Power grid problems

This month’s panel discusses the national grid, its problem and innovations, and how to prepare for the digital future.

04/01/2008


This month’s panel discusses the national grid, its problem and innovations, and how to prepare for the digital future.

 

CSE: Is there a general consensus that the national grid is unreliable and in need of overhaul?

 

DAVID PERKINS: There are definitely signs the national electric grid is seeing strain that may lead to reduced reliability. Historically, grid reliability has been addressed by providing generating capacity margin in excess of anticipated peak demand. The Electric Reliability Council of Texas has published information showing capacity could fall below prescribed target margins of 12.5% by 2009.

 

Elsewhere, the ability to bring additional generation capacity online has been hampered by environmental concerns. While coal has historically been the least expensive fuel for large-scale base power production, it also contributes the most to greenhouse gas emissions. Resource Media (2008) published a report showing more than two dozen coal-fired plant proposals were upended in 2007—the result of strong public opposition and uncertainty over the cost of complying with future carbon caps and emissions policies.

 

Paul Joskow (2006) suggests that competitive wholesale electricity markets no longer provide financial incentive for the investment in peaking power plants that have high capital costs, low utilization rates, and uncertain demand requirements. Where free-market practices have led to capacity shortages, utilities and distribution companies have been forced to contract for additional capacity by mandate.

 

CAREY COOK: The need for overhaul is driven by the fact that the grid will be used in different ways in the future. In the past, there were several regional grids around the country that, to different degrees, could be connected together to permit power flow, at least to adjacent grid sections. But, if there was a problem in one grid section, it could be quickly isolated from the other sections to minimize the extent of the problem. I don’t believe it was ever intended that electricity could be generated in, say, Florida and shipped to Washington state. But that seems to be the vision today, and it is in this context that the grid needs to be modernized. Quite apart from the fact that one state might have to live with the social costs of having the generating plant located therein, while a far-away state benefits from the electricity, there are other technical issues to address. For example, a regional grid section might choose to load their transmission lines conservatively, only to be told by national regulators that they must transmit power from Florida to Washington state, and never mind the fact that the transmission lines might be overloaded. To achieve a true national grid that will operate optimally, the existing regional grids will have to be updated to accommodate higher capacity levels. It will also be necessary to upgrade the interties between grid sections to increase power transfers and to improve protection and control equipment.

 

CSE: Is the electrical grid keeping up with the digital economy? It would appear that the digital economy requires a level of power quality and reliability that the grid cannot deliver.

 

PERKINS: It would be cost prohibitive for utilities to invest in infrastructure requirements needed to ensure near 100% system availability required by data centers and other digital economy users. Many utility customers can tolerate brief sags and outages and it would be unreasonable to place the cost burden of business continuity on the broader population of users.

 

COOK: The grid provides bulk power, the distribution system provides local power. Power quality problems can be addressed at the distribution system level. Work on the grid should be focused on reliability (continuity of service). There are lots of solutions to power quality issues (sags and surges) that can be applied to individual loads up to entire distribution feeders.

 

CSE: How must the situation change?

 

COOK: Utilities are already encouraged to improve their performance (reliability and power quality) through the regulatory process. Individual facilities can apply local solutions if their already high level of reliability and power quality is not high enough.

 

PERKINS: Businesses will become creative in how they manage their power reliability needs. We know of one utility that offers high availability “premium power” service to several customers. In this case, the utility arranged for financing of high-efficiency UPS equipment from a third party institution, installed the UPS systems at the customer’s facility, and is recouping the cost through the premium utility rate that it charges to the customer. Others with a need for continuous power will provide for their own power security via UPS and generator, through the use of on-site generation in parallel with the grid or a combination thereof. On-site combined-heat- and-power systems provide opportunities for reliability improvement and long-term energy savings.

 

CSE: Does electric grid unreliability have an impact on power system designs for buildings?

 

PERKINS: Enterprise class data centers have historically led the way in providing for their own power system availability. Large financial institutions, hosting centers, etc., have continuous power requirements and rely extensively on highly redundant power systems including redundant UPS systems and emergency generators. For these customers, there has recently been more attention placed on how system redundancy impacts energy consumption and cost, so the cost of reliability has gained some attention, but in all other respects attention to reliability has been business as usual.

 

We have seen a growing number of industrial customers deploying high-efficiency UPS systems for their factory production systems. As these systems become more automated, utility interruptions cause loss of automation control, which in turn influences production rates. In many instances, downtime required to restart a process after a sag or outage causes control computers to reboot and is far greater than the downtime of the utility itself.

 

COOK: Certain facilities such as semiconductor fabrication plants and data centers can utilize whole building UPS systems that maintain power until a backup generator starts.

 

CSE: What technologies do you see being used to prevent grid unreliability and utility-caused power quality problems from affecting facilities?

 

COOK: The application of new energy storage technologies such as NaS (sodium sulfur) batteries can reduce peaks. Such storage devices also can allow parts of the grid to continue to be served with power when the larger distribution system is down. This is referred to as islanding. Distribution automation also can reduce the time it takes to isolate a faulted section and restore power to the balance of the system.

 

PERKINS: Again, the most common means of preventing grid related power issues from affecting facility operations is through the use of UPS and backup generation. Reducing facility peak demand is usually done for economic reasons (i.e., peak demand charge and/or time of use charge avoidance, etc.). Load shifting systems such as ice storage have been used in many buildings, particularly in the southern U.S. states, to reduce peak air conditioning demand.

 

CSE: What are some innovations in the area of in-plant power metering that help a facility safeguard itself from power quality problems coming in from the utility grid?

 

COOK: The broader deployment of lower-cost power quality and energy demand (usage) meters will make power quality problems more obvious—and more quickly. Demand meters promote conservation.

 

PERKINS: There are a variety of power quality analyzers available that can indicate if some corrective action should be taken. However, meters alone cannot provide the necessary safeguards for correction. High-efficiency UPS provide a means of correcting power quality disturbances including sags, surges, undesirable harmonics and as a bridge to backup generator, providing protection against long-term outages.

 

CSE: Is the number of brownouts and blackouts increasing or decreasing nationally?

 

PERKINS: As electricity consumption increases, we might expect the number of events to increase as well. If the number of events increases in direct proportion to consumption (i.e., events per GWh, etc.), we might say the reliability of the grid is constant. Increasing outages per unit consumption might indicate decreasing reliability and conversely, a decreasing rate might indicate increasing reliability even though the total number of events increases with time.

 

An often-quoted resource for utility voltage disruption is the Electric Power Research Institute report TR-106294 (1996). The report data considered the degree of voltage disturbance in terms of percent voltage sag and event duration. We are unaware of a follow-on report that is available to assess changes with time that is needed to comment on the issue of brownouts.

 

The Energy Information Assn. compiles data on major outages nationwide and it is possible to chart this data to observe trends.

 

CSE: Who maintains the grid?

 

PERKINS: Nationally, grid reliability is regulated by the Federal Energy Regulatory Commission (FERC). FERC delegates reliability management to the North American Reliability Corp. (NERC). There are eight regional entities that report to NERC. NERC publishes reliability standards.

 

CSE: Are energy efficiency programs having an impact on electrical generation capacity?

 

PERKINS: PG&E, an investor owned utility, is on its way to deferring 700 megawatts of generation through efficiency incentives and rebates. PG&E is able to profit from incentives by working closely with the California Public Utility Commission to allocate a percentage of fees towards efficiency programs. Elsewhere, municipal utilities such as Austin Energy provide incentives via mandates such as compliance with City of Austin Climate Protection Plan. In general, the costs of incentive programs are spread across all utility customer bills.

 

Participants

Carey Cook

 

Senior Strategic Marketing Manager

 

S&C Electric Company

 

Chicago

 

David Perkins

 

Chief Technical Officer

 

Active PowerAustin, Texas

 

Additional reading

• Electric Reliability Council of Texas,

 

• Energy Information Assn.,

 

• North American Reliability Corp.,

 

• Edison Electric Institute,

 

• Resource Media fact sheet: “$45.3 Billion In US Coal-Fired Power Plants Cancelled in 2007: Rising Costs Force Energy Firms to Ditch Plans for 31 New Plants,”

 

• Joskow, Paul. (2006). “Competitive Electricity Markets and Investment in New Generating Capacity,” Center for Energy and Environmental Policy Research, MIT.



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