As companies continue to "go green," the concept of sustainable energy management has become a top priority for a variety of sectors and companies across the globe. And for good reason: Improving the energy efficiency of a manufacturing plant can mitigate potentially negative impacts on the environment, while simultaneously boosting the company's bottom line. In some regions, including Europe, companies are required to trade allowances representing their carbon emissions, and comparable regulations could eventually arrive in the U.S. via a mandated cap-and-trade system.
Some corporate executives might assume that all sustainable energy management measures require costly capital expenditures to retool plants and purchase new equipment, in part because the majority of total energy usage for energy-intensive manufacturing facilities is consumed by the manufacturing process itself. But there are numerous simple, relatively low-cost steps that deliver a high return on investment and a fast payback for facilities that pursue them. The growing interest in such measures is being driven by corporate and governmental concerns for the environment, as well as industry's desire to operate manufacturing facilities as efficiently and as profitably as possible.
These low and no-cost measures can be identified by professional engineers trained to complete energy efficiency assessments of plant operations. These reviews typically include "good housekeeping" procedures, such as equipment maintenance reviews, process controls, detailed and conceptual design improvement, and the integration of processes to maximize efficiencies. Many companies, including my firm, provide this type of assessment for businesses of all sizes across many sectors.
Often, these conservation measures reduce total energy consumption by 5% to 10% within the first year and provide a significant return quickly. Considering that many large-scale manufacturing facilities spend millions of dollars each year to power their facilities, these conservation efforts can translate into significant annual savings well into the six figures.
While looking for ways to use energy more efficiently in the manufacturing process, some leading manufacturers also take the opportunity to examine ways to reduce the intensity of water use as water is becoming an increasingly valuable commodity, particularly in certain parts of the world.
Energy-saving strategies can be simple -- assuming the person conducting the assessment knows what to look for. By turning off cooling water circulation pumps during the weekend, for instance, a plant could reduce energy usage by 100 MWh, cutting the energy bills by as much as $9,000. Another company saved $300,000 per year, or almost 50,000 mmBtu, by reducing the extraction of preheated air in a process.
In Belgium, a fine chemical sector client of MWH agreed to participate in the Belgian Energy Efficiency Benchmarking Voluntary Agreement, agreeing to take steps to become among the world's leaders in energy efficiency by 2012. Approximately 180 total sites throughout Belgium, each spending more than $5 million annually on energy, have also signed this agreement.
After completing an energy efficiency assessment and adopting the proposed changes, the company reduced its energy consumption by 21%, after accounting for production fluctuations. Some of the low- and no-cost measures implemented to achieve these savings included:
- Reduction of pump speeds based on the actual demand of process, cooling and chilled water circuits
- Elimination of heat loss by closing a bypass in the hot oil circuit
- Modification of the thermal oxidizer
For companies seeking a more aggressive overhaul, these low- and no-cost measures can be combined with more capital-intensive projects to yield even greater cost savings. An Italian aerospace company, for instance, has worked with MWH to conduct more than 20 energy efficiency assessments since 2005. Those efforts resulted in combined energy savings of 61,000 MWh of electricity and 45,000 MWh of natural gas and fuels, resulting in a greenhouse gas (GHG) emission reduction of more than 42,000 tons of CO2.
The energy-saving measures identified will cost $39 million to fully implement. While that is significant, the company will recoup that investment within three years, as the efforts will yield annual savings of $15 million. Some of the capital-intensive changes being pursued by this company include:
- Evaluating set points and improving process controls, including increasing the chilled water temperature and trimming steam boiler oxygen
- Detailed design improvements, including resizing pumps, installing high-efficiency motors and improving the insulation of steam pipelines
- Integrating heat recovery from spray booths
Energy efficiency is more than just a feel-good buzz word; the practice translates into better operations and profits for companies that pursue it. While many European companies have leveraged sustainable energy management techniques for years to boost their bottom lines, U.S. manufacturers are now showing increased interest. By analyzing and better understanding the manufacturing process, many low- and no-cost energy saving measures represent a win-win proposition for manufacturers and the environment.
Bert Wellens oversees the Sustainable Energy Management practice for MWH, a global environmental engineering firm. www.mwhglobal.com
