Hospital co-gen plant threw off our demand analysis

Started by David Johnson — 2 months ago — 44 views
Auditing a regional hospital with an on-site 2MW co-gen plant. Their demand charges look wildly inconsistent month-to-month and I can't tell if the utility is metering net demand correctly or if the co-gen telemetry is off. Anyone audited a facility with behind-the-meter generation?
Co-gen audits are a different animal. You need: (1) interval data from the utility meter, (2) interval output data from the co-gen, (3) the interconnection agreement. Demand is usually metered as gross load minus co-gen output at 15-min intervals. If the co-gen has outages you'll see demand spikes that look like billing errors but aren't. Get the O&M logs.
Hospital co-gen analysis is its own specialty. The interaction between self-generation credits and demand charges requires tariff-level expertise most generalists don't have.