This credit applies repowers or engine rebuilds from a lower to a higher tier engine.
Repowers/rebuilds completed before Mar 1, 2009: You get credit for any repower/rebuild from a lower to higher tier. For example, replacing if you replaced a 300 hp Tier 0 engine with a Tier 1 engine you would get a 300 hp credit.
Repowers/rebuilds completed after Mar 1, 2009: You get credit for a repower/rebuild from a Tier 0/1 to a Tier 2 or higher tier engine. Unlike the preceding no credit is granted here for a repower/rebuilt from Tier 0 to Tier 1. The repower/rebuild must be Tier 2 or higher and a higher tier than the engine being replaced.
To use the credit to meet a BACT obligation the repowered/rebuilt engine must remain in your fleet for that compliance date.
For a listing of when the engine tiers take effect click on the box "Get in-use emission rates" in the compliance chart.