According to an E Source article by commercial energy advisor Lee Hamilton, the industrial sector accounts for approximately 31 percent of all energy consumption in the United States. Much of this is used for manufacturing processes. Manufacturing facilities use an average of 95.1 kilowatt-hours (kWh) of electricity and 536,500 Btu of natural gas per square foot annually, though actual consumption varies widely depending on the sector.
The top five sectors by usage are process intensive:
- Petroleum and coal: 25 percent
- Chemicals: 20 percent
- Pulp and paper: 10 percent
- Primary metals: 5 percent
- Food: 5 percent
Although the energy consumption of these manufacturing subsectors varies, there are four common categories identifying the top energy users for the manufacturing sector as a whole. Process heating, drivepower, cogeneration, and conventional boiler use collectively account for over 85 percent of the energy used in the top five subsectors. Facility HVAC and lighting are the next-largest categories of energy consumers, and, though both account for less than 4 percent of total energy consumption, these categories offer proven improvement opportunities for energy efficiency that won’t interrupt plant processes.
How to decrease usage?
Given these statistics, the Wisconsin Manufacturing Extension Partnership published a useful list of ways to reduce manufacturing energy costs:
- Install energy-efficient lighting, such as florescent or LED fixtures, and consider lowering light levels if possible.
- Optimize air compressors and fix leaks. Many people don’t realize air compressors are one of the most energy-intensive pieces of equipment in a facility. A rule of thumb: if you can hear the hiss of an air leak, that one leak can cost you at least $500 per year (depending on size). It’s not uncommon to find dozens or, in some cases, hundreds of costly leaks in a production environment.
- Overhaul or replace aging HVAC systems and consider reducing the amount of air exhausted from your facility by the HVAC system. The installation of economizers (mechanical devices that reduce energy consumption) will also help reduce cooling costs. Retro-commissioning of HVAC and other equipment can result in significant energy savings.
- Create an energy management team comprised of maintenance, engineering, production, accounting, and management staff to meet regularly, monitor energy usage, and identify and evaluate potential energy-reduction projects.
- Where possible, reschedule usage of high-powered electric machinery to avoid high peak demand (kW) utility charges.
- Make sure energy reduction is folded into your continuous improvement strategy and encourage everyone at your company to be involved.
- Conduct an energy assessment to identify how much energy is being used at different times of the year and at different production/activity levels. Have your energy management team train with an energy engineer and learn to identify energy efficiency measures that can be readily implemented.
The Current State
Increasingly, sustainable energy goals are driving development across a host of manufacturing sectors. According to Green Car Reports, “… All the major automakers are making strides towards improving their factories these days (in addition to their vehicles), with low waste plans, solar power and more.” Ford plans to reduce energy use in its plants by 20 percent by 2016, and cut water usage and waste by 30 percent by 2015, according to Wards. The benefits are significant: for example, in 2012, Ford saved $3 million in water savings alone. Daimler, Volkswagen, Tesla, and Subaru are other automakers cited for building production facilities with energy efficiency as a prime design concern.
Bottom line: greater energy efficiency reduces costs for manufacturers; this is no longer considered an afterthought but rather a strategic imperative as new facilities are being built and existing ones made more sustainable. For an overview of energy use and energy efficient opportunities for manufacturing plants, you can go here.