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ESA-186-2 Public Report
The Norpac Foods Stayton plant produces frozen and canned vegetable products. The plant’s operations are seasonal; 67% of the annual energy consumption occurs during the high season months of July, August, September, and October.
Natural gas usage rates range from 9 MMBtu/h in the low season to 43 MMBtu/h in the high season. The plant purchases 100% of its electric demand. The average demand ranges from 2,000 kW in the low season to 6,300 kW in the high season.
The plant is equipped with four natural gas-fired package boilers. Process steam uses include blanchers, cookers, retorts, and heating of sanitation water.
Objective of ESA:
The objective of the Energy Savings Assessment (ESA) was to:
- Perform an abbreviated Energy Savings Assessment using the DOE’s suite of Steam Tools
- Train the staff in the use of the Steam Tools so that they can identify additional energy savings opportunities after the Energy Savings Assessment
- Enable Norpac to apply to other plants the knowledge gained in the Stayton ESA
Focus of Assessment:
Boilers, steam distribution system, condensate return system, and process uses of steam
Approach for ESA:
The approach of the training assessment was to provide training on DOE Steam Tools suite and use them to identify and analyze potential opportunities.
- Identified opportunities and best practices using the Steam System Scoping Tool (SSST)
- Modeled the steam system using the Steam System Assessment Tool (SSAT)
- Used SSAT to estimate savings from opportunities identified in SSST and plant tours
- Demonstrated the use of E3PLUS to evaluate insulation-related opportunities
General Observations of Potential Opportunities:
Annual Energy Consumption:
In 2006 the plant consumed 0.18 TBtu of natural gas and 30,105 MWh of electric energy.
||2006 Consumption (MMBtu)
Energy Savings Opportunities:
The following points should be considered when evaluating the potential opportunities identified on page 1 and described below:
- There is an opportunity to improve the plant instrumentation and data recording systems. This will enable plant staff to gain additional insight into steam system performance and to have greater confidence in the results of the baseline SSAT model and potential energy savings opportunities. There are no steam meters at the plant. Total steam consumption was estimated based on total gas consumption and estimates of boiler efficiency. There was no data available to support the allocation of the estimated total steam flow to the HP and LP headers.
- The estimated savings of most of the individual opportunities described in this report will be influenced by decisions made regarding other individual opportunities. In other words, the total savings will be different than the sum of the individual projects.
- During this training assessment, the plant was modeled in SSAT using annual average data. But because the plant has two distinct operating seasons, it will be useful for Norpac to use the knowledge gained during the training to create two or more models that more accurately reflect plant operating modes.
- The seasonal nature of some energy-intensive operations and the significant distances between some steam system components make it difficult to justify, from an economic perspective, some types of energy savings opportunities.
- There are some energy savings opportunities associated with end-use equipment such as blanchers, continuous cookers, and retorts; however, SSAT is not designed to analyze specific pieces of end-use equipment. To estimate savings associated with these types of equipment, Norpac will have to first perform some non-SSAT analyses. The results of some of those analyses can be entered into SSAT to estimate the economic impacts on the overall steam system. For example, steam demand savings estimated in a non-SSAT analysis of blancher performance or operation can be entered in SSAT Project 1 (Reduce Steam Savings)1.
1 The DOE’s Steam System Assessment Tool (SSAT) includes a number of predefined energy savings opportunities common to many, but not all, industrial steam systems. The opportunities are referred to in SSAT as Projects. Project 1 is simply a reduction in facility steam demand.