Data last collected:
PowerPlantFactsEvidence report · prepared 19 October 2026https://powerplantfacts.com/entity/3847
EIA plant 3847
Ariel · Cowlitz · WA
Merwin
Operated by PacifiCorp
Published location
Where is Merwin?
This locator uses the coordinates in the approved source record. It shows geographic context, not a site boundary, safety zone or property-risk area.
45.956700, -122.554444
Open the interactive map ↗Map data © OpenStreetMap contributors
Capacity is not generation. Nameplate MW describes equipment; annual MWh describes recorded output. Proposed and retired units are not added to operating capacity.
Equipment mix
Operating capacity by technology
Grouped from this plant’s represented generator records. Use the WA plant index for regional peers.
See the evidence
Electricity output across the year
Monthly net generation shows the seasonal shape of this plant's represented output. A negative value is retained when the source reports net consumption.
166,902
257,894
341,572
433,434
544,575
634,826
718,469
814,688
923,272
1018,323
1152,656
1260,706
MWh net generation · 2024 final edition · EIA 923 represented operating rows. 12 of 12 supplied rows shown; 0 missing values omitted. Months with no reported numeric value are omitted, not treated as zero.
Read the chart as a table
| Record | MWh net generation |
|---|---|
| 1 | 66,902 |
| 2 | 57,894 |
| 3 | 41,572 |
| 4 | 33,434 |
| 5 | 44,575 |
| 6 | 34,826 |
| 7 | 18,469 |
| 8 | 14,688 |
| 9 | 23,272 |
| 10 | 18,323 |
| 11 | 52,656 |
| 12 | 60,706 |
2024 monthly net generation
| Month | Net generation |
|---|---|
| 1 | 66,902 MWh |
| 2 | 57,894 MWh |
| 3 | 41,572 MWh |
| 4 | 33,434 MWh |
| 5 | 44,575 MWh |
| 6 | 34,826 MWh |
| 7 | 18,469 MWh |
| 8 | 14,688 MWh |
| 9 | 23,272 MWh |
| 10 | 18,323 MWh |
| 11 | 52,656 MWh |
| 12 | 60,706 MWh |
Operating generators
| ID | Technology | Fuel | MW | Status |
|---|---|---|---|---|
| 1 | Conventional Hydroelectric | WAT | 45 | OP |
| 2 | Conventional Hydroelectric | WAT | 45 | OP |
| 3 | Conventional Hydroelectric | WAT | 45 | OP |
| House | Conventional Hydroelectric | WAT | 1 | OP |
Continue exploring
Similar-capacity plants in the same state
Identity, technology and limitations
EIA plant ID
3847
Sector
Electric Utility
Water source
Lewis River
Data edition
2024-final
Use this record
Questions this evidence can answer
01What exactly is this record?
Use the name, place, date and identifiers above to confirm that you have the right Merwin power plant: capacity and generation | PowerPlantFacts record.
02What does the evidence establish?
Read the reported values with their units, coverage dates and source notes. Keep observed facts separate from estimates or interpretation.
03What should I verify next?
Follow the primary-source links and check the limitations before using this evidence for a decision, comparison or citation.
A closer look at Merwin
Variation in the published months
Across 12 numeric monthly generation entries, 1 has the highest recorded value (66,902 MWh) and 8 the lowest (14,688 MWh). Their difference is 52,214 MWh. Missing months have not been treated as zero.
Reading the MW column
In the 4 numeric rows displayed in this table, MW ranges from 1 (House) to 45 (1, 2, 3). The difference is 44 in the column's stated units. This summary covers the displayed rows and retains the table's period and scope.
Generator capacity in different operating conditions
| Generator ID | Technology | Nameplate MW | Summer MW | Winter MW | Minimum load MW |
|---|---|---|---|---|---|
| 1 | Conventional Hydroelectric | 45.0 | 50.0 | 50.0 | 0.1 |
| 2 | Conventional Hydroelectric | 45.0 | 50.0 | 50.0 | 0.1 |
| 3 | Conventional Hydroelectric | 45.0 | 50.0 | 50.0 | 0.1 |
| House | Conventional Hydroelectric | 1.0 | 1.0 | 1.0 | 0.1 |
EIA-860 2024 final source. Ratings describe capacity, not actual generation or availability. Missing ratings are not zero.
Source: US Energy Information Administration Form EIA-860 2024 plant and operable-generator workbooks; archive 2024. US EIA-authored information is generally public domain; cite EIA, preserve third-party exceptions, changes and no-endorsement context. Source-specific derived data.