2nd largest plant in Hawaii · 769th nationally
Waiau is a oil power plant in Hawaii with a nameplate capacity of 475 MW. It generates roughly 1.3M MWh per year — enough to power about 122,251 average U.S. homes.
Its capacity factor of 31% reflects intermittent or peaking operation. At 1856 lb CO₂/MWh, its emission rate sits above the national grid average of roughly 800 lb/MWh.
Ghost bars are each month's theoretical maximum (475 MW nameplate × hours in the month). Filled bars are actual net generation reported to EIA Form 923. The gap between them is capacity factor made visible.
| Plant Name | Waiau |
|---|---|
| Operator | Hawaiian Electric Co Inc |
| City | Pearl City |
| County | Honolulu County |
| State | Hawaii |
| ZIP | 96782 |
| Coordinates | 21.38900, -157.96152 |
This plant highlighted in navy-ringed pin; other generators within 25 miles shown as fuel-colored dots.
| ID | Technology | Fuel | Capacity | Status | Online |
|---|---|---|---|---|---|
| W7 | Petroleum Liquids | Residual Oil | 81.6 MW | Operating | 1966 |
| W8 | Petroleum Liquids | Residual Oil | 81.6 MW | Operating | 1968 |
| W5 | Petroleum Liquids | Residual Oil | 54.4 MW | Operating | 1959 |
| W6 | Petroleum Liquids | Residual Oil | 54.4 MW | Operating | 1961 |
| W10 | Petroleum Liquids | Distillate Oil | 51.3 MW | Operating | 1973 |
| W9 | Petroleum Liquids | Distillate Oil | 51.3 MW | Operating | 1973 |
| W3 | Petroleum Liquids | Residual Oil | 50.0 MW | Operating | 1947 |
| W4 | Petroleum Liquids | Residual Oil | 50.0 MW | Operating | 1950 |
| CO₂ | 1.2M metric tons |
|---|---|
| SO₂ | 3.5k metric tons |
| NOₓ | 2.0k metric tons |
| CO₂ Rate | 1856 lb/MWh |
Annual totals and CO₂ rate reported by EPA eGRID for 2023. Reference averages are approximate U.S.-wide figures from the same dataset.
Oil-fired plants typically run only during peak demand or grid emergencies because oil is expensive compared to gas and coal. They have the highest CO₂ emissions per MWh of any common generation technology.