Glen Canyon Hydropower 

Production and Value

Status and Trends, 2022

S. Clayton Palmer

Annual Reporting Meeting

January 24-25, 2023
Glen Canyon Electrical Production

Year Release 

Volume (maf)

Electrical 

Production (GWhs)

2022 7.0 3,443

2021 8.23 4,258

1992-2022 

Average

9.11 5,400

Power production in 2022 was 19% less than 2021 

and 36% less than the 30-year average

2
Changes in Hydropower Head Affects the 

Efficiency of Electrical Production

Hydropower head = elevation of Lake Powell – elevation of GCD 

tailrace

• Example: 

• At full pool, it takes 1.9 acre feet to produce 1 MWh

• At elevation 3522.16 (Jan 23), it takes 2.75 Acre Feet to produce 

1 MWh

3
WAPA-199: Description & Consequences

• WAPA-199 is a new SLCA/IP rate -

implemented December 2021

• Customers are charged a SLCA/IP 

rate for the electric power that is 

actual generation. Firming energy 

purchases, beyond what is actually 

generated, are charged to 

customers at the end of the month

• Customers can avoid these 

charges by taking only their share 

of what is generated

• SLCA/IP customers must either 

generate more of their own power 

or buy more power on the market

• Customers are interested in more 

water release from the CRSP units 

in peak electrical months

4
0

100

200

300

400

500

600

700

800

900

147

101316192225283134374043464952555861646770737679828588919497

100103106109112115118121124127130133136139142145148151154157160163166

Typical January – for illustration

SHP

5

WAPA-199

Comparison of SHP versus WAPA-199 Energy
Purchase Power

6
$8,475,841

$12,063,317

$1,000,000

$500,000

$0

$500,000

$1,000,000

$1,500,000

$2,000,000

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Purchases/WRF WY 2022

Net Annual Purchase Power Glen Canyon Release

2022 = $22.7 million 2022 = 7.0 maf

7

Purchases/WRF WY 2022
DROA: Higher Flaming Gorge Releases

8
9
Macroinvertebrate Flows – Summer 2022

10
Macroinvertebrate Flows Costs - Summer 

2022

Month Cost

May $238k

June $235k

July $468k

August $213k

Total $1.154M

In comparison:

• 2018: $165k

• 2019: $330k

• 2020: $940k

• 2022 a priori estimate: $1.4m

Why have Bug Flow expenses 

increased over these years?

• Summer wholesale market 

prices have risen

11
CRSP Hydropower Drought Analysis

• From WY 2000 - 2022 the cumulative reduction in total generation 

compared to the pre-drought period is 32,624 GWh.

• $1.5B in economic value

• GCD 19% capacity reduction

• The CRSP rate is almost 50% higher

12
CRSP Hydropower Drought Analysis (continued)

13
Smallmouth Bass Experiments

Electrical Power Impacts

• The National Renewable Energy Laboratory, Argonne National 

Laboratory, and WAPA developed an analysis of the impacts of the 

proposed GCD SMB flow options on CRSP hydropower and the 

attached electrical systems

• NREL calibrated the PLEXOS energy system model for this analysis

• Argonne modeled the CRSP hydropower system using the GTMAX 

SL model

• The modeling was done under WAPA’s sponsorship and guidance 

using Reclamation’s descriptions of the flow options and WAPA’s 

modeling of these options.

14
Smallmouth Bass Experiments

Electrical Power Impacts (continued)

Assumptions for PLEXOS model runs:

• Geographic scope is the WECC system

• Time frame is June – October 2023

• Assumes “free exchange” of generating sources to meet WECC retail 

electrical demand

• Analysis does not include new construction or uprates

• PLEXOS model is constrained by transmission capacity

• Treats Glen Canyon hourly power generation as “must run”, i.e., SMB flow 

options are strictly adhered to

• For each PLEXOS model run, assumes just one flow option is 

implemented for the entire time frame

15
Smallmouth Bass Experiments

Electrical Power Impacts (continued)2

Assumptions for GTMAX SL model runs:

• For each GTMAX model run, only one flow option is implemented 

for the entire time frame

• Assumes that, during the experiment, WAPA purchases firming

energy to make up the difference between GCD “normal” 

operations and the experiment.

• “Normal" operations is a "no experiment" condition: GCD operates 

according to the LTEMP operating criteria

• Market prices used to estimate firming expenses are forecasted by 

ARGUS (with hourly adjustments)

16
Smallmouth Bass Experiments

Electrical Power Impacts (continued)3

Research Questions (analysis is in progress)

• Is replacement energy available?

• Since the CRSP transmission grid was built to distribute GCD power 

to federal points of delivery, if replacement energy is available, can 

it be transmitted from new generation sites to retail load?

• Will reductions in GCD power production decrease the reliability or 

stability of the electrical system?

• How will flow options impact exchange prices?

• How much will firming expenses be and how will these expenses 

impact the CRSP Basin Fund

17
Lost Generation: 563.7 GWh

Penstock release Bypass release

18

Flow Option A

GTMAX model results – Reduction in GCD Power Production
Lost Generation: 600.7 GWh

Penstock release Bypass release

19

Flow Option B

GTMAX model results – Reduction in GCD Power Production
Lost Generation: 322.3 GWh

Penstock release Bypass release

20

Flow Option C

GTMAX model results – Reduction in GCD Power Production
Lost Generation: 380.2 GWh

Penstock release Bypass release

21

Flow Option D

GTMAX model results – Reduction in GCD Power Production
Questions?

S. Clayton Palmer

cspalmer@wapa.gov

801-771-5669 22