IOA News Letters Summary

A paper was presented at the PACON'90 Conference Tokyo, Japan on July 17, 1990. The paper assessed " The Near Term Market Potential for OTEC in the Pacific Basin." It was authored by Dr. Luis A Vega and Mr. Andrew R. Trenka of the Pacific International Center for High Technology Research (PICHTR). The paper presented a straight forward analytical model to compare the cost of electricity produced either with OTEC or with petroleum or coal fired plants. Two generalized markets were considered; the industrialized islands such as Oahu or Taiwan, and smaller less developed islands with modest needs such as Western Samoa, etc. The model was used to establish scenarios under which OTEC could be competitive. The analysis showed that the combined production of electricity and fresh water utilizing the principle of OTEC is cost effective under certain scenarios defined by the fuel cost of the electricity production with conventional fossil fuel plants and the production cost of water. At least four scenarios were identified. They are presented below in Table 1:

NOMINAL NET POWER (MWe) TYPE SCENARIO REQUIREMENTS SCENARIO AVAILABILITY
1 Land-Based OC-OTEC with 2nd-Stage additional Water Production ¡E $45/barrel of diesel
¡E $1.6/m3 water
South Pacific Island Nations by Year 1995
10 Land-Based
(as above)
¡E $25/barrel of fuel oil
¡E $0.85/m3 water
-or-
¡E $30/barrel with
¡E $0.8/m3 water
American Island Territories And other Pacific Islands by Year 2000
40 Land-Based Hybrid (ammonia power cycle with Flash Evaporator downstream) ¡E $44/barrel of fuel oil

¡E $0.4/m3 water
-or-
¡E $0.8/m3 water

Hawaii if fuel or water cost doubles by Year 2000
40 ¡E Closed-Cycle Land-Based
¡E Closed-Cycle Plant-ship
¡E $36/barrel
¡E $23/barrel
by Year 2005
OC-OTEC limited by turbine technology to 2.5 MW modules or 10 MW plant (with four modules).
CC-OTEC or Hybrid (water production downstream of closed-cycle with flash evaporator).

Table 1. OTEC Market Penetration Scenarios.

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The capital costs required to build OTEC plants were discussed in the paper. The estimates for land-based plants rated at 10 and 40 MW-net are summarized in Table 2 and 3 respectively. Production rates are for 0.8 capacity factors (i.e., 7000 hours of operation per year).

PLANT NOMINAL SIZE: 10MW;OC-OTEC 10 MW;OC-OTEC
with 2nd -Stage
PRODUCTION:
Electricity
Water
CAPITAL COST:
YEAR DEPLOYED:
70x106 kWh
4 MGD(15,000m3/day)
11,000 $/kw-net
2000
63x106kWh
8MGD(30,000m3/day)
15,000 $/kW
2000

Table 2. Capital Cost Estimates ($/kw-net)for 10 MW Land-Based Plants in 1989 Dollars.

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PLANT NOMINAL SIZE: 40 MW;CC-OTEC 40 MW; Hybrid

Ammonia Power Cycle

with 2nd-Satge Water Production

PRODUCTION:
Electricity
Water
CAPITAL COST:
YEAR DEPLOYED:

336x106 kWh
n/a
6,000 $/kw
2000 to 2005

280x106 kWh
16MGD (60,600m3/day)
9,200 $/kW
2000 to 2005

Table 3. Capital Cost Estimates ($/kW-net)for 40MW Land-Based Plants in 1989 Dollars.

To consider the moored or slowly drifting OTEC plant-ship, a capital cost of 4,500$/kw-net was estimated for an electrical production of 380¡Ñ106 Kwh. The above cost estimate was also given in 1989 dollars for a system to be deployed by the Year 2000 to 2005 assuming modest engineering development. The technologies needed for designing cold water pipes suspended from a vessel are already available.

The authors also proposed a plan aimed at achieving the development of OTEC under the scenarios determined in their report. The major elements of their plan are presented as follows:

OTEC Development Program Required
Years Project Funds Required
1990-1995 A) ¡D Develop advanced bottom- mounted Cold
Water Pipes(CWP);
¡DReduce the cost of Surface Condensers;
and,
¡DDevelop Low Pressure Steam Turbines rated
at about 3 MWe.
$ 10 M
B)OC-OTEC/2nd-satge Demon-& nbsp; stration Plant
(1 MWe/3,500m3/day) using state-of- the-art.
$ 30 M
1995-2000 C) Deploy Land-Based Plants Optimized form (B) (Total  5 MWe/17,500m3/day ). International

Banking/Aid

Community

D) Hybrid Land-Based Demon-  stration Plant (5 MWe/7,500 m3/day)using newly developed  CWP. $ 75 M
E) CC-OTEC Plantship Demon-  stration Plant (5 MWe) using existing technology. $ 60 M
2000-2005 F) Deploy 300 MWe of Land-  Based Plants in Pacific and Asia. Optimized from (D). Private
G) Deploy several 50 MWe Plant-  ship in Tropical
Waters. Optimized from (E).
Private
2005-2010 H) Provide Projected Power and  Water Increase in Small Pacific  Islands, and part thereof in Oahu,Taiwan, Philippines, etc.,   and Plantships.  (Cumulative Deployed Power: 2100 MW). Cumulative

Capital

Investment

$13 Billion