A number of factors are pressuring companies into going green and conserving energy. Uncertainty about spiking prices and an increasingly stringent regulatory environment, not to mention changing public perception, are all driving companies to curtail energy consumption and reduce emissions.
Plant and machine operators need to make significant reductions in the amount of energy they use. The list of areas being targeted includes heating/refrigeration, lighting, compressed air and many others.
The potential for savings is huge. Taking a national view, more than one-third of all energy in the United States is used by industry. That rises to more than 40 percent if transportation of manufactured goods is included.
Companies around the globe are highlighting their efforts to improve energy efficiency. Between 2005 through 2008, GM reduced its global manufacturing energy demands more than 23 percent. This equates to enough energy to heat and power 700,000 homes. Perhaps more importantly, this energy reduction contributes almost a half billion dollars to GM’s bottom line.
Coca-Cola developed an Energy-Efficiency Guidance Manual that provides best practices which can improve energy efficiency by more than 10%, preventing greenhouse gas emissions by about 500,000 metric tons per year.
These changes are part of a global emphasis to trim energy consumption. In Germany, Mercedes-Benz set a goal of reducing the amount of energy input per unit produced by 20% over five years.
Though the focus on energy efficiency has increased significantly in recent years, American manufacturers have been making major strides for decades. Between 1970 and 2003, there was roughly a 50% reduction in energy intensity, the amount of energy it takes to produce one dollar of goods. It went from 9.13 thousand Btu in 1970 to 4.32 thousand in 2003, according to a joint study by the National Association of Manufacturers and the Alliance to Save Energy.
That study, Efficiency and Innovation In U.S. Manufacturing Energy Use, noted that the average facility can reduce its energy consumption by 10 to 20%. At least 30% of industry’s overall energy savings potential can be obtained without capital expense, by simply making changes to procedures and behavior.
Even greater gains can be made when equipment is brought into the equation. While they move to cut energy consumption by changing processes, equipment buyers are also searching for more efficient equipment.
These end users requirements are being passed on to equipment manufacturers. They are responding by designing machines and plants that show clearly the amount of energy they use. Most new equipment also provides ways to enhance energy efficiency.
Some leading companies have developed broad strategies that address the many phases of upgrading complex industrial facilities. Siemens is addressing this demand with a continuous improvement process that encompasses three stages: Identify, Evaluate and Realize.
The first step, Identify, means clearly showing the amount of energy a machine or plant uses. That task is handled by the Simatic WinCC/PCS 7 powerrate add-on to the supervisory system. It creates an energy management system, which combines a range of underlying measurement techniques. WinCC/PCS 7 powerrate collects, processes and stores all energy relevant data in the data base.
In the second stage, Evaluate, tools (e.g. load curves of power consumption) display the energy which is used by a machine or a motor and can also warn the operator when critical usage conditions or patterns are detected. Reports compare energy consumption of tools, produced goods or even batches day over day, week over week… to analyze the potential scope for improvement.
In the third stage, Realize, the results from the first two steps are implemented with a view towards creating a more energy-efficient plant. A couple examples are more energy-efficient drives at the process level or a rearranged production schedule to avoid peak demand charges. A load management system also steps in if the power demand limit within the 15min interval will be exceeded. This situation is anticipated by the system and the operator will be notified to cut off certain loads temporarily (e.g. HVAC units, compressed air production units). This job can be done automatically by the system in a more accurate and timely manner. Additionally the loads can be arranged in priority lists with specific parameters like minimum on/off time, rotate sequence … to avoid switching off the same loads over and over again.
Siemens provides products and solutions to support every phase of the customer’s energy management operations. Sentron PAC power monitoring devices measure hundreds of parameters of an electrical power distribution system. Even parameters of other kinds of energy (e.g. water, steam, gas) can be collected due to the standard interfaces of those devices.
Additional power management software that can be used during the evaluation phase includes Simatic WinCC/PCS 7 powerrate. During the costing phase, software solutions come into play. In the final phase, implementation, many products such as motors and inverters can be deployed to help companies save energy and reduce emissions.
Networking groups are also addressing the global demand to improve energy efficiency. Late last year, PROFIBUS & PROFINET International (PI) introduced PROFIenergy, a PROFINET-based solution for energy management of production equipment. It’s one of a handful of specialized variations of the Ethernet-compatible version of PROFIBUS that make it simpler to manage facilities.
Solutions applied in the past, which involved manual cutoff during production rest periods, are time-consuming and unreliable. PROFIenergy now allows unused loads to be automatically switched off during rest periods or their power consumption to be automatically reduced. PROFIenergy helps network managers establish rules that automatically cut the power consumption by selectively cutting off individual functions and/or devices, not only during major stops but also during short breakfast breaks.
PROFIenergy uses a standardized data set which enables simple programming of even complex switching operations. A non-reactive integration into existing standards is expected to also provide investment protection for the user.
The new standard will be applicable to all manufacturing industries and industries with typical production rest periods. Initial PROFIenergy products, also from Siemens, are expected to make their appearance in 2010.
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