Mexico Border Wall Won’t Stop Cross-border Power Push

Relations between the United States and Mexico are strained at the national level, with President Donald Trump pushing his promised border control wall and demanding a U.S.-favored rewrite of the North American Free Trade Agreement (NAFTA). But Mexico and the southwestern states have continued working towards an international agenda for electricity, and regional players are talking up a first set of projects due to be completed before Trump’s term is up — projects that put the region on a path to a far more electrically-porous border.

These projects include a trio of new crossborder links between California, Arizona and Mexico to be completed in the next three years. They also include grid studies, revised market rules, and new power lines within Mexico that could rapidly expand flows over all of the U.S.-Mexico interties. “The proposition right now is fairly small because the interconnections are small. But that’s going to change,” says Carl Zichella, director for Western transmission at the Natural Resources Defense Council.

SENER Cross-Border-Interconnections-Mexico-Ministry-of-Energy

Many US-Mexico electric interties operate at relatively low voltage (ie low tensión) and are used infrequently – some only during emergencies. Credit: Mexico Ministry of Energy (SENER)

Transmission experts such as Zichella trace today’s momentum back to energy reforms enshrined in Mexico’s constitution in 2014. Those reforms opened up Mexico’s state-dominated energy sector, providing access to private and foreign investment for energy infrastructure and unleashing rapid development of some of North America’s best renewable energy resources.

In 2016 wind and solar capacity grew 33 percent and 114 percent, respectively, according to Mexico’s power grid and market operator, the Centro Nacional de Control de Énergía. CENACE’s 2017-2031 grid development plan (reviewed here in English) foresees wind and solar meeting two-thirds of an estimated 55,840 megawatts of demand growth through 2031.

A more porous border will ease the challenge of backing up that variable renewable power, which is growing on both sides of the border. Duncan Wood, director of the Mexico Institute at the Wilson Center in Washington, D.C. highlights the opportunity to trade wind power between Mexico’s San Fernando Valley, where wind blows hard during the day, and the West Texas wind power farms that run strongest overnight. “If you can link those you might be able to meet peak demand in both the U.S. and Mexico and avoid having natural gas backup,” says Wood.

Mexico’s power grids presently intersect with their U.S. counterparts at 11 points, but more than half of those links can exchange just 100 megawatts (MW) or less and almost half operate only during grid emergencies [see map below]. There are also a few dedicated lines serving individual power plants, such as one that links a natural gas-fired generator in Mission, Texas to Mexican consumers.

Today’s cross-border construction plans, in contrast, go well beyond spur lines and emergency links. The focus is on robust connections between Mexico and the giant synchronized zone operated by the Western Electricity Coordinating Council (WECC) which shares alternating current amongst most of the western U.S. and Canada as well as the northernmost portion of Baja California in Mexico.

“Everything has just gone lightning speed. The political will is there,” says Antonio Ortega, who manages governmental affairs and communications for the Imperial Irrigation District (IID), which operates the grid in California’s Imperial Valley. IID and CENACE signed a memorandum in May to study exchanging up to 600 MW, and Ortega says they now have plans mapped out for a pair of interties to be completed in 2019 and 2020.

Ortega says IID has secured a substation site for one link, and is fielding calls from local geothermal developers and solar developers eager to access the Mexican market. “If all 600 MW of renewable energy development is built it would be an economic boon to the region,” he says.

CENACE and the California Independent System Operator (CAISO), which controls the state’s major grids, are looking to get more out of the existing 800-MW link between the San Diego region and Baja California. Roberto Bayetti, a CAISO working closely with Mexico’s power sector, says the link is used sporadically such as when an outage leaves one side or the other short temporarily. Now they are talking about using the link to integrate renewable energy.

Bayetti says 675-MW of renewable generation under development in Baja California could help the San Diego region, which has relied heavily on imports since the region’s San Onofre nuclear power station closed down in 2013. “That would alleviate some of that congestion for us and provide a big opportunity for both sides to reduce carbon,” says Bayetti.

Greater opportunity for both IID and CAISO will open up thanks to internal transmission projects in Mexico. One that is in advanced planning is a high-voltage direct current (HVDC) line that will, for the first time, link northern Baja (and thus California’s grids) to Mexico’s main grid. “There is huge potential. Now we’re not talking about 800 MWs. We’re talking about thousands of MWs that could be transferred,” says Bayetti.

CENACE’s grid plan sees future developments pushing east to Texas, including additional cross-border HVDC links at Ciudad Juarez and Reynosa and a possible East-West HVDC line tracking south of the border from Baja to close to the Gulf of Mexico. Those projects would expand exchanges with the Texas grid – a stand-alone AC zone managed by the Electric Reliability Council of Texas (ERCOT).

Power system experts are optimistic that the U.S.-Mexico agenda will survive the Trump era, since the action is between regional entities. “Things are just marching along underneath any type of political discussion at the higher elevations,” says Paul Roberti, executive director for power and utilities with EY México, a branch of global accountancy and consulting firm Ernst and Young.

As for President Trump’s border wall? Eight prototypes have been erected near the Otay Mesa border crossing between San Diego and Tijuana [see photo at top]. But the wall itself may be stillborn since, as Reuters noted this week, “Congress has so far shown little interest in appropriating the estimated $21.6 billion it would cost to build the wall.”

This post was created for Energywise, IEEE Spectrum’s blog about the future of energy, climate, and the smart grid


Solar Microgrids May Not Fix the Caribbean’s Devastated Power Systems

After the destruction inflicted across the Caribbean by hurricanes Harvey, Irma, and Maria, renewable energy advocates are calling for a rethink of the region’s devastated power systems. Rather than simply rebuilding grids that delivered mostly diesel generation via damage-prone overhead power lines, renewables advocates argue that the island grids should leapfrog into the future by interconnecting hundreds or thousands of self-sufficient solar microgrids.

“Puerto Rico will lead the way for the new generation of clean energy infrastructure. The world will follow,” asserted John Berger, CEO for Houston-based solar developer Sunnova Energy in a tweet before meeting in San Juan with Puerto Rico Governor Ricardo Rosselló this week. Rosselló appears to be on board, inviting Elon Musk via tweet to use Puerto Rico as a “flagship project” to “show the world the power and scalability” of Tesla’s technologies, which include photovoltaic (PV) rooftops and Powerwall battery systems.

Some power system experts, however, say the solar-plus-batteries vision may be oversold. They say that the pressing need to restore power, plus equipment costs and other practical considerations, call for sustained reliance on centralized grids and fossil fuels in the Caribbean. “They need to recover from the storm. Unfortunately I think the quickest way to do that is to go back to how things were before,” says Brad Rockwell, power supply manager for the Kauaʻi Island Utility Cooperative that operates one of the most renewable-heavy grids in the U.S.

Now is a tough time for a debate, given the ongoing power and communications blackouts afflicting many Caribbean islands, including Puerto Rico, the U.S. and British Virgin Islands, Dominica, and St. Martin. As of Thursday 12 October—more than three weeks after Maria’s cyclonic wrecking ball crossed the region—over four-fifths of customers in Puerto Rico and the U.S. Virgin Islands remained without power, according to U.S. Department of Energy status reports.

Puerto Rico lost major transmission lines that dispatched electricity generated at oil, coal, and natural gas-fired power plants on its lightly populated South shore to all corners of the territory. Its outage level actually slipped from 88.3 to 89.4 percent earlier this week after a tie line went down near San Juan. But it bounced back slightly, to an estimated 83 percent outage level, by yesterday.

What is clear is that several firms are trying to move fast while they talk, equipping rooftop solar systems with battery storage that enables consumers to operate independently of stricken grids. For example:

  • German storage system manufacturer sonnen launched a PV-plus-battery collaboration with local Aguadilla-based solar developer Pura Energía early this month;
  • Sunnova is crafting storage options for roughly 10,000 customers in Puerto Rico that it has already equipped with PV systems;
  • Tesla says it is sending “hundreds” of its Powerwall battery systems to Puerto Rico and, after reports of price gouging by independent installers, plans to dispatch experienced installers from the mainland to expand its local teams.

Peter Asmus, a microgrids analyst with Navigant Research, says that such solar microgrids will deliver power to solar system owners far faster than grid restoration, which is still months away for many customers. He says microgrids will also make the island systems more resilient in the long run.

Asmus sees the situation as reminiscent of post-war Europe, when devastated European grids left a vacuum that enabled something better. “They built a more advanced grid than we have in the U.S.,” says Asmus. He says the Caribbean has a similar opportunity today: “The infrastructure was devastated so severely. They can start over with a cleaner slate.”

Some suppliers see microgrids actually supplanting some of the region’s largest transmission lines. “The grid in Puerto Rico will never be built back the way it used to be,” wrote John Merritt, applications engineering director for Austin, Texas-based Ideal Power in an email to IEEE Spectrum. Ideal Power’s multi-port power converters enable microgrids to efficiently swap power between their alternating current and direct current components, including PV systems, generators, and storage batteries.

Giving up big transmission lines sounds optimistic to Rockwell at the Kauaʻi Island Utility Cooperative (KIUC). It would, he says, represent a major system overhaul and thus lost time that Puerto Rico’s residents and economy can ill afford. “The people of Puerto Rico are not going to want to withstand any more delays than they have to while people figure out how to rebuild in a different way,” he says.

Rockwell adds that batteries are still a rather costly way to balance variable renewable generation. He speaks from experience. KIUC’s grid is over four-fifths solar-powered during some midday hours. Several utility-scale storage systems help integrate such a high degree of  variable power by quickly covering for lost PV generation when clouds pass overhead or by absorbing surplus midday generation and discharging it after the sun sets. But Rockwell says high battery costs mean KIUC still relies heavily on its diesel power plants.

Merritt at Ideal Power acknowledges that the same is true for microgrids. Integrating solar can cut an island microgrid’s fuel consumption by 60 to 70 percent, slashing operating costs and pollution, but he says diesel generators remain “important” assets. “Moving a site from 24/7 diesel-powered microgrid to a 24/7 solar + storage microgrid would be cost prohibitive in most cases,” says Merritt.

There are also questions about PVs’ hardiness. Harvey, Irma, and Maria left many PV systems in shambles. Merritt says that a microgrid for a commercial facility on Saint Croix that Ideal Power participated in assembling before storms is operating without its six 33-kilowatt solar arrays. While they are out of commission for the next few months, the microgrid is relying solely on its diesel generators, battery, and converters.

Some utility-scale solar plants also took a beating, especially Puerto Rico’s Humacao solar array. PV panels shattered and flew out of their frames when Maria’s Category-4 winds ripped over the Humacao solar plant, where its French owner Reden Energie was in the process of doubling capacity from 26 to 52 megawatts.

Houston-based microgrid developer Enchanted Rock advocates rugged microgrids supported by natural gas, which is cheaper and cleaner than diesel and more reliable than both diesel and solar during heavy weather. “You can build community-type microgrids that have some combination of natural gas generation, solar and storage,” says Enchanted Rock CEO Thomas McAndrew.

Enchanted Rock made a name for itself during Hurricane Harvey when its natural gas-powered microgrids at Houston-area grocery stores and a truck stop turned into hubs for first responders and weary residents. Diesel deliveries were hard to come by for 4-5 days, says McAndrew, but natural gas kept flowing underground throughout the storm.

At present few Caribbean islands have access to natural gas, and even Puerto Rico’s gas infrastructure is limited to one liquefied natural gas (LNG) import terminal that pipes the fuel to two power plants. Rosselló had been working to expand LNG imports so more of its oil-fired power plants could burn gas.

Enchanted Rock’s McAndrew favors a network to distribute the gas instead, which he says would be cheaper than putting power lines underground to protect them from weather. He acknowledges that his proposal is ambitious, but says the outside investors that Puerto Rico will need to attract to support its revival can insist on infrastructure that will survive future storms. As McAndrew puts it: “Whether it’s private or government money, there’s got to be some sense that we might want to do this differently so we don’t just end up rebuilding it every couple of years.”

This post was created for Energywise, IEEE Spectrum’s blog about the future of energy, climate, and the smart grid

Floating Wind Turbines on the High Seas


Norwegian oil and gas giant Statoil positions 6-megawatt turbines off the coast of Scotland for the world’s first floating wind farm. Photo: Roar Lindefjeld/Woldcam/Statoil

The world’s first wind farm employing floating turbines is taking shape 25 kilometers off the Scottish coast and expected to begin operating by the end of this year. New research by atmospheric scientists at the Carnegie Institution for Science in Stanford, Calif. suggests that the ultimate destination for such floating wind farms could be hundreds of kilometers out in the open ocean. The simulations, published today in the Proceedings of the National Academy of Sciences, show that winds over the open ocean have far greater staying power than those over land.

Wind power generation is obviously contingent on how fast and how often winds blow. But only over the past decade have scientists and wind farm developers recognized that the winds measured prior to erecting turbines may not endure. For one thing, dense arrays of wind turbines act as a drag on the wind, depleting local or even regional wind resources. Continue reading

Rumble Royale: Can the U.S. Grid Work With 100% Renewables?

Four Days in 2055: Dynamic heat and power supply in the mid-century wind, water and sunlight-fuelled Continental U.S. simulated by Stanford’s Mark Jacobson. Credit: ASU/PNAS

A battle royale between competing visions for the future of energy blew open today on the pages of a venerable science journal. The conflict pits 21 climate and power system experts against Stanford University civil and environmental engineer Mark Jacobson and his vision of a world fuelled 100 percent by renewable solar, wind, and hydroelectric energy. The criticism of his “wind, water and sun” solution and an unapologetic rebuttal from Jacobson and three Stanford colleagues appear today in the Proceedings of the National Academy of Sciences (PNAS).

The critics enumerate what they view as invalid modeling tools, modeling errors, and “implausible and inadequately supported assumptions” in a projection of the mid-century U.S. energy supply that Jacobson and his coauthors published in PNAS in 2015. “The scenarios of [that paper] can, at best, be described as a poorly executed exploration of an interesting hypothesis,” write the experts, led by Christopher Clack, CEO of power grid modeling firm Vibrant Clean Energy.

Clack says their primary goal is accurate science, the better to equip policymakers for critical decisions: “We’re trying to be scientific about the process and honest about how difficult it could be to move forward.”

The text and statements by Clack’s coauthors question Jacobson’s evaluation of competing energy technologies, and specifically his rejection of two non-renewable energy options: fossil fuel power plants equipped to capture their own carbon dioxide pollution and nuclear reactors.

Jacobson calls Clack’s attack, “the most egregious case of scientific fraud I have encountered in the literature to date.”

In fact, while both sides claim to be objectively weighing the energy options, the arguments and backgrounds of the protagonists belie well-informed affinities for various energy sources (and informed biases against others). As sociologists of science would say, their choice of data and their reading of it reflects hunches, values, and priorities.

Consider Clack’s coauthor Ken Caldeira, a climate scientist at the Carnegie Institution for Science. Caldeira’s press release broadcasting their critique argues that removing carbon dioxide from the U.S. power supply is a massive job demanding the biggest tool box possible: “When you call a plumber to fix a leak, you want her to arrive with a full toolbox and not leave most of her tools at home,” says Caldeira.

The same document then abandons this technology-agnostic tone to call out nuclear energy and carbon capture as technologies that “solving the climate problem will depend on.” And Caldeira has appealed for deploying a new generation of nuclear reactors which he and other nuclear boosters such as former NASA scientist Jim Hansen say are needed because renewables “cannot scale up fast enough.” Continue reading

Can Synthetic Inertia from Wind Power Stabilize Grids?

p1110724As renewable power displaces more and more coal, gas, and nuclear generation, electricity grids are losing the conventional power plants whose rotating masses have traditionally helped smooth over glitches in grid voltage and frequency. One solution is to keep old generators spinning in sync with the grid, even as the steam and gas turbines that once drove them are mothballed. Another emerging option will get a hearing next week at the 15th International Workshop on Large-Scale Integration of Wind Power in Vienna: synthetic inertia.

Synthetic inertia is achieved by reprogramming power inverters attached to wind turbines so that they emulate the behavior of synchronized spinning masses.

Montréal-based Hydro-Québec TransÉnergie, which was the first grid operator to mandate this capability from wind farms, will be sharing some of its first data on how Québec’s grid is responding to disruptive events such as powerline and power plant outages. “We have had a couple of events quite recently and have been able to see how much the inertia from the wind power plants was working,” says Noël Aubut, professional engineer for transmission system planning at Hydro-Québec. Continue reading

Wind Could Provide Over 26% of Chinese Electricity by 2030

Last month I argued that the primary reason Chinese wind farms underperform versus their U.S.-based counterparts is that China’s grid operators deliberately favor operation of coal-fired power plants. Such curtailment of wind power has both economic and technical roots, and it has raised serious questions about whether China can rely on an expanding role for wind energy. New research published today appears to put those concerns to rest, arguing that wind power in China should still grow dramatically.

The report today in the journal Nature Energy projects that wind energy could affordably meet over one-quarter of China’s projected 2030 electricity demand—up from just 3.3 percent of demand last year.

In fact the researchers, from MIT and Tsinghua University, project that modest improvements to the flexibility of China’s grid would enable wind power to grow a further 17 percent. That, they argue, means that China’s non-fossil resources could grow well beyond the 20 percent level that China pledged to achieve under the Paris Climate Agreement. Continue reading

Solar Power Towers Aren’t the Avian Annihilators Once Thought

Solar power towers have had a reputation as alleged avian vaporizers since preliminary reports emerged in 2014 of birds being burned in mid-air as they flew through the intense photonic flux at California’s Ivanpah solar thermal plant. Their reputation was muddied even more during tests early this year at SolarReserve’s Crescent Dunes power tower in Nevada; the solar thermal plant just recently began producing power. California public radio station KCET reported that as many as 150 birds were killed during one six-hour test in January.

It is obviously upsetting to imagine birds ignited in the name of renewable energy. (KCET reporter Chris Clarke, who has tracked the issue since BrightSource Energy began building Ivanpah in the Mojave Desert, described burning birds as “beyond the pale” in a recent article suggesting that power towers may be finished in California.)

But, upsetting as any killing of birds is, avian mortality is a downside common to many modern human creations—including buildings, highways, and powerlines. The best data on bird mortality at Ivanpah, macabre as it might be, shows the death rate to be small and likely of little ecological significance.

Meanwhile, operational adjustments at both Ivanpah and Crescent Dunes are pushing avian impacts even further below levels that could threaten local bird populations. “The data does support a low level of avian mortalities and hopefully, through adaptive management and deterrence, it will go even lower,” says Magdalena Rodriguez, a senior environmental scientist with the California Department of Fish and Wildlife. Continue reading