How do you calculate energy cost per bottle in blow molding?

Multiply the line's connected load (kW) by runtime (hours) by your electricity rate ($/kWh) to get total energy cost, then divide by accepted containers. With 145 kW over 12 hr at $0.12/kWh making 42,000 good bottles, that is $208.80 total, or $0.004971 per bottle.

What is a good energy cost per bottle?

For single-serve PET bottles, many lines land between $0.003 and $0.008 per unit depending on resin, wall thickness and local power price. The example $0.00497 per bottle is healthy; values above $0.01 usually signal compressed-air leaks, oversized chillers or low throughput.

Why is compressed air such a big driver of blow molding energy?

High-pressure blow air can account for a third or more of a line's electricity. Generating 40 bar is expensive, and leaks plus over-pressuring the blow station quietly inflate the connected load you enter here, raising cost per bottle.

How many kWh does a blow molding line use per shift?

In the worked example the line draws 145 kW for 12 hours, so 1,740 kWh per shift. Multiply by your rate and divide across good units to convert that energy into a per-bottle cost.

Should I use accepted units or total units in the denominator?

Use accepted (good) containers. Scrap still consumed energy, so dividing by good units correctly loads the cost of bad bottles onto the ones you can sell — that is why scrap directly inflates energy per bottle.

How do I lower energy cost per bottle?

Fix air leaks, right-size blow pressure, recover compressor heat, insulate barrels, and raise good-part throughput. Because the denominator is accepted units, cutting scrap lowers the per-bottle figure even if total kWh stays flat.

Blow Molding & Hollow Plastic Products calculator

Energy per Bottle Calculator

Energy per bottle is the electricity cost embedded in every accepted container coming off a blow molding line, expressed in dollars. Extrusion and stretch blow lines are energy-hungry — barrel heaters, the air compressor feeding 30-40 bar blow pressure, chillers and drive motors all draw continuously — so process engineers and plant cost accountants track this number to see whether a line's power draw is justified by its throughput. It matters because energy is often the second or third largest variable cost behind resin, and a fraction of a cent per bottle multiplied across millions of units swings annual cost by six figures. Tracking it shift over shift exposes drifting heater bands, leaking air, and runs that bleed power while making scrap.

What this calculator does

Estimate electricity cost and energy use for blow molded bottle or container production from connected load, runtime, energy rate, and units processed.
a blow molding operation needs to estimate energy cost per bottle, container, or hollow part for a production run
It computes total electricity cost for a blow molding run and divides it by accepted containers to give a per-bottle energy cost.

Formula used

Blow molding energy cost = blow molding line connected load × line runtime × blended electricity rate
Energy cost per bottle = blow molding energy cost ÷ accepted containers processed

Inputs explained

Blow molding line connected load:
Production runtime:
Blended electricity rate:
Accepted containers processed:

How to use the result

Use it when quoting a new container, comparing line efficiency, or building an energy baseline for a continuous-improvement target.
It treats connected load as a flat average; real draw swings with start-up heat soak, mold changes and idle dwell, so a single load figure can understate or overstate true kWh.

Current U.S. benchmarks

As of Apr 2026, industrial electricity averages 8.7 cents per kWh across the U.S. (EIA), up 5.5% from a year earlier. State averages range widely, so plants should confirm against their own tariff.
The producer price index for plastic resins and materials stands at 319.371 (BLS, May 2026), up 19.5% from a year earlier. Quotes priced off last quarter's material cost miss this move.
The U.S. has 9,635 plastics product manufacturing establishments employing about 677,302 workers (Census County Business Patterns, 2023).

Common questions

How do you calculate energy cost per bottle in blow molding? Multiply the line's connected load (kW) by runtime (hours) by your electricity rate ($/kWh) to get total energy cost, then divide by accepted containers. With 145 kW over 12 hr at $0.12/kWh making 42,000 good bottles, that is $208.80 total, or $0.004971 per bottle.
What is a good energy cost per bottle? For single-serve PET bottles, many lines land between $0.003 and $0.008 per unit depending on resin, wall thickness and local power price. The example $0.00497 per bottle is healthy; values above $0.01 usually signal compressed-air leaks, oversized chillers or low throughput.
Why is compressed air such a big driver of blow molding energy? High-pressure blow air can account for a third or more of a line's electricity. Generating 40 bar is expensive, and leaks plus over-pressuring the blow station quietly inflate the connected load you enter here, raising cost per bottle.
How many kWh does a blow molding line use per shift? In the worked example the line draws 145 kW for 12 hours, so 1,740 kWh per shift. Multiply by your rate and divide across good units to convert that energy into a per-bottle cost.
Should I use accepted units or total units in the denominator? Use accepted (good) containers. Scrap still consumed energy, so dividing by good units correctly loads the cost of bad bottles onto the ones you can sell — that is why scrap directly inflates energy per bottle.

Last reviewed 2026-05-12.