Assessment of Hydrokinetic Energy Resources in Alaska Rivers

Preliminary results from 17 sites on the Yukon and Kuskokwim Rivers

Tom Ravens, Nyree McDonald, Garrett Yager, Taylor Harper, Erin Eggleston, Aaron Butterer, Jenny Mills,

Daniel King, Michael UlmgrenUniversity of Alaska Anchorage

Funded by Alaska Energy Authority

What is hydrokinetic energy and hydrokinetic devices?

• Under water windmills

• Water velocity (Kinetic energy) turns turbine blades and spins a generator producing electricity

• Power/area = (Cp) 0.5 density x velocity3

• Devices can be placed in rivers or tidal inlets without significantly impacting the water course

• Distinct from conventional hydropower where damming is required

Photos courtesy of UEK Corporation

Eagle Hydrokinetic Turbine Project

TurbineUEK® System

Horizontal cross-flow turbine(Ocean Renewable Power)

Vertical cross-flow turbines (EnCurrent, New Energy Corporation)

Paddle wheel hydrokinetic device (Don Eller, Tanana)

Project Goals and Objectives

Step 1: measure discharge, velocity, topography, bathymetry, and water level at each site.

Step 2: Determine discharge as a function of time (using water level data, and hydraulic/hydrologic models).

Step 3: Determine velocity as a function of space and time (using discharge data and models).

Step 4: Assess hydrokinetic energy potential at the 24 sites.

Overall goal: Assess hydrokinetic energy potentialat 24 Alaska sites

Sites for hydrokinetic assessment on the Yukon and Kuskokwim Rivers

Pilot Station survey transects

RTK-GPS base station and hydrographic survey boat

Data collection and navigation on board

Topographic survey crew surveyed shallow water and river banks

Velocity measured in Pilot Station

Velocity as a fnc. of depth

Example water level datafrom St. Mary’s

12.5

13

13.5

14

14.5

15

7/26/2009 8/15/2009 9/4/2009 9/24/2009 10/14/2009 11/3/2009

date

Depth[m]

How to use data to determine Q(t) or V(t)?

h1. 2. h

t

3.Q

h

4. Q

t

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

Dis

char

ge, m

^3/s

Date and Time

Yukon Discharge Summary

Moutain Village

St. Mary's

Grayling

Kaltag

Nulato

Koyukuk

Galena

Stevens Village

Galena (upstream)

Stevens Village (USGS, far upstream)

St. Mary’s (downstream)

0

500

1000

1500

2000

2500

Dis

char

ge, m

^3/s

Date and Time

Kuskokwim Discharge Summary

Aniak

Chuathbaluk

Napaimiut

HEC-RAS model of water level and velocity (Pilot Station, July-Aug/2009)

Preliminary power density estimate for Pilot Station

0

50

100

150

200

250

300

350

400

450

500

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

7/6/09 7/26/09 8/15/09 9/4/09 9/24/09 10/14/09 11/3/09

Pow

er p

er a

rea

(W/s

q. m

)

velo

city

(m/s

)

date

velocity (m/s)

power per area (W/sq m)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 2 4 6 8 10 12

Velo

city

(m/s

)

Project Site

Peak Velocity on Yukon River Galena

threshold

Mountain Village

Peak velocity at various sites along the Yukon River

Peak velocity at various sites along the Kuskokwim

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

0 1 2 3 4 5 6

Velo

city

(m/s

)

Project Site

NapaimuteLower Kalskag

River slope on Yukon River

0

0.00001

0.00002

0.00003

0.00004

0.00005

0.00006

0.00007

0.00008

0.00009

0.0001

0 2 4 6 8 10 12

Rive

r slo

pe (m

/m)

Project site (Yukon River)

Galena

Mountain Village

River slope on Kuskokwim River

0

0.00005

0.0001

0.00015

0.0002

0.00025

0.0003

0.00035

0.0004

0.00045

0.0005

0 1 2 3 4 5 6

Rive

r slo

pe (m

/m)

Project site (Kuskokwim River)

Napaimute

Lower Kalskag

Yukon River water velocity in winter (from EPRI)

Year round hydrokinetic power density (from EPRI)

Future work?

2010 Hydro Kinetic Feasibility Sites

Upper YukonTanana

Stevens VillageBeaver

Fort YukonCircle

Tanana River

TokTanacross

Copper River

SlanaChistochina

Chitina

SusitinaRiver

TalkeetnaSutton/Chickaloon

Upper Kuskokwim

Crooked CreekRed DevilSleetmute

Stony RiverMcGrath

Teller

Hydrokinetic assessment of USA(DOE-funded with EPRI and UAF)

Hydrokinetic Energy Environmental Impacts

• On fish

• On marine mammals

• On water level

• On sediment transport

Questions?

Peak and average velocity on Yukon River

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 2 4 6 8 10 12

Velo

city

(m/s

)

Project Site

Summary Data