AFP UK

Emmanuel Mignot, professor of sleep medicine at Stanford University, and his narcoleptic dog, Watson

Emmanuel Mignot is one of the world’s leading experts on narcolepsy, a sleep disorder that he finds both “strange” and “fascinating.”

The French-born Mignot has dedicated his life to studying the causes of narcolepsy and shedding light on one of the great biological mysteries — sleep.

His discovery of the genetic and molecular causes of the disorder led to his receiving a prestigious Breakthrough Prize on Thursday along with Japan’s Masashi Yanagisawa, who made related findings around the same time.

Because of their discoveries, new treatments for narcolepsy — which causes people to suddenly fall asleep — and other sleep disorders are being developed.

About one in every 2,000 people suffers from narcolepsy. Some may experience catalepsy — a sudden trance-like state.

“I am quite proud because what I have discovered is making an enormous difference for my patients,” Mignot said in a telephone interview with AFP. “It’s the best reward that one could receive.”

The 63-year-old Mignot is a sleep researcher at Stanford University in California.

Thirty years ago, when he was a medical student, Mignot fulfilled his military service requirements in France by coming to Stanford to study a French-made drug that was being used to treat narcolepsy.

At the time, he said, the disease was “virtually unknown” and no one was actively studying it.

He became “completely fascinated.”

“I told myself it’s incredible, this disease, people fall asleep all the time, we have no idea why, and if we could discover the cause we might understand something new about sleep.”

Stanford was already home to a renowned sleep center and its laboratory housed narcoleptic dogs, which Mignot began studying in an effort to find a genetic cause of the disease.

Genome sequencing was very primitive at that time and “everybody told me I was crazy,” said Mignot, who currently has an adopted narcoleptic dog called Watson.

“I thought it would take a few years and it ended up taking 10.”

In 1999, Mignot found a mutation in the genome of narcoleptic dogs. It was located on membrane receptors in the brain that respond to molecules outside the cell, similar to a lock and a key.

– ‘Remake a key’ –

The Japanese scientist Yanagisawa, meanwhile, had been studying orphan receptors — receptors of unknown function — in mice.

He discovered that a molecule that he named orexin binds to the same receptor Mignot detected as abnormal in dogs.

Mice who were deprived of orexin developed narcolepsy.

Mignot immediately began research on human subjects and found that orexin levels in the brain of narcolepsy patients were zero.

Normally, the molecule is produced in great quantities during the day, especially in the evening, allowing one to fight fatigue.

“You don’t make a discovery like this twice in your life,” Mignot said. “We found the cause of a disease.

“The advantage, is that we can remake a key,” he said, referring to orexin.

For the moment, most patients are treated with a combination of powerful sedatives to help them sleep more soundly and amphetamines to keep them awake during the day.

Mignot said tests using a drug that mimics orexin have been “really miraculous.”

Patients are fully awake and “transformed.”

The challenge is to develop the right dose to be delivered at the right time.

Several companies, including Takeda of Japan, are working on it, and drugs could be authorized in the next few years.

They could be applied to other patients — people suffering from depression, for example — who have difficulty waking up, or to those in a coma.

Mignot meanwhile is studying whether narcolepsy may be caused by a flu virus.

The body’s immune system may be confusing a flu virus with the cells that produce orexin and T-cells that fight infection are attacking them as a result.

“I’ve become interested in how the immune system works in the brain,” a field he said is “beginning to explode.”

As for sleep, Mignot remains fascinated by it even if he has uncovered one of the great mysteries.

“What is it that sleep does that it is so important that we have to do it every day?” he asked. “It’s true that we still don’t know.”

The hot gas bubble is thought to orbit slightly outside the orange ring

Astronomers said Thursday they have spotted a hot bubble of gas spinning clockwise around the black hole at the centre of our galaxy at “mind blowing” speeds.

The detection of the bubble, which only survived for a few hours, is hoped to provide insight into how these invisible, insatiable, galactic monsters work.

The supermassive black hole Sagittarius A* lurks in the middle of the Milky Way some 27,000 light years from Earth, and its immense pull gives our home galaxy its characteristic swirl.

The first-ever image of Sagittarius A* was revealed in May by the Event Horizon Telescope Collaboration, which links radio dishes around the world aiming to detect light as it disappears into the maw of black holes.

One of those dishes, the ALMA radio telescope in Chile’s Andes mountain range, picked up something “really puzzling” in the Sagittarius A* data, said Maciek Wielgus, an astrophysicist at Germany’s Max Planck Institute for Radio Astronomy.

Just minutes before ALMA’s radio data collection began, the Chandra Space Telescope observed a “huge spike” in X-rays, Wielgus told AFP.

This burst of energy, thought to be similar to solar flares on the Sun, sent a hot bubble of gas swirling around the black hole, according to a new study published in the journal Astronomy and Astrophysics.

The gas bubble, also known as a hot spot, had an orbit similar to Mercury’s trip around the Sun, the study’s lead author Wielgus said.

But while it takes Mercury 88 days to make that trip, the bubble did it in just 70 minutes. That means it travelled at around 30 percent of the speed of light.

“So it’s an absolutely, ridiculously fast-spinning bubble,” Wielgus said, calling it “mind blowing”.

Residents wait in the street in Mexico City after a strong earthquake jolted the capital during the night

A strong earthquake jolted Mexico on Thursday, leaving at least two people dead as residents rushed into the streets of the capital in the middle of the night days after another powerful tremor.

A woman died in Mexico City after falling down some stairs and hitting her head when the quake triggered early warning alarms, while a second victim in the capital suffered a heart attack, authorities said.

The epicenter of the 6.9-magnitude earthquake was near the Pacific coast, 84 kilometers (52 miles) south of Coalcoman in the western state of Michoacan, the national seismological agency reported.

The US Geological Survey (USGS) estimated the magnitude at 6.8.

It was the strongest of more than 1,200 aftershocks from a magnitude 7.7 quake that struck the same area on Monday, the national seismological agency said.

That tremor left two people dead in western Mexico, damaged several thousand buildings and sparked panic more than 400 kilometers away in Mexico City.

The latest quake again triggered alarms in the capital shortly after 1:00 am (0600 GMT) and caused buildings to shake and sway.

Many people quickly evacuated their homes when the alarms sounded, some still dressed in pajamas and carrying their pet dogs.

“We had a 6.9 magnitude aftershock with an epicenter in Coalcoman,” President Andres Manuel Lopez Obrador said on Twitter.

“Unfortunately, two people lost their lives in Mexico City,” he said, adding that there were no reports of victims in the western states of Michoacan, Colima and Jalisco.

Mexico City Mayor Claudia Sheinbaum said official helicopters had flown over the capital and that there were no initial reports of destruction.

“So far there is no damage in the city after the earthquake,” she tweeted.

The quake hit at a depth of 12 kilometers, according to the national seismological agency, while the USGS estimated the depth at 24 kilometers, located about 410 kilometers from Mexico City.

– Traumatic anniversary –

Monday’s tremor came less than an hour after millions of people in Mexico City participated in emergency drills on the anniversary of two deadly earthquakes in 1985 and 2017.

The timing was no more than a coincidence, the national seismological agency said.

“There is no scientific reason to explain it,” it added.

On September 19, 1985, an 8.1-magnitude quake killed more than 10,000 people and destroyed hundreds of buildings.

On the anniversary of that earthquake in 2017, a magnitude 7.1 quake left around 370 people dead, mainly in the capital.

During Monday’s earthquake, a man was killed by falling debris in a shopping center in Manzanillo in the western state of Colima.

A woman later died of injuries caused by a falling wall in the same city.

Mexico sits in the world’s most seismically and volcanically active zone, known as the Ring of Fire, where the Pacific plate meets surrounding tectonic plates.

Mexico City, which together with surrounding urban areas is home to more than 20 million people, is built in a natural basin filled with the sediment of a former lake, making it particularly vulnerable to earthquakes.

The capital has an early warning alarm system using seismic monitors that aims to give residents enough time to evacuate buildings when earthquakes hit seismic zones near the Pacific coast.

Residents wait in the street in Mexico City after a strong earthquake jolted the capital during the night

A strong earthquake jolted Mexico on Thursday, leaving two people dead as residents rushed out into the streets of the capital in the middle of the night days after another powerful tremor.

A woman died in Mexico City after falling down some stairs and hitting her head when the quake triggered early warning alarms, while the second victim suffered a heart attack, authorities said.

The epicenter of the 6.9-magnitude earthquake was near the Pacific coast, 84 kilometers (52 miles) south of Coalcoman in the western state of Michoacan, the national seismological agency reported.

The US Geological Survey (USGS) estimated the magnitude at 6.8.

It was the strongest of more than 1,200 aftershocks from a magnitude 7.7 quake that struck the same area on Monday, the national seismological agency said.

That tremor left two people dead in western Mexico, damaged several thousand buildings and sparked panic more than 400 kilometers away in Mexico City.

The latest quake again triggered alarms in the capital shortly after 1:00 am (0600 GMT) and caused buildings to shake and sway.

Many people quickly evacuated their homes when the alarms sounded, some still dressed in pajamas and carrying their pet dogs.

“We had a 6.9 magnitude aftershock with an epicenter in Coalcoman,” President Andres Manuel Lopez Obrador said on Twitter.

“It was felt in Michoacan (and the other states of) Colima, Jalisco, Guerrero and Mexico City. So far there are no reports of damage,” he added.

Mexico City Mayor Claudia Sheinbaum said official helicopters had flown over the city and that there were no initial reports of destruction.

“So far there is no damage in the city after the earthquake,” she tweeted.

The quake hit at a depth of 12 kilometers, according to the national seismological agency, while the USGS estimated the depth at 24 kilometers, located about 410 kilometers from Mexico City.

– Traumatic anniversary –

Monday’s tremor came less than an hour after millions of people in Mexico City participated in emergency drills on the anniversary of two deadly earthquakes in 1985 and 2017.

The timing was no more than a coincidence, the national seismological agency said.

“There is no scientific reason to explain it,” it added.

On September 19, 1985, an 8.1-magnitude quake killed more than 10,000 people and destroyed hundreds of buildings.

On the anniversary of that earthquake in 2017, a magnitude 7.1 quake left around 370 people dead, mainly in the capital.

During Monday’s earthquake, a man was killed by falling debris in a shopping center in Manzanillo in the western state of Colima.

A woman later died of injuries caused by a falling wall in the same city.

Mexico sits in the world’s most seismically and volcanically active zone, known as the Ring of Fire, where the Pacific plate meets surrounding tectonic plates.

Mexico City, which together with surrounding urban areas is home to more than 20 million people, is built in a natural basin filled with the sediment of a former lake, making it particularly vulnerable to earthquakes.

The capital has an early warning alarm system using seismic monitors that aims to give residents enough time to evacuate buildings when earthquakes hit seismic zones near the Pacific coast.

Pilot whales beached on Macquarie Harbour, in Tasmania

Almost 200 whales have perished at an exposed, surf-swept beach on the rugged west coast of Tasmania, where Australian rescuers were only able to save a few dozen survivors Thursday.

After an arduous, day-long effort in difficult conditions, state wildlife services said just 32 of the 226 beached long-finned pilot whales were strong enough to be rescued. 

“We’ve been refloating those whales that have been deemed suitable for release back to sea,” Sam Thalmann, a marine biologist, told AFP.

“Every whale that has been released has been tagged,” he said. “There may be a few that restrand unfortunately, but we expect that by far the majority will head out to sea.”

Locals had covered some of the mammals with blankets and doused them with buckets of seawater to keep them alive until more help arrived.

But many of the whales were too far gone.

By nightfall, scores of the glossy black whales were strewn along Ocean Beach, their carcasses pock-marking the waterline where the frigid southern ocean meets the sand.

“Unfortunately we do have a high mortality rate on this particular stranding,” said state wildlife operations manager Brendon Clark.

“The environmental conditions, the surf out there on the exposed west coast, Ocean Beach, is certainly taking its toll on the animals.”

Efforts will now turn to the considerable task of disposing of the whale bodies safely.

If left in shallow waters or on the beach, they could attract sharks and can carry disease. 

“There is a lot more work to be done with the carcass disposal,” said Thalmann, who added that “valuable biological samples” would need to be collected from the animals.

Those could help scientists understand how and why “the animals strand at this location”.

“There (are) certainly some local characteristics that lead to this spot being repeatedly a site for mass whale stranding.”

Two years ago, Macquarie Harbour was the scene of the country’s largest-ever mass stranding, involving almost 500 pilot whales.

More than 300 pilot whales died during that event, despite the efforts of dozens of volunteers who toiled for days in Tasmania’s freezing waters to free them.

Clark said the conditions of the latest stranding were tougher for the whales than two years ago, when the animals were in “much more sheltered waters”.

– Distress signals –

Scientists still do not fully understand why mass strandings occur.  

Some have suggested pods go off track after feeding too close to shore.

Pilot whales — which can grow to more than six metres (20 feet) long — are also highly sociable, so they may follow pod-mates who stray into danger.

That sometimes occurs when old, sick or injured animals swim ashore and other pod members follow, trying to respond to the trapped whale’s distress signals.

Others believe gently sloping beaches like those found in Tasmania confuse the whales’ sonar, making them think they are in open waters.

The latest stranding came days after a dozen young male sperm whales were reported dead in a separate mass stranding on King Island — between Tasmania and the Australian mainland.

State officials said that incident may have been a case of “misadventure”.

Strandings are also common in nearby New Zealand.

There, around 300 animals beach themselves annually, according to official figures, and it is not unusual for groups of between 20 and 50 pilot whales to run aground. 

But numbers can run into the hundreds when a “super pod” is involved — in 2017, there was a mass stranding of almost 700 pilot whales.

Pilot whales beached on Macquarie Harbour, in Tasmania

Almost 200 whales have perished at an exposed, surf-swept beach on the rugged west coast of Tasmania, where Australian rescuers were only able to save a few dozen survivors Thursday.

After an arduous day-long effort in difficult conditions, state wildlife services said just 34 of the 226 beached long-finned pilot whales were strong enough to be rescued. 

“We’ve been refloating those whales that have been deemed suitable for release back to sea”, Sam Thalmann, a marine biologist, told AFP.

“Every whale that has been released has been tagged,” he said. “There may be a few that restrand unfortunately, but we expect that by far the majority will head out to sea.”

Locals had covered some of the creatures with blankets and doused them with buckets of seawater to keep them alive until more help arrived.

But many of the whales were too far gone.

By nightfall, scores of the glossy black mammals were strewn along Ocean Beach, their carcasses pock-marking the waterline where the frigid southern ocean meets the sand.

“Unfortunately we do have a high mortality rate on this particular stranding,” said state wildlife operations manager Brendon Clark.

“The environmental conditions, the surf out there on the exposed west coast, Ocean Beach, is certainly taking its toll on the animals.”

Efforts will now turn to the considerable task of disposing of the whale bodies safely.

If left in shallow waters or on the beach, they could attract sharks and can carry disease. 

“There is a lot more work to be done with the carcass disposal,” said Thalmann, who added that “valuable biological samples” would need to be collected from the animals.

Those could help scientists understand how and why “the animals strand at this location”.

“Ocean Beach-Macquarie Harbour is a global hotspot for mass strandings of these whales — long-finned pilot whales — there (are) certainly some local characteristics that lead to this spot being repeatedly a site for mass whale stranding.”

Two years ago, Macquarie Harbour was the scene of the country’s largest-ever mass stranding, involving almost 500 pilot whales.

More than 300 pilot whales died during that event, despite the efforts of dozens of volunteers who toiled for days in Tasmania’s freezing waters to free them.

Clark said the conditions of the latest stranding were tougher for the whales than two years ago, when the animals were in “much more sheltered waters”.

– Distress signals –

Scientists still do not fully understand why mass strandings occur.  

Some have suggested pods go off track after feeding too close to shore.

Pilot whales — which can grow to more than six metres (20 feet) long — are also highly sociable, so they may follow pod-mates who stray into danger.

That sometimes occurs when old, sick or injured animals swim ashore and other pod members follow, trying to respond to the trapped whale’s distress signals.

Others believe gently sloping beaches like those found in Tasmania confuse the whales’ sonar, making them think they are in open waters.

The latest stranding came days after a dozen young male sperm whales were reported dead in a separate mass stranding on King Island — between Tasmania and the Australian mainland.

State officials said that incident may have been a case of “misadventure”.

Strandings are also common in nearby New Zealand.

There, around 300 animals beach themselves annually, according to official figures, and it is not unusual for groups of between 20 and 50 pilot whales to run aground. 

But numbers can run into the hundreds when a “super pod” is involved — in 2017, there was a mass stranding of almost 700 pilot whales.

Residents wait in the street in Mexico City after a strong earthquake jolted the capital during the night

A strong earthquake jolted Mexico on Thursday, leaving one person dead as people rushed out into the streets of the capital in the middle of the night, days after another powerful tremor.

A woman died in Mexico City after falling down some stairs and hitting her head when the quake triggered early warning alarms, authorities said.

The epicenter of the 6.9-magnitude quake was near the Pacific coast, 84 kilometers (52 miles) south of Coalcoman in the western state of Michoacan, the national seismological agency reported.

The US Geological Survey (USGS) estimated the magnitude at 6.8.

Michoacan had been hit by a powerful magnitude 7.7 earthquake on Monday that left two people dead, damaged several thousand buildings and sparked panic more than 400 kilometers away in Mexico City.

The latest quake again triggered alarms in the capital shortly after 1:00 am (0600 GMT) and caused buildings to shake and sway.

Many people quickly evacuated their homes when the alarms sounded, some still dressed in pajamas and carrying their pet dogs.

“We had a 6.9 magnitude aftershock with an epicenter in Coalcoman,” President Andres Manuel Lopez Obrador said on Twitter.

“It was felt in Michoacan (and the other states of) Colima, Jalisco, Guerrero and Mexico City. So far there are no reports of damage,” he added.

Mexico City Mayor Claudia Sheinbaum said official helicopters had flown over the city and that there were no initial reports of destruction.

“So far there is no damage in the city after the earthquake,” she tweeted.

The quake hit at a depth of 12 kilometers, according to the national seismological agency, while USGS estimated the depth at 24 kilometers, located about 410 kilometers from Mexico City.

– Traumatic anniversary –

Monday’s tremor came less than an hour after millions of people in Mexico City participated in emergency drills on the anniversary of two deadly earthquakes in 1985 and 2017.

The timing of Monday’s tremor was no more than a coincidence, the national seismological agency said.

“There is no scientific reason to explain it,” it added.

On September 19, 1985, an 8.1-magnitude quake killed more than 10,000 people and destroyed hundreds of buildings.

On the anniversary of that earthquake in 2017, a magnitude 7.1 quake left around 370 people dead, mainly in the capital.

During Monday’s earthquake, a man was killed by falling debris in a shopping center in Manzanillo in the western state of Colima.

A woman later died of injuries caused by a falling wall in the same city.

Mexico sits in the world’s most seismically and volcanically active zone, known as the Ring of Fire, where the Pacific plate meets surrounding tectonic plates.

Mexico City, which together with surrounding urban areas is home to more than 20 million people, is built in a natural basin filled with the sediment of a former lake, making it particularly vulnerable to earthquakes.

The capital has an early warning alarm system using seismic monitors that aims to give residents enough time to evacuate buildings when earthquakes hit seismic zones near the Pacific coast.

Whale sonar navigation

The death of about 200 pilot whales at a Tasmanian beach has renewed questions about what causes such mass strandings and whether they can be prevented.

With the help of Karen Stockin, a whale stranding expert at New Zealand’s Massey University, here are the answers to five key questions:

What causes mass strandings?

Scientists are still trying to work that out. They do know that there are multiple types of stranding events, with several explanations that can overlap. The causes can be natural, based on bathymetry — the shape of the ocean floor — or they can be species-specific. 

Pilot whales and several smaller dolphin species are known to regularly mass strand, especially in the southern hemisphere, according to Stockin. In some instances, a sick whale headed towards shore and a full group unwittingly followed them. 

Does it happen in certain areas?

There are a few global hotspots. In the southern hemisphere, Tasmania and New Zealand’s Golden Bay have seen several instances, and in the northern hemisphere, the United States bay of Cape Cod, Massachusetts, is another hotspot. 

In those areas, there are similarities between the topography of the beaches and environmental conditions. For example, Cape Cod and Golden Bay share a prominent narrow coastal land feature and shallow water with large tidal variations. Some people call such areas “whale traps” because of the speed at which the tide can recede.

Are strandings becoming more common?

Possibly. Strandings are natural phenomena and have been documented since the days of Aristotle. The health of the oceans has, however, deteriorated in recent decades.

Strandings could become more common as human use of the seas, shipping traffic and chemical pollution all increase. 

Epizootic diseases — outbreaks of sickness that affect a specific animal species — could also lead to more. But there is still much to understand about the phenomenon, Stockin said. 

Is climate change a factor?

Research on how climate change is affecting marine mammals is still in its infancy. Experts know that climate change can give rise to changes in prey and predator distribution. For some species, this may result in whales coming closer to shore. 

For example, recent research based on current climate prediction models suggests that by the year 2050, the distribution of sperm whales and blue whales in New Zealand could vary considerably.

Can strandings be prevented?

Not really. As strandings occur for a multitude of reasons, there is no one-size-fits-all solution. But Stockin said that by better understanding whether and how human-induced changes are causing more mass strandings, solutions could be found. 

Residents wait in the street in Mexico City after a strong earthquake jolted the capital during the night

A strong earthquake jolted Mexico on Thursday, sending people rushing out into the streets of the capital in the middle of the night, days after a powerful tremor left at least two people dead.

The epicenter of the 6.9-magnitude quake was near the Pacific coast, 84 kilometers (52 miles) south of Coalcoman in the western state of Michoacan, the national seismological agency reported.

The US Geological Survey (USGS) estimated the magnitude at 6.8.

Michoacan had been hit by a powerful magnitude 7.7 earthquake on Monday that damaged several thousand buildings and sparked panic more than 400 kilometers away in Mexico City.

The latest quake again triggered early warning alarms in the capital at 1:16 am (0616 GMT) and caused buildings to shake and sway.

Many people quickly evacuated their homes when the alarms sounded, some still dressed in pajamas and carrying their pet dogs.

“We had a 6.9 magnitude aftershock with an epicenter in Coalcoman,” President Andres Manuel Lopez Obrador said on Twitter.

“It was felt in Michoacan (and the other states of) Colima, Jalisco, Guerrero and Mexico City. So far there are no reports of damage,” he added.

Mexico City Mayor Claudia Sheinbaum said official helicopters had flown over the city and that there were no initial reports of destruction.

“So far there is no damage in the city after the earthquake,” she tweeted.

The quake hit at a depth of 12 kilometers, according to the national seismological agency, while USGS estimated the depth at 24 kilometers, located about 410 kilometers from Mexico City.

– Traumatic anniversary –

Monday’s tremor came less than an hour after millions of people in Mexico City participated in emergency drills on the anniversary of two deadly earthquakes in 1985 and 2017.

The timing of Monday’s tremor was no more than a coincidence, the national seismological agency said.

“There is no scientific reason to explain it,” it added.

On September 19, 1985, an 8.1-magnitude quake killed more than 10,000 people and destroyed hundreds of buildings.

On the anniversary of that earthquake in 2017, a magnitude 7.1 quake left around 370 people dead, mainly in the capital.

During Monday’s earthquake, a man was killed by falling debris in a shopping center in Manzanillo in the western state of Colima.

A woman later died of injuries caused by a falling wall in the same city.

Mexico sits in the world’s most seismically and volcanically active zone, known as the Ring of Fire, where the Pacific plate meets surrounding tectonic plates.

Mexico City, which together with surrounding urban areas is home to more than 20 million people, is built in a natural basin filled with the sediment of a former lake, making it particularly vulnerable to earthquakes.

The capital has an early warning alarm system using seismic monitors that aims to give residents enough time to evacuate buildings when earthquakes hit seismic zones near the Pacific Coast

California has abundant solar energy, harnessing a growing amount of the rays that land on its rooftops, but when the sun sets, there can be a shortfall

Dire predictions of blackouts in California during a fearsome heat wave this month never came to pass, with technology — and a dose of community spirit — helping the creaking grid through its most testing period ever.

The mercury topped 110 Fahrenheit (43 Celsius) on consecutive days, as a thrumming heat dome parked itself over the western United States.

But the grid never failed, thanks in part to the state’s quietly acquired battery fleet.

“Batteries stepped in and… played a critical role” in rebalancing electricity demand, said Weikko Wirta, director of operations at AES Southland, a 400 megawatt installation at Long Beach near Los Angeles.

The huge electricity storage facility, which resembles an enormous server farm, is one of the largest in the state.

Sunny California has abundant solar energy at its disposal, and harnesses a growing amount of the rays that land on its rooftops.

During daylight hours, solar and other renewables provide around 30 to 40 percent of the state’s electricity needs.

But as the sun dips, there can be a shortfall — especially on very hot days when air conditioners are switched on as everyone gets home from work and school.

“When the solar goes away at the end of the day, (batteries) stepped right in to fill that void between four o’clock in the afternoon… and 10 o’clock at night,” said Wirta.

Nearly every day of the lengthy heat wave that gripped California, Nevada and Arizona, the grid’s operator called on consumers to limit their electricity use.

Automated phone calls rang out urging households to turn up their thermostats, and not to use large appliances — including charging electric vehicles — during peak hours.

– ‘Conserve energy now’ –

“Conserve energy now to protect public health and safety,” read one urgent text message from the California Governor’s Office of Emergency Services.

“Extreme heat is straining the state energy grid. Power interruptions may occur unless you take action. Turn off or reduce nonessential power.”

That message, sent on the day demand reached its highest, seemed to do the trick.

“Within moments, we saw a significant amount of load reduction,” said Elliot Mainzer, president of the California Independent System Operator, the grid operator.

“That significant response from California consumers… allowed us to restore our operating reserves and took us back from the edge.”

Fresh in the minds of many Californians was August 2020, when the grid collapsed, leaving 800,000 homes without power over a two-day period.

Critics have blasted energy policy in the Golden State, insisting its increasing reliance on renewables at the expense of reliable, but dirty, fossil fuels puts needless strain on supply.

Climate change-skeptics took particular glee in pointing out that the call to conserve power came just days after California said it would no longer sell gasoline-powered cars from 2035.

“California’s threat of rolling blackouts ought to be a warning about how the government force-fed green energy transition is endangering grid reliability,” tweeted Kevin McCarthy, a US representative from the state and the lead Republican in the House.

For energy researchers like Eric Fournier at UCLA’s Institute of the Environment and Sustainability, this kind of sentiment is a non-starter.

“Dealing with the source of the problem and stopping emitting so many greenhouse gases into the atmosphere is the only rational way to address the problem” of climate change, he said.

“Instead of criticizing the renewables, we should be championing the value of battery storage.”

And that’s what California has been quietly doing, as it works towards a policy of 100 percent carbon-neutral energy by 2045.

– Peak power –

Over the last two years, battery storage capacity has increased tenfold; at the peak of the heat wave, these batteries were able to put 3,300 megawatts into the grid.

“That’s more combined power than the state’s largest power plant… which is rated at about 2200 megawatts,” said Mike Ferry, research director at the UC San Diego Center for Energy Research.

During the last heat wave “batteries that were interconnected to the grid played a barely noticeable role in meeting that peak power.”

“This time around, everything has changed, and batteries… played a key role in allowing the state to avoid power outages.”

For Fournier, battery solutions are impressive, but not the whole answer; Californians’ impressive voluntary cutbacks could once again be the missing piece of the puzzle.

“Paying people to not ask for power for a small number of hours may be a better option,” he says.