Introduction
Major blackouts like the one in North America on August 14 illustrate how much we depend on electricity to support a stable, diverse, and growing economy.
It also highlights the need for energy consumers and suppliers to manage risk before major disruptions happen. They must be prepared to diagnose power problems and control energy usage, and a cost-effective approach is the use of enterprise energy management (EEM) systems. These networks of distributed "smart meters" and Internet-ready software instantly deliver information from all parts of the electrical system and respond to changing demands for energy.
Businesses still face considerable challenges: an evolving regulatory environment, uncertain growth in demand, scarcity of land and limitations in geography, and new emission control standards. All these factors make any improvements to generation and transmission capacity more complex. While EEM is not a panacea, it delivers the real-time monitoring, communications, and control technology necessary to make these improvements a reality.
Diagnosis and Prevention
EEM software and "smart meters" add vital information and control on both the supply and demand sides of the energy infrastructure. EEM systems continuously track sequences of events, report data immediately across public or private data networks, and manage loads in step with changing energy needs.
In emergency situations, with these intelligent meters acting as "black boxes" at generators, substations, service entrances, and feeders, plus enterprise-wide software correlating events, energy system operators can trace exactly what happened, when, and where. Using this audit trail of system events, they can quickly verify performance and identify remedial steps that will prevent problems from recurring. And with the modular nature of EEM components, they're also able to cost-effectively add more monitoring and control where necessary at any point in the electrical system. (A plant engineer is shown here inspecting power quality and reliability indicators on the graphic display of an intelligent digital meter.)
When a utility outage occurs unexpectedly, large energy users may need the automatic load preservation capabilities of an EEM system to keep their most critical systems operating. An EEM system continuously monitors loads and utility feeds. By keeping an up-to-date account of conditions at the instance of the outage, the system can make decisions about which loads to shut off based on shifting priorities and the availability of generation.
Maintaining the Supply-Demand Balance
Power interruptions can happen when generation or transmission capacity is insufficient to meet demand. One way of encouraging reductions in demand is to enable direct supply-demand interactions, which lead to price increases when supply is scarce.
Electricity markets can achieve a better balance between supply and demand through the use of demand response programs, interruptible rates, and real-time pricing, all supported by EEM technology. These programs offer economic incentives for large industrial or commercial businesses to decrease demand in reaction to various electrical system conditions. Because they represent the largest proportion of a utility's load, these businesses have the biggest impact on the electrical system and can effectively participate in the electricity market by reducing overall demand and moderating price fluctuations.
For example, a demand response session calls for utility customers to quickly reduce load after receiving warning signals from the utility. Both sides then benefit -- customers receive credits on their electricity bill while the utility stabilizes the availability of electricity and prevents problems from escalating to the point where the grid might crash.
In a real-time pricing situation, instead of waiting for a utility to notify them of a load curtailment session, large energy users curtail their loads based solely on spot market prices.
Once they get the appropriate utility or market signals, energy consumers can immediately react by shedding unnecessary loads or starting up their own generators.
This immediate, "real-time" response is important because energy is a unique commodity. It cannot be stored, so its generation, delivery, and consumption must be managed instantly, or in "real time."
That's where EEM fits in. It gives all market participants enough real-time information to make decisions and the real-time tools to act upon them. EEM meters and software confirm supply-side and demand-side operations and transactions in seconds and correlate all events with subsecond precision. EEM also provides the intelligence to shut down or start up the necessary equipment such as generators at an end-user facility.
Expectations for Reliability
For mission-critical businesses such as data centers, call centers, and semiconductor fabrication plants, there is huge financial risk related to unexpected disruptions to the energy infrastructure. These unplanned events can cost millions of dollars an hour in lost production and customer transactions.
These enterprises require nearly 100% uptime to guarantee the integrity of their products or services, but the power grid typically delivers only 99.9% uptime or "three nines" of power, the equivalent of eight hours of outages per year.
Improving reliability on the supply side is difficult and expensive because long-distance transmission lines are routinely exposed to damage from animals, trees, lightning, and other intrusions. Some organizations are looking at smaller, distributed generators as an alternative because they connect to end users through shorter transmission lines and reduce the cost and environmental impact of larger projects.
While the transmission and distribution infrastructure is a stunning achievement, given the vast geographies and variable demand levels, the U.S. Energy Department recently reported that "the nation's aging electromechanical electric grid cannot keep pace with innovations in the digital information and telecommunications network . . . Power outages and power quality disturbances cost the economy billions of dollars annually. America needs an electric superhighway to support our information superhighway."
Given the limitations of grid reliability, and the possibility of power quality problems lurking within end-user sites, an industrial or commercial facility needs to prepare for any event that leads to downtime, whether it's a full utility outage or a small power disturbance. Momentary disturbances are especially troublesome for the microprocessor-based devices, causing unexpected process shutdowns, lost or corrupted data, and equipment damage at a potential cost of millions of dollars an hour.
The way to achieve a higher level of power quality, and closer to 100% uptime, is through an EEM system that monitors electricity throughout a facility 24 hours a day and captures unexpected voltage sags, swells, transients, or harmonics for later analysis.
The causes of these disturbances vary. Voltage sags result from utility transmission line faults, or more commonly on the end-user side, because of motor startups, defective wiring, and short circuits, which reduce voltage until a protective device kicks in. Transients may happen due to utility capacitor bank switching or grounding problems at the energy user. Harmonics often originate at end-user sites, from non-linear loads such as variable speed motor drives, arc furnaces, and fluorescent ballasts.
An EEM system monitors these conditions, as well as incoming utility feeds, to help trace the real source of disturbances, alert personnel to potential failures, and point to the right remedies.
Remedies include power mitigation equipment such as uninterruptible power supplies, standby generators, flywheels, or static transfer switches, which maintain a continuous level of power, and also may rely on an EEM system to manage their operations.
Conclusion
Fundamentally, energy is a business-critical commodity that must be managed in real time to reduce exposure to financial risk and ensure economic stability. An EEM system serves this purpose -- it reduces risk by managing the cost, quality, and reliability of energy.
(Photo courtesy of Power Measurement)
