Extraction & Processing Facility Energy Loads: CO2, Ethanol, and Hydrocarbon Methods Compared

How a lab's load differs from a grow's

A cultivation facility is a lighting load with HVAC attached, running two long flat shifts a day. The Northwest Power and Conservation Council's producer survey put lighting at 66 percent of grow electricity, with cooling at 15 percent and ventilation at 12 percent, and estimated indoor canopy in Oregon at 128 kWh per square foot per year [nwpcc-cannabis]. An extraction and processing facility looks nothing like that. Its lighting is ordinary; its load is process equipment: compressors, pumps, heaters, chillers, vacuum pumps, and exhaust fans, most of which run for hours at a time during a shift and then stop.

For scale, the average U.S. commercial building used 12.6 kWh per square foot of electricity in 2018, and the median was 8.6 [eia-cbecs-2018-c14]. A busy lab sits well above that, but nowhere near a grow. What matters more than the annual kWh is the shape of the load, which is why the rest of this page is organized around the equipment and the profile rather than a single intensity number.

The equipment, and what it draws

Manufacturer specifications give a good picture of what individual pieces pull. These are nameplate or rated figures; actual draw depends on setpoint and duty cycle.

Two things stand out. First, the solvent recovery step dominates an ethanol lab: 79.4 amps at 240 volts three-phase is about 33 kVA for a single evaporator [trusteel-autovap-15], more than a whole rack of ovens. Second, a lot of that heat has to be taken back out. Every kilowatt of heater energy that boils ethanol becomes a kilowatt of vapor that a condenser and chiller must remove, so the chiller side of a recovery system draws a large fraction of what the heater does.

CO2, ethanol, and hydrocarbon: three load profiles

Supercritical CO2. The process runs at high pressure, which means a pump or compressor and a motor to drive it, plus a chiller to keep the CO2 liquid at the pump inlet and heaters to bring the extraction vessel to setpoint. Run times are long, commonly several hours per batch, and larger systems recycle CO2 continuously. The profile is a plateau: a sizable three-phase motor load plus chiller that switches on at the start of the run and stays on. Post-processing is lighter than ethanol because there is no bulk solvent to boil off, though winterization of the crude can add an ethanol step and a rotovap. Demand is set at run start when pump, chiller, and heaters all come up together; energy is high per batch but the daily pattern is predictable, which makes CO2 labs good candidates for night runs on time-of-use tariffs.

Ethanol. Cold ethanol extraction itself is cheap: a chilled tank, a centrifuge or agitator, and a filter. The bill comes from what happens next. The extract is dilute, so every gallon of solvent used has to be recovered, and that means heaters and chillers running for hours. A 20 gallon-per-hour recovery unit at roughly 33 kVA [trusteel-autovap-15] and a 20 L rotovap at 4.3 kW [across-solventvap-20l] for the last pass, plus the chillers serving both, can be the majority of the lab's peak. Add the freezer or chiller that keeps the ethanol at extraction temperature, which runs continuously. Ethanol labs have the highest kWh of the three methods at equal throughput and a peak that is very sensitive to whether the evaporator and the rotovap are started in the same interval.

Hydrocarbon (butane and propane). The solvent boils at low temperature, so recovery needs only modest heat and a chiller to condense it back into the tank. Process electrical load is the smallest of the three: a recovery pump, a chiller of a few horsepower, warm-water baths, and the vacuum ovens for purging, which at 1.5 to 3 kW each [across-eco-vacuum-oven] [across-500c-vacuum-oven] are the long-running piece since purges take many hours. What the hydrocarbon lab carries instead is the code-required room. Colorado Springs' fire department, for example, requires the extraction room to be electrically classified as Class 1, Division 1, monitored by a gas detector that alarms at set thresholds, ventilated to keep gas concentration at acceptable levels, built as an F-1 occupancy separated by a one-hour fire barrier, and equipped only with systems on its approved equipment list [csfd-extraction]. The exhaust fans and detection in that room run around the clock in most designs, which gives a hydrocarbon lab a flat baseline that never goes to zero. Requirements vary by jurisdiction; confirm yours with the fire marshal.

Why load factor decides the bill

Load factor is average demand divided by peak demand. A grow with a 12-hour photoperiod runs at maybe 60 to 70 percent load factor because the lights hold the peak for half the day. A lab that peaks at the start of a recovery run and sits nearly idle overnight can run at 25 to 35 percent. Utilities bill demand on the peak 15- or 30-minute interval, so at equal kWh the lab pays more per kWh delivered. The mechanics are in demand charges explained and peak demand vs. peak usage.

Two consequences follow. First, a lab is often better off on a different rate class than the grow next door, and sometimes better off on a non-demand small commercial class if its peak can be held under the threshold; see utility rate classes explained. Second, a shared meter with a cultivation operation hides the lab's profile inside the grow's and usually costs the combined account money, which is the case for submetering multi-tenant cannabis buildings.

A worked example

Every figure below is an input we chose to make the arithmetic followable. Substitute your own equipment list and tariff.

Assume an ethanol lab running one eight-hour shift, five days a week. Equipment and assumed electrical draw at full operation:

Energy: during the shift the lab averages about 60 kW (not everything runs at once), so 60 kW x 8 h x 22 days = 10,560 kWh. Overnight and weekends the continuous loads (ethanol chilling, exhaust, some HVAC, a few ovens finishing a purge) average about 14 kW: 14 kW x (720 h minus 176 h) = 7,616 kWh. Monthly total about 18,200 kWh. Load factor: 18,200 kWh / (89 kW x 720 h) = 28 percent.

Bill, on an assumed tariff with a 15 dollar per kW demand charge and an energy price of 14.5 cents per kWh (near Illinois' June 2026 commercial average of 14.53 cents [eia-epm-5-6-a]):

• Demand: 89 kW x 15 dollars = 1,335 dollars
• Energy: 18,200 kWh x 0.145 = 2,639 dollars
• Total about 3,975 dollars, of which demand is 34 percent

Now change one thing. Start the rotovap and the vacuum ovens an hour after the falling film evaporator and its chiller. The evaporator, chiller, continuous loads, HVAC, and lighting now peak at about 79 kW, and the later rotovap-and-ovens block, which starts after the evaporator has settled, peaks lower still. Demand falls to 79 x 15 = 1,185 dollars, a saving of 150 dollars a month, about 1,800 dollars a year, with no change in kWh. Hold the HVAC setpoint a degree wider during that first hour and the peak drops further. On a tariff with a ratchet, the saving arrives only after the old peak ages out.

Compare the same 18,200 kWh drawn by a grow at 65 percent load factor: its peak would be 18,200 / (0.65 x 720) = 39 kW and its demand charge 585 dollars. Same energy, less than half the demand cost. That is the whole story of extraction lab billing.

Practical steps for a processing site

1. Get the interval data. Ask the utility for 15-minute kW for the last year and find which interval sets each month's peak. In a lab it is almost always a heater and chiller starting in the same window.
2. Sequence equipment starts. A simple controls rule, or a written SOP, that staggers evaporator, rotovap, oven, and chiller starts by 15 to 30 minutes does most of the work.
3. Recover solvent off-peak where you have a time-of-use rate. Recovery does not need daylight.
4. Check the rate class every time the equipment list changes. Adding a second evaporator can push a lab across a class threshold; removing one can bring it back.
5. Treat ventilation as a design variable. Code sets minimums for the extraction room [csfd-extraction]; exhaust sized far beyond them is a permanent load. Confirm with the authority having jurisdiction before changing anything.
6. Plan standby power for the right loads. A lab does not need a generator for the ovens, but gas detection, exhaust, and product freezers are a different question; see backup generators and standby power.

You can compare your site's intensity to other facility types in the facility type benchmark lookup.