Boundaries help distinguish what operations (energy systems, processes, equipment, people/functions) will be included when tracking energy production and energy consumption. Proper operational boundary determination ensures efforts remain focused, data is accurate, and performance can be properly measured or accounted for.
For the purposes of the Beverage Sector, boundaries commonly include all processes under company operational and financial control. In determining boundaries, the following are useful questions to consider:
- Do you have a building or location that you are not including? Process or product line? Equipment? Activities or specific areas of operations?
- Can you isolate or subtract out the energy use from all excluded operations?
- What is the reasoning for excluding operations:
- Insufficient energy information and data?
- Ability to engage employees and secure manager commitment?
- Resource allocation?
- Other reasoning?
Figure 1 schematically illustrates the fundamental items to be considered when setting the operational boundaries, and are assumed to occur on-site and within the fenceline of the facility. Company and third-party owned processes are both commonly considered during the boundary determination with the objective of involving all energy users. It is critical to subtract out or meter separately all excluded processes.
Figure 1. Boundary Energy Management
The letters and numbers in Figure 1 correspond with the Energy Production and Consumption Definitions found below.
Energy Production Definitions
These definitions describe all energy producers that are included in and contribute to the total energy consumption of the plant. The numbers below correspond to those in Figure 1.
- Fuel used for on-site generation of electricity or steam / hot water: the generation can either take place in a combined heat and power plant; or with backup generators. All fuel used for this process is accounted for as energy used by the site.
- Fuel used for on-site boilers to generate steam of hot water: all fuel used for this process is accounted for as energy used by the site.
- Fuels purchased from third parties: fuel used to support the operation of select utilities and transportation.
- Electricity purchased from the grid: electricity purchased from the grid. All electricity purchased from the grid is accounted for as energy used by the site. The values used are the values of the consumption, meaning no grid losses are accounted for, and no ‘primary’ energy values are used. The kWh’s stated on the electricity bills as actual usage are the numbers used for this purpose.
- Steam, hot water, cold water, compressed air: these are utilities that are needed for the beverage processes that are purchased from a 3rd party operation off-site. The amounts used, converted to kWh (or MJ), with defined Conversion Factors (click to view), are all accounted for as energy used by the site.
- Biomass: if the site is using waste products from production as biomass for its boilers or Combined Heat and Power plant, the amount of biomass should be accounted for in the total energy consumption of the plant.
- Steam/hot water generated on-site: this steam or hot water is generated by the on-site steam (or hot water) boilers. The amounts of heat should NOT be accounted for in the total energy use of the plant, but only for internal records. The fuel used to generate this heat is already accounted for in (2).
- Biogas: if the site has an anaerobic treatment system and is using the biogas as fuel for its boilers or Combined Heat and Power plant, the amount of biogas should be accounted for in the total energy consumption of the plant.
- Excess electricity or steam/hot water: if the on-site electricity generation (generators, renewables or Combined Heat and Power plant) produce an excess of electricity or heat and this heat is sold to others (e.g. returned to the grid or sold to neighboring companies), this energy should be deducted from the total energy consumption of the plant. The exclusion of on-site power generation is only allowed if the heat or power is used by an external party.
- Electricity generated on-site: this electricity should NOT be accounted for in the total energy use of the plant, but only for internal records. The fuel used to generate this electricity (see number 1 above), is accounted for, while the efficiency of this generation is the site’s accountability.
- Waste steam/hot water: if the site utilizes a Combined Heat and Power plant to generate electricity, there is also a waste heat (steam of hot water) that is used elsewhere in the beverage production. The amounts of heat should NOT be accounted for in the total energy use of the plant, but only for internal records. The fuel used to generate this heat is already accounted for in (3).
- Renewable Electricity generated on-site: this electricity should be accounted for in the total energy use.
Energy Consumption Definitions
These definitions describe all energy users that are included in and contribute to the total energy consumption of the plant and correspond with the letters in Figure 1.
- Waste Water Treatment Plant (WWTP): the on-site treatment of the facilities waste water in order to discharge the effluent to the water cycle with minimal environmental issues.
- Production: all processes on-site associated with the beverage production, like water treatment, raw material processing, brewing, fermentation, filling, packaging, bottle blowing, etc., as well as auxiliaries and utilities, like compressed air, lighting, chilled water systems, etc.
- Indirect Use: this includes on-site offices, warehouses, technical areas, etc.
- Utilities: all energy consumed by on-site utilities should be accounted for, such as air compressors, chilled water systems, boilers, CO2 manufacturing, etc.
- On-Site Transportation: includes all energy consumed by forklifts, (small) trucks, cars, etc. that operate on-site, are owned by the company and use liquid fuels.
Proper boundary determination ensures efforts remain focused, data is accurate, and energy management performance can be properly measured or accounted for.
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For operations that will be excluded, how will you isolate or subtract out the energy use?
Source: Energy Baseline Methodologies for Industrial Facilities, October 2013.