彭博报道欧洲、美国和澳大利亚家庭通过光伏储能参与电力套利和虚拟电厂

For many Europeans, this summer’s heat was a powerful reminder of the damage climate change has wrought — from illness and devastated crops to high energy bills. For Andrew Austin, a 34-year-old homeowner in Shropshire, England, the stubbornly high temperatures were a chance to make some money.

Power demand was rising as London crossed 34C (93F) on June 24. Energy prices spiked as the sun set and solar panels across the UK stopped generating electricity. That’s when Austin knew he could take advantage of his 200 kilowatt-hour home battery, which he had charged up using cheap power from the grid during the daytime. He sold the power back to the grid for £60 ($82) from 4 p.m. to 9 p.m. In just a few hours, Austin had earned about as much as an apartment dweller would typically pay for electricity every month.

All this happened without Austin having to press a single button. He has set up a computer to conduct this energy trading while he goes about his life as normal. The computer downloads electricity prices for every 30-minute period from his utility Octopus Energy, which publishes them at 4 p.m. each day. That allows him to know when electricity will be cheap to charge his batteries, and when power prices on the grid are high, the computer sells it back to the grid.

Many parts of the world, especially Europe, are struggling with high electricity bills after the wars in Ukraine and the Middle East caused oil and natural-gas prices to soar. At the same time, the cost of electricity technologies manufactured mainly in China is falling. It’s why tens of millions of people are switching to electric options like solar panels and batteries, regardless of whether they worry about climate change.

Austin’s going one step further — not just offsetting his energy bills, but making money. He’s taking advantage of an opportunity that used to be available only to professional traders: arbitrage on volatile electricity markets. He views the current market volatility very differently than many consumers. “To me, it’s not a crisis, it’s an opportunity,” he says.

The history of retail energy markets can be summed up as one transaction repeated trillions of times: Companies sell consumers fuel to burn. That basic relationship is now changing for the first time, as millions of people use their solar panels and batteries to generate energy and sell excess back to the grid.

For an increasing fraction of those millions, it means buying electricity from the grid when it’s cheap or generating it using solar panels for free, then storing it in batteries for a few hours. When power prices are high, typically after the sun goes down, it means discharging the battery and selling the power back to the grid — making a tidy sum in return. Europe, the US and Australia are just a few places where consumers are making this shift.

“If you have all these electricity assets and wide intraday power price spreads, then you can use all of it to reduce your bills and even make a bit of money,” says Yara van Ingen, analyst at BloombergNEF covering home and building decarbonization.

Austin estimates that, after using electricity to charge his electric cars and run his household, his battery strategy makes him £400 on average in the summer months and £300 in the winter — enough to buy monthly groceries for a family of four in the UK.

While Austin’s strategy hasn’t let him down yet, leaving the walled garden of regulated electricity prices comes with risks. Arbitrage done right can earn money, but a poor execution of a trading strategy means opening up to extremely high electricity prices at certain times. How much money you can make or lose depends on where you live, what kind of electricity assets you own, how open your regulators are to letting you trade and how smart you are in setting up your trading strategy.

The development of these electricity technologies has given people like Aaron Wilkes new agency. “When the Ukraine war started, I wanted to delete gas from my property,” he says. Europe was heavily dependent on natural-gas imports from Russia and he wanted to protect himself from energy spikes.To start, the 36-year-old train driver installed heat pumps, solar panels and batteries in his home in Kent, England. An electric car — and then another — followed. Once he had all these devices, he wondered whether he could optimize their use and lower his bills — and maybe even make some money on the side by selling power back to the grid.

For Wilkes to become a commodity seller required not just technological progress, but also important regulatory changes to create a system that lets him participate in the marketplace. Three recent trends have made it possible: the rise in electrification of homes through rooftop solar panels, home lithium-ion batteries and electric cars; increased volatility in electricity prices as intermittent renewables make up a bigger share of the total supply; and forward-thinking regulators allowing utilities to offer dynamic pricing at a household level.

Electricity grids are either state-owned or heavily regulated across the world. One reason is that electricity is the crucial source of energy for most activities and blackouts can cause huge political and economic problems. Another reason is that electricity is a weird commodity. Unlike corn or gasoline, it cannot be stored in huge amounts. That forces an electricity market to manage supply and demand instantaneously, with very little margin for error.

Those tight supply-demand margins make pricing more volatile. While the price at a gas pump only changes a few times a week and typically by less than 10% of the average price, wholesale electricity prices can vary hugely in a day, easily rising to 10 times the average in some hours or, at very sunny or windy times, go negative (which is when the utility pays the consumer to use electricity because there’s too much of it on the grid).

It’s why many governments are still quite reluctant to expose consumers to full dynamic pricing. While most of the world is enjoying access to cheap solar panels and batteries, only a handful of countries — Australia, most countries in Europe and in some parts of the US — allow citizens to sell electricity at a price that changes every hour or half hour.

If citizens are to participate in such a marketplace, one of the first regulatory shifts needed is making those rapidly-changing prices available. That’s done through the installation of a smart meter, which doesn’t just measure how much electricity the home consumes, but communicates the price of electricity at the moment of consumption. Countries like Sweden, Italy, Spain, Finland, Denmark and the Netherlands have near universal adoption of smart meters, while the European average is above 60%.

The idea is that consumers will use this information as a tool to change how they consume, produce or store energy. “In Finland, everyone has an app that shows electricity prices for every hour of the day in advance,” says BNEF’s van Ingen. “Everyone’s looking at the app and so they’re very responsive.” That means choosing to do certain energy-intensive activities, such as putting on a dishwasher or charging the car, when prices are low. It also means selling excess electricity when prices are high.

Wilkes wanted to find a way to automate these microdecisions. So he asked ChatGPT. “I don’t have any training in coding,” he says. “That’s why I went towards AI.”

Soon he was giving Codex, OpenAI’s coding platform, access to the accounts of his various electrical devices, including his two Tesla cars. Then he asked the AI to download pricing data from his utility. The devices “came alive with an AI agent inside,” he says.

With a few simple instructions about what kind of temperature he likes at home at what times and when he drives to work, the AI now decides when is the best time to charge the car or discharge the home battery. When he has excess electricity, he sells it back to the grid when the prices are the highest. So far, most of the benefit from this trading has been offsetting his energy bills with payouts for exports typically less than about £10 ($14) a month.

This kind of trading is not for everyone. What if the agent gets things wrong? “It’s happened on numerous occasions,” he says. Wilkes has a screen set up in the living room that shows electricity prices and what his electrical devices are doing. (You too can check out what’s happening in his house right now.)

One time Wilkes saw that the prices were high and the car was being charged, which led to him interrogating AI. The answer: the AI lost access to the car and wasn’t able to turn off the charging. It was a costly mistake, but he had some protection. Octopus Energy has a price cap for customers like Wilkes of about £1 per kWh, even if wholesale electricity prices are much higher.

Even among the few countries that have opened up markets to dynamic pricing, governments are reluctant to fully expose citizens or grid operators to these kinds of risks. 1KOMMA5°, a tech company which allows customers to access these dynamic prices to buy energy at cheap times, says its customers in Germany can’t always access the lucrative payments that Wilkes benefits from, but are capped at much more modest prices when selling the electricity.

Cheap, intermittent renewables have forced grids to become two-way energy highways and adapt to more unpredictable supply-and-demand dynamics. Australia has done more than most countries to address this new reality. More than 40% of all homes in the country have rooftop solar, which makes electricity cheap or even free during the day. But dirty, expensive gas power plants still come online when the sun goes down. When natural gas prices started soaring because of Russia’s attack on Ukraine, Mark Purcell felt the pain.

Electricity bills for his house in Queensland, Australia reached A$1,000 ($710) a quarter. Purcell, 59, is a navy veteran and electrical engineer. He bought solar and batteries, then programmed a simple Raspberry Pi computer to trade using hourly pricing from his utility Amber Electric — buying low and selling high.

Purcell started making money immediately. Some nights, prices were so high that the computer discharged the batteries and made Purcell as much as A$200 while he was sleeping.

In conservative-leaning Queensland where few people worry about climate change, he’s persuaded some neighbors to install solar panels and batteries. Purcell says he likes the idea that he’s helping people access electricity more cheaply. “How do we convince Australians to save the planet?” he asks. “The answer is we show them how much money they’re going to save.”

Purcell and Austin are able to do this kind of trading because their local grids support the level of power flow. Wilkes would like to install much bigger batteries and trade more electricity, but his local grid operator said Wilkes would have to fork out tens of thousands of dollars for the upgrades. That would not be economical.

For those who have the right local grid and don’t want to learn coding (or vibe code with AI) to buy and sell electricity at home, it’s still possible to make a lot of money this way.

Greg Robinson, 65, lives near Phoenix in Arizona. After retiring from the city’s water department and being concerned about climate change, he covered his roof with solar panels more than two years ago. But the utility wasn’t paying him very much for the excess power he was generating, which meant it would take more than 10 years to get a return on his investment. Adding batteries helped, because he could store the solar power generated in the day and avoid drawing power from the grid in the evening when prices are high.

But the big breakthrough came after FranklinWH Energy Storage Inc. told him about a deal they have with nonprofit utility Ava Community Energy to combine batteries across thousands of homes into a “virtual power plant” and provide power to the grid when it’s under strain. Robinson can choose whether to make available 40%, 60% or 80% of his battery’s capacity for use on the grid. In return, he earns money for letting the utility draw power when it needs to.

In December, Robinson received $1,055 for signing up and selling some electricity back. The downside is that he has little control over when the program needs his batteries and thus when he can make money. So far, he has been paid only once for such a use. But Robinson finds ceding control of his own asset an acceptable trade-off. “If I profit from it, then I’m okay with it.”