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Coal to Gas Capability
Benefits & Impacts
Presented to:
Southeastern Construction Owners & Associates Roundtable
Edward C. Healy, P.E.
October 13, 2016
Presentation Outline
• Southern Company Overview
• Southern Company Interest in Natural Gas
– Economic fuel for power generation
– Ability to leverage for MATS compliance
• MATS Overview
• Coal to Gas Capability
– Range of project costs
– Unit specific studies
– Typical coal to gas scope
– Schedule
– Emissions
• Brief Project Review
• Questions
Southern Company Overview
Southern Company Major Subsidiaries
Coal to Gas Spread
0
2
4
6
8
10
12
14
16
18
2015 2020 2025 2030 2035 2040
No
min
al$
/MM
Btu
Henry Hub Natural Gas Price Comparisons - Nominal$
AEO 2016 Ref
AEO 2016 Ref w/o CPP
AEO 2016 High economic growth
AEO 2016 Low economic growth
AEO 2016 High oil price
AEO 2016 Low oil price
AEO 2016 High oil and gas resource and technology
AEO 2016 Low oil and gas resource and technology
MISO - July 2016
NYMEX - September 20, 2016
Natural Gas Forward Price Curve
Southern Company Interest in Natural Gas
• Southern Company tripled its percentage of natural gas as a source of generation in the past decade
• Third-largest consumer of natural gas in the U.S.
• Natural gas is an effective environmental compliance tool
• Acquisition of Southern Company Gas (formerly AGL Resources)– Better positions company to develop necessary natural gas
infrastructure to meet customers’ growing energy needs
• Announced acquisition of 50 percent equity interest in Kinder Morgan’s Southern Natural Gas pipeline system (pending)
Diverse Energy Mix
Mercury and Air Toxics Standards
• Emission rate (lb/mmBtu) standards for specified pollutants
– Mercury
– Non-mercury metals (measured as PM)
– Acid gases (measured as HCL or SO2 surrogate standard)
• Does not apply to natural gas units
• Defined as:
– A unit that meets the CAA § 112(a)(8) definition of an EGU but that combusts natural gas exclusively or in combination with another fossil fuel
– If the EGU combusts natural gas in combination with another fossil fuel, the natural gas must constitute at least 90% of the average annual heat input during any 3 consecutive years or 85% of the average annual heat input in 1 year.
$50 - $75
kW
Preliminary Cost Based on Literature
Leveraging Natural Gas Study Units
Boiler
Class Plant Unit
Nameplate
Capacity
(MW)
Boiler
Manuf Boiler Type
Natural Gas Fuel Switch
Study Unit
1 125 CE Tangential fired
2 125 CE Tangential fired
3 225 CE Tangential fired
8 156 CE Tangential fired
9 165 CE Tangential fired <-- Nat Gas Study Unit
1 100 CE Tangential fired Surrogate for Class 1
2 100 CE Tangential fired
3 125 CE Tangential fired
1 125 CE Tangential fired
2 125 CE Tangential fired
1 272 B & W Wall fired <-- Nat Gas Study Unit
2 272 B & W Wall fired Surrogate for Class 2
3 272 B & W Wall fired
4 245 B & W Wall fired
F 1 250 B & W Opp Wall Fired <-- Nat Gas Study Unit
G 1 250 B & W Wall fired Surrogate for Class 3
1 100 B & W Wall fired
2 100 B & W Wall fired
3 100 B & W Wall fired
I 2 250 Riley Front Wall Fired <-- Nat Gas Study Unit
J 2 319 Riley Wall fired Surrogate for Class 4
3 480 B & W Wall fired
4 490 B & W Wall fired No Study Unit
L 4 500 FW Wall fired
M 4 350 CE Tangential fired
6 350 CE Tangential fired No Study Unit
7 350 CE Tangential firedN
1
6
4
3
2
A
B
D
C
E
H
K5
Site Specific Vendor Engineering Studies
B&W 272 MW B&W 250 MW
Riley 250 MW Alstom 165 MW Alstom 350 MW
$40 - $50kW
Class 2 (272 MW)
Group 4 (250 MW)
Group 1 (183 MW)
Gas Capability Cost (excluding Lateral)
Coal to Gas Boiler Conversion Study
• Contracted with boiler OEM to conduct feasibility studies to evaluate boiler performance for converting from coal to natural gas firing.
• Approach was to determine boiler predicted performance while firing natural gas without pressure part modifications and identify components that may need to be modified.
• Components investigated include pressure parts, attemperators, burners, flame scanners, igniters, economizers and fans.
• In general, the converted boiler results in a lower flue gas flow, a higher FEGT and higher attemperation spray flows due to a shift from more radiant heat transfer for PC firing to more convective heat transfer for natural gas firing.
Coal to Gas Boiler Conversion Study
• Based on the results of modeling, estimated reduction in boiler efficiency ranged 3% to 6%
• In study boilers, all were able to maintain maximum continuous rating (MCR) main steam flow at superheater outlet conditions and reheat steam flow at reheater outlet
• Caution that predictions show tresses exceeding ASME’s allowable limits in some pressure part tubes and headers.
Typical Dual Fuel Burner
Natural Gas Capability – Wall Fired Burners
Natural Gas Capability – Wall Fired Burners
Natural Gas Capability – Wall Fired Burners
Natural Gas Capability – Tangential Fired Burners
Courtesy: WPCA Gas to Coal Conversion Seminar – Alstom Power
Natural Gas Fuel Skid at Burner Elevation
Thermal Stresses in Convective Pass
Generic Natural Gas Capability Schedule
2012 2013 2014 2015
Transmission Build Gas Lateral
Preparation
Engineering DesignEngineering
Permitting Regulatory Review
Construction Outage
Equipment Fabrication
Natural Gas Emissions
• VOC emission must be checked and could be an issue.
• Boiler CO emission on natural gas assumed to be lower than that of coal. Controls: assumed prudent combustion practice.
• Boiler NOx on natural gas is assumed to be ½ that of NOx on coal. Controls: SNCR or SCR
• SCR cost for asset valuation taken from mid-1980 boiler retrofits in California.
Uncontrolled Emission Rates
Coal Natural Gas
Units MCR Mid. Control MCR Mid. Control
LOAD % 100 65 26 100 71 53
NOx lb/106 Btu 0.432 0.365 0.277 0.16 0.13 0.13
CO lb/106 Btu 0.042 0.052 0.05 0.09 0.07 0.07
VOC lb/106 Btu 0.004 0.004 0.004
SCR / CO Arrangements
Gaston Units 1-4 - MATS Compliance Project
Gaston Units 1-4 Wall Fired Burners
Gaston Units 1-4 Simplified Flow Diagram
Key Project Milestones
Milestones Activities Finish Date
Construction
Gas Lateral – In Service Apr '15
COD - Aux Boiler Aug '15
COD – Unit 4 Jun '15
COD – Unit 1 Nov '15
COD – Unit 2 Dec '15
COD – Unit 3 Jan '16
Auxiliary Boiler
Natural Gas Conditioning Station
Greene County Gas Capabilities
Burner Disassembly
New Gas Infrastructure
Thank You for Your Attention
Edward C. Healy, P.E.
Southern Company Services
42 Inverness Center Parkway
Birmingham, AL 35242
205-992-5212
