The Iceland Deep Drilling Project (IDDP) represents a new and challenging step
forward in the development of geothermal resources worldwide (see
http://www.iddp.is). The IDDP is designed to assess the economic potential of
producing deep, supercritical, geothermal fluids as a source of steam for power
production. A two-year long feasibility study concluded that drilling to reach
high-temperature supercritical fluids is possible, and that producing the
resultant superheated steam could yield a power output ten times that of a
conventional well producing subcritical steam with the same volumetric flow
rate. However, in order to reach the required temperatures of 400-600°C,
drilling to depths of 4 to 5 km is necessary, at a cost three to four times that of
a conventional 2 to 3 km deep well. The first deep well will be drilled in 2008 at
Krafla at the northern end of the central rift zone of Iceland within a volcanic
caldera that has had recent volcanic activity. In the coming decade we
anticipate that the IDDP will drill a series of deep holes in other geothermal
fields in Iceland, including the Reykjanes peninsula in SW Iceland.
A recent comprehensive assessment of the potential for “enhanced”
geothermal systems (EGS) within the USA, (by a panel headed by J.W.Tester of
MIT)*, indicates that a cumulative capacity of more than 100,000 MWe from EGS
can be achieved in the United States within 50 years with modest multiyear
government investment. However, given the environmental and economic
incentives of producing an order of magnitude more energy from geothermal
wells occupying the same area, but at less than an a half order of magnitude
increased cost, supercritical volcanic geothermal resources are an especially
attractive component of EGS. Such deep unconventional geothermal resources
(DUGR’s) are not restricted to Iceland, For example, in the USA, the resource
base of conventional hydrothermal resources is estimated to be 2,400-9,600
Exajoules (1 EJ = 1018 J), whereas the supercritical volcanic EGS resource base
is estimated to be as much as 74,100 EJ (excluding sytems in National Parks). A
preliminary review of existing data from Europe suggests that DUGR’s are likely
to occur in Italy, Turkey, Greece, the Canary Islands, in the Azores and in
Russia (Kamchatka). A systematic survey of the potential of DUGR’s in Europe is
therefore desirable and plans should be developed to investigate these
potentially large resources further.
* “The Future of Geothermal Energy: Impact of Enhanced Geothermal Systems
(EGS) on the United States in the 21st Century”. (see
http://geothermal.inel.gov)
|
Overview
support
Slides