Reunion island aims to be zero CO2

By Reuters


NFPA 70e Training

Our customized live online or in‑person group training can be delivered to your staff at your location.

  • Live Online
  • 6 hours Instructor-led
  • Group Training Available
Regular Price:
$199
Coupon Price:
$149
Reserve Your Seat Today
Ringed by volcanic rock, sandy beaches and the blue swell of the Indian Ocean, France's Reunion island is hardly a major polluter.

But hit by rising fuel costs and worried about the impact of global warming, particularly on its delicate flora and fauna, the small island nation has set itself the ambitious goal of cutting its greenhouse gas emissions to zero.

By 2025, the French territory wants to use renewable energy sources to produce 100 percent of its electricity, and to power all of its transport by 2050.

"We have water, sunshine, we even have an active volcano. We have more energy than we need for our development," Paul Verges, president of Reunion's regional council, said after Group of Eight (G8) leaders agreed a 50 percent cut in carbon dioxide (CO2) emissions by 2050.

"We will be fighting 100 percent against CO2 at the same date that you (the G8 rich nations) will be at 50 percent," Verges told journalists in July on the sidelines of a biodiversity conference.

Some 36 percent of Reunion's electricity already comes from renewables, mostly hydroenergy and sugar cane fiber, bagasse.

But it wants to boost that figure by expanding its existing sources, cutting inefficiencies and exploring new technologies.

"What's possible in Reunion should also be possible in France, and should also be possible for the planet," France's Overseas Territories Minister Yves Jego told Reuters.

Reunion is expanding its photovoltaic, hydro and wind energy projects to produce up to 750 megawatts (MW), 120 MW and 60 MW respectively, said Jules Dieudonne, head of the Regional Plan for Renewable Energies and the Rational Use of Energy (PRERURE).

"Our ambition is to have 750 hectares of (photovoltaic) panels eventually installed," he said.

Some 115 million euros ($180 million) of public money is being spent between 2007 and 2017 to reach the targets, while preferential costings mean private energy firms get more money to produce electricity from renewable sources than from fossil fuels, he added.

"Today, we (wind energy) are at about 15 megawatts, 16 megawatts. So there are other projects, which are feasible," Serge Borchiellini, the Reunion representative for renewable energy firm Aerowatt, told Reuters, as an onshore breeze made wind turbines behind him whirr.

Biomass from sugar cane fiber and waste will also be part of Reunion's power future, while scientists are testing the potential of hydrogen, geothermal energy from La Piton de la Fournaise, one of the world's most active volcanoes, and even ocean energy.

Dieudonne said the temperature difference between sea water at the surface and at a 1,000-metre depth is about 22 degrees Celsius (71F).

"This difference in temperature can allow us to make electric energy," he said, also citing possible kinetic energy from the ocean swell.

But as in other countries, the island's rapidly growing energy demands threaten to delay the targets.

Living mostly along the coastline, Reunion's population is set to grow more than 20 percent to more than one million people by 2030 from about 800,000 at present.

Reunion's average energy consumption per person is growing at 5 percent per year, according to official figures.

"The big problem in Reunion is the summer heat - everybody wants air conditioning," said Pierre-Yves Ezavin of Reunion's Regional Energy Agency (ARER), adding air conditioning accounts for about 80 percent of office electricity bills.

While Reunion's traditional homes made good use of wood and plenty of windows, low-cost housing of recent years was built with concrete using cheaper methods that trap the heat inside. "We have to take care of construction," Ezavin said.

His agency is running a public information campaign to encourage the use of green technologies such as better construction methods and materials, solar water heaters - already a common sight - and bicycles. But attitudes are slow to change.

"We've heard about it (renewable energy). I don't know what to think," Jean-Francois Sery, a taxi driver, said.

"It hasn't yet entered people's thinking," he said, adjusting his air conditioning while he waited in a traffic jam that snaked along the coastal road.

Accounting for 70 to 75 percent of Reunion's energy use, transport is the key issue for reducing its greenhouse gases.

And seeking to counter the extra 30,000 cars - about 10 percent of existing traffic - that appear on Reunion's congested roads every year, the island is set to complete the first 34-km (21-mile) phase of an electrically powered tram-train by 2013 at a cost of 1.4 billion euros, PREURE's Dieudonne said.

Ironically perhaps, Reunion is also building an enormous road in the west, la Route des Tamarins, in a bid to ease congestion. And with tourism a major source of jobs and income, airplanes are not part of Reunion's energy targets.

"Our ambition is not to invent a new (carbon neutral) airplane. Our ambition is to do everything we can do in Reunion to become independent of fossil fuels," Dieudonne said.

Related News

U.S. Speeds Up Permitting for Geothermal Energy

Geothermal Emergency Permitting accelerates BLM approvals on public lands via categorical exclusions for exploratory drilling and geophysical surveys, boosting domestic energy security, cutting timelines by up to a year, and streamlining low-impact reviews.

 

Key Points

A policy fast-tracking geothermal exploration on public lands, using BLM categorical exclusions to cut review delays.

✅ Categorical exclusions speed exploratory drilling approvals

✅ Cuts permitting timelines by up to one year

✅ Focused on public lands to enhance energy security

 

In a significant policy shift, the U.S. Department of the Interior has introduced emergency permitting procedures aimed at expediting the development of geothermal energy projects. This initiative, announced on May 30, 2025, is part of a broader strategy to enhance domestic energy production, seen in proposals to replace Obama's power plant overhaul and reduce reliance on foreign energy sources.

Background and Rationale

The decision to fast-track geothermal energy projects comes in the wake of President Donald Trump's declaration of a national energy emergency, which faces a legal challenge from Washington's attorney general, on January 20, 2025. This declaration cited high energy costs and an unreliable energy grid as threats to national security and economic prosperity. While the emergency order includes traditional energy resources such as oil, gas, coal, and uranium and nuclear energy resources, it notably excludes renewable sources like solar, wind, and hydrogen from its scope.

Geothermal energy, which harnesses heat from beneath the Earth's surface to generate electricity, is considered a reliable and low-emission energy source. However, its development has been hindered by lengthy permitting processes and environmental reviews, with recent NEPA rule changes influencing timelines. The new emergency permitting procedures aim to address these challenges by streamlining the approval process for geothermal projects.

Key Features of the Emergency Permitting Procedures

Under the new guidelines, the Bureau of Land Management (BLM) has adopted categorical exclusions to expedite the review and approval of geothermal energy exploration on public lands. These exclusions allow for faster permitting of low-impact activities, such as drilling exploratory wells and conducting geophysical surveys, without the need for extensive environmental assessments.

Additionally, the BLM has proposed a new categorical exclusion that would apply to operations related to the search for indirect evidence of geothermal resources. This proposal is currently open for public comment and, if finalized, would further accelerate the discovery of new geothermal resources on public lands.

Expected Impact on Geothermal Energy Development

The implementation of these emergency permitting procedures is expected to significantly reduce the time and cost associated with developing geothermal energy projects. According to the Department of the Interior, the new measures could cut permitting timelines by up to a year for certain types of geothermal exploration activities.

This acceleration in project development is particularly important given the untapped geothermal potential in regions like Nevada, which is home to some of the largest undeveloped geothermal resources in the country.

Industry and Environmental Reactions

The geothermal industry has largely welcomed the new permitting procedures, viewing them as a necessary step to unlock the full potential of geothermal energy. Industry advocates argue that reducing permitting delays will facilitate the deployment of geothermal projects, contributing to a more reliable and sustainable energy grid amid debates over electricity pricing changes that affect market signals.

However, the exclusion of solar and wind energy projects from the emergency permitting procedures has drawn criticism from some environmental groups. Critics argue that a comprehensive approach to energy development should include all renewable sources, not just geothermal, to effectively address climate change, as reflected in new EPA pollution limits for coal and gas power plants, and promote energy sustainability.

The U.S. government's move to implement emergency permitting procedures for geothermal energy development marks a significant step toward enhancing domestic energy production and reducing reliance on foreign energy sources. By streamlining the approval process for geothermal projects, the administration aims to accelerate the deployment of this reliable and low-emission energy source. While the exclusion of other renewable energy sources from the emergency procedures has sparked debate, especially after states like California halted an energy rebate program during a federal freeze, the focus on geothermal energy underscores its potential role in the nation's energy future.

 

Related News

View more

Drought, lack of rain means BC Hydro must adapt power generation

BC Hydro drought operations address climate change impacts with hydropower scheduling, reservoir management, water conservation, inflow forecasting, and fish habitat protection across the Lower Mainland and Vancouver Island while maintaining electricity generation from storage facilities.

 

Key Points

BC Hydro drought operations conserve water, protect fish, and sustain hydropower during extended heat and low inflows.

✅ Proactive reservoir releases protect downstream salmon spawning.

✅ Reduced flows at Puntledge, Coquitlam, and Ruskin/Stave facilities.

✅ System relies on northern storage to maintain electricity supply.

 

BC Hydro is adjusting its operating plans around power generation as extended heat and little forecast rain continue to impact the province, a report says.

“Unpredictable weather patterns related to climate change are expected to continue in the years ahead and BC Hydro is constantly adapting to these evolving conditions, especially after events such as record demand in 2021 that tested the grid,” said the report, titled “Casting drought: How climate change is contributing to uncertain weather and how BC Hydro’s generation system is adapting.”

The study said there is no concern with BC Hydro being able to continue to deliver power through the drought because there is enough water at its larger facilities, even as issues like crypto mining electricity use draw scrutiny from observers.

Still, it said, with no meaningful precipitation in the forecast, its smaller facilities in the Lower Mainland and on Vancouver Island will continue to see record low or near record low inflows for this time of the year.

“In the Lower Mainland, inflows since the beginning of September are ranked in the bottom three compared to historical records,” the report said.

The report said the hydroelectric system is directly impacted by variations in weather and the record-setting, unseasonably dry and warm weather this fall highlights the impacts of climate change, while demand patterns can be counterintuitive, as electricity use even increased during Earth Hour 2018 in some areas, hinting at challenges to come.

It noted symptoms of climate change include increased frequency of extreme events like drought and intense storms, and rapid glacial melt.

“With the extremely hot and dry conditions, BC Hydro has been taking proactive steps at many of our South Coast facilities for months to conserve water to protect the downstream fish habit,” spokesperson Mora Scott said. “We began holding back water in July and August at some facilities anticipating the dry conditions to help ensure we would have water storage for the later summer and early fall salmon spawning.”

Scott said BC Hydro’s reservoirs play an important role in managing these difficult conditions by using storage and planning releases to provide protection to downstream river flows. The reservoirs are, in effect, a battery waiting to be used for power.

While the dry conditions have had an impact on BC Hydro’s watersheds, several unregulated natural river systems — not related to BC Hydro — have fared worse, with rivers drying up and thousands of fish killed, the report said.

BC Hydro is currently seeing the most significant impacts on operations at Puntledge and Campbell River on Vancouver Island as well as Coquitlam and Ruskin/Stave in the Lower Mainland.

To help manage water levels on Vancouver Island, BC Hydro reduced Puntledge River flows by one-third last week and on the Lower Mainland reduced flows at Coquitlam by one-third and Ruskin/Stave by one quarter.

However, the utility company said, there are no concerns about continued power delivery.

“British Columbians benefit from BC Hydro’s integrated, provincial electricity system, which helps send power across the province, including to Vancouver Island, and programs like the winter payment plan support customers during colder months,” staff said.

Most of the electricity generated and used in B.C. is produced by larger facilities in the north and southeast of the province — and while water levels in those areas are below normal levels, there is enough water to meet the province’s power needs, even as additions like Site C's electricity remain a subject of debate among observers.

The Glacier Media investigation found a quarter of BC Hydro's power comes from the Mica, Revelstoke and Hugh Keenleyside dams on the Columbia River. Some 29% comes from dams in the Peace region, including the under-construction Site C project that has faced cost overruns. At certain points of the year, those reservoirs are reliant on glacier water.

Still, BC Hydro remains optimistic.

Forecasts are currently showing little rain in the near-term; however, historically, precipitation and inflows show up by the end of October. If that does not happen, BC Hydro said it would continue to closely track weather and inflow forecasts to adapt its operations to protect fish, while regional cooperation such as bridging with Alberta remains part of broader policy discussions.

Among things BC Hydro said it is doing to adapt are:

Continuously working to improve its weather and inflow forecasting;
Expanding its hydroclimate monitoring technology, including custom-made solutions that have been designed in-house, as well as upgrading snow survey stations to automated, real-time snow and climate stations, and;
Investing in capital projects — like spillway gate replacements — that will increase resiliency of the system to climate change.

 

Related News

View more

Ottawa sets out to protect its hydro heritage

Ottawa Hydro Substation Heritage Designation highlights Hydro Ottawa's 1920s architecture, Art Deco facades, and municipal utility history, protecting key voltage-reduction sites in Glebe, Carling-Merivale, Holland, King Edward, and Old Ottawa South.

 

Key Points

A city plan to protect Hydro Ottawa's 1920s substations for architecture, utility role, and civic electrical heritage.

✅ Protects five operating voltage-reduction sites citywide

✅ Recognizes Art Deco and early 20th century utility architecture

✅ Allows emergency demolition to ensure grid safety

 

The city of Ottawa is looking to designate five hydro substations built nearly a century ago as heritage structures, a move intended to protect the architectural history of Ottawa's earliest forays into the electricity business, even as Ottawa electricity consumption has shifted in recent years.

All five buildings are still used by Hydro Ottawa to reduce the voltage coming from transmission lines before the electricity is transmitted to homes and businesses, and when severe weather causes outages, Sudbury Hydro crews work to reconnect service across communities.

Electricity came to Ottawa in 1882 when two carbon lamps were installed on LeBreton Flats, heritage planner Anne Fitzpatrick told the city's built heritage subcommittee on Tuesday. It became a lucrative business, and soon a privately owned monopoly that drew public scrutiny similar to debates over retroactive charges in neighboring jurisdictions.

In 1905, city council held a special meeting to buy the electrical company, which led to a dramatic drop in electricity rates for residents, a contrast with recent discussions about peak hydro rates for self-isolating customers.

The substations are now owned by Hydro Ottawa, which agreed to the heritage designations on the condition it not be prevented from emergency demolitions if it needs to address incidents such as damaging storms in Ontario while it works to "preserve public safety and the continuity of critical hydro electrical services."

Built in 1922, the substation at the intersection of Glebe and Bronson avenues was the first to be built by the new municipal electrical department, long before modern battery storage projects became commonplace on Ontario's grid.

The largest of the substations being protected dates back to 1929 and is found at the corner of Carling Avenue and Merivale Road. It was built to accommodate a growing population in areas west of downtown including Hintonburg and Mechanicsville.

The substation on Holland Avenue near the Queensway is different from the others because it was built in 1924 to serve the Ottawa Electric Railway Company. The streetcar company operated from 1891 to 1959, and urban electrical infrastructure can face failures such as the Hydro-Québec manhole fire that left thousands without power.

This substation on King Edward Avenue was built in 1931 and designed by architect William Beattie, who also designed York Street Public School in Lowertown and the substation on Carling Avenue. 

The last substation to be built in a 'bold and decorative style' is at 39 Riverdale Ave. in Old Ottawa South, according to city staff. It was designed in an Art Deco style by prominent architect J. Albert Ewart, who was also behind the Civic Hospital and nearby Southminster Church on Bank Street.

 

Related News

View more

Stellat'en and Innergex Sign Wind Deal with BC Hydro

Nithi Mountain Wind Project delivers 200 MW of renewable wind power in British Columbia under a BC Hydro electricity purchase deal, producing 600 GWh yearly, led by Stellat'en First Nation and Innergex.

 

Key Points

A 200 MW wind farm in British Columbia producing 600 GWh yearly, co-owned by Stellat'en First Nation and Innergex.

✅ 30-year BC Hydro take-or-pay PPA, CPI-indexed

✅ 200 MW capacity, ~600 GWh per year for ~60,000 homes

✅ 51% Stellat'en First Nation; operations targeted for 2030

 

In December 2024, a significant development unfolded in British Columbia's renewable energy sector, where the clean-energy regulatory process continues to evolve, as Stellat'en First Nation and Innergex Renewable Energy Inc. announced the signing of a 30-year electricity purchase agreement with BC Hydro. This agreement pertains to the Nithi Mountain Wind Project, a 200 MW initiative poised to enhance the province's clean energy capacity.

Project Overview

The Nithi Mountain Wind Project is a collaborative venture between Stellat'en First Nation, which holds a 51% stake, and Innergex Renewable Energy Inc., which holds a 49% stake. Located in the Bulkley-Nechako region of British Columbia, the project is expected to generate approximately 600 GWh of renewable electricity annually, comparable to other large-scale projects like the 280 MW wind farm in Alberta now online, sufficient to power around 60,000 homes. The wind farm is scheduled to commence commercial operations in 2030.

Economic and Community Impact

This partnership is anticipated to create approximately 150 job opportunities during the development, construction, and operational phases, thereby supporting local economic growth and workforce development, and aligns with recent federal green electricity procurement efforts that signal broader market support. The long-term electricity purchase agreement with BC Hydro is structured as a 30-year take-or-pay contract, indexed to a predefined percentage of the Consumer Price Index (CPI), ensuring financial stability and protection against inflation.

Environmental and Cultural Considerations

The Nithi Mountain Wind Project is being developed in close collaboration with First Nations in the area, guided by collaborative land-use planning. The project integrates cultural preservation, environmental stewardship, and economic empowerment for Indigenous communities in the Bulkley-Nechako region, while other solutions such as tidal energy for remote communities are also advancing across Canada. The project is committed to minimizing environmental impact by avoiding sensitive cultural and ecological resources and integrating sustainability at every stage, with remediation practices to restore the land, preserve cultural values, and enhance biodiversity and wildlife habitats if decommissioned.

Broader Implications

This agreement underscores a growing trend of collaboration between Indigenous communities, exemplified by the Ermineskin First Nation project emerging nationwide, and renewable energy developers in Canada. Such partnerships are instrumental in advancing sustainable energy projects that respect Indigenous rights and contribute to the nation's clean energy objectives, as renewable power developers find that diversified energy sources strengthen project outcomes. The Nithi Mountain Wind Project exemplifies how integrating traditional knowledge with modern renewable energy technologies can lead to mutually beneficial outcomes for both Indigenous communities and the broader society.

In summary, the Nithi Mountain Wind Project represents a significant step forward in British Columbia's renewable energy landscape, highlighting the importance of collaboration between Indigenous communities and renewable energy developers. The project promises substantial economic, environmental, and cultural benefits, setting a precedent for future partnerships in the clean energy sector, as large-scale storage acquisitions like Centrica's battery project illustrate complementary pathways to unlock wind potential.

 

Related News

View more

How Ukraine Unplugged from Russia and Joined Europe's Power Grid with Unprecedented Speed

Ukraine-ENTSO-E Grid Synchronization links Ukraine and Moldova to the European grid via secure interconnection, matching frequency for stability, resilience, and energy security, enabling cross-border support, islanding recovery, and coordinated load balancing during wartime disruptions.

 

Key Points

Rapid alignment of Ukraine and Moldova into the European grid to enable secure interconnection and system stability.

✅ Matches 50 Hz frequency across interconnected systems

✅ Enables cross-border support and electricity trading

✅ Improves resilience, stability, and energy security

 

On February 24 Ukraine’s electric grid operator disconnected the country’s power system from the larger Russian-operated network to which it had always been linked. The long-planned disconnection was meant to be a 72-hour trial proving that Ukraine could operate on its own and to protect electricity supply before winter as contingencies were tested. The test was a requirement for eventually linking with the European grid, which Ukraine had been working toward since 2017. But four hours after the exercise started, Russia invaded.

Ukraine’s connection to Europe—which was not supposed to occur until 2023—became urgent, and engineers aimed to safely achieve it in just a matter of weeks. On March 16 they reached the key milestone of synchronizing the two systems. It was “a year’s work in two weeks,” according to a statement by Kadri Simson, the European Union commissioner for energy. That is unusual in this field. “For [power grid operators] to move this quickly and with such agility is unprecedented,” says Paul Deane, an energy policy researcher at the University College Cork in Ireland. “No power system has ever synchronized this quickly before.”

Ukraine initiated the process of joining Europe’s grid in 2005 and began working toward that goal in earnest in 2017, as did Moldova. It was part of an ongoing effort to align with Europe, as seen in the Baltic states’ disconnection from the Russian grid, and decrease reliance on Russia, which had repeatedly threatened Ukraine’s sovereignty. “Ukraine simply wanted to decouple from Russian dominance in every sense of the word, and the grid is part of that,” says Suriya Jayanti, an Eastern European policy expert and former U.S. diplomat who served as energy chief at the U.S. embassy in Kyiv from 2018 to 2020.

After the late February trial period, Ukrenergo, the Ukrainian grid operator, had intended to temporarily rejoin the system that powers Russia and Belarus. But the Russian invasion made that untenable. “That left Ukraine in isolation mode, which would be incredibly dangerous from a power supply perspective,” Jayanti says. “It means that there’s nowhere for Ukraine to import electricity from. It’s an orphan.” That was a particularly precarious situation given Russian attacks on key energy infrastructure such as the Zaporizhzhia nuclear power plant and ongoing strikes on Ukraine’s power grid that posed continuing risks. (According to Jayanti, Ukraine’s grid was ultimately able to run alone for as long as it did because power demand dropped by about a third as Ukrainians fled the country.)

Three days after the invasion, Ukrenergo sent a letter to the European Network of Transmission System Operators for Electricity (ENTSO-E) requesting authorization to connect to the European grid early. Moldelectrica, the Moldovan operator, made the same request the following day. While European operators wanted to support Ukraine, they had to protect their own grids, amid renewed focus on protecting the U.S. power grid from Russian hacking, so the emergency connection process had to be done carefully. “Utilities and system operators are notoriously risk-averse because the job is to keep the lights on, to keep everyone safe,” says Laura Mehigan, an energy researcher at University College Cork.

An electric grid is a network of power-generating sources and transmission infrastructure that produces electricity and carries it from places such as power plants, wind farms and solar arrays to houses, hospitals and public transit systems. “You can’t just experiment with a power system and hope that it works,” Deane says. Getting power where it is it needed when it is needed is an intricate process, and there is little room for error, as incidents involving Russian hackers targeting U.S. utilities have highlighted for operators worldwide.

Crucial to this mission is grid interconnection. Linked systems can share electricity across vast areas, often using HVDC technology, so that a surplus of energy generated in one location can meet demand in another. “More interconnection means we can move power around more quickly, more efficiently, more cost effectively and take advantage of low-carbon or zero-carbon power sources,” says James Glynn, a senior research scholar at the Center on Global Energy Policy at Columbia University. But connecting these massive networks with many moving parts is no small order.

One of the primary challenges of interconnecting grids is synchronizing them, which is what Ukrenergo, Moldelectrica and ENTSO-E accomplished last week. Synchronization is essential for sharing electricity. The task involves aligning the frequencies of every energy-generation facility in the connecting systems. Frequency is like the heartbeat of the electric grid. Across Europe, energy-generating turbines spin 50 times per second in near-perfect unison, and when disputes disrupt that balance, slow clocks across Europe can result, reminding operators of the stakes. For Ukraine and Moldova to join in, their systems had to be adjusted to match that rhythm. “We can’t stop the power system for an hour and then try to synchronize,” Deane says. “This has to be done while the system is operating.” It is like jumping onto a moving train or a spinning ride at the playground: the train or ride is not stopping, so you had better time the jump perfectly.

 

Related News

View more

Was there another reason for electricity shutdowns in California?

PG&E Wind Shutdown and Renewable Reliability examines PSPS strategy, wildfire risk, transmission line exposure, wind turbine cut-out speeds, grid stability, and California's energy mix amid historic high-wind events and supply constraints across service areas.

 

Key Points

An overview of PG&E's PSPS decisions, wildfire mitigation, and how wind cut-out limits influence grid reliability.

✅ Wind turbines reach cut-out near 55 mph, reducing generation.

✅ PSPS mitigates ignition from damaged transmission infrastructure.

✅ Baseload diversity improves resilience during high-wind events.

 

According to the official, widely reported story, Pacific Gas & Electric (PG&E) initiated power shutoffs across substantial portions of its electric transmission system in northern California as a precautionary measure.

Citing high wind speeds they described as “historic,” the utility claims that if it didn’t turn off the grid, wind-caused damage to its infrastructure could start more wildfires.

Perhaps that’s true. Perhaps. This tale presumes that the folks who designed and maintain PG&E’s transmission system are unaware of or ignored the need to design it to withstand severe weather events, and that the Federal Energy Regulatory Commission (FERC) and North American Electric Reliability Corp. (NERC) allowed the utility to do so.

Ignorance and incompetence happens, to be sure, but there’s much about this story that doesn’t smell right—and it’s disappointing that most journalists and elected officials are apparently accepting it without question.

Take, for example, this statement from a Fox News story about the Kincade Fires: “A PG&E meteorologist said it’s ‘likely that many trees will fall, branches will break,’ which could damage utility infrastructure and start a fire.”

Did you ever notice how utilities cut wide swaths of trees away when transmission lines pass through forests? There’s a reason for that: When trees fall and branches break, the grid can still function, and even as the electric rhythms of New York City shifted during COVID-19, operators planned for variability.

So, if badly designed and poorly maintained infrastructure isn’t the reason PG&E cut power to millions of Californians, what might have prompted them to do so? Could it be that PG&E’s heavy reliance on renewable energy means they don’t have the power to send when a “historic” weather event occurs, especially as policymakers weigh the postponed closure of three power plants elsewhere in California?

 

Wind Speed Limits

The two most popular forms of renewable energy come with operating limitations, which is why some energy leaders urge us to keep electricity options open when planning the grid. With solar power, the constraint is obvious: the availability of sunlight. One doesn’t generate solar power at night and energy generation drops off with increasing degrees of cloud cover during the day.

The main operating constraint of wind power is, of course, wind speed, and even in markets undergoing 'transformative change' in wind generation, operators adhere to these technical limits. At the low end of the scale, you need about a 6 or 7 miles-per-hour wind to get a turbine moving. This is called the “cut-in speed.” To generate maximum power, about a 30 mph wind is typically required. But, if the wind speed is too high, the wind turbine will shut down. This is called the “cut-out speed,” and it’s about 55 miles per hour for most modern wind turbines.

It may seem odd that wind turbines have a cut-out speed, but there’s a very good reason for it. Each wind turbine rotor is connected to an electric generator housed in the turbine nacelle. The connection is made through a gearbox that is sized to turn the generator at the precise speed required to produce 60 Hertz AC power.

The blades of the wind turbine are airfoils, just like the wings of an airplane. Adjusting the pitch (angle) of the blades allows the rotor to maintain constant speed, which, in turn, allows the generator to maintain the constant speed it needs to safely deliver power to the grid. However, there’s a limit to blade pitch adjustment. When the wind is blowing so hard that pitch adjustment is no longer possible, the turbine shuts down. That’s the cut-out speed.

Now consider how California’s power generation profile has changed. According to Energy Information Administration data, the state generated 74.3 percent of its electricity from traditional sources—fossil fuels and nuclear, amid debates over whether to classify nuclear as renewable—in 2001. Hydroelectric, geothermal, and biomass-generated power accounted for most of the remaining 25.7 percent, with wind and solar providing only 1.98 percent of the total.

By 2018, the state’s renewable portfolio had jumped to 43.8 percent of total generation, with clean power increasing and wind and solar now accounting for 17.9 percent of total generation. That’s a lot of power to depend on from inherently unreliable sources. Thus, it wouldn’t be at all surprising to learn that PG&E didn’t stop delivering power out of fear of starting fires, but because it knew it wouldn’t have power to deliver once high winds shut down all those wind turbines

 

Related News

View more

Sign Up for Electricity Forum’s Newsletter

Stay informed with our FREE Newsletter — get the latest news, breakthrough technologies, and expert insights, delivered straight to your inbox.

Electricity Today T&D Magazine Subscribe for FREE

Stay informed with the latest T&D policies and technologies.
  • Timely insights from industry experts
  • Practical solutions T&D engineers
  • Free access to every issue

Download the 2025 Electrical Training Catalog

Explore 50+ live, expert-led electrical training courses –

  • Interactive
  • Flexible
  • CEU-cerified