Auditing a 400-bed hospital in Pittsburgh. Duquesne Light Rate GS-Large. Monthly demand runs 4,200-4,800 kW. The facilities director says theyve looked at every possible demand reduction measure but critical care equipment, operating rooms, and life safety systems cant be curtailed or shifted. He says demand charges are just a cost of doing business for hospitals. Is he right?
Hospital demand charges ? critical loads make reduction nearly impossible
Richard ? the facilities director is half right. Clinical loads are non-negotiable. But hospitals have enormous non-clinical loads that ARE controllable: kitchen equipment, laundry, parking garage lighting and ventilation, administrative building HVAC, and chilled water plant staging. I audited a 500-bed hospital in Columbus on AEP Ohio and found $34,000 in annual demand savings just from optimizing chiller staging to prevent multiple chillers from starting in the same 15-minute interval.
David is exactly right about chiller staging. Hartford Hospital was paying $180,000 annually in demand charges on Eversource Rate 57. The chillers were set to start based on building temperature without any demand-aware sequencing. Installing a simple demand controller that prevents more than one chiller from starting in any 15-minute interval reduced peak demand by 340 kW. Annual demand charge savings of $41,000 for a $12,000 control investment.
Alice ? $41,000 savings from a $12,000 investment. Thats a 3.5 month payback. The facilities director at my Pittsburgh hospital was thinking about clinical loads exclusively and ignoring mechanical plant sequencing. Im going to focus the audit on chiller plant, boiler plant, and kitchen equipment staging.
Vernon ? thermal energy storage is great for large hospitals but the upfront cost is significant. For smaller hospitals and medical office buildings in Hartford area I focus on three things: 1) HVAC scheduling ? many medical offices run full HVAC outside of occupied hours because nobody updated the schedule 2) Electric water heater timing ? shifting water heating to off-peak 3) Lighting controls in parking structures. Low cost, no clinical impact.
Dont forget to check the rate classification itself. Hospitals often qualify for institutional or government rates that have lower demand charges than standard commercial rates. A hospital in suburban Chicago was on ComEd Rate 6 general commercial when they should have been on Rate 6H institutional. Demand charge rate dropped from $11.50 per kW to $8.75 per kW. No load reduction needed ? just correct rate classification.
Marcus ? rate reclassification is a great point. Ill check what institutional rates Duquesne Light offers. If the demand charge rate itself is wrong the savings accumulate without any operational changes. Thats the cleanest audit finding possible.
Had a similar win at a medical center in Savannah. Georgia Power has Rate PLL for large power and light loads and Rate PLM for large industrial. The medical center was on PLL when their load profile actually qualified for PLM which has a lower demand charge structure. Reclassification saved $28,000 annually. Always check every available tariff option.
Follow up on this thread ? Duquesne Light does have an institutional rider. Applied for it and it was approved. Demand charge rate dropped from $14.20 to $10.85 per kW. At 4,500 kW average demand thats $15,075 per month savings or $180,900 annually. Combined with chiller sequencing recommendations the total annual savings package is $215,000. Hospital administrator called it the best consulting engagement theyve ever approved.
Former TVA ops ? hospitals are actually ideal demand charge audit targets because they have large controllable mechanical loads that can be optimized without any impact on patient care. In Chattanooga I saw a hospital reduce demand by 600 kW just by installing thermal energy storage that makes ice at night and uses it for cooling during peak demand hours. Capital intensive but the demand charge savings pay for it in 4-5 years.