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GE director cautions utilities
to plan well for PV challenges

McDonald speaks in Mexico, SDG&E wrestles with voltage

ROCKVILLE, MD (November 1, 2013) -- Mexico may be rich in solar power but utilities there should not hurry the resource onto the grid without planning for the voltage variation that comes with it, John McDonald, GE Digital Energy's director of technology strategy and business development, told Smart Grid Today -- the leading independent, daily, professional news journal of the smart grid industry -- in an exclusive interview. Smart Grid Today publisher Modern Markets Intelligence, Inc. is sharing it here, free of charge.

The story has been slightly edited for this format and is included in its entirety here and at

Mexican power firms can learn from utilities around the world that have integrated large solar loads and then struggled with voltage variation, McDonald added. He recently returned from keynoting a renewables conference in Mexico City, where his message was pointed. "I emphasized the impact of high-penetration of renewables… the impact that it can have on the grid. After learning about the grid in Mexico City, my caution was, 'be careful, guys,'" he recounted.

Even utilities that plan for the disruptions that renewables can cause their grids do get burned. San Diego Gas & Electric (SDG&E), "with all of the investment that they put into their grid, is experiencing some very unusual issues as the result of high penetration of solar PV that, really, all utilities will experience if the policy incentivizes customers to get rooftop solar PV," said McDonald. He also chairs the Smart Grid Interoperability Panel's (SGIP) board of directors.

The task of integrating renewable sources can be all the harder when a grid is plagued by power loss, as Mexico's is. Industry experts describe power loss as either technical or non-technical. Technical loss is due to an equipment or engineering failure.

Non-technical loss is simply theft. About 33-34% of the power on Mexico City's grid is lost to one of these causes, McDonald said.

Mexico City municipal utility Luz y Fuerza is at the center of the problem. When Comisión Federal de Electricidad (CFE), the giant state-owned utility serving about 100 million people, acquired Luz y Fuerza, CFE may not have known the extent of the municipal utilities' power-loss issues, McDonald said.

Former head of the Colorado PUC Ron Binz observed Luz y Fuerza's power-loss problems firsthand and told Smart Grid Today he believes AMI can help overcome them.

CFE seeks help

CFE is now keen on plugging the power leaks in Luz y Fuerza and, in turn, elsewhere on its grid. The utility asked Dr Ricardo Mota-Palomino of Instituto Politécnico Nacional, one of Mexico's largest public universities, to probe the causes of power losses and offer remedies, McDonald said.

The Mexican utility is also soliciting help from Silicon Valley to help with PV integration. San Jose, Calif-based power products supplier Varentec is working with CFE on a pilot project aimed at correcting for the volatility in voltage that rooftop PV often brings to a network, he added.

Varentec makes the ENGO-V, a power electronics box that is placed on a low-voltage network and can help with voltage and reactive power variability, he explained. This hardware addresses the problem where it lies, on the low-voltage network, rather than higher up at the substation, he added.

A Varentec representative could not be reached in time to comment on this article.

Voltage regulators overtaxed

The voltage variability caused by added PV penetration on a utility's network "triggers the operation of electro-mechanical devices designed for voltage regulation… far more frequently than intended by their original design," McDonald wrote last month in an IEEE newsletter. "In turn, that higher number of operations dramatically shortens those devices' lifecycles, without necessarily resolving the variability, leading to unanticipated costs and a search for mitigating technologies," he added.

McDonald would like the utility industry's search for mitigating technologies to focus, in part, on the low-voltage network, he told Smart Grid Today.


Smart Grid Today's mission is to deliver daily, unbiased, comprehensive and original reporting on emerging trends, applications and policies driving the modern utility industry -- in a signature format our founders have developed over decades in the trade news business, featuring highly concise and easy-to-understand news copy based on trusted reporting, exclusive interviews, informed analysis and strategic insights that our subscribers rely on to succeed every business day.  Smart Grid Today is published by Modern Markets Intelligence, Inc.


Brett Brune
VP of Editorial
Modern Markets Intelligence, Inc.

Season Crawford
VP of Marketing
Modern Markets Intelligence, Inc.


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