New Proposed Permits

Old Proposed Permits
EPA Comments
EPA Objections
Final Permits
Facility List
All Documents
U.S. EPA Region 9 Electronic Permit Submittal System
Document Filer
Use "Back" key in your browser to return
Main EPSS Home
Air Permit Home
Region 9 Home

Note: * indicates required field. Updated:04/22/2002
Hide details for Detailed InformationDetailed Information
Permitting Authority: HAWAII DEPARTMENT OF HEALTH

County: HAWAII AFS Plant ID: 15-001-00519

Facility: HAWAII ELECTRIC LIGHT COMPANY, INC.

*Document Type: Engineering Report
-----------------------------------------------------------------

1
COVERED SOURCE PERMIT REVIEW - PERMIT 0237-01-C

Facility Title: Waimea Generating Station
UTM: 217.7 km East, 2,216.9 km North
Located at: Kamuela, Hawaii

Applicant: Hawaii Electric Light Company, Inc. (HELCO)

Responsible Official: Warren H.W. Lee Point of Contact: Barry Nakamoto
Company's Mailing Address: Hawaii Electric Light Company, Inc.
Project:
The Waimea Generating Station (WGS) operated six diesel engine generators, but three units, unit nos. 8, 9, and 10, are being permanently shutdown. For the purposes of this permit, the WGS will operate three diesel engine generators, unit nos. 12, 13 and 14, for commercial electric power generation (Table 1). The three diesel engine generators are rated at 2.5 MW each. All of the units are fired on fuel oil no. 2 with a maximum sulfur content of 0.5 percent by weight.

The fuel oil no. 2 is delivered to the generators from two 1,015 barrel above ground storage tanks nos. TK-1 and TK-2.
TABLE 1
LIST OF EMISSIONS UNITS
Stack No.
Unit No.
Equipment Description
Fuel Type
12
12
2.5 MW Diesel Engine GeneratorFuel Oil No. 2
13
13
2.5 MW Diesel Engine GeneratorFuel Oil No. 2
14
14
2.5 MW Diesel Engine GeneratorFuel Oil No. 2
NA
TK-1
1,015 bbl Fuel Oil Storage TankFuel Oil No. 2
NA
TK-2
1,015 bbl Fuel Oil Storage TankFuel Oil No. 2
Air Pollution Controls:

Sulfur emissions are controlled by limiting the fuel sulfur content to 0.5 percent by weight. PM, PM10, CO, and VOCs are controlled by good combustion practices.

Applicable Requirements:
Hawaii Administrative Rules (HAR)
Chapter 11-59 Ambient Air Quality Standards
Chapter 11-60.1 Air Pollution Control
Non-Applicable Requirements:
PSD
A PSD review is not applicable because this is not a new major source nor is any significant modification to this existing major source being proposed.

NESHAP
NESHAP is not applicable since the facility is not a major source of HAP emissions. Furthermore, a NESHAP for the specific source category of fuel combustion in diesel engine generators has not yet been promulgated.

NSPS
NSPS is not applicable since there is no specific NSPS for the specific source category of diesel engine generators. 40 CFR Part 60 Subparts K, Ka, and Kb are not applicable to the petroleum storage tanks because the petroleum liquids stored have a true vapor pressure of less than 3.5 kPa.

BACT Requirements:
A best available control technology (BACT) analysis is not required for this facility since there are no new major sources and no new modifications to the existing major sources.

Applicable Requirements:
NEDS
NEDS reporting is applicable to this facility since the point source emissions exceed the trigger levels of 40 CFR Part 51 Subpart Q.

CDS
CDS inspection is applicable to this facility because the facility is a major source.

Insignificant Activities/Exemptions:
The two 1,015 barrel above ground petroleum storage tanks, TK-1 and TK-2, store fuel oil no. 2 and are insignificant activities based on the low vapor pressure of fuel oil no. 2. The tanks are exempt from NSPS for the same reason. Other insignificant activities based on size, emission level, or production rate, are as follows:


HAR Section Description
11-60.1-82(f)(6) Several paint spray booths are used for maintenance purposes.
11-60.1-82(g)(1) Welding booths are used for maintenance purposes.
11-60.1-82(g)(2) Handheld power tools are used for maintenance and testing purposes.
11-60.1-82(g)(3) Laboratory equipment is used for chemical and physical analysis.
11-60.1-82(g)(11) Sewer stacks and vents prevent escape of sewer gases through plumbing traps.


Alternate Operating Scenarios:
There are five alternate operating scenarios that were requested by the permittee.
1. In the event of an equipment failure or a major overhaul of an installed piece of equipment possibly causing interruption in electrical service, the down unit would be replaced with an equivalent unit. Air emissions from the replacement unit will comply with the original unit's emission limits.

2. Start-up, shutdown, maintenance and testing scenario.

3. The ability to switch primary fuel. Upon written approval from the Department, the permittee could switch fuels. The burning of an alternative fuel cannot result in an increase in emissions of any air pollutant or in the emission of any air pollutant not previously emitted.

4. Unpredictable periods of equipment failure, upsets, or emergency conditions. During any emergency condition, HELCO will operate the subject equipment in such a manner as to minimize emissions and comply with the Emergency Provisions of HAR 11-60.1-16.5.

5. The use of fuel additives to control algae and inhibit corrosion. Additives associated with this scenario will not affect emission estimates.

Project Emissions:
The applicant used AP-42 emission factors, section 3.4 revised 10/96, to calculate the maximum potential emissions for SO2 and NOX from the three diesel engine generators. SO2 emissions were estimated using AP-42 emission factor of 1.01S, where S is the sulfur content of the fuel. HELCO is proposing to burn fuel oil no. 2 with a maximum sulfur content of 0.5 percent sulfur by weight. Thus, S = 0.50. The NOX emissions were estimated using the AP-42 emission factor of 3.2 lb/MMBtu. The applicant used emission factors greater than the AP-42 emission factors for PM10, CO and TOC/VOC. PM10 emissions were estimated using an old AP-42 emission factor of 0.076 lb/MMBtu which is greater than the current AP-42 emission factor of 0.0573 lb/MMBtu. For CO emissions, HELCO used an emission factor of 1.215 lb/MMBtu, which is greater than the AP-42 emission factor of 0.85 lb/MMBtu. HELCO also used a higher emission factor for TOC/VOC, 0.55 lb/MMBtu versus the AP-42 emission factor of 0.09 lb/MMBtu.

Emission estimates for all pollutants were calculated assuming the units operated 24 hours per day, seven days per week. The heating value used for fuel oil no. 2 was 138,356 Btu/gal. This heating value has been used by HELCO in the past to calculate annual emissions and fees. Table 2 lists the estimated maximum potential emissions and emissions factors used to calculate the estimated emissions.
TABLE 2
MAXIMUM POTENTIAL EMISSIONS PER GENERATOR
Pollutant
AP-42
EF
(lb/MMBtu)
AP-42
Emissions a
(TPY)
Applicant
EF
(lb/MMBtu)
Applicant
Emissions a
(TPY)
Applicant
Emissions a
(lb/hr)
SO2
0.51
64.4
0.51
65.8
15.02
NOX
3.20
407.8
3.20
407.9
93.12
CO
0.85
108.3
1.22
154.9
35.36
TOC/VOC
0.09
11.5
0.55
25.5
5.82
PM10
0.06
7.3
0.08
9.69
2.21
a Emissions per generator.

Except for formaldehyde, the applicant used emission factors from AP-42 section 3.4, revised 10/96, to estimate HAP emissions. Formaldehyde emissions were calculated using an emission factor of 4.71 x 10-4 lb/MMBtu which is greater than the AP-42 of 7.89 x 10-5. The emission factor is from the EPRI PISCES Air Toxic Database. The estimated emission rates for HAPs are listed in Table 3 below. All calculations were based on operating 8,760 hours per year.
TABLE 3
MAXIMUM POTENTIAL HAP EMISSIONS PER GENERATOR
Pollutant
AP-42
EF
(lb/MMBtu)
AP-42
Emissions a
(TPY)
Applicant
EF
(lb/MMBtu)
Applicant
Emissions a
(TPY)
Applicant
Emissions a
(lb/hr)
Acetaldehyde
2.52 x 10-5
3.21 x 10-3
2.52 x 10-5
3.21 x 10-3
7.33 x 10-4
Acrolein
7.88 x 10-6
1.00 x 10-3
7.88 x 10-6
1.00 x 10-3
2.29 x 10-4
Benzene
7.76 x 10-4
9.89 x 10-2
7.76 x 10-4
9.89 x 10-2
2.26 x 10-2
Formaldehyde
7.89 x 10-5
1.01 x 10-2
4.71 x 10-4
6.00 x 10-2
1.37 x 10-2
Naphthalene
1.30 x 10-4
1.66 x 10-2
1.30 x 10-4
1.66 x 10-2
3.78 x 10-3
Toluene
2.81 x 10-4
3.58 x 10-2
2.81 x 10-4
3.58 x 10-2
8.18 x 10-3
Xylene
1.93 x 10-4
2.46 x 10-2
1.93 x 10-4
2.46 x 10-2
5.62 x 10-3
a Emissions for each diesel engine generator.
For the two petroleum storage tanks, VOC emission rates were calculated using AP-42, Section 7.1, revised 9/97. The estimated emissions for each storage tank are tabulated in Table 4 below.

TABLE 4
MAXIMUM POTENTIAL EMISSIONS PER PETROLEUM STORAGE TANK
Pollutant
Emission Rate a
(lbs/hr)
Annual Emissions a
(tons/yr)
Criteria Pollutants
VOC
8.22 x 10-3
3.6 x 10-2
Hazardous Air Pollutants
Benzene
8.50 x 10-5
3.72 x 10-4
Hexane
3.03 x 10-5
1.32 x 10-4
o-Xylene
1.06 x 10-5
4.66 x 10-5
Ethylbenzene
1.06 x 10-5
4.66 x 10-5
p-Xylene
1.31 x 10-5
5.73 x 10-5
m-Xylene
3.76 x 10-5
1.65 x 10-4
Toluene
1.74 x 10-4
7.63 x 10-4
a Emissions for each petroleum storage tank.

The maximum potential emissions for the facility are summarized in Table 5. The Waimea Generating Station is a major covered source because the NOx (as NO2), SO2, and CO emissions are each greater than 100 tons per year. The facility is not a major source for HAPs, as the HAP emissions are less than 10 tons per year individually and less than the 25 tons per year combined.

TABLE 5
FACILITY MAXIMUM POTENTIAL EMISSIONS, ALL SOURCES
Pollutant Type
Total Emissions (tons/yr)
Criteria Pollutants
NO2
1,224
SO2
197
PM10
29
CO
465
VOC
77
Hazardous Air Pollutants
Acetaldehyde
9.63 x 10-3
Acrolein
3.00 x 10-3
Benzene
2.97 x 10-1
Ethylbenzene
9.32 x 10-5
Formaldehyde
1.80 x 10-1
Hexane
2.64 x 10-4
Naphthalene
4.98 x 10-2
Toluene
1.09 x 10-1
Xylene
7.43 x 10-2
Total HAP emissions (TPY)
7.24x 10-1

Air Quality Assessment:
ISC_RTDM was used to predict the ambient air quality impacts from the Waimea Generating Station's three diesel engine generators. The model was chosen because the area surrounding the WGS is both simple and complex terrain. The ISC_RTDM model is a combination of the two USEPA guideline models, ISCST3 and RTDM, and is capable of modeling simple, intermediate and complex terrain. For simple terrain, the model replicates the ISCST3 model and implements the USEPA procedures for intermediate terrain. The model also replicated the RTDM model in complex terrain. The ISC_RTDM model was developed for HELCO and has received USEPA approval for use in 1996. Since then, the ISC_RTDM model has been revised to incorporate the latest versions of ISCST3 and RTDM.

The area surrounding the WGS is considered rural, as the percentage of urban classification is less than 50 percent. The rural determination was done following the guidelines of 40 CFR 51 Appendix W.

The results from the USEPA BPIP, which was used to determine the dominant downwash conditions, were used in the ISC_RTDM model. The 10-m meteorological data used in the model was collected at Kawaihae from August 31, 1991 to August 30, 1992. Mean mixing height data is from the Hilo Airport, collected from 1984-1991.

Receptors were placed in a coarse grid of 500 meters to locate the areas of maximum impact. At the areas of maximum impact, a refined receptor grid spacing of 50 meters for simple terrain and 30 meters for complex terrain were used. This is in accordance with the Department's guidelines for air modeling.

Air dispersion modeling using ISC_RTDM was conducted for the following criteria pollutants: nitrogen oxides (NOX as NO2), sulfur dioxide (SO2), particulate matter equal to and less than 10 microns (PM10), and carbon monoxide (CO). Hazardous air pollutants (HAP) were not included in the impact analysis since HAPs emissions were below major source threshold of 10 tons per year (TPY) for a single HAP or 25 TPY total HAPs. Stack parameters and flow rates of the pollutants are shown in Table 6.

Since the WGS is an existing source and there are no modifications being proposed, the ambient air quality impacts assessment does not need to include background concentrations nor impacts from other near-by sources. The ambient air quality impact assessment need only include the impact from the source. As shown in Table 7, the results of the ISC_RTDM model predicted that the concentrations of the criteria pollutants will remain below the NAAQS and SAAQS.
TABLE 6
SOURCE EMISSION RATES AND STACK PARAMETERS FOR AIR MODELING
EMISSION RATES
STACK PARAMETERS
STACK COORDINATES
Equip.
No.
SO2
(g/s)
NOx
(g/s)
CO
(g/s)PM10
(g/s)Height
(m)Temp.
(K)Velocity
(m/s)Dia.
(m)Easting
(m)Northing
(m)Base
Elev.
(m)
12
1.89
11.73
4.460.286.1677.623.350.81217,7152,216,913749.8
13
1.89
11.73
4.460.286.1677.623.350.81217,7232,216,921749.8
14
1.89
11.73
4.460.286.1677.623.350.81217,7292,216,922749.8


TABLE 7
RESULTS OF THE AMBIENT AIR QUALITY IMPACT ANALYSIS
Pollutant
Averaging
Period
Maximum
Concentration
(g/m3)
NAAQS
(g/m3)
SAAQS
(g/m3)
Percent
of
SAAQS
SO2
3-hr
1,209
1,300
1,300
93%
24-hr
214
365
365
58%
annual
12
80
80
15%
PM10
24-hr
32
150
150
21%
annual
2
50
50
4%
NO2a
annual
56
100
70
80%
CO
1-hr
4,796
40,000
10,000
48%
8-hr
1,296
10,000
5,000
26%
a – assumes NO2 = NOX * (0.75), 40 CFR 51 Appendix W, section 6.2.3.



Conclusion and Recommendation:
This is an existing source and the applicant has demonstrated compliance with the NAAQS/SAAQS. Emissions estimates used to demonstrate compliance are conservative because the estimates were based on all the units operating 8,760 hours per year. Also, several of the emission factors used to estimate emissions were greater than the USEPA approved AP-42 emission factors. Therefore, it is recommend that the issuance of a Covered Source Permit for the facility be granted, subject to public comment and USEPA review.