February 2022
Table of Contents
- Introduction
- Methodology
- Electricity benchmarks
- Overall Packhouse electricity consumption benchmark
- Electricity usage profile
- Electricity cost
- Energy Management Practices
- Conclusion
- Recommendations
1. Introduction
In 2021, Blue North Sustainability was contracted by the Packhouse Action Group (PAG) to benchmark the electricity consumption in pome fruit packhouse and cold storage operations. This was the first round of electricity benchmarks, compared to the fourth round of water benchmarks that have just been completed. The objectives of the project were to:
- Conduct an electricity consumption benchmark study to highlight areas where packhouses can save energy.
- Identify and compare energy management practices applied.
- Encourage industry knowledge sharing.
This report presents the results of electricity use benchmarks from January to December 2020 and summarises the different energy management methodologies applied at the packhouses.
2. Methodology
Packhouses were onboarded with a virtual call to introduce them to the project and provide them with training on how to complete the data collection tool. A guidance video on the data collection tool was also sent to all participating packhouses.
2.1 Data collection
Data was collected via an Excel-based data collection tool and sense-checked by the project team. Data anomalies were discussed with participants and, where applicable, rectified or reasons for the anomalies were recorded.
2.2 Scope of the data collection
The following three areas in pome fruit packhouses were benchmarked in terms of electricity consumption:
- Packhouse operations: All operational electricity consumption in the packhouse (pre-sort, packing lines, ablutions, canteens, and offices).
- Controlled Atmosphere (CA) operations: All electricity consumption relevant only to CA operations (refrigeration plant, compressors, condensers, fans, cooling towers, etc.)
- Regulated Atmosphere (RA) operations: All electricity consumption relevant only to RA operations (refrigeration plant, compressors, condensers, fans, cooling towers, etc.)
2.3 Participation
Twenty-one packhouses were contacted, of which 11 provided data. One packhouse committed to providing data but did not respond after multiple follow-ups. Four more packhouses did not provide data but committed to participating in future data collection rounds.
2.4 Notes on the data
- All data sets refer to the 2020 calendar year (January to December).
- Packhouses are anonymised in the report (named A to N). Packhouse A could only provide data on electricity cost.
- Caveats apply to some data points and, where applicable, they are acknowledged in this report under “Notes”.
- In graphs, blue bars indicate accurate/metered data, whereas yellow bars indicate calculated or estimated data.
3. Electricity benchmarks
3.1 Packhouse operations
3.1.1 Calculation
The packhouse operations benchmark is calculated as:
Packhouse operations electricity consumption (kWh) / Tonnes of pome fruit packed
Unit of Measure: Kilowatt-Hour per Tonne of pome fruit packed.
3.1.2 Results
Only packhouses who provided data are shown.
Notes:
- Electricity consumption of Packhouses K and L were estimated due to insufficient metering.
- Packhouse I: Benchmark includes RA operations consumption.
- Packhouse N: Benchmark includes CA and RA storage electricity consumption as allocation between the different areas in the packhouse was not possible.
Taking only metered/accurate data into consideration, electricity consumption for packhouse operations ranged from 8 kWh to 41 kWh per tonne of fruit. This is slightly lower than the benchmark of 15–44 kWh/ton found in a similar study by Bouwer (2011), which could indicate increased energy efficiency over time.
Packhouse G and H used up to five times less electricity per tonne of fruit in packhouse operations than the other packhouses, possibly due to specific energy management practices:
- Packhouse G: Sonoff switches to switch off unnecessary lights off-site, all lights replaced with LEDs, solar energy for ablutions, canteens, and offices.
- Packhouse H: Uses LED lighting and skylight panels for natural light.
3.2 CA operations
3.2.1 Calculation
CA operations electricity consumption (kWh) / CA Tonne.Days
Unit of Measure: Kilowatt-Hour per Tonne.Day of fruit stored.
Tonne.Days = Tonnes stored × Number of days stored.
3.2.2 Results
Only packhouses who provided data are shown.
Notes:
- Electricity consumption of Packhouses B, D, K, L, H, and M were estimated due to insufficient metering.
Metered/accurate data: CA operations electricity benchmarks ranged from 0.8 to 2.2 kWh per Tonne.Day, significantly lower than the benchmark of 5.5–9.5 kWh/Ton.Day found by Bouwer (2011).
- Packhouse C: Uses LED lighting, Power Factor Correction, variable speed drives, and solar energy.
- Packhouse I: Cold rooms set on timers to run only when necessary overnight; solar energy used during the day; SCADA system manages cold room settings and timers.
3.3 RA operations
3.3.1 Calculation
RA operations electricity consumption (kWh) / RA Tonne.Days
Unit of Measure: Kilowatt-Hour per Tonne.Day of fruit stored.
3.3.2 Results
Only packhouses who provided data are shown.
Notes:
- Electricity consumption of Packhouses B, D, H, K, L, and M were estimated due to insufficient metering.
Metered/accurate data: RA operations electricity benchmark is 3 kWh per Tonne.Day, also significantly lower than that found by Bouwer (2011).
4. Overall Packhouse electricity consumption benchmark
The overall benchmark for each packhouse incorporates electricity use for all sections, excluding electricity consumption allocated as “other”. The unit is kWh per tonne of pome fruit packed.
The large variation in the overall electricity consumption benchmarks can be ascribed to the unique combination of facilities at the packhouse and the different energy management practices applied. The general consensus is that approximately 100–300 kWh of electricity was consumed per tonne of fruit packed.
5. Electricity usage profile
It is useful to compare the electricity use profiles of different packhouses. The percentage of electricity consumed for different areas/activities in each of the participating packhouses is shown below.
Notes:
- Packhouse C provided accurate data and this profile can be used for comparison.
Table 1: Summary of packhouse data quality for the different areas/activities
| Packhouse | Packing operations | CA operations | RA operations |
|---|---|---|---|
| A | No data | No data | No data |
| B | Metered | Estimated | Estimated |
| C | Metered | Metered | Metered |
| D | Metered | Estimated | Estimated |
| G | Metered | N/A | Metered |
| H | Metered | Estimated | Estimated |
| I | Estimated | Metered | No data |
| K | Estimated | Estimated | Estimated |
| L | Estimated | Estimated | Estimated |
| M | Metered | Estimated | Estimated |
| N | Estimated | No data | No data |
5.1.1 Variation in electricity use profiles
Large variances in the electricity use profiles of participating packhouses could be attributed to:
- Lack of metering (resulting in estimated data).
- Electricity consumption that is metered but cannot be clearly allocated to specific areas.
- Errors in electricity consumption records.
- Different types of energy management practices applied.
- Different CA storage capacities and strategies applied.
6. Electricity cost
The cost per kWh ranged from R1/kWh to R1.70/kWh.
Table 2: Source of electricity cost data per packhouse
| Packhouse | Grid | Renewable |
|---|---|---|
| A | Eskom invoice – Megaflex | Bought in at R1/kWh |
| B | Municipal invoice | Own meter reading |
| C | Municipal invoice | Estimated |
| D | Estimated | N/A |
| G | Own meter reading | N/A |
| H | Eskom invoice – Ruraflex | N/A |
| I | Eskom invoice – Ruraflex | Own meter reading |
| K | Eskom invoice – Ruraflex | N/A |
| L | Municipal invoice | Municipal invoice |
| M | Own meter reading | N/A |
| N | No data | No data |
7. Energy Management Practices
Packhouses were asked a series of qualitative questions around energy management practices applied in the different areas of activity. A summary is shown below.
7.1 Pre-sort/packing line
Seven packhouses apply energy management practices in their pre-sort and packing lines:
- One switches off most lights during tea and lunch breaks in both day and night shifts.
- One uses Power Factor Correction.
- Two have soft starters installed.
- Three have variable speed drives installed in electronic motors (e.g., water pumps).
- One has Sonoff switches to switch off unnecessary lights.
- One does not use machinery in the offseason during peak tariff times.
- Three use LED lights.
- Two use solar energy.
7.2 Refrigeration
Nine packhouses apply energy management practices in their refrigeration plants:
- Five have variable speed drives in compressors and fans.
- Two use a PLC program to manage condensers.
- One uses a PLC to control lights in CA and RA cold rooms (lights switch off during breaks).
- Two use LED lights in cold storage.
- Two use solar energy in cold storage.
- One uses Power Factor Correction.
- One does auto-scheduling based on RURAFLEX peak tariff periods.
- One uses maximum demand controllers.
- One has timer systems for fans in cold rooms (off during peak hours).
- One sets cold rooms on timers to run only overnight.
- One has soft starters on compressors, cooling fans, and some cooling towers.
- One uses a SCADA system to manage peak & off-peak periods.
7.3 Ablutions, canteen, and offices
Seven packhouses apply energy management practices in their staff facilities:
- One switches off hot water boilers at close of business on Friday, restarts on Monday.
- Five use LED lights.
- Two use solar energy.
- Two use Power Factor Correction.
- One has Sonoff switches for unnecessary lights.
- One uses motion sensors on office lights.
- One applies absolute energy monitoring and vacuum breakers.
7.4 Additional energy saving practices
Four packhouses indicated additional practices:
- One switches off glue machines over weekends.
- One changed forklift batteries to lithium-ion.
- One installed a solar energy system.
- One replaces maintenance/redundant equipment with energy-efficient motors and uses solar geysers.
8. Conclusion
The project provided valuable insights into the energy consumption of pome fruit packhouses and cold stores. The quantitative results can serve as a baseline for improvement, while also providing a guide for improvement targets.
The large variation in benchmark results indicates much room for improvement, particularly the need for metering and accurate record keeping. Differences in energy management practices could also explain some of the variances.
The use of more efficient equipment and good energy management practices can greatly improve energy use efficiency. Most participating packhouses already have some practices in place. More accurate data from more packhouses is needed for further analysis.
Areas of concern:
- Many packhouses do not meter electricity use in specific areas, so they lack an accurate picture of consumption.
- In some cases, meters are not read or readings are not recorded, resulting in poor usage history and undermining management decisions.
It is positive that electricity consumption benchmarks in this study are lower than previously found, indicating improved efficiency. Continued studies would help establish year-on-year trends.
9. Recommendations
- Communicate the impact of metering, record keeping, and data issues on benchmark results, with examples.
- Understand reasons for metering issues experienced by packhouses in future rounds.
- Consider renewable energy financing and other cost data in future data collection.
- Ask participating packhouses for suggestions to improve the data collection tool and processes.
- Continue the project annually for year-on-year comparisons.