Strategies for High Energy Buildings – Part 2
PART 2 – MANUFACTURING FACILITIES
Recall that in the Part 1 of this series (Defining and Identifying High Energy Buildings in the U.S.) we reviewed the current state of the U.S. energy use and environmental impact on a global scale and defined and identified high energy building categories. From that review we determined that manufacturing facilities are the highest energy use building types in the U.S., accounting for approximately 54% (18,834 billion kBtu) of the energy consumed in the U.S. each year. In Part 2 we will identify the high energy use manufacturing industries, their energy end-use categories, and strategies for successful projects for manufacturing facilities.
IDENTIFYING HIGH ENERGY MANUFACTURING INDUSTRIES & END-USE CATEGORIES
An analysis was performed on the Manufacturing Energy Consumption Survey 2014 (“2014 MECS”) dataset to identify the top high energy manufacturing industries to form the basis for discussing strategies for high energy buildings in manufacturing. The results are shown in Figure 1 and summarized in Table 1. In this analysis, the average site energy use (in million kBtu) was used instead of the average site energy use intensity (“EUI” in kBtu/SF) in combination with Total Energy Use (in billion kBtu) to identify the high energy manufacturing industries. In this context, the average site EUI is generally a poor benchmarking metric for manufacturing facilities when defined as energy use per unit of floor area because there is not a strong correlation between site energy use and facility size. A better method to define site energy use intensity for manufacturing facilities is energy use per unit of production because there is generally a strongly positive correlation between energy use and production volume. Since the 2014 MECS dataset did not include manufacturing production data, I could not calculate average site EUI values in terms of production for the manufacturing industry categories. Figure 1 shows a comparison of the 21 manufacturing industry categories in the 2015 MECS dataset relative to their average site energy use (in million kBtu) and average floor area (in SF). The size of each bubble represents the total energy use of all facilities classified under each manufacturing industry category in the U.S. Visually, it is clear there are four manufacturing categories that have higher average site energy use and total energy use than the other categories: petroleum and coal products, chemicals, paper, and primary metals. These four manufacturing industry categories constitute a total energy use of 14,193 (~75%) out of the 18,834 billion kBtu total energy use from all manufacturing facilities in the U.S. and can be identified as the high energy manufacturing industry categories.
For the top four manufacturing industry categories, an analysis was performed to identify the top energy end-use categories to help provide context behind the high average site energy use. Identifying high energy end-uses is a useful strategy to identifying potential energy-savings opportunities while managing energy assessment level of effort and cost (see the “Strategies for Successful Projects” section below for more information). The analysis results are summarized in Table 2, where the ranking of the energy end-use categories was determined based on the average value of the four high energy manufacturing industries for each category ordered from highest to lowest. The breakdown analysis identified that Process Heating, Combined Heat & Power (“CHP”) and/or Cogeneration Process, Machine Drive, and Conventional Boiler Use constitutes between ~90% and ~94% of the average site energy use for three of the four manufacturing industry categories (petroleum and coal products, chemicals, and paper). For the primary metals manufacturing industry process heating, machine drive, electro-chemical processes, and CHP and/or cogeneration process constitute ~84% of the average site energy use.
Figure 1. Total energy use, and average site EUI and size by Manufacturing Industry Category in the U.S. based on 2014 MECS data.
Table 1. Manufacturing Industry Categories List highlighting the High Energy categories.
Table 2. Breakdown of the top High Energy Manufacturing Industries highlighting the High Energy End-Use Categories
STRATEGIES FOR SUCCESSFUL MANUFACTURING PROJECTS
There are a variety of considerations when beginning an energy assessment of any building. This is especially true for manufacturing buildings. The strategies listed below can be deployed in concert with common project management best practices to help successfully identify energy-savings opportunities in high energy manufacturing facilities. There are a couple of examples shown below to illustrate how the strategy can be deployed on a project.
Account for Site-to-Site Variations: Relative to energy use, manufacturing is a diverse category due to the nature of their purpose. For example, a tomato canning facility will have a much different energy use intensity and make-up compared to a meat processing facility due to their unique production requirements for maximizing yield. The tomato canning facility will have much higher heating energy demand because of the various needs for steam to process tomatoes for canning. Conversely, meat processing sites will have much higher electrical energy demand because of the refrigeration requirements to prevent the loss of moisture and maintain freshness. Understanding these variations at a high level before beginning the energy assessment will help provide context to the information and data that will be gathered and analyzed from the manufacturing facility.
Engage with the Facility Operators: In most cases, the facility’s operations staff can provide a wealth of knowledge and history about the project site. This information can be used to help prioritize systems and operational challenges that need to be investigated. In some cases, the operations staff can provide information on past attempts to reduce energy use and costs at their facility, whether or not any strategies have been deployed, and potential challenges to deploying energy-saving measures.
Identify Key Energy Drivers: Generally, production volume is the most important key driver of energy use for manufacturing buildings. However, there may be others that need to be factored into the energy assessment. Understanding the primary mission of the manufacturing building and the specific manufacturing process at the facility being assessed need to be clearly understood before these key drivers of energy use can be identified.
Gather Key Data and Information: Unlike most commercial buildings, information and data related to equipment, energy use, and production volume is generally not centralized or easily accessible from one particular point of contact at the manufacturing facility. Although one should start with sending a request for information to the facility primary point of contact (generally established at the beginning of the project), be prepared for that person to direct the request to others at the facility. Ultimately, this process will help form your key contacts list for the project and may provide additional insights. In some cases, trend reporting from the automation system and/or metering may need to be deployed to establish reasonable baselines.
Establish KPIs: Key performance indicators (“KPIs”) are very common in the manufacturing market. Understanding the types of KPIs used by the manufacturer will help define the types of energy KPIs that will make sense to the decision maker(s) and should be defined for the project. Most manufacturers constantly measure their production efficiency, typically defined as money spent to manufacture a specified volume of product. For example, paper manufacturers may measure their production efficiency in US$/ton of paper. This production efficiency is a KPI and is also measured against a specified target based on the business’ needs for increased profitability.
Perform a Breakdown Analysis: The size of manufacturing sites can vary significantly from site to site, varying from tens of thousands to millions of square feet. Especially for the larger manufacturing facilities, performing a breakdown analysis early in the project will help focus the efforts on identifying energy-savings opportunities that will generally yield the most impact on site energy use and costs, help identify a list of ECMs to be reviewed and the necessary data/information to gather before any on-site work is performed, and help minimize the impact to site operations to support the energy assessment process.
Identify Potential Measures before Performing On-Site Work: A list of potential energy-saving measures for the project can be identified before performing any on-site work by leveraging the results of a breakdown analysis. Reviewing industry whitepapers, articles, and other resources specific to energy savings in manufacturing facilities can be useful in understanding the types of measures generally available, key data and information needed from the site, and foundations for performing energy savings analyses. For example, the Energy Star® Industries in Focus web page has resources and Energy Guides for a variety of manufacturing industries. Like performing a breakdown analysis, the list of potential measures can also be used to help manage level of effort and impact to site operations during the on-site work.
Perform the Right Financial Analysis: Most owners have established financial criteria for assessing the value of potential projects as part of their Capital Expenditure (“CapEx”) approvals process. It is important that these criteria are clearly understood, documented, and used to analyze the financial strength of energy-savings opportunities before they are presented to the owner for their consideration. It is much easier to meet with the owner to review and select energy-saving measures for deployment when the right financial metrics are presented. As necessary, reasonable assumptions for analysis inputs such as energy cost rates, depreciation, cost of capital, and period may need to be established with the owner. Don’t be afraid to ask for this information and present options.
EXAMPLE: POLYETHYLENE PLANT
The example project is a 120,000 SF polyethylene plant located in Garland, TX. The plant has annual site energy use (783 million kBtu/yr) and an energy end-use profile similar to an average site in the chemical manufacturing industry shown in Tables 1 and 2 above. Review of the utility data gathered from the plant shows it has annual electricity and natural energy costs of $10M/yr (45% electricity / 55% natural gas) and produces 500k tons/yr of polyethylene. In this example we will perform a breakdown analysis to identify the highest energy end-use categories to use to identify potential measures before performing on-site investigations.
Establish KPIs: An energy performance KPI needs to be defined for this project that can be used to identify key energy end-uses and tie potential energy and cost savings to improved plant performance. Recall that review of the site utility and production data showed the plant spends $20M per year on electricity and natural gas energy and produced 1M tons per year of polyethylene. Using this information, we can establish the Energy Cost Intensity (“ECI”) as the KPI for this project, with a value of $20.00/ton. This means that the plant spends $20 of energy per ton of polyethylene produced.
Perform a Breakdown Analysis: In this example we will perform a breakdown analysis to identify the highest energy end-use categories that can be used to help identify potential energy-saving measures that need to be reviewed during the on-site work. Aforementioned, the example project is a Petrochemical plant that has annual site energy use (783 million kBtu/yr) and an energy end-use profile similar to an average site in the Chemical manufacturing industry shown in Tables 1 and 2 above. Based on this information, the 2014 MECS data can be used to estimate the breakdown of site energy use by end-use category as shown in Table 3 below. Note that using the 2014 MECS data should be used to form a basis, and the values should be updated based on the known data and information for the project site. For the purpose of this example, let’s assume the values shown in Table 3 below are accurate for our project site. As shown in Table 3 below, the highest end-use categories are CHP, Process Heating, Conventional Boiler Use, and Machine Drive and constitute 90% of the annual site energy use. Additionally, the data in Table 3 can be used to estimate the impact on the ECI established above. The results are shown in Figure 2 below, which confirm the findings shown in Table 3 and express the results in terms the client key stakeholders can better understand. Based on this information, it is reasonable to assume that focusing efforts on investigating the systems and equipment related to CHP, Process Heating, Conventional Boiler Use, and Machine Drive would facilitate identifying potential energy-saving measures that would yield the most energy and cost savings.
Table 3. Breakdown of Energy Use by End-Use Category.
Figure 2. Breakdown of Plant ECI by End-Use Category (* “Others” includes Facility Lighting, Other Facility Support, Other Nonprocess Use, Onsite Transportation, and Conventional Electricity Generation energy end-uses).
Identify Potential Measures before Performing On-Site Work: CHP, Process Heating, Conventional Boiler Use, and Machine Drive end-uses were identified from the breakdown analysis above as the highest contributors to the project site annual energy use. Based on review of Energy Efficiency Improvement and Cost Saving Opportunities for the Petrochemical Industry, a list of potential measures that should be reviewed during the on-site investigation of the site is shown in Table 4 below. This list should be used as a basis for drafting site visit agenda and a list of additional data/information needed from the site. Although this list of potential measures could be further refined based on the potential savings range, this is not recommended because it could limit the total number of cost-effective energy-saving options presented to the owner for consideration. During the on-site work these potential measures should be investigated to determine their relevance to the project and gather the necessary data and information to evaluate the energy and cost savings. This list can also be used to identify the site operations staff needed during the on-site work to assist in data/information gathering.
Table 4. Potential Measures for CHP, Process Heating, Conventional Boiler Use, and Machine Drive End-Uses in Petrochemical Facilities.
In the next post we will explore energy-saving strategies for the second highest energy building category in the U.S.: Sports & Entertainment.
 Maarten Neelis et al. Energy Efficiency Improvements and Cost Savings Opportunities for the Petrochemical Industry: An ENERGY STAR Guide for Energy and Plant Managers. Ernest Orlando Lawrence Berkeley National Laboratory. June, 2008. https://www.energystar.gov/sites/default/files/buildings/tools/Petrochemical_Industry.pdf