The Benefits of Benchmarking
Benchmarking is becoming an increasingly popular way to ensure energy compliance and motivate facilities to improve their efficiency. Last year, for example, the District of Columbia published final regulations to implement a new requirement that all large private buildings benchmark their energy and water performance annually. And New York City’s Local Law 84, instituted in 2009, requires benchmarking for all buildings over 50,000 sq.ft. One of the key goals of the new regulations is to expand the benefits of benchmarking by making buildings’ energy ratings information publicly available to potential buyers and tenants.
Benchmarking is rooted in common sense. As the axiom goes, you can’t control what you don’t measure. It’s a low-cost way to compare the energy performance of a building with a database of similar buildings. This comparison identifies underperforming buildings as well as superior performance and provides owners a tool for tracking and comparing energy consumption on an ongoing basis. Having a context and framework for your energy use can be a powerful gateway experience to revving up your energy management program, or at least tightening up any energy slack. A recent study by the Environmental Protection Agency indicated that, on average, buildings that are benchmarked consistently use 2.4% less energy than those that aren’t, presumably because people are more aware of energy performance.
Establish your baseline
What goes for buildings holds true for processing plants too. For plastics manufacturing facilities in particular, benchmarking can help assess efforts to reduce energy and water use as well as effluent discharges. The first step is to establish a baseline measurement of resource consumption and waste output. This enables you to determine a ratio for improvements made over time. You will be analyzing the specific energy consumption (SEC) from the total energy used and tonnage processed. Technically, SEC is normally expressed as kilowatt-hours per kilogram (kWh/kg).
A simple calculation is:
Total energy used in 12 month–period = x (kWh)
Total tonnage produced in 12 month–period = y (tonnes)
Specific energy consumption (kWh/kg) = x/1,000y
There are other generic performance ratios available that can calculate both the process and non-process consumption of energy and water use, as well as formulas devoted to lighting, heating, ventilation and air conditioning. The primary source for your calculations will be your utility bill. Once you establish an accurate baseline, you will be able to track your improvements by seeing a decrease in your ratios. And for large pieces of equipment not covered under the generic ratios, you should be able to devise a similar ratio tailor-made to that particular piece of process equipment. To help you get started, here’s a checklist of some key benchmark indicators:
Raw materials usage
Unit electrical energy use
Unit natural gas energy use
Reduction in carbon dioxide emissions per unit of energy
Unit water use
From baseline to bottom-line
Performance data is a powerful motivator for self-improvement. Once you know where you stand in usage, you can prioritize your energy improvement projects. A recent Department of Energy study in California indicates "energy performance benchmarking prompted energy efficiency investment in over 60 percent of participants through improved energy management processes, building upgrades, and behavioral efficiency projects."
The process of comparing your manufacturing facility with other similar facilities can also trigger a bit of constructive competitiveness. As Ashok Kamal, cofounder of Bennu, a green social media–marketing firm says, “If you are not greening, you are not competing.” The Energy Star Portfolio Manager can be used to manage the energy and water use of any building.
Be warned however—it’s important to carefully ensure that you’re using valid and comparable data. In plastics processing, many processes have varying energy requirements. You may be hard-pressed to find precisely identical conditions in other locations, and many companies may be reluctant to share detailed information with their competitors.
Don’t get too caught up in comparisons, as the most useful comparison may be against your own facility’s performance over time. The ultimate goal of benchmarking is to focus on improved performance and give the organization specific goals to work toward.
