Using Web-based monitoring enables demand response

A well-executed Web-based system can make demand response much easier to install, operate, and monitor.

11/10/2011


The structure of power generation is changing more rapidly now than at any time since the 1920s. These changes can have wide-reaching implications for every user of electrical power connected to the grid. Many factors influence this profound and rapid change. However, key issues include ongoing power generation network deregulation, government Kyoto obligations, green initiatives, and carbon reduction programs (see Figure 1). 

The electrical supply network must play a constant balancing act to ensure that there is always enough power available to meet consumers’ demands. It must also meet efficiency goals and maintain a mandated level of stability. If this balance is lost, the results can be significant. For example, network operators and the 200,000 affected customers remember the East Coast Blackout of August 2003 very well. The U.S. Dept. of Energy compiled the final report on the blackout, which includes causes and recommendations.

Increasing economic pressures are pushing network operators in one direction while the pressures of meeting obligations from environmental perspectives are pushing them in the other. Demand response is a critical aspect of relieving these pressures; it can benefit operators of embedded power generation equipment by providing a valuable revenue stream from otherwise dormant equipment and help ensure a better environmental future.

The need for demand response

Why is demand response needed? The consumption of energy is not uniform. While energy use generally follows predictable patterns, there is the need to ensure that sufficient reserve is available to meet consumer demands. It is common for network operators to monitor certain TV shows where the cliff-hanger of a long-running drama climaxes in a simultaneous rush by consumers to boil the kettle to make a cup of tea. While this is extreme, a similar story plays out every day as consumers go about their normal lives and make decisions on using or not using various electrical appliances.

If matching supply with demand is not challenging enough, consider the impact of variable energy production in the mix. The push for renewable energy means more of the grid capacity is made from less-than-predictable power generation sources. Wind, solar, and tidal power systems contribute significantly when the conditions are right, but also fail to contribute if conditions are less than ideal. For example, a stiff breeze can happily drive the wind farms in one area all morning only to drop to nothing by lunchtime, picking up again mid-afternoon. The network needs to have enough capacity available to cover for this short-term lull.

Traditional power stations are not capable of being switched on and off at short notice. Taking many hours to go from dormant to online, they fail to provide the flexibility needed. Large fossil-fueled thermoelectric plants could either remain idling ready to come online, or operate at less than ideal loads until more load is needed. These expensive power generation sources are operating even more inefficiently and contributing to carbon emissions.

Using relatively small diesel or gas generators for demand response can provide the flexibility the network operators need. The system is surprisingly simple: a standard genset—or better, many tens or hundreds of them—can start when requested and parallel with the grid. Once in parallel, it must ramp up the generator load so that the power is exported to grid, immediately contributing to the capacity available for consumers. In return, the exported energy provides a revenue stream to the genset owner.

Many generators are available, installed in office buildings, hotels, hospitals, utility systems, and banking infrastructure. Many are underused insurance policies to use in case the electrical network fails. This ideal scene is marred only by the need to control the generators to get them online when requested.

Modern electronic control solutions make it relatively simple to upgrade the generator to allow it to start on request and control the synchronizing and parallel export power control. Still missing is the system for monitoring and controlling which generators are available as well as their status.

Traditionally, modem-based systems have been used for handling such equipment, but they fail to perform when the system is scaled up into the numbers required. It simply is not possible to dial up, handshake with the remote system, and perform the necessary steps to get the generator online and then move onto the next one—especially within the time constraints imposed by demand response requirements. The very nature of this point-to-point limitation means that simultaneously monitoring this multitude of running assets becomes complex and unreliable.

This is where the power of Internet communications becomes valuable. The Internet is design to provide simultaneous communication to millions of devices over a wide area. This matches demand response system requirements—many generators over a wide area.

A typical Web-based system solves many of these problems by allowing network operators to simultaneously monitor and control many generators over a wide area. This works by connecting the generator to the Internet and registering its existence with a suitable Web-based control system. Then a simple Internet browser can be used to start and stop the genset as required by the demands of the electrical network.

Using a Web interface further simplifies the system as there are several ways the network can request its demand response customers to contribute. The simpler systems are manual, where the electrical network operator simply calls by phone and informs of the requirement to run. The generator operator uses the website to see which of his assets are available to run and how much power he can provide to meet the network demands. A few clicks later, the revenue starts to stream in.

More complex systems allow the powerful features of interconnected systems to make the process seamless. By linking computer systems, the generator owners and the network operator can automatically operate with each other. The network operator can see the status of all the generators registered for demand response operation—in near real-time—and can start and stop them as required. The generator owner can see at a glance which of his machines are contributing to the grid and also obtain reports on the electricity produced, availability and downtime, engine hours, and fuel consumption (see Figure 2).

Supermarket case study

Consider the supermarket chain that joined a demand response initiative and is receiving revenue from the use of its standby generators for demand response. A well-known supermarket brand examined its costs of maintaining and operating standby generators at its branches and decided to turn them into a revenue stream.

It entered into a demand response program with the electrical network operator and was able to convert its underused assets into a revenue source. The key is being able to know what assets are available for the demand response agreement without adding significant overhead costs. A Web-based system provides the ability to centralize the information coming in from each store, distribute that information to the right team, and control the assets accordingly (see Figure 3).

Investment company case study

Consider the global investment company that took advantage of revenue available for demand response. The electrical networks’ need for demand response is such that they are prepared to pay significant feed-in tariffs for partners who contribute. This attracts new players into the market who are speculating on the revenue opportunity.

Many projects are running with global investment companies backing them. They obtain the demand response license and install a significant number of gensets in various key locations (see Figure 4). A third party is appointed to maintain and operate the systems with agreed-upon performance contracts.

Web-based demand response plays a key role in allowing the various interested parties to monitor their investment or obligation from remote locations. The user and account permission systems inherent in the Web-based solution allow monitoring, control, and event notification to be managed easily. A Web-linked iPhone app enables even nonexecutive interested parties to review the status for peace of mind.

Conclusion

Demand response clearly has a future in balancing electrical network supply. However, because of the distributed nature of generation equipment, control and monitoring become significant problems as the number of assets increases.

Web-based monitoring provides a relatively simple and readily available solution, making partnership in demand response initiatives achievable by a wide range of genset owners.


Revell is sales director of ComAp Spol S.r.o., Prague, Czech Republic; and Roscoe, Ill. (U.S. office), a manufacturer of genset controls and Web-based monitoring systems. He has nearly 25 years of experience in the power generation industry and was educated at Hull University in England.



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