Necessity is the mother of invention, goes the old saw. Whether driven by regulations, stockholder pressure, concerns over the price of energy, the desire to be a good corporate citizen or even just seeing a good marketing strategy on the horizon, sustainability initiatives are quickly evolving from being "nice-to-haves" to corporate "must-haves." And one of the easiest jumps onto the sustainability bandwagon is via energy savings. Even the most cynical global warming skeptic can appreciate a five-, six- or even seven-figure saving on energy bills. At that point, whether the practice is "sustainable" or not is irrelevant. It's simply good economics.
One of the bottom line basics of a good energy-saving strategy—as well as process optimization and quality control—is data. You need to know how much you're spending, what you're spending it on, and how well your processes are operating within given parameters. The answers to these questions lie not just in the office of the CFO or the heads of your most senior operators, but in the multitude of data in your PLCs, sensors, SCADA systems, HMIs and all the other basic monitoring systems in your factories and facilities.
The challenge has always been to get that data from the "islands of automation" into the hands of the people who can make decisions about how to manipulate processes in a way to both optimize the processes and systems to reap the savings that can be derived from optimized operation. Fortunately, getting from here to that ideal of real-time information, which enables the decisions that make energy savings (and other process optimization) possible, is getting easier. This is thanks to the happy confluence of improved hardware and sensor technology, connectivity solutions, GUIs and understanding of the implications of the Internet and both its promises and problems for the process industries.
The good news for end users is that most every major automation vendor has jumped on this energy-saving bandwagon to one degree or another, and has offerings that can meet the needs of both the simplest and most complex applications. The other piece of good news is that these kinds of changes in operation can be incremental. It's relatively easy (and inexpensive) to start small and build on little successes. Of course, sometimes, it makes more sense to go big from the beginning.
Take the case of Tata Steel, the sixth largest steel company in the world with an annual production capacity of 30 million metric tons (tonnes). Tata's Jamshedspur Steel Works in Jamshedpur, India, is the company's home base and its first plant, established in 1907. In 2010-11, it produced approximately 7.5 million tonnes of iron, 6.8 million tonnes of crude steel and 6.7 million tonnes of saleable steel, including rolled and forged bars, hot-rolled coils and strips, cold-rolled coils and semi-finished steel. The Jamsedpur facility is equipped with six coke oven batteries, four sintering plants, seven blast furnaces, five Linz-Donawitz converters, three billet steel shops, two slab steel shops and rolling mills that produce wire rod, bar, plate, and hot and cold strip products. Not surprisingly, an operation of this size consumes a lot of energy and produces a lot of CO2 emissions.
Energy saving and emission reduction has been part of Tata's plan long before either of them became missions du jour for process operations in general. The company has already reduced the amount of energy it needs to make a tonne of steel in half over the last 40 years. Now it has added the goal of cutting CO2 emissions by another 20%. The India division alone has set a target of reducing CO2 emissions from 1.8 tons per ton of liquid steel to 1.5 tons. To get the job done, the company has set up an Energy Management Center with a SCADA system that gathers all the plant site energy information, and manages the load dispatch. Honeywell is the chosen automation partner for the project.
Tata's latest efforts began in 1998 when the company acquired eight PLC-based remote terminal units (RTU). More were added to the network between 2006 and 2010, along with field instrumentation and modifications to the SCADA system. The company also installed a plantwide, dedicated, more than 100-km, fiberoptic network to connect the various shops spread over the facility.
Honeywell's ExperionPKS automation system, the SCADA system and the network have enabled Tata to get accurate measurements and records of energy consumption, correlate energy consumption of process units to their measured output, and set benchmarks using data from the historian. The system also gives plantwide access to the energy supply and consumption of the entire site through a centralized server to enable monitoring of individual energy networks and process units in real time, all of which will enable Tata to meet its emission-lowering goals.
While not as massive an operation as Tata Steel, Murray Goulburn (MG), a cooperative of some 3000 dairy farmers and the largest milk processor in Australia, also uses its sliced-and-diced data to improve its operations and quality of its product and save energy.