Coal to Gas Capability Benefits & Impacts … · Coal to Gas Capability Benefits & Impacts...

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

ECHEALY@southernco.com

205-992-5212