‘They milk them to the max’: Fuse Energy accused of mistreating staff

Fuse Energy burst onto the UK market three years ago, with cheerful branding and a promise to “accelerate energy abundance”. Backed by heavyweight investors, the green energy startup has taken on 200,000 customers, earning a $5bn valuation in the process. It has also burnished its affable image by signing up as the lead sponsor of The Rest is Politics, the UK’s second-most popular podcast, anchored by former politicians Rory Stewart and Alistair Alastair Campbell.

But behind Fuse’s ambitions is a company whose management, former employees allege, has publicly shamed young workers and pressured some inexperienced staff members to work up to 100-hour weeks. Twelve former senior employees, analysts and interns have told The Observer they believe Fuse’s green ambitions and low costs have been driven to a degree by overworked, exploited staff.

Fuse Energy denied fostering a harsh work environment, and said employee wellbeing is a priority. “We do not expect or encourage 100-hour work weeks. The company maintains high standards in a fast-paced environment, but does not exploit talent or job market conditions.”

Fuse reported making more money than it was spending by late 2025, with $400m in annual recurring revenue. But the website Sifted reported that accounts for one of its main UK subsidiaries had racked up heavy operating losses, raising eyebrows over the firm’s recent valuation. Fuse describes itself as one of the fastest growing companies in Europe.

The London-based startup aims to be one of the UK’s cheapest fixed tariffs in a n energy market dominated by Octopus and British Gas. The UK’s largest energy supplier, Octopus, overtook British Gas last January with 12.9m household accounts and is valued at $9bn. Fuse’s most recent valuation was set by lead investors Lowercarbon Capital, and another previous investor, Balderton Capital.

Fuse was founded in 2022 by Alan Chang and Charles Orr, both alumni of the British fintech Revolut, which prides itself on its competitive, fast-paced culture. Orr was the fintech’s leader of special projects, while the fiercely ambitious Chang, 32, was Revolut’s fifth hire and has been described as the “physical embodiment of Revolut’s ‘get shit done’ ethos”. He has admitted to carrying Revolut’s work ethic to Fuse.

Chang appeared to think of himself as “the next Elon Musk”, former senior colleagues said, and has claimed he works up to 90 hours a week. Not all employees share this approach: one post from a former staffer, commenting anonymously on the employer review site Glassdoor, complains of a “toxic atmosphere”. Another comment, apparently from a current intern, describes a “sink or swim mentality”. When asked about those complaints by the Telegraph, Chang said: “Fuse is not for everyone”.

Fuse promises customers they can “chat to our London team in under a minute, 24/7, 365”. To power this, a team which now counts about 100 graduate interns, from top Stem courses at Imperial, Oxbridge and LSE, was hired to answer chats on rotation, with up to 10 new employees joining every week.

But aspects of the Silicon Valley-style culture sometimes turned toxic, several sources claimed. They say team members were at times encouraged to “out” their peers’ mistakes on Slack, the internal messaging service, and that they had a mandatory daily “chat scan” meeting with team leaders, where poorly rated customer service chats were criticised and interns were grilled in front of their cohort.

According to sources, it was not uncommon for Chang to call out a staffer’s abilities on Slack channels visible to others in the company. In company-wide Slack messages seen by The Observer, Chang asks a junior staffer: ‘Can you not read?’.” The use of Slack for public feedback “created a paranoid environment where you never knew who you could trust”, said a former operations team member.

Staff warned each other to “manage expectations” before performance reviews, with Slack messages seen by The Observer claiming Chang and Orr “only focused on negatives”.

A Fuse spokesperson said the company has a zero-tolerance policy towards unprofessional conduct of any kind, and that “feedback is delivered constructively, both informally and through 1:1s and biannual reviews”.

In Slack messages seen by The Observer, Chang said there wouldn’t be a Christmas party, “because at Fuse we celebrate achievements, not calendar occasions”. He said there would be a party when Fuse hit one million customers – Fuse currently has 200,000 customers.

Working hours were often long and gruelling, sources said. Contracts seen by The Observer show interns have been hired on a £30,000 salary for work taking place between 8am-10pm, with the possibility of additional hours without specified overtime pay. Eight sources claim they regularly worked 70-hour weeks, while five former interns recalled working 100-hour weeks. Some of the interns and senior staffers The Observer spoke to claimed teams were left “understaffed and exhausted”.

A Fuse spokesperson said overtime waivers are standard practice across many industries and that expectations are communicated clearly during interviews. The company denied allegations that Fuse’s culture is toxic.

“Working time limits exist for a reason – to protect people’s health. Any so-called opt-outs must be genuinely voluntary, not used as a loophole to pressure workers into exhaustion,” said Paul Nowak, general secretary of the TUC. “Extreme working hours don’t drive success – they wreck morale, burn people out and undermine productivity.” Interns, in particular, are “likely to be more vulnerable to bullying and harassment”, said Stephen Isherwood, joint CEO of the Institute of Student Employers.

Sources said the first days of each month are blocked out for “bill weeks”, where customer bills are processed. Operations interns work three consecutive days of nine- to 10-hour shifts, answering a flurry of customer queries and manually checking meter readings from photos, allegedly without additional pay for overtime. The Fuse spokesperson said customer service employees working out-of-hours receive additional compensation. The Observer understands interns received overtime pay for overnight shifts (10pm-2am and 2am-8am), but not for bill weeks.

International graduates were hired in large numbers, former staff said, and they depended on the company for visa sponsorship and the right to remain in the UK. One former intern, an international graduate, said: “If you didn't make yourself irreplaceable or weren't working as much as you could, there was a real sense of fear that you could just be let go”.

Many who spoke to The Observer have been profoundly affected by their time at Fuse. A former talent team member, who was dismissed at the end of their probation period, said it felt like the founders “almost took pride in being like ‘We’re a horrible place to work. We treat people like shit’”.

“You're treated very harshly, so it's up to you what you want to make out of it,” agreed one former intern who progressed to an analyst role.

“[Those in charge are aware] the job market is tough. Even if you push these interns to 100-plus hour weeks, they’re not going to quit, so they milk them to the maximum.” A Fuse spokesperson said: “Fuse is one of the fastest growing startups in Europe. We hired over 100 people in 2025 alone. This includes both software engineers and skilled trade roles across the country. Our electricians receive competitive compensation packages, and we invest in upskilling them to do solar, battery, and other installations that help the renewable transition while lowering the cost of energy for customers.

A Fuse spokesperson said: “Fuse is not for everyone. It’s an ideal environment for someone who is very smart, very ambitious, and wants to build things that have a positive impact. We are very direct. When someone does a great job, we tell them. If someone doesn’t meet our standards, we tell them [those who do] great work quickly advance into positions of more responsibility.”