Nevada Power Company d/b/a NV Energy owns and operates the Silverhawk Generating Station (Silverhawk), a nominal 520-megawatt power plant located in North Las Vegas, Nevada. The facility uses aqueous ammonia solution (29 percent by weight) in the selective catalytic reduction process for controlling the nitrogen oxides emissions.
The scope of this RMP is based on the 40 CFR Part 68 and other published guidelines by U.S.EPA. The aqueous ammonia storage and handling system is the only process at Silverhawk that triggers the RMP requirements. This process was determined to be covered by federal RMP Program Level 1 requirements.
The aqueous ammonia storage and handling system at the facility is comprised of a single storage tank, pumps, and piping which terminate at the vaporizer where the aqueous ammonia is atomized to concentrations below 20 percent. The tank is 30,000 gallons in volume and is equipped with pressure relief valves, temperature, pressure, and level indicators. The facility has an administrative storage limit of 85% of the maximum storage capacity. The tank is also surrounded by a dike for containing the entire contents of the storage tank in case of equipment failure.
Offsite Consequence Analysis Results
The offsite consequence analysis was conducted using the EPA's RMP Guidance for Offsite Consequence Analysis (March 2009). The worst-case release scenario was developed assuming that the entire contents of the aqueous ammonia storage tank are released through a failed tank or pipe into the secondary containment dike that is large enough to contain the entire volume. Under worst-case meteorological conditions, 1.5 m/s wind speed and a stable (Pasquill F) atmospheric stability class, the ammonia cloud could travel 0.2 miles before dispersing sufficiently to no longer pose a health hazard to the public.
Summary of the Five-Year Accident History
There have been no accidental releases from the aqueous ammonia storage and handling system at the facili
ty in the past five years that have resulted in deaths, injuries, or significant property damage on site, or known offsite deaths, injuries, evacuations, sheltering in place, property damage, or environmental damage.
Summary of the Emergency Response Program
The emergency action plan for the facility includes the following core elements:
1) Specific actions to be taken in response to an accidental release of ammonia; 2) Procedures to notify local and public agencies including the Clark County Fire Department, the Nevada Office of Emergency Management, and the National Response Center as necessary; 3) Information regarding the training of employees; and 4) The facility staff have also discussed the emergency action plan with the Clark County Fire Department and local emergency planning committee (Clark County Office of Emergency Management).
NV Energy will coordinate emergency response with the North Las Vegas (Clark County) Fire Department, Clark County Office of Emergency Management and Nevada Division of Environmental Protection in case of any emergency event.
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| Owner or Operator Name | NV Energy |
| Owner or Operator Address Line 1 | 6226 West Sahara Avenue |
| Owner or Operator Address Line 2 | MS #30 |
| Owner or Operator City | Las Vegas |
| Owner or Operator State | NV |
| Owner or Operator Zip | 89146 |
| Parent Dun and Bradstreet Number | 0 |
| Second Parent Dun and Bradstreet Number | 0 |
| Number of Full Time Employees | 25 |
| Number of FTE CBI Flag | No |
| Covered by OSHA PSM Standard | No |
| Covered by EPCRA Section 302 | Yes |
| Covered by CAA Title V | Yes |
| CAA Title V Air Operating Permit ID | 1584 |
| Last Safety Inspection Date | 01/15/2009 |
| Last Safety Inspection By | Fire Department |
| OSHA Star or Merit Ranking | No |
| LEPC Name | Clark County LEPC |
| Number of RMP Accidents | 0 |
| Number of Processes | 1 |
| Number of Process Chemicals | 1 |
| Number of Toxic Worst-case Scenarios | 1 |
| Number of Toxic Alternate Case Scenarios | 0 |
| Number of Flammable Worst-case Scenarios | 0 |
| Number of Flammable Alternate Case Scenarios | 0 |
| RMP Accident Flammable Total (lbs) | 0 |
| RMP Accident Toxic Total (lbs) | 0 |
| RMP Accident Amount Total (lbs) | 0 |
| Total RMP Accident Deaths | 0 |
| Total RMP Accident Injuries | 0 |
| Total RMP Accident Evacuated/Sheltering In Place | 0 |
| Total RMP Accident Property Damage | $0 |
| Percent Weight (Within Mixture) | 29 |
| Physical State | Liquid |
| Model Used | EPA's OCA Guidance Reference Tables or Equations |
| Release Duration (minutes) | 2,734.6 |
| Wind Speed (meters/sec) | 1.5 |
| Atmospheric Stability Class | F |
| Topography | Urban |
| Passive Mitigation - Dikes | Yes |
| Passive Mitigation - Enclosures | No |
| Passive Mitigation - Berms | No |
| Passive Mitigation - Drains | No |
| Passive Mitigation - Sumps | No |
| Confidential Business Information | No |
