Energy Consumption, Wastage & Costs FAQs
Understand machine energy consumption, idle energy wastage, W and kWh, energy factors, and electricity costs with simple examples.
Understand Your Energy Figures
The Watchmen Platform helps you review energy used during production, preparation, and idle time, together with the associated costs.
| Your question | Read the answer |
|---|---|
| How much energy does the machine use? | Energy consumption |
| How much energy is used while idle? | Energy wastage |
| What does the total energy cost? | Energy consumption costs |
| What does idle energy cost? | Energy wastage costs |
What Is the Difference Between W, kW, and kWh?
- W (watts) and kW (kilowatts) measure power: how quickly energy is being used. 500 W = 0.5 kW.
- kWh (kilowatt-hours) measures energy used over time. A constant 0.5 kW for 2 hours uses 1 kWh.
- €/kWh is the electricity price per unit of energy.
Formula for constant power: Energy (kWh) = power (kW) × duration (hours).
A rating of 500 W is a power value, not “500 watts per hour.” Convert watts to kilowatts before calculating kWh.
How Is Energy Consumption Calculated?
Energy consumption combines energy used while idle with energy used during active production and preparation.
Formula: Total energy (kWh) = idle energy (kWh) + production and preparation energy (kWh).
The machine's configuration influences a calculated estimate:
| Input | What it represents |
|---|---|
| Power rating | The machine's rated power in W or kW |
| Machine energy factor | A factor accounting for components such as filters, pumps, and motors; used in the idle-energy calculation below |
| Machine intensity factor | The relationship between operating intensity or speed and energy use during active operation |
| State durations | How long the machine was producing, preparing, or idle |
Example: Active Energy Plus Idle Energy
For this separate energy example, assume 2 hours idle and 4 hours of production plus preparation. The machine has a 500 W power rating and an energy factor of 0.35.
- Idle energy: 2 × 0.5 × 0.35 = 0.35 kWh.
- For illustration, assume average active power is 0.5 kW for all four active hours: 4 × 0.5 = 2 kWh.
- Total energy in this simplified example: 0.35 + 2 = 2.35 kWh.
The 0.5 kW active average is an example assumption. The intensity factor varies, so the rating and durations alone do not determine the actual active energy. Check the machine's energy-monitoring setup when comparing an estimate with a measured value.
Use Machine Configuration to understand the setup areas, or follow Configure a Machine.
How Is Energy Wastage Calculated?
The frontend describes Energy wastage as energy consumed while the machine is not producing. The exact inclusion of preparation and off time is not confirmed. The following idle-energy calculation is an illustration, not a verified dashboard formula. An idle machine can still power components.
Formula: Idle energy (kWh) = idle duration (hours) × power rating (kW) × machine energy factor.
Using the same energy example:
2 hours × 0.5 kW × 0.35 = 0.35 kWh of energy wastage.
Here, the factor of 0.35 gives an estimated idle power of 0.175 kW, or 175 W. Idle does not mean switched off.
Is Energy Wastage Added on Top of Total Consumption?
Idle energy is already part of total energy consumption. In this example, the total is 2.35 kWh, including 0.35 kWh of idle energy. Adding the idle energy again would count it twice.
Use Timeline Analysis to find long or recurring idle periods. The production metrics FAQs explain how idle and off time affect availability and performance.
How Are Energy Consumption Costs Calculated?
Energy consumption costs estimate the electricity cost of the total energy used.
Formula: Energy cost (€) = total energy (kWh) × electricity price (€/kWh).
For a reporting period with 20 kWh consumption and a price of €0.15/kWh:
20 × €0.15 = €3.00.
If the price were €0.20/kWh, the same 20 kWh would cost €4.00. The energy quantity stays the same; only the price changes.
Is This the Full Cost of Running the Machine?
This calculation covers electricity consumption at the chosen unit price. It does not calculate labor, maintenance, or other operating costs. Compare it with the energy portion of your costs.
How Are Energy Wastage Costs Calculated?
Energy wastage costs are the electricity costs associated with idle energy.
Formula: Wastage cost (€) = idle energy (kWh) × electricity price (€/kWh).
If 5 kWh of the 20 kWh reporting-period total were idle energy, at €0.15/kWh:
5 × €0.15 = €0.75 of wastage costs.
The €0.75 is already included in the €3.00 total energy cost. It shows the idle-related share, rather than an additional charge.
What Could Reducing Idle Time Save?
In the smaller machine example, one idle hour uses 0.5 × 0.35 = 0.175 kWh. Avoiding that hour at €0.15/kWh would save €0.02625, or about 2.6 cents, assuming no replacement energy use. This is an illustration, not a guaranteed saving.
Why Do My Energy or Cost Figures Look Different?
- Match the machine and reporting period, including active and idle durations.
- Check units: convert W to kW and minutes to hours before calculating energy.
- Check the power rating, energy factor, and intensity assumptions used for an estimate.
- Check whether you are comparing calculated estimates with energy-monitor readings.
- Use the same electricity price and round only the final cost.
- Keep idle energy and its costs within the total; do not add them twice.
See the shared calculations reference for the confirmed energy definitions and remaining calculation limits.
Where Can I Find More Information?
- Organization Statistics: review consumption, wastage, costs, and energy trends.
- Configure a Machine: review energy-monitoring setup.
- Timeline Analysis: understand time spent in machine states.
- Quality, Availability, Performance & OEE FAQs: understand the related production indicators.
- Help Center: return to all help topics.