Rhode Island – Proposed Permit Regulations and Credit for CHP

The Rhode Island Department of Environmental Management’s Office of Air Resources recently issued two new regulations. The regulations are - Regulation No. 43, “General Permits for Smaller-Scale Electric Generation Facilities,” and amendments to Regulation No. 9, “Air Pollution Control Permits.” Regulation No. 43 applies output based emission standards and provides credit for CHP applications. Both of these regulations will become effective on May 15, 2007.

Regulation No. 43

Regulation No. 43, http://www.dem.ri.gov/pubs/regs/regs/air/air43_07.pdf, establishes a simplified permitting process (a general permit) for specified types of emergency generators, CHP projects, and DG projects. With the implementation of Regulation No. 43, these generators mentioned above will no longer have to go through the more complicated minor source permitting process required under Regulation No. 9. Regulation No. 43 has emission standards, compliance criteria, monitoring requirements and recordkeeping and reporting guidelines that facilities must meet in order to qualify for the simpler permitting process. The regulation applies output based emission standards to reward energy efficiency.

Regulation No. 43 requires CHP systems to have a power-to-heat ratio of between 4.0 and 0.15 and an efficiency of at least 55%, in order to be eligible for emissions credits related to thermal output. The credits will be calculated based on the following assumptions and calculations:

1. The emission rates for a displaced thermal system (i.e. boiler) will be:
   a. For CHP installations in new facilities, the emission limits that apply to new natural gas-fired boilers located in 40 CFR 60, subparts Da, Db, and Dc, in lb/MMBtu. The federal regulations 40 CFR 60, can be found here, http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&tpl=/ecfrbrowse/Title40/40cfr60_main_02.tpl. The following are the types of units the above mentioned subparts apply to.

Subpart DA – Standards for Electric Utility Steam Generating Units

Subpart DB – Standards of Performance for Industrial-Commercial-Institutional Steam Generating Units

Subpart DC – Standards of Performance for Small Industrial-Commercial-Institutional Steam Generating Units

b. CHP systems that replace existing thermal systems with historic emission data, the historic emission rates cannot exceed the following:

2. The credit for CHP systems that meet the above criteria will be calculated by first using the following equation:

Credit lbs/MWh emissions = [(boiler limit lbs/MMBtu)/(boiler efficiency)] x [3.412/(power to heat ratio)]

For new systems (boilers, or other process heat systems) the efficiency of the avoided thermal system will be assumed to be 80%. Then the credit, as calculated in the above equation, will be subtracted from the actual rate of the CHP unit to obtain the emission rate that will be used for compliance.

Regulation No. 9

Regulation No. 9, http://www.dem.ri.gov/pubs/regs/regs/air/air09_07.pdf, provides guidelines for preconstruction permitting of certain facilities. The finalized amendments to Regulation No. 9 provide for the following:

• An alternative permitting process established by Regulation No. 43
• This simplifies the permitting process by eliminating the need for a permit in certain instances, creating a simplified permitting process (general or temporary permits) or allows for an expedited permit process for applicants that use the more detailed permitting application.