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HomeMy WebLinkAboutYakutat Study by Atmocean 081011© 2011 Atmocean, Inc. Proprietary & Confidential. For Use By Designated Recipient ONLY. Atmocean, Inc. - 607 Cerrillos Road - Santa Fe, NM 87505. 505-310-2294. www.atmocean.com Page 1 Atmocean Wave Energy Feasibility Study for Yakutat, AK Prepared by Philip W. Kithil, CEO Updated August 10, 2010 This study evaluates whether the Atmocean wave energy system could substantially reduce diesel as the energy source for the City of Yakutat, Alaska, while providing a high-level comparison against the AquaMarine “Oyster” wave energy system. We are grateful for, and have relied on, power consumption and cost data as well as the EPRI feasibility study for the AquaMarine “Oyster” technology dated November 30, 2009, both provided by Scott Newlun, Manager for the City of Yakutat Electric Utility. We also are grateful for the interest of Ian Fisk, Yakutat lobbyist, who first contacted us. Our study used wave energy for NDBC data buoy #46082, 84nm SE of Cordova, as it had more complete data than data buoy #46083, 92nm SE of Yakutat, used by EPRI. Comparative wave energy data for 2010 is shown here. Below we show artistic renderings of the Atmocean and AquaMarine wave energy systems. Table 1 compares key attributes. Atmocean AquaMarine Table 1. Key Attributes of Atmocean and AquaMarine Wave Energy Systems Attribute Atmocean AquaMarine Operating Depth >25m 12-16m Ocean regime Offshore Nearshore Power transmission Hydraulic Hydraulic Wave energy physics Wave steepness Surge force Seawater Tube at 10-15m depth 20-40m spacing - 500 1,000 1,500 2,000 2,500 3,000 3,500 1 2 3 4 5 6 7 8 9 10 11 12Vertical Meters Per HourMonth Atmocean 46082 Data vs EPRI 46083 Data (2010) © 2011 Atmocean, Inc. Proprietary & Confidential. For Use By Designated Recipient ONLY. Atmocean, Inc. - 607 Cerrillos Road - Santa Fe, NM 87505. 505-310-2294. www.atmocean.com Page 2 Transmission line type Hose on seafloor Pipe under seafloor Transmission fluid/cycle Seawater open loop Freshwater closed loop Nominal Line Pressure 120-200 psi 1750 psi Seafloor attachment Standard slack moorings Fixed foundation on seafloor Shoreline crossing Pipe on beach (self burying by beach sand) Directional drilled pipeline System weight <1 t per device 450 t System configuration 1 array = 50 connected devices 1 unit System size (transport) 4’ x 4’ x 6’ each device (20 per 40’ container) 85’ x 43’ x 43’ (not able to containerize for shipping) Generator Tie to existing generator 3 phase induction generator Converter Tied to existing converter Step up transformer to 11/33kV Effective power output 1,000 MWh per year/array 2,596 MWh per year /unit Extreme wave protection Buoy submerges in waves > 3.5 m Unknown – problematic Seafloor disturbance Minimal (mooring and flexible hose are only components contacting seafloor) Local disturbance of seafloor from foundation placement Effect on fish, marine mammals & avian species Beneficial due to upwelling of nutrients which replenish the ocean food chain. Minimal unless fish or mammals become entangled. Effects of tides None May not operate1 1 According to http://tbone.biol.sc.edu/tide/tideshow.cgi, 2010 tide range was +12.4’ to – 2.7’ in Yakutat Bay. Several key benefits of the Atmocean system emerge from this comparison: 1. Atmocean’s system is located in deeper water where the waves tend to be greater. 2. Because the Atmocean system relies on wave steepness as well as wave height, it is able to produce power in low waves with short periods. 3. Atmocean’s distributed architecture aggregates the power generated by many small, inexpensive devices, avoiding loss of the system if a few devices fail. 4. Atmocean’s system utilizes seawater transmission, eliminating concern over leakage. 5. Atmocean reduced line pressure saves cost. 6. In large waves (above 3.5m), the Atmocean buoy submerges, preventing excessive loading of connectors, cables, and underwater parts, greatly improving the probability of survival under extreme ocean conditions. Compared to AquaMarine, the main disadvantages of the Atmocean system are the greater hydraulic transmission distance to the shore-based generator (more than offset by not duplicating generation equipment); and need to minimize corrosive effects of seawater on accumulator/storage, and hydraulic motor components. Atmocean analysis proceeded as follows: 1. Sort chronological 2010 wave data by wave height and period. 2. Referencing the Atmocean wave energy lookup table, enter the power generated by a single device for each wave height/period (above 3.5m waves, we use the 3.5m power). Re-sort the data chronologically. © 2011 Atmocean, Inc. Proprietary & Confidential. For Use By Designated Recipient ONLY. Atmocean, Inc. - 607 Cerrillos Road - Santa Fe, NM 87505. 505-310-2294. www.atmocean.com Page 3 3. Compare the annual power produced by one array to annual demand. Add arrays until the power produced by the Atmocean system is roughly equal to Yakutat’s 2010 diesel-generated power. We present the graphical results of this process below. Step 1: Obtain 2010 data, then sort from smallest to largest wave heights. Notice the wave period for each wave height ranges from a few seconds to about 15 seconds – suggesting small waves with short periods are steep and will produce power. Step 2: Reference Atmocean’s wave energy lookup table to enter power for each wave height and period; re-sort chronologically. Step 3: Determine number of arrays required to meet annual kWh demand. In this analysis, five arrays (1,250 devices) are optimum. - 2 4 6 8 10 12 14 16 - 0.50 1.00 1.50 2.00 0.61.11.31.61.82.02.22.42.62.83.13.5Wave Period (s)Power (kW)Wave Height (m) Wave Energy Lookup Table kW DPD - 5 10 15 - 0.20 0.40 0.60 0.80 1.00 1.20 0.60.81.01.11.21.31.41.5Wave Period (s)Power (kW)Wave Height (m) Wave Energy Lookup Table -Low Waves Detail kW DPD - 5 10 15 20 - 3.0 6.0 9.0 12.0 15.0 Wave Period (s)Wave Height (m)Hourly Samples for 2010 2010 Data Sorted By Wave Height WVHT DPD -25 -15 -5 5 15 25 - 3.0 6.0 9.0 12.0 15.0 110012001300140015001600170018001Period (s)Wave Height (m)Hourly Samples 2010 Wave Height and Period wvht DPD (2.00) (1.00) - 1.00 2.00 3.00 - 3.0 6.0 9.0 12.0 15.0 110012001300140015001600170018001kW per hourWave Height (m)Hourly Samples 2010 Wave Height and Atmocean Power Per Device wvht Kw - 1,000,000 2,000,000 3,000,000 4,000,000 5,000,000 6,000,000 7,000,000 J F M A M J J A S O N DCumulative kWhMonth Three WEST Arrays Estimated kWh vs. 2010 Diesel Actual kWh 2010 Diesel Generation WEST Array © 2011 Atmocean, Inc. Proprietary & Confidential. For Use By Designated Recipient ONLY. Atmocean, Inc. - 607 Cerrillos Road - Santa Fe, NM 87505. 505-310-2294. www.atmocean.com Page 4 Based on Google Earth ocean depth profiles, our preliminary choice for array location is at the 3 mile boundary of state waters, adjacent to Cannon Beach. Assuming the ten-year total cost of two arrays, including general inflation at 3%/year and diesel inflation at 10%/year, investment payback occurs in Year 4. Annual diesel fuel cost in 2015 is reduced from $3,698 to $270 per person. This feasibility study provides an initial guide to deployment of the Atmocean wave energy system in offshore waters adjacent Yakutat, AK. As significant engineering work remains, and cost estimates are very rough approximations, the costs, power output, and payback periods should be refined as the project moves forward. In addition to confirming ocean depth and seafloor characteristics, many other factors must be considered, and permitting arranged, before proceeding with an installation.