State Guidelines for Greenhouse Gas Emissions from Existing Electric Utility Generating Units
In the advance notice of proposed rulemaking, State Guidelines for Greenhouse Gas Emissions from Existing Electric Utility Generating Units, is the EPA Administrator Scott Pruitt even sure what the regulatory history is of GHG emissions? In 2012, the EPA attempted to regulate GHGs under the Greenhouse Gas Tailoring rule, which provided a three-step framework for the implementation of greenhouse gas regulations under PSD and the title V Operating Permit Program. However, in Utility Air Regulatory Group v. Environmental Protection Agency (2014), which, among other things, vacated the PSD and title V regulations under review in that case to the extent that they require a stationary source to obtain a PSD or title V permit solely because the source emits or has the potential to emit GHGs above the applicable major source thresholds. Nonetheless, the EPA tried yet again, to regulate carbon dioxide and greenhouse gas emissions under the Clean Power Plan (CPP) in 2015. The CPP has since been stayed and is in the process of being repealed. If the Administrator read these two previous rulemakings, he would be aware that all of the solicitation for information and comments in the advance notice of proposed rulemaking has been answered.
The advance notice of proposed rulemaking does provide a review of current and past rulemakings, as well as provides great resources for power plant operators to improve the heat rate of their plants including:
Table 1—Example Equipment Upgrades and Technology to Improve Heat Rates at Utility Boilers
Equipment upgrade(s)
Potential heat rate improvement
Replace materials handling motors and drives with more efficient motors and/or variable frequency drives to reduce ancillary energy consumption
Negligible.
Improve coal pulverizers to produce more finely ground coal to improve combustion efficiency
0.52-2.6%.
Use waste heat to dry low-grade coal and improve combustion efficiency
N/A.
Automate boiler drains to manage make-up water intake
N/A.
Improve boiler, furnace, ductwork, and pipe insulation to reduce heat loss
N/A.
Upgrade economizer to increase heat recovery
50-100 Btu/kWh.
Install a neural network and advanced sensors and controls to optimize plant station operation
0-150 Btu/kWh.
Install intelligent sootblowers to enhance furnace efficiency
30-150 Btu/kWh.
Improve seals on regenerative air pre-heaters to reduce air in-leakage and increase heat recovery
10-40 Btu/kWh.
Install sorbent injection system to reduce flue gas sulfuric acid content and allow increased energy recovery at the air heater
50-120 Btu/kWh.
Upgrade steam turbine internals to improve efficiency and replace worn seals to reduce steam leakage
100-300 Btu/kWh; 1.5-5.5%.
Retube the condenser to restore efficiency or expand condenser surface area to improve efficiency
3-70 Btu/kWh; 1.0-3.5%.
Replace feedwater pump seals to reduce water loss
N/A.
Install solar systems to pre-heat feedwater to improve efficiency
N/A.
Increase feedwater heating surface to improve efficiency
N/A.
Overhaul or upgrade boiler feedwater pumps to improve efficiency
25-50 Btu/kWh.
Replace centrifugal induced draft (ID) fans with axial ID fans
10-50 Btu/kWh.
Replace ID fan motors with variable frequency drives
10-150 Btu/kWh.
Upgrade flue-gas desulfurization components (e.g., co-current spray tower quencher, turning vanes, variable frequency drives) to reduce pressure drop, improve flow distribution, and reduce ancillary energy consumption
0-50 Btu/kWh.
Upgrade the electrostatic precipitator energy system (e.g., high voltage transformer/rectifier sets) to improve particulate matter capture and reduce energy consumption
0-5 Btu/kWh.
Replace older motors with more efficient motors to reduce ancillary energy consumption
0-21 Btu/kWh.
Refurbish and/or upgrade cooling tower packing material to improve cycle efficiency
0-70 Btu/kWh.
Install condenser tube cleaning system to reduce scaling, improve heat transfer and restore efficiency
N/A.
Table 2—Example Good Practices to Improve Heat Rates at Utility Boilers
Good practice(s)
Potential heat rate improvement
Reduce excess air to improve combustion efficiency
N/A.
Optimize primary air temperature to improve combustion efficiency
N/A.
Measure and control primary and secondary air flow rates to improve combustion efficiency
N/A.
Tune individual burners (balance air/fuel ratio) to improve combustion efficiency
N/A.
Conduct more frequent condenser cleanings to maintain cycle performance
30-70 Btu/kWh.
Monitor condenser performance to track efficiency/performance
N/A.
Use secondary air for ammonia vaporization and dilution to reduce ancillary energy consumption
0-5 Btu/kWh.
Careful monitoring of the water treatment system for optimal feedwater quality and cooling water performance to reduce scale build-up and corrosion plus maintain efficiency
N/A.
Conduct maintenance of cooling towers (e.g., replace missing/damaged planks) to restore cooling tower efficiency
N/A.
Chemical clean scale build-up on feedwater heaters to improve heat transfer
N/A.
Repair steam and water leaks (e.g., replace valves and steam traps) to reduce makeup water consumption
N/A.
Repair boiler, furnace, ductwork, and air heater cracks to reduce air in-leakage and auxiliary energy consumption
N/A.
Clean air pre-heater to improve heat transfer
N/A.
Adopt sliding pressure operation to reduce turbine throttling losses
N/A.
Reduce attemperator activation to reduce heat input
N/A.
Clean turbine blades to remove deposits and improve turbine efficiency
N/A.
Maintain instrument calibration to ensure valid operating data
N/A.
Perform on-site appraisals to identify areas for improved heat rate performance
N/A.
Adopt training program for operating and maintenance staff on heat rate improvements
N/A.
Adopt incentive program to reward actions to improve heat rate
N/A.
Implement heat rate analytics to identify real-time heat rate deviations
N/A.
Plant lighting upgrades to reduce ancillary energy consumption
N/A.
Use predictive maintenance to avoid outages and de-rate events
N/A.
These practices should be used at all plants across the U.S. to reduce costs, increase utilization, and reduce emissions. The EPA does not need a rule for industry to do these upgrades and best practices.
The Administrator should read the Greenhouse Gas Tailoring rule and the CPP to realize the gains the EPA has already made and should also not repeal the CPP.
