Offshore wind farm stirs up tempest

Spring Storm Grid Risks highlight tornado outbreaks, flooding, power outages, and transmission disruptions, with NOAA flood outlooks, coal and barge delays, vulnerable nuclear sites, and distribution line damage demanding resilience, reliability, and emergency preparedness.

Key Points

Spring Storm Grid Risks show how tornadoes and floods disrupt power systems, fuel transport, and plants guide resilience.

✅ Tornado outbreaks and derechos damage distribution and transmission

✅ Flooding drives outages via treefall, substation and plant inundation

✅ Fuel logistics disrupted: rail coal, river barges, road access

The storm and tornado outbreak that recently barreled through the US Midwest, South and Mid-Atlantic was a devastating reminder of how much danger spring can deliver, despite it being the “milder” season compared to summer and winter.  

Danger season is approaching, and the country is starting to see the impacts. 

The event killed at least 32 people across seven states. The National Weather Service is still tallying up the number of confirmed tornadoes, which has already passed 100. Communities coping with tragedy are assessing the damage, which so far includes at least 72 destroyed homes in one Tennessee county alone, and dozens more homes elsewhere. 

On Saturday, April 1–the day after the storm struck–there were 1.1 million US utility customers without power, even as EIA reported a January power generation surge earlier in the year. On Monday morning, April 3, there were still more than 80,000 customers in the dark, according to PowerOutage.us. The storm system brought disruptions to both distribution grids–those networks of local power lines you generally see running overhead to buildings–as well as the larger transmission grid in the Midwest, which is far less common than distribution-level issues. 

While we don’t yet have a lot of granular details about this latest storm’s grid impacts, recent shifts in demand like New York City's pandemic power patterns show how operating conditions evolve, and it’s worth going through what else the country might be in for this spring, as well as in future springs. Moreover, there are steps policymakers can take to prepare for these spring weather phenomena and bolster the reliability and resilience of the US power system. 

Heightened flood risk 
The National Oceanic Atmospheric Administration (NOAA) said in a recent outlook that about 44 percent of the United States is at risk of floods this spring, equating to about 146 million people. This includes most of the eastern half of the country, the federal agency said. 

The agency also sees “major” flood risk potential in some parts of the Upper Mississippi River Basin, and relatively higher risk in the Sierra Nevada region, due in part to a historic snowpack in California.  

Multiple components of the power system can be affected by spring floods. 

Power lines – Floods can saturate soil and make trees more likely to uproot and fall onto power lines. This has been contributing to power outages during California’s recent heavy storms–called atmospheric rivers–that started over the winter. In other regions, soil moisture has even been used as a predictor of where power outages will occur due to hurricanes, so that utility companies are better prepared to send line repair crews to the right areas. Hurricanes are primarily a summer and fall phenomenon, and summer also brings grid stress from air conditioning demand in many states, so for now, during spring, they are less of a concern.  

Fuel transport – Spring floods can hinder the transportation of fuels like coal. While it is a heavily polluting fossil fuel that is set to continue declining as a fuel source for US electricity generation, with the EIA summer outlook for wind and solar pointing to further shifts, coal still accounted for roughly 20 percent of the country’s generation in 2022.   

About 70 percent of US coal is transported at least part of the way by trains. The rail infrastructure to transport coal from the Powder River Basin in Montana and Wyoming–the country’s primary coal source–was proven to be vulnerable to extreme floods in the spring of 2011, and even more extreme floods in the spring of 2019. The 2019 floods’ disruptions of coal shipments to power plants via rail persisted for months and into the summertime, also affecting river shipments of coal by barge. In June 2019, hundreds of barges were stalled in the Mississippi River, through which millions of tons of the fossil fuel are normally transported. 

Power plants – Power plants themselves can also be at risk of flooding, since most of them are sited near a source of water that is used to create steam to spin the plants’ turbines, and conversely, low water levels can constrain hydropower as seen in Western Canada hydropower drought during recent reservoir shortfalls. Most US fossil fuel generating capacity from sources like methane gas, which recently set natural gas power records across the grid, and coal utilizes steam to generate electricity. 

However, much of the attention paid to the flood risk of power plant sites has centered on nuclear plants, a key source of low-carbon electricity discussed in IAEA low-carbon electricity lessons that also require a water source for the creation of steam, as well as for keeping the plant cool in an emergency. To name a notable flood example here in the United States–both visually and substantively–in 2011, the Fort Calhoun nuclear plant in Nebraska was completely surrounded by water due to late-spring flooding along the Missouri River. This sparked a lot of concerns because it was just a few months after the March 2011 meltdown of the Fukushima Daiichi nuclear plant in Japan. The public was thankfully not harmed by the Nebraska incident, but this was unfortunately not an isolated incident in terms of flood risks posed to the US nuclear power fleet. 

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US Nuclear Generating Costs 2017 show USD33.50/MWh for nuclear energy, the lowest since 2008, as capital expenditures, fuel costs, and operating costs declined after license renewals and uprates, supporting a reliable, low-carbon grid.

Key Points

The 2017 US nuclear average was USD33.50/MWh, lowest since 2008, driven by reduced capital, fuel, and operating costs.

✅ Average cost USD33.50/MWh, lowest since 2008

✅ Capital, fuel, O&M costs fell sharply since 2012 peak

✅ License renewals, uprates, market reforms shape competitiveness

Average total generating costs for nuclear energy in 2017 in the USA were at their lowest since 2008, according to a study released by the Nuclear Energy Institute (NEI), amid a continuing nuclear decline debate in other regions.

The report, Nuclear Costs in Context, found that in 2017 the average total generating cost - which includes capital, fuel and operating costs - for nuclear energy was USD33.50 per megawatt-hour (MWh), even as interest in next-generation nuclear designs grows among stakeholders. This is 3.3% lower than in 2016 and more than 19% below 2012's peak. The reduction in costs since 2012 is due to a 40.8% reduction in capital expenditures, a 17.2% reduction in fuel costs and an 8.7% reduction in operating costs, the organisation said.

The year-on-year decline in capital costs over the past five years reflects the completion by most plants of efforts to prepare for operation beyond their initial 40-year licence. A few major items - a series of vessel head replacements; steam generator replacements and other upgrades as companies prepared for continued operation, and power uprates to increase output from existing plants - caused capital investment to increase to a peak in 2012. "As a result of these investments, 86 of the [USA's] 99 operating reactors in 2017 have received 20-year licence renewals and 92 of the operating reactors have been approved for uprates that have added over 7900 megawatts of electricity capacity. Capital spending on uprates and items necessary for operation beyond 40 years has moderated as most plants are completing these efforts," it says.

Since 2013, seven US nuclear reactors have shut down permanently, with the Three Mile Island debate highlighting wider policy questions, and another 12 have announced their permanent shutdown. The early closure for economic reasons of reliable nuclear plants with high capacity factors and relatively low generating costs will have long-term economic consequences, the report warns: replacement generating capacity, when needed, will produce more costly electricity, fewer jobs that will pay less, and, for net-zero emissions objectives, more pollution, it says.

NEI Vice President of Policy Development and Public Affairs John Kotek said the "hardworking men and women of the nuclear industry" had done an "amazing job" reducing costs through the institute's Delivering the Nuclear Promise campaign and other initiatives, in line with IAEA low-carbon lessons from the pandemic. "As we continue to face economic headwinds in markets which do not properly compensate nuclear plants, the industry has been doing its part to reduce costs to remain competitive," he said.

"Some things are in urgent need of change if we are to keep the nation's nuclear plants running and enjoy their contribution to a reliable, resilient and low-carbon grid. Namely, we need to put in place market reforms that fairly compensate nuclear similar to those already in place in New York, Illinois and other states," Kotek added.

Cost information in the study was collected by the Electric Utility Cost Group with prior years converted to 2017 dollars for accurate historical comparison.

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Ontario Clean Energy Adjustment lowers hydro bills by shifting global adjustment costs, cutting time-of-use rates, and using OPG debt financing; ratepayers get inflation-capped increases for four years, then repay costs over 20 years.

Key Points

A 20-year line item repaying debt used to lower rates for 10 years by shifting global adjustment costs off hydro bills.

✅ 17% average bill cut takes effect after royal assent

✅ OPG-managed entity assumes debt for 10 years

✅ 20-year surcharge repays up to $28B plus interest

Ontarians will see lowered hydro bills for the next 10 years, but will then pay higher costs for the following 20 years, under new legislation tabled Thursday.

Ten weeks after announcing its plan to lower hydro bills, the Liberal government introduced legislation to lower time-of-use rates, take the cost of low-income and rural support programs off bills, and introduce new social programs.

It will lower time-of-use rates by removing from bills a portion of the global adjustment, a charge consumers pay for above-market rates to power producers. For the next 10 years, a new entity overseen by Ontario Power Generation will take on debt to pay that difference.

Then, the cost of paying back that debt with interest -- which the government says will be up to $28 billion -- will go back onto ratepayers' bills for the next 20 years as a "Clean Energy Adjustment."

An average 17-per-cent cut to bills will take effect 15 days after the hydro legislation receives royal assent, even as a Nov. 1 rate increase was set by the Ontario Energy Board, but there are just eight sitting days left before the Ontario legislature breaks for the summer. Energy Minister Glenn Thibeault insisted that leaves the opposition "plenty" of time for review and debate.

Premier Kathleen Wynne promised to cut hydro bills and later defended a 25% rate cut after widespread anger over rising costs helped send her approval ratings to record lows.

Electricity bills in the province have roughly doubled in the last decade, due in part to green energy initiatives, and Thibeault said the goal of this plan is to better spread out those costs.

"Like the mortgage on your house, this regime will cost more as we refinance over a longer period of time, but this is a more equitable and fair approach when we consider the lifespan of the clean energy investments, and generating stations across our province," he said.

NDP critic Peter Tabuns called it a "get-through-the-election" next June plan.

"We're going to take on a huge debt so Kathleen Wynne can look good on the hustings in the next few months and for decades we're going to pay for it," he said.

The legislation also holds rate increases to inflation for the next four years. After that, they'll rise more quickly, as illustrated by a leaked cabinet document the Progressive Conservatives unveiled Thursday.

The Liberals dismissed the document as containing outdated projections, but confirmed that it went before cabinet at some point before the government decided to go ahead with the hydro plan.

From about 2027 onward -- when consumers would start paying off the debt associated with the hydro plan -- Ontario electricity consumers will be paying about 12 per cent more than they would without the Liberal government's plan to cut costs in the short term, even though a deal with Quebec was not expected to reduce hydro bills, the government document projected.

But that was just one of many projections, said Energy Minister Glenn Thibeault.

"We have been working on this plan for months, and as we worked on it the documents and calculations evolved," he said.

The government's long-term energy plan is set to be updated this spring, and Thibeault said it will provide a more accurate look at how the hydro plan will reduce rates, even as a recovery rate could lead to higher hydro bills in certain circumstances.

Progressive Conservative critic Todd Smith said the "Clean Energy Adjustment" is nothing more than a revamped debt retirement charge, which was on bills from 2002 to 2016 to pay down debt left over from the old Ontario Hydro, the province's giant electrical utility that was split into multiple agencies in 1999 under the previous Conservative government.

"The minister can call it whatever he wants but it's right there in the graph, that there is going to be a new charge on the line," Smith said. "It's the debt retirement charge on steroids."

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Great Northern Transmission Line delivers 250 MW of carbon-free hydropower from Manitoba Hydro, strengthening Midwest grid reliability, enabling wind storage balancing, and advancing Minnesota Power's EnergyForward strategy for cleaner, renewable energy across the region.

Key Points

A 500 kV cross-border line delivering 250 MW of carbon-free hydropower, strengthening reliability and enabling renewables.

✅ 500 kV, 224-mile line from Manitoba to Minnesota

✅ Delivers 250 MW hydropower via ALLETE-Minnesota Power

✅ Enables wind storage and grid balancing with Manitoba Hydro

Minnesota Power, a utility division of ALLETE Inc. (NYSE:ALE), has energized its Great Northern Transmission Line, bringing online an innovative delivery and storage system for renewable energy that spans two states and one Canadian province, similar to the Maritime Link project in Atlantic Canada.

The 500 kV line is now delivering 250 megawatts of carbon-free hydropower from Manitoba, Canada, to Minnesota Power customers.

Minnesota Power completed the Great Northern Transmission Line (GNTL) in February 2020, ahead of schedule and under budget. The 224-mile line runs from the Canadian border in Roseau County to a substation near Grand Rapids, Minnesota. It consists of 800 tower structures which were fabricated in the United States and used 10,000 tons of North American steel. About 2,200 miles of wire were required to install the line's conductors. The GNTL also is contributing significant property tax revenue to local communities along the route.

"This is such an incredible achievement for Minnesota Power, ALLETE, and our region, and is the culmination of a decade-long vision brought to life by our talented and dedicated employees," said ALLETE President and CEO Bethany Owen. "The GNTL will help Minnesota Power to provide our customers with 50 percent renewable energy less than a year from now. As part of our EnergyForward strategy, it also strengthens the grid across the Midwest and in Canada, enhancing reliability for all of our customers."

With the GNTL energized and connected to Manitoba Hydro's recently completed Manitoba-Minnesota Transmission Project at the border, the companies now have a unique "wind storage" mechanism that quickly balances energy supply and demand in Minnesota and Manitoba, and enables a larger role for renewables in the North American energy grid.

The GNTL and its delivery of carbon-free hydropower are important components of Minnesota Power's EnergyForward strategy to transition away from coal and add renewable power sources while maintaining reliable and affordable service for customers, echoing interties like the Maritime Link that facilitate regional power flows. It also is part of a broader ALLETE strategy to advance and invest in critical regional transmission and distribution infrastructure, such as the TransWest Express transmission project, to ensure grid integrity and enable cleaner energy to reduce carbon emissions.

"The seed for this renewable energy initiative was planted in 2008 when Minnesota Power proposed purchasing 250 megawatts of hydropower from Manitoba Hydro. Beyond the transmission line, it also included a creative asset swap to move wind power from North Dakota to Minnesota, innovative power purchase agreements, and a remarkable advocacy process to find an acceptable route for the GNTL," said ALLETE Executive Chairman Al Hodnik. "It marries wind and water in a unique connection that will help transform the energy landscape of North America and reduce carbon emissions related to the existential threat of climate change."

Minnesota Power and Manitoba Hydro, a provincial Crown Corporation, coordinated on the project from the beginning, navigating National Energy Board reviews along the way. It is based on the companies' shared values of integrity, environmental stewardship and community engagement.

"The completion of Minnesota Power's Great Northern Transmission Line and our Manitoba-Minnesota Transmission Project is a testament to the creativity, perseverance, cooperation and skills of hundreds of people over so many years on both sides of the border," said Jay Grewal, president and CEO of Manitoba Hydro. "Perhaps even more importantly, it is a testament to the wonderful, longstanding relationship between our two companies and two countries. It shows just how much we can accomplish when we all work together toward a common goal."

Minnesota Power engaged federal, state and local agencies; the sovereign Red Lake Nation and other tribes, reflecting First Nations involvement in major transmission planning; and landowners along the proposed routes beginning in 2012. Through 75 voluntary meetings and other outreach forums, a preferred route was selected with strong support from stakeholders that was approved by the Minnesota Public Utilities Commission in April 2016.

A four-year state and federal regulatory process culminated in late 2016 when the federal Department of Energy approved a Presidential Permit for the GNTL, similar to the New England Clean Power Link process, needed because of the international border crossing. Construction of the line began in early 2017.

"A robust stakeholder process is essential to the success of any project, but especially when building a project of this scope," Owen said. "We appreciated the early engagement and support from stakeholders, local communities and tribes, agencies and regulators through the many approval milestones to the completion of the GNTL."

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Electricity System Climate Resilience underpins grid reliability amid heatwaves and drought, integrating solar, wind, hydropower, nuclear, storage, and demand response with efficient transmission, flexibility, and planning to secure power for homes, industry, and services.

Key Points

Power systems capacity to endure extreme weather and integrate clean energy, maintaining reliability and flexibility.

✅ Grid hardening, transmission upgrades, and digital forecasting.

✅ Flexible low-carbon supply: hydropower, nuclear, storage.

✅ Demand response, efficient cooling, and regional integration.

Summer is just half done in the northern hemisphere and yet we are already seeing electricity systems around the world struggling to cope with the severe strain of heatwaves and low rainfall.

These challenges highlight the urgent need for strong and well-planned policies and investments to improve the security of our electricity systems, which supply power to homes, offices, factories, hospitals, schools and other fundamental parts of our economies and societies. This means making our electricity systems more resilient to the effects of global warming – and more efficient and flexible as they incorporate rising levels of solar and wind power, as solar is now the cheapest electricity in history according to the IEA, which will be critical for reaching net-zero emissions in time to prevent even worse impacts from climate change.

A range of different countries, including the US, Canada and Iraq, have been hard hit by extreme weather recently in the form of unusually high temperatures. In North America, the heat soared to record levels in the Pacific Northwest. An electricity watchdog says that five US regions face elevated risks to the security of their electricity supplies this summer, underscoring US grid climate risks that could worsen, and that California’s risk level is even higher.

Heatwaves put pressure on electricity systems in multiple ways. They increase demand as people turn up air conditioning, driving higher US electricity bills for many households, and as some appliances work harder to maintain cool temperatures. At the same time, higher temperatures can also squeeze electricity supplies by reducing the efficiency and capacity of traditional thermal power plants, such as coal, natural gas and nuclear. Extreme heat can reduce the availability of water for cooling plants or transporting fuel, forcing operators to reduce their output. In some cases, it can result in power plants having to shut down, increasing the risk of outages. If the heat wave is spread over a wide geographic area, it also reduces the scope for one region to draw on spare capacity from its neighbours, since they have to devote their available resources to meeting local demand.

A recent heatwave in Texas forced the grid operator to call for customers to raise their thermostats’ temperatures to conserve energy. Power generating companies suffered outages at much higher rates than expected, providing an unwelcome reminder of February’s brutal cold snap when outages – primarily from natural gas power plants – left up to 5 million customers across the US without power over a period of four days.

At the same time, lower than average rainfall and prolonged dry weather conditions are raising concerns about hydropower’s electricity output in various parts of the world, including Brazil, China, India and North America. The risks that climate change brings in the form of droughts adds to the challenges faced by hydropower, the world’s largest source of clean electricity, highlighting the importance of developing hydropower resources sustainably and ensuring projects are climate resilient.

The recent spate of heatwaves and unusually long dry spells are fresh warnings of what lies ahead as our climate continues to heat up: an increase in the scale and frequency of extreme weather events, which will cause greater impacts and strains on our energy infrastructure.

Heatwaves will increase the challenge of meeting electricity demand while also decarbonizing the electricity supply. Today, the amount of energy used for cooling spaces – such as homes, shops, offices and factories – is responsible for around 1 billion tonnes of global CO2 emissions. In particular, energy for cooling can have a major impact on peak periods of electricity demand, intensifying the stress on the system. Since the energy demand used for air conditioners worldwide could triple by 2050, these strains are set to grow unless governments introduce stronger policy measures to improve the energy efficiency of air conditioning units.

Electricity security is crucial for smooth energy transitions
Many countries around the world have announced ambitious targets for reaching net-zero emissions by the middle of this century and are seeking to step up their clean energy transitions. The IEA’s recent Global Roadmap to Net Zero by 2050 makes it clear that achieving this formidable goal will require much more electricity, much cleaner electricity and for that electricity to be used in far more parts of our economies than it is today. This means electricity reaching much deeper into sectors such as transport (e.g. EVs), buildings (e.g. heat-pumps) and industry (e.g. electric-arc steel furnaces), and in countries like New Zealand's electrification plans it is accelerating broader efforts. As clean electricity’s role in the economy expands and that of fossil fuels declines, secure supplies of electricity become ever-more important. This is why the climate resilience of the electricity sector must be a top priority in governments’ policy agendas.

Changing climate patterns and more frequent extreme weather events can hit all types of power generation sources. Hydropower resources typically suffer in hot and dry conditions, but so do nuclear and fossil fuel power plants. These sources currently help ensure electricity systems have the flexibility and capacity to integrate rising shares of solar and wind power, whose output can vary depending on the weather and the time of day or year.

As governments and utilities pursue the decarbonization of electricity systems, mainly through growing levels of solar and wind, and carbon-free electricity options, they need to ensure they have sufficiently robust and diverse sources of flexibility to ensure secure supplies, including in the event of extreme weather events. This means that the possible decommissioning of existing power generation assets requires careful assessments that take into account the importance of climate resilience.

Ensuring electricity security requires long-term planning and stronger policy action and investment
The IEA is committed to helping governments make well-informed decisions as they seek to build a clean and secure energy future. With this in mind, here are seven areas for action for ensuring electricity systems are as resilient as possible to climate risks:

1. Invest in electricity grids to make them more resilient to extreme weather. Spending today is far below the levels needed to double the investment for cleaner, more electrified energy systems, particularly in emerging and developing economies. Economic recovery plans from the COVID-19 crisis offer clear opportunities for economies that have the resources to invest in enhancing grid infrastructure, but much greater international efforts are required to mobilize and channel the necessary spending in emerging and developing economies.

2. Improve the efficiency of cooling equipment. Cost-effective technology already exists in most markets to double or triple the efficiency of cooling equipment. Investing in higher efficiency could halve future energy demand and reduce investment and operating costs by $3 trillion between now and 2050. In advance of COP26, the Super-Efficient Equipment and Appliance Deployment (SEAD) initiative is encouraging countries to sign up to double the energy efficiency of equipment sold in their countries by 2030.

3. Enable the growth of flexible low-carbon power sources to support more solar and wind. These electricity generation sources include hydropower and nuclear, for countries who see a role for one or both of them in their energy transitions. Guaranteeing hydropower resilience in a warming climate will require sophisticated methods and tools – such as the ones implemented in Brazil – to calculate the necessary level of reserves and optimize management of reservoirs and hydropower output even in exceptional conditions. Batteries and other forms of storage, combined with solar or wind, can also provide important amounts of flexibility by storing power and releasing it when needed.

4. Increase other sources of electricity system flexibility. Demand-response and digital technologies can play an important role. The IEA estimates that only a small fraction of the huge potential for demand response in the buildings sector is actually tapped at the moment. New policies, which associate digitalization and financial behavioural incentives, could unlock more flexibility. Regional integration of electricity systems across national borders can also increase access to flexible resources.

5. Expedite the development and deployment of new technologies for managing extreme weather threats. The capabilities of electricity utilities in forecasting and situation awareness should be enhanced with the support of the latest information and communication technologies.

6. Make climate resilience a central part of policy-making and system planning. The interconnected nature of recent extreme weather events reminds us that we need to account for many contingencies when planning resilient power systems. Climate resilience should be integral to policy-making by governments and power system planning by utilities and relevant industries, and debates over Canadian climate policy underscore how grid implications must be considered. According to the recent IEA report on climate resilience, only nine out of 38 IEA member and association countries include concrete actions on climate adaptation and resilience for every segment of electricity systems.

7. Strengthen international cooperation on electricity security. Electricity underpins vital services and basic needs, such as health systems, water supplies and other energy industries. Maintaining a secure electricity supply is thus of critical importance. The costs of doing nothing in the face of growing climate threats are becoming abundantly clear. The IEA is working with all countries in the IEA family, as well as others around the world, by providing unrivalled data, analysis and policy advice on electricity security issues. It is also bringing governments together at various levels to share experiences and best practices, and identify how to hasten the shift to cleaner and more resilient energy systems.

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Hurricane Grid Resilience examines how utilities manage outages with renewables, microgrids, and robust transmission and distribution systems, balancing solar, wind, and batteries to restore service, harden infrastructure, and improve storm response and recovery.

Key Points

Hurricane grid resilience is a utility approach to withstand storms, reduce outages, and speed safe power restoration.

✅ Focus on T&D hardening, vegetation management, remote switching

✅ Balance generation mix; integrate solar, wind, batteries, microgrids

✅ Plan 12-hour shifts; automate forecasting and outage restoration

When operators of Duke Energy's control room in Raleigh, North Carolina wait for a hurricane, the mood is often calm in the hours leading up to the storm.

“Things are usually fairly quiet before the activity starts,” said Mark Goettsch, the systems operations manager at Duke. “We’re anxiously awaiting the first operation and the first event. Once that begins, you get into storm mode.”

Then begins a “frenzied pace” that can last for days — like when Hurricane Florence parked over Duke’s service territory in September.

When an event like Florence hits, all eyes are on transmission and distribution. Where it’s available, Duke uses remote switching to reconnect customers quickly. As outages mount, the utility forecasts and balances its generation with electricity demand.

The control center’s four to six operators work 12-hour shifts, while nearby staff members field thousands of calls and alarms on the system. After it’s over, “we still hold our breath a little bit to make sure we’ve operated everything correctly,” said Goettsch. Damage assessment and rebuilding can only begin once a storm passes.

That cycle is becoming increasingly common in utility service areas like Duke's.

A slate of natural disasters that reads like a roll call — Willa, Michael, Harvey, Irma, Maria, Florence and Thomas — has forced a serious conversation about resiliency. And though Goettsch has heard a lot about resiliency as a “hot topic” at industry events and meetings, those conversations are only now entering Duke’s control room.

Resilience discussions come and go in the energy industry. Storms like Hurricane Sandy and Matthew can spur a nationwide focus on resiliency, but change is largely concentrated in local areas that experienced the disaster. After a few news cycles, the topic fades into the background.

However, experts agree that resilience is becoming much more important to year-round utility planning and operations as utilities pursue decarbonization goals across their fleets. It's not a fad.

“If you look at the whole ecosystem of utilities and vendors, there’s a sense that there needs to be a more resilient grid,” said Miki Deric, Accenture’s managing director of utilities, transmission and distribution for North America. “Even if they don’t necessarily agree on everything, they are all working with the same objective.”

Can renewables meet the challenge?

After Hurricane Florence, The Intercept reported on coal ash basins washed out by the storm’s overwhelming waters. In advance of that storm, Duke shut down one nuclear plant to protect it from high winds. The Washington Post also recently reported on a slowly leaking oil spill, which could surpass Deepwater Horizon in size, caused by Hurricane Ivan in 2004.

Clean energy boosters have seized on those vulnerabilities.They say solar and wind, which don’t rely on access to fuel and can often generate power immediately after a storm, provide resilience that other electricity sources do not.

“Clearly, logistics becomes a big issue on fossil plants, much more than renewable,” said Bruce Levy, CEO and president at BMR Energy, which owns and operates clean energy projects in the Caribbean and Latin America. “The ancillaries around it — the fuel delivery, fuel storage, water in, water out — are all as susceptible to damage as a renewable plant.”

Duke, however, dismissed the notion that one generation type could beat out another in a serious storm.

“I don’t think any generation source is immune,” said Duke spokesperson Randy Wheeless. “We’ve always been a big supporter of a balanced energy mix, reflecting why the grid isn't 100% renewable in practice today. That’s going to include nuclear and natural gas and solar and renewables as well. We do that because not every day is a good day for each generation source.”

In regard to performance, Wade Schauer, director of Americas Power & Renewables Research at Wood Mackenzie, said the situation is “complex.” According to him, output of solar and wind during a storm depends heavily on the event and its location.

While comprehensive data on generation performance is sparse, Schauer said coal and gas generators could experience outages at 25 percent while stormy weather might cut 95 percent of output from renewables, underscoring clean energy's dirty secret about variability under stress. Ahead of last year’s “bomb cyclone” in New England, WoodMac data shows that wind dropped to less than 1 percent of the supply mix.

“When it comes to resiliency, ‘average performance’ doesn't cut it,” said Schauer.

In the future, he said high winds could impact all U.S. offshore wind farms, since projects are slated for a small geographic area in the Northeast. He also pointed to anecdotal instances of solar arrays in New England taken out by feet of snow. During Florence, North Carolina’s wind farms escaped the highest winds and continued producing electricity throughout. Cloud cover, on the other hand, pushed solar production below average levels.

After Florence passed, Duke reported that most of its solar came online quickly, although four of its utility-owned facilities remained offline for weeks afterward. Only one was because of damage; the other three remained offline due to substation interconnection issues.

“Solar performed pretty well,” said Wheeless. “But did it come out unscathed? No.”

According to installer reports, solar systems fared relatively well in recent storms, even as the Covid-19 impact on renewables constrained projects worldwide. But the industry has also highlighted potential improvements. Following Hurricanes Maria and Irma, the Federal Emergency Management Agency published guidelines for installing and maintaining storm-resistant solar arrays. The document recommended steps such as annual checks for bolt tightness and using microinverters rather than string inverters.

Rocky Mountain Institute (RMI) also assembled a guide for retrofitting and constructing new installations. It described attributes of solar systems that survived storms, like lateral racking supports, and those that failed, like undersized and under-torqued bolts.

“The hurricanes, as much as no one liked them, [were] a real learning experience for folks in our industry,” said BMR’s Levy. “We saw what worked, and what didn’t.”          

Facing the "800-pound gorilla" on the grid

Advocates believe wind, solar, batteries and microgrids offer the most promise because they often rely less on transmitting electricity long distances and could support peer-to-peer energy models within communities.

Most extreme weather outages arise from transmission and distribution problems, not generation issues. Schauer at WoodMac called storm damage to T&D the “800-pound gorilla.”

“I'd be surprised if a single customer power outage was due to generators being offline, especially since loads where so low due to mild temperatures and people leaving the area ahead of the storm,” he said of Hurricane Florence. “Instead, it was wind [and] tree damage to power lines and blown transformers.”

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