. Overall well-field development for a standard 50-MW
project with ten production wells, two injection wells and two reserve wells,
at an average cost of USD 2 million per well (depending on depth), can reach
USD 32 million. Power plant engineering, design, construction, and start-up
are complicated but not unique to geothermal; the oil industry and other
mining companies face similar challenges.
Commercial operations and field and plant expansion: As noted earlier,
geothermal plants have an availability factor of 98%, and can be operated at
full load 24 hours a day with energy efficiency of about 97% for CHP and
7-10% for electricity production. It is common to develop multiple power
plants or subsequent units over time. However, before installing a second
unit at the same site, it must be ensured that new wells will not affect the
productivity of existing ones.
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