European Grid Operators 1, Solar Eclipse 0

Solar forecast for March 20 via Energy-Charts.de, with previous days' generation

Solar forecast for March 20 from Energy-Charts.de, with prior days’ solar output

Weather forecasts calling for bright sun today across Europe drove up tensions in advance of the partial solar eclipse that blocked the sun’s rays and plunged much of the continent into a brief period of darkness this morning. Grid operators were bracing for record swings in solar power generation because of the celestial phenomenon. Some power distributors in Germany had warned of fluctuations in frequency, notifying customers and suggesting that they shut down sensitive equipment.

In the end, while clear weather made for some excellent eclipse viewing, the electrical story ultimately felt more like Monty Python’s radio coverage of the 1972 eclipse. As if audio coverage of a quintessentially visual event isn’t absurd enough, the Pythons closed their fictitious report in the ultimate anticlimax, as a sudden rainstorm swept in to spoil the solar spectacle. Europe’s interconnected power grid brought about an equally anticlimactic ending today by delivering rock-solid stability throughout the 2.5-hour eclipse.

In fact, according to Enrico Maria Carlini, Head of Electric System Engineering for National Dispatching at Rome-based transmission system operator Terna, the grid was more stable than normal. Carlini had joked last week about doing a rain dance to dampen solar output during before and after the eclipse. Today he took satisfaction from the fact that the frequency of Europe’s power barely budged from its 50 hertz standard.

If transmission system operators had been struggling to keep power capacity and demand in balance during the eclipse, the frequency would have diverged strongly from 50 hertz. But according to Carlini, it strayed only ±25 millihertz all morning, which he says is about the half of normal variability in Europe’s grid frequency.

The grid rolled over the solar swings partly because they were smaller than the worst case scenarios for which operators had been preparing for many months. In all, Europe lost and regained about 17 gigawatts of solar power generation this morning, according to the European Network for Transmission System Operators for Electricity (ENTSO-E) in Brussels. That is a lot of power—just shy of the total solar capacity installed across the United States as of the start of 2015—but just half of the swing that ENTSO-E had warned of in its February eclipse analysis.

TSOs thus confronted the possibility of solar swings with overwhelming force. German TSOs had double the normal personnel on hand in their control rooms. They also had enough gas- and coal-fired power capacity on standby to double the effectiveness of their standard contingency plans for keeping the grid balanced, says Bruno Burger, an expert in renewable energy integration at the Fraunhofer Institute for Solar Energy Systems in Freiburg. “The TSOs really massively prepared,” says Burger.

Today’s solar swings still represented the biggest power gyrations that Germany’s TSOs have ever confronted, according to Burger. Germany’s solar generation was at nearly 13 GW when the lunar shading began. At the peak of the eclipse, at around 10:30 CET, it had crashed to just 5.4 GW. Then, by noon, it had rushed back up to about 20 GW. That post-eclipse surge would have soaked up about 50 percent more than the maximum negative power reserve capacity that Germany’s TSOs had in place in 2013 and 2014. “This was a big challenge for the TSOs,” says Burger.

Still, they could have handled plenty more, claims an analysis (in German) by Burger’s group, which estimates that Germany’s power installations can provide up to 25.6 GW of regulating capacity per hour. Bloomberg reported today that TSOs called up only about 30 percent of the balancing power that plant owners tendered.

Terna, whose Italian power plants are less conventional than the ones its German TSO counterparts can call upon, took an additional measure to balance this morning’s eclipse-driven solar swings: For the first time ever, it exercised its authority to order the nation’s largest, most advanced solar power plants to regulate themselves.

“Those plants were ordered to limit their output to about 30 percent of total capacity from 7 am to 2 pm CET,” says Carlini. That action, he says, reduced the solar power deflation during the eclipse by about 500 megawatts and trimmed the post-eclipse rebound by 2 GW. Under Italian law, solar plant owners will absorb the lost revenue because this was an “emergency procedure,” says Carlini, who doesn’t expect that authority to be wielded again before the next eclipse in 2027..

Burger says Germany’s TSOs could have also shut down solar capacity, but chose not to because German law requires TSOs to compensate the solar plants. An analysis by Berlin-based research group Energy Brainpool estimated that would be more expensive than ramping fossil-fired power plants up and down. As reported by PV Magazine yesterday, shutting down solar generation could nearly triple the cost of handling the eclipse to €9.95 million (US$10.7 million).

This post was created for Energywise, IEEE Spectrum’s blog on green power, cars and climate

Solar Eclipse Will Test European Power Grids

imgA partial eclipse of the sun headed for Europe next Friday has grid operators in a tizzy. On the morning of March 20 Europe’s skies will darken for the first time since solar power became a meaningful piece of some countries’ power supply, and the impact could be dramatic.

“It’s a very, very big challenge for the transmission system operators in Europe,” says Enrico Maria Carlini, Head of Electric System Engineering for National Dispatching at Rome-based Italian transmission system operator Terna.

The Brussels-based European Network for Transmission System Operators for Electricity (ENTSO-E) judges in an eclipse impact analysis released last month that it poses a, “serious challenge to the regulating capability of the interconnected power system.”

While an eclipse markedly reduced solar generation in western North America last October according to energy tracking firm Opower, Europe’s far greater levels of solar power make for bigger stakes. ENTSO-E projects that the moon’s jaunt across the sun’s path next Friday could slash more than 30 gigawatts (GW) of solar generation in Continental Europe over one hour if clouds are scarce and solar generation is high. That’s the equivalent of turning off 30 big coal or nuclear power stations. Continue reading

EPA Coal Cuts Light Up Washington

A meeting at the U.S. Federal Energy Regulatory Commission’s (FERC’s) Washington headquarters yesterday lived up to expectations that it would be one of the most exciting sessions in the agency’s history. Buttoned up policy wonks, lobbyists, and power market experts showed up in droves—over 600 registered—to witness a discussion of what President Obama’s coal-cutting Clean Power Plan presaged for the U.S. power grid. The beltway crowd was joined by activists for and against fossil fuels—and extra security.

Inside proceedings, about the Environmental Protection Agency (EPA) plans’ impact on power grid reliability, protesters against fracking and liquid natural gas exports shouted “NATURAL GAS IS DIRTY” each time a speaker mentioned coal’s fossil fuel nemesis. Outside, the coal industry-backed American Coalition for Clean Coal Electricity distributed both free hand-warmers and dark warnings that dumping coal-fired power would leave Americans “cold in the dark.”

As expected, state regulators and utility executives from coal-reliant states such as Arizona and Michigan hammered home the ‘Cold in the Dark’ message in their exchanges with FERC’s commissioners. Gerry Anderson, Chairman and CEO of Detroit-based utility DTE Energy, called the Clean Power Plan “the most fundamental transformation of our bulk power system that we’ve ever undertaken.”

EPA’s critics argue that the plan’s timing is unrealistic and its compliance options are inadequate. Anderson said Michigan will need to shut down, by 2020, roughly 40 percent of the coal-fired generation that currently provides half of the state’s power. That, he said, “borders on unachievable and would certainly be ill-advised from a reliability perspective.”

EPA’s top air pollution official, Janet McCabe, defended her agency’s record and its respect for the grid. “Over EPA’s long history developing Clean Air Act standards, the agency has consistently treated electric system reliability as absolutely critical. In more than 40 years, at no time has compliance with the Clean Air Act resulted in reliability problems,” said McCabe.

McCabe assured FERC that EPA had carefully crafted its plan to provide flexibility to states and utilities regarding how they cut emissions from coal-fired power generation, and how quickly they contribute to the rule’s overall goal of lowering power sector emissions by 30 percent by 2030 from 2005 levels. (Michigan has state-verified energy conservation and renewable energy options to comply with EPA’s plans according to the Natural Resources Defense Council.)

McCabe said EPA is considering additional flexibility before it finalizes the rule, as early as June. EPA would consider, for example, specific proposals for a “reliability safety valve” to allow a coal plant to run longer than anticipated if delays in critical replacement projects—say, a natural gas pipeline or a transmission line delivering distant wind power—threatened grid security.

As it turned out, language codifying a reliability safety valve was on offer at yesterday’s meeting from Craig Glazer, VP for federal government policy at PJM Interconnection, the independent transmission grid operator for the Mid-Atlantic region. The language represents a consensus reached by regional system operators from across the country—one that is narrowly written and therefore unlikely to give coal interests much relief. “It can’t be a free pass,” said Glazer.

A loosely-constrained valve, explained Glazer, would undermine investment in alternatives to coal-fired power, especially for developers of clean energy technologies. “Nobody’s going to make those investments because they won’t know when the crunch time really comes. It makes it very hard for these new technologies to jump in,” said Glazer.

Clean energy advocates at the meeting, and officials from states that, like California, are on the leading edge of renewable energy development, discounted the idea that additional flexibility would be needed to protect the grid. They pushed back against reports of impending blackouts from some grid operators and the North American Electric Reliability Corporation(NERC). Those reports, they say, ignored or discounted evidence that alternative energy sources can deliver the essential grid services currently provided by conventional power plants.

NERC’s initial assessment, issued in November, foresees rolling blackouts and increased potential for “wide-scale, uncontrolled outages,” and NERC CEO Gerald Cauley says a more detailed study due out in April will identify reliability “hotspots” caused by EPA’s plan. At the FERC meeting, Cauley acknowledged that “the technology is out there allowing solar and wind to be contributors to grid reliability,” but he complained that regulators were not requiring them to do so. Cauley called on FERC to help make that happen.

Cleantech supporters, however, are calling on the government to ensure that NERC recognizes and incorporates renewable energy’s full capabilities when it issues projections of future grid operations. They got a boost from FERC Commissioner Norman Bay. The former chief of enforcement at FERC and Obama’s designee to become FERC’s next chairman in April, Bay pressed Cauley on the issue yesterday.

Bay asked Cauley how he was going to ensure that NERC is more transparent, and wondered whether NERC would make public the underlying assumptions and models it will use to craft future reports. Cauley responded by acknowledging that NERC relied on forecasts provided by utilities, and worked with utility experts to “get ideas on trends and conclusions” when crafting its reliability studies.

Cauley also acknowledged that they were not “entirely open and consensus based” the way NERC’s standards-development process was. And he demurred on how much more open the process could be, telling Bay, “I’ll have to get back to you on that.”

The challenge from Bay follows criticism leveled at NERC in a report issued last week by the Brattle Group, an energy analytics firm based in Boston. Brattle found that compliance with EPA’s plan was “unlikely to materially affect reliability.”

Brattle’s report concurred with renewables advocates who have argued that NERC got it wrong by focusing too much on the loss of coal-fired generation and too little on that which would replace it: “The changes required to comply with the CPP will not occur in a vacuum—rather, they will be met with careful consideration and a measured response by market regulators, operators, and participants. We find that in its review NERC fails to adequately account for the extent to which the potential reliability issues it raises are already being addressed or can be addressed through planning and operations processes as well as through technical advancements.”

This post was created for Energywise, IEEE Spectrum’s blog on green power, cars and climate

Will Shuttering Coal Plants Really Threaten the Grid?

Does President Obama’s plan to squelch carbon emissions from coal-fired power plants really threaten the stability of the grid? That politically-charged question is scheduled for a high-profile airing today at a meeting in Washington to be telecast live starting at 9 am ET from the Federal Energy Regulatory Commission (FERC).

Such “technical meetings” at FERC are usually pretty dry affairs. But this one could be unusually colorful, presenting starkly conflicting views of lower-carbon living, judging from written remarks submitted by panelists.

On one side are some state officials opposed to the EPA Clean Power Plan, which aims to cut U.S. power sector emissions 30 percent by 2030 from 2005 levels. Susan Bitter Smith, Arizona’s top public utilities regulator, argues that EPA’s plan is “seriously jeopardizing grid reliability.” Complying with it would, she writes, cause “irreparable disruption” to Arizona’s (coal-dependent) power system.

Environmental advocates and renewable energy interests will be hitting back, challenging the credibility of worrisome grid studies wielded by Bitter Smith and other EPA critics. Some come from organizations that are supposed to be neutral arbiters of grid operation, such as the standards-setting North American Electric Reliability Corporation (NERC). Clean energy advocates see evidence of bias and fear-mongering in these studies, and they are asking FERC to step in to assure the transparency and neutrality of future analyses. Continue reading

Solar Power and Grid Stability: Scenarios and solutions

hawaii.gridx299Renewable energy is often intermittent, and that variability presents a variety of challenges to power grids. The nature and magnitude of the challenges depends on the time frame — from fractions of a second to seasonal or even multiyear variations — as well as the nature of the grid itself. The latter is evident in two of my articles from last week looking at how seconds-to-minutes fluctuations in solar power complicate grid controllers’ efforts to maintain alternating current at the 60 hertz frequency and the roughly 110 volt power levels required by North American devices.

Fluctuating AC frequency stars in my Technology Review dispatch from the paradise of Kauai, where the island utility is riding an electrical roller coaster as it pushes solar towards 80 percent of peak power flows Continue reading

Amid Blackouts, India’s New Leader Vows 24-7 Power for All

Blackouts this week in New Delhi and surrounding states are providing a dramatic backdrop for a bold promise by India’s new prime minister, Narendra Modi, whose Hindu nationalist party swept to power in a landslide election last month. As a scorching heatwave drove power consumption beyond the grid’s capacity, Modi’s government vowed to deliver “round-the-clock power for all by 2022,” reports the Wall Street Journal.

That will be an awesome task. Nearly one-quarter of India’s 1.26 billion citizens lack grid access. And India’s utilities have struggled to keep up with demand from those who are connected. Power cuts are frequent. Continue reading

Blackouts Ahead on Our Unruly Power Grids

ImageTen years after the Northeast Blackout that shut off power in seven U.S. states and Ontario cascading power grid failures remain a fact of life. And, as I argue today on Spectrum’s Energywise blog, engineers are little closer to predicting and preventing them.

The good news is that engineers are beginning to accept that they have a complex system problem on their hands — an insight that could help them find solutions.

Such understanding was in short supply one year after the Northeast blackout, as I discovered with the publication of my August 2004 cover story for IEEE Spectrum commemorating its one-year anniversary profiling the apparent mathematical inevitability of cascading power-system failures. That message raised a firestorm of protest from engineers who saw their can-do creed under attack.

Today, however, the black sheep who spotted the tell-tale signs of a chaotic self-organizing system in blackout databases have come in from the cold. The University of Wisconsin’s Ian Dobson, for example, says he is having success attracting grants — no mean feat for interdisciplinary research targeting the uber-unsexy field of power transmission. And the IEEE set up a task force on cascading failures (with Dobson at the table).

One obvious cause for rising consciousness is the fact that blackouts just keep happening Continue reading