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

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Hawaii Says ‘Aloha’ to a 100% Renewable Power Grid

Credit: Blue Planet Foundation

Credit: Blue Planet Foundation

Hawaii’s legislature voted yesterday to stake the state’s future on renewable energy. According to House Bill 623, the archipelago’s power grids must deliver 100 percent renewable electricity by the end of 2045. If the compromise bill is signed by the governor as expected, Hawaii will become the first U.S. state to set a date for the total decarbonization of its power supply.

Renewable energy has been booming since 2008 when the state set a goal of making renewables 40 percent of its power mix by 2030, and government and utility incentives ignited wind power and solar installations. By the end of 2013, renewable energy had jumped from 7.5 percent to 18 percent of the state’s capacity. HB623 seeks to extend and turbo-boost that trend, calling for 30 percent renewables in 2020 and 70 percent by 2030 en route to the final leap to 100 percent.

That last jump could be difficult, says Peter Crouch, a power grid simulation expert and dean of engineering at the University of Hawaii’s flagship Manoa campus. “Today I don’t know whether we can do it,” he says. Continue reading

Storing Solar Energy: A great idea caught on contested ground

Adding energy storage to sites with rooftop solar power generation offers a range of potential benefits. A battery can help smooth out solar’s inherently variable supply of power to the local grid, and even keep buildings powered during blackouts. Consequently, power-conversion innovators are developing a host of new products designed to reduce the cost and improve the efficiency of integrated solar-storage systems.

Some analysts project a boom in the co-location of solar and energy storage. GTM Research, for example, foresees that co-located PV and storage will grow from $42 million in 2014 to more than $1 billion by 2018. However, the market is moving slower than it might thanks to a little-discussed regulatory roadblock in the United States.

According to Vic Shao, CEO for the Santa Clara, California-based energy storage startup Green Charge Networks, tightly integrating storage with photovoltaics in some key states—including Hawaii and California—runs afoul of the “net metering” rules by which PV owners earn lucrative retail rates for the surplus power they feed to the grid. Adding storage can disqualify solar systems for net metering, in which utilities can pay their owners wholesale power rates that are several times lower than retail. “That is obviously a pretty big problem for anybody considering solar. That could kill a lot of projects,” says Shao. Continue reading

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

Beacon Power Hits a Speed-bump, but it’s No Solyndra

Flywheel energy storage developer Beacon Power filed for bankruptcy last weekend, prompting immediate comparisons to infamously failed solar manufacturer Solyndra. But while both firms used millions of dollars in federal loan guarantees to expand their businesses, Beacon Power — which Spectrum profiled this summer — has working assets and a good shot at restructuring and carrying on. Continue reading

Deja Vu as France Plans National EV Charging Network – Again

paris-ev-charge-station-sign-credit-peter-fairleyFrance’s government launched a working group this week to coordinate installation of a standardized national charging network for plug-in hybrid electric vehicles and battery-powered EVs. Many may be experience deja vu, so to speak, because this would apparently be the second such charging network the country has installed.

President Nicolas Sarkozy has set a goal of seeing 100,000-plus electric-mode vehicles on the road in 2012 and has offered French automakers bailout funding partially tied to development of EVs as summarized by Earth Times. But as French state minister for industry Luc Chatel told French business magazine Usine Nouvelle [French], “Their battery serves no point without the infrastructure to go with it.” Hence the working group struck last week, representing automakers, energy distributors such as state-owned nuclear utility EDF, municipalities and other players, which is to deliver a plan in June.

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FERC Boss Dubs the Plug-in a ‘Cashback’ Hybrid

nrel-prius-plug-in-hybrid-demo-vehicleThe head of the Federal Energy Regulatory Commission (FERC) predicts that plug-in hybrid vehicles will provide immense benefit to power grid operators — enough for utilities to provide kickbacks to their customers, paying down the extra cost of a plug-in in as little as three years. Jon Wellinghoff, FERC’s acting chairman, made that comment at a Las Vegas trade show last week according to coverage by the Las Vegas Review-Journal (which I picked up on thanks to the keen newswatching eyes of specialty publication EV World).

Wellinghoff’s comments refer to plug-in hybrids equipped with the smarts to communicate with the power grid, which he termed the “Cashback Hybrid” according to the Review-Journal article:

When the Cashback is plugged in, motorists can allow the utility to vary the speed at which the battery recharges so that the utility can more closely match supply and demand for power on the electric grid…In return, the car owner could obtain cash back or a credit from the utility that makes the electricity free, he said.

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