Compressed-air energy efficiency projects: OSE or Custom Offer?
Hydro-Québec funds energy efficiency projects through its Solutions efficaces program, which has two offers: the Offre simplifiée (simplified offer, using the OSE tool with predefined measures) and the Offre sur mesure (custom offer for complex projects). Compressed air is a prime candidate, because energy accounts for about 92% of the system’s life-cycle cost. Before choosing a program, an assessment measures your installation and determines with certainty which project pays off and which offer applies.
Compressed-air life-cycle cost ≈ 3% purchase · 5% maintenance · 92% energy| Offre simplifiée (OSE) | Offre sur mesure | |
|---|---|---|
| For what | Predefined measures (> 200) | Complex, innovative, customized projects |
| Compressed air | Compressor ≤ 200 HP, storage, dryer, sequencer | Compressor > 200 HP, process optimization |
| Minimum | Minimum savings threshold to access a subsidy | ≥ 25,000 kWh/yr |
| Financial support | Pre-set calculation in OSE | The lesser of several caps — rates and caps confirmed per application |
| Measurement | None required | Before/after where possible |
| Approval | At submission | Prior approval mandatory |
No subsidy guarantee. Financial-support rates, conditions and terms are confirmed for each project: only Hydro-Québec’s acceptance of the application confirms project eligibility and the subsidy’s terms. Onyx M3 does not guarantee any financial support.
This assumes a Quebec business rate and continuous operation: the cost benchmarks below are computed at 0.08 $/kWh and 8,760 h/yr. Adjust them to your rate and actual hours.
What compressed air really costs
Compressed air is often seen as “free.” In reality, the electricity bill dominates. A lubricated screw compressor produces about 100 cfm per 18 kW (≈ 24 HP at the motor) at a service pressure around 110 psig.
Annual energy cost = specific power (kW/100 cfm) × hours/yr × rate ($/kWh)| Symbol | Meaning | Benchmark |
|---|---|---|
| Specific power | Energy to produce the air | 18 kW / 100 cfm @ ~110 psig |
| Hours/yr | Operation | 8,760 h (continuous) |
| Rate | Electricity cost | 0.08 $/kWh |
For 100 cfm continuously: 18 kW × 8,760 h = 157,680 kWh/yr, i.e. ≈ $12,600/yr — about $126 per cfm per year, energy only.
The cost of preventive maintenance
Maintenance adds to that. A common industry benchmark is $100 per HP per 8,760 hours of operation.
Annual preventive maintenance ≈ $100 × motor power (HP) [8,760 h basis]| Motor power | Preventive maintenance / yr | Air produced (≈ 4.1 cfm/HP) |
|---|---|---|
| 50 HP | ≈ $5,000 | ≈ 207 cfm |
| 100 HP | ≈ $10,000 | ≈ 414 cfm |
| 200 HP | ≈ $20,000 | ≈ 829 cfm |
Per unit of production, maintenance adds ≈ $24 per cfm per year. Energy + maintenance ≈ $150 per cfm per year: that is the true reference cost of a compressed cfm, and the basis of any payback calculation.
The hidden cost of drying and filtration
Drying and filtering the air also carry a recurring cost, often overlooked.
Refrigerated dryer energy. Typical full-load power for a 2,000 SCFM cycling dryer is about 13.5 kW (air-cooled) and 10.4 kW (water-cooled), averaging ≈ 0.60 kW / 100 cfm.
Dryer energy ≈ 0.60 kW/100 cfm → 52 kWh/cfm/yr → ≈ $4.20/cfm/yr @ 0.08 $/kWhLine-filter elements. From the Walker Alpha catalogue (18 sizes, 6 to 1,500 SCFM), a replacement element costs ≈ $1/SCFM in the usual plant range (50 to 500 SCFM), a bit less for large systems. A typical install has a coalescing pre-filter + after-filter, i.e. ≈ $2/SCFM per year in elements (annual replacement); a carbon stage (oil vapour) adds a third element.
| Item (refrigerated dryer + 2 filters) | Annual benchmark |
|---|---|
| Dryer energy | ≈ $4.20/SCFM |
| Pre-filter + after-filter elements | ≈ $2/SCFM |
| Drying + filtration subtotal | ≈ $6/SCFM/yr |
On top of that comes the pressure-drop penalty: the dryer (~3.5 psi) and clogged filters add a few psi, and every ~2 psi is worth about 1% of compressor energy. Hence the value of an efficient dryer and filter maintenance — two levers eligible for the programs.
Two offers, one entry point: the assessment
The choice between the Offre simplifiée and the Offre sur mesure depends on the project’s nature and the targeted savings. That is the role of the assessment: to measure, quantify and determine with certainty which project pays off and which offer applies.
- Measure — record consumption, pressure, load profile and losses (the baseline scenario Hydro-Québec requires).
- Quantify — compare the current cost (≈ $150/cfm/yr) to the efficient scenario; estimate savings in kWh/yr.
- Direct — if the project matches a predefined measure (e.g. a drive on a ≤ 200 HP compressor), it is the Offre simplifiée (OSE); if it is complex or > 200 HP, it is the Offre sur mesure.
Hydro-Québec also offers an Energy Analysis component that covers part of the analysis cost, in two payments (the second after measures are implemented) — percentages and caps confirmed by Hydro-Québec for each application.
Which measures are eligible
Both offers fund only new equipment, certified or approved. For compressed air:
- Offre simplifiée (OSE) — variable-speed drive (VSD) on an air- or water-cooled compressor motor ≤ 200 HP, storage (receiver), heat-regenerated desiccant dryer, energy sequencer. Details: Offre simplifiée (OSE).
- Offre sur mesure — any system equipment generating ≥ 25,000 kWh/yr in savings (e.g. a compressor > 200 HP with a drive, heat recovery, process optimization). Details: Offre sur mesure.
Important: a subsidy funds a project, not maintenance
A common misunderstanding: leak repair is not eligible. Repairing leaks, lowering pressure or performing preventive maintenance are maintenance activities — useful and profitable (up to ~20% savings), but they are not “energy efficiency projects” under the programs. Subsidies fund the purchase and installation of new, efficient equipment.
The two are not at odds: you first fix leaks and pressure (so you don’t subsidize waste), then submit the equipment project under the right offer.
With Onyx M3 tools
- Compressed-air assessment — measures and quantifies your system, and determines the applicable offer. →
- Compressed-air audit — the before/after measurement process required by the Offre sur mesure (Onyx M3 is a Solutions efficaces program partner). →
- Calculator — leak cost and savings — quantify your losses and savings potential. →
- Offre simplifiée (OSE) and Offre sur mesure — the details of each program. →
References
- Hydro-Québec — Programme Solutions efficaces — Volet Moyennes et grandes entreprises (participation guide, October 2024) — offers, eligibility, eligible costs, support calculation.
- Hydro-Québec — Solutions efficaces — Participant guide (2020G255) — simplified and custom offers, 200 HP threshold for compressed air.
- Hydro-Québec — Offer presentation to partners (2025) — eligible compressed-air measures, rebate tables, case simulations.
- Technical data for a 2,000 SCFM cycling refrigerated dryer (manufacturer datasheet) — dryer power (kW/100 cfm).
- Walker Filtration / CAG catalogue — replacement element prices per SCFM.
Why it matters. Knowing the real cost of a cfm (≈ $150/cfm/yr) turns an “invisible” expense into a profitable, subsidizable project. A compressed-air assessment provides the required baseline figures and points to the right offer — Onyx M3 supports you whether or not you buy the equipment from us.