OTEC Environmental Impact
Operational
Noise
OTEC
Warm Water Intake:
•Entrainment
•Impingement
Cold water intake:
•Entrainment
Biota attraction or
avoidance
Discharge Plume:
•Redistribution of nutrients
•Algae blooms
•Altered temperature and pH
•Where will it settle?
OTEC Environmental Impact
• 1981 EIS+: update to current oceanographic standards
• What data do we need? Stakeholder meeting, June 2010
– Oceanography: baseline nutrients, carbon cycle, T, S, O
– Plankton, fish larvae: distributions and density
– Megafauna habitat use
• What data is already available?
NOAA. 1981. Ocean thermal energy conversion final environmental impact statement.” OME.
NOAA. 2010. “OTEC: Assessing potential physical, chemical, and biological impacts and risks.” CRRC. 39pp.
Discharge plume: what data is available?
The Hawaii Ocean Time Series (HOTS)
– 1989 – present
– Temperature, Salinity, oxygen, pH,
chlorophyll a
Gaps in data:
• Nutrients (1989-2001 only)
• Alkalinity and DIC at deep depths
• Trace metals
Entrainment: Warm Water Pipe
Boehlert and Mundy 1994. Mar Ecol. Prog. Ser. 107:1-13
+Seapy. 2008. Mar. Biol. 154(6): 985-995
++Poe and Norenburg. 1999. Deep-Sea Res. (1 Oceanogr. Res. Pap.) 46(7): 1201-1220
Entrainment: Cold Water Pipe
Entrainment: NELHA deep water pipe
2 months, 2009
18
Fish
Flow rate of 0.8m3/s
Crustaceans
Compare to pilot plant:
25m3/s
21
30
Cnidarians
62
Other
Invertebrates
West Hawai’i Explorations Academy
and commercial plant:
500m3/s
Baseline monitoring
• Stakeholder meeting++
–
–
–
–
Oceanography : 3 years
Ichthyoplankton: 1 year+
Marine Mammals and turtles: 1 year
Plankton: 2 years
• Taking into account available datasets….
Baseline Monitoring Suggestions
1 year:
Nutrients, trace metals, and
deep water carbon cycle
cafethorium.whoi.edu
Discrete-depth sampling for
bacteria, copepods, total
biomass
Consistent monitoring of CWP at
NELHA
Don’t forget:
Background acoustics
Fishing/backscatter for nekton
Megafaunal habitat use