The booming rooftop solar panel industry nosedived overnight when the coronavirus forced homeowners to rein in spending and keep their distance from would-be installers.
Now, in their struggle to survive, companies on both sides of the Atlantic are turning to online marketing rather than knocking on doors, using drones to inspect roofs, arranging digital permits and coming up with attractive new financing plans, according to interviews with 12 executives.
At stake is the future of a key driver of the global transition from fossil fuels to renewable energy: solar power was the second-fastest growing renewable source after wind in 2019, according to the International Energy Agency.
And rooftop installations, which generate electricity used by homes or businesses rather than feeding into the grid, made up more than 40 per cent of the market before COVID-19 struck.
Energy research firm Wood Mackenzie has slashed its rooftop solar installation forecasts for Europe and the United States by a whopping 30 per cent this year, while lifting its forecast by 3 per cent in Asia, where China provides strong government support.
Joana Palau, 42, a council worker on the Spanish island of Ibiza, was one of the few in her neighbourhood who pressed ahead with a plan to install 12 solar panels on her farmhouse in June: "If I had not been working and did not have the stability of a salary every month, I definitely wouldn't have done it."
By contrast, large-scale solar installations that power the grid have fared relatively well. Wood Mackenzie trimmed its forecast by less than 10 per cent for Europe and barely touched its US outlook as rock-bottom prices, subsidies and government mandates helped insulate larger projects from the pandemic.
In the United States, the third biggest rooftop solar market after China and Japan, about 80 per cent of the 100,000 job losses in the solar sector so far have been at rooftop installers, the Solar Energy Industries Association said.
Many of the staff who were not laid off, however, began to focus on one of the industry's most persistent challenges: how to cut the cost of identifying homeowners with suitable roofs, and then persuading them to buy panels, executives said.
Quickly, companies made sales appointments virtual.
Leading US installers SunPower Corp, Vivint Solar Inc and Sunrun Inc said that reassured potential clients worried about the virus. It also cut the cost of acquiring customers, which Wood Mackenzie puts at nearly $4,000, or 22 per cent of the average $18,000 cost of a US system.
Normally reliant on door-to-door visits, an effective but expensive sales tactic, Vivint trained hundreds of salespeople to canvass by phone as its sales slumped 60 per cent following state lockdowns, chief executive David Bywater said.
By early May, sales were down only 30 per cent.
"It was a radical shift," said Bywater, adding that it had hastened Vivint's plan to diversify sales strategies and cut costs: "I hope we never lose that and we accelerate that."
In fact, the strategy was so successful that larger rival Sunrun announced on 7 July that it had agreed to buy Vivint in an all-stock deal valued at $3.2 billion, saving $90 million a year and creating a solar player with half a million customers.
Sunrun bought Vivint because of its focus on direct selling, a model Sunrun chief executive Lynn Jurich said had become even more durable during the COVID-19 pandemic: "Both companies are delivering above where we expected."
Rival SunPower has also seen a massive shift to digital sales, with about three-quarters of consultations now happening via video chat, up from a 10th previously.
Chief executive Tom Werner said he expected half of its sales would be digital from now on. He said it was harder to close deals in virtual chats but that was offset by cutting out travel time between appointments.
"Ideally, you have the day when solar is like Amazon, so you can buy and be fulfilled in a very efficient process," he said.
Sunrun, meanwhile, had to pull its salespeople out of stores such as Costco and Home Depot during lockdowns, outlets that had been bringing in nearly a third of its sales.
Within two weeks, Sunrun had moved its field sales team online and launched a promotion offering six months of home solar power for $6. While initial online commitments were lower, the percentage of customers following through was higher.
Sunrun said innovations like virtual sales and automating permits to avoid physical processing by authorities will trim about $2,000 off the cost of an array over the next year or so.
EmPower Solar, a rooftop installer based in Long Island, spent New York's lockdown on "game changing initiatives" such as digitising sales and paperwork, and using satellite imagery and drones to inspect roofs, said chief executive David Schieren.
He said, however, that it was harder to build rapport with potential customers without face-to-face contact.
In Europe, rooftop solar firms developed more enticing finance plans as the pandemic made clients wary about spending.
SotySolar in Gijon in northern Spain accelerated the roll-out of a "Netflix-style" subscription model. It installs panels and charges a monthly fee though homeowners can buy them or end their contract when they like, said co-founder Daniel Fernandez.
"We have been thinking about doing this for a while but we brought it forward because of this situation," he said, adding that he expected to triple installations with the offer.
In Barcelona, renewable energy utility Holaluz has accelerated an initiative to install panels free for people with available roof space - and use them to generate power for all its customers. It aims to extend the plan to apartment blocks and commercial buildings.
Holaluz expects to boost clients to one million and carry out 50,000 rooftop solar installations by 2023. It estimates fewer than 10,000 Spanish homes currently have panels.
"This is the rooftop revolution," said co-founder Carlota Pi. "We have spent so much time at home, we have become much more conscious of the value you can create by transforming your roof into a source of energy generation."
Nevertheless, despite such innovations, the industry will take time to bounce back, according to industry groups.
In Italy, one of Europe's biggest rooftop solar markets, one in five companies fear they may close due to COVID-19, according to a survey in May by Italian solar trade group Italia Solare.
In Spain, solar association UNEF, for example, has slashed its forecast for rooftop installations this year by a third.
Nevertheless, European firms are hoping moves by the European Union and governments in Spain, Germany and elsewhere to pursue "green" post-pandemic economic recoveries will help.
"The sector looks set to undergo a quick recovery," said Michael Schmela, head of market intelligence at industry association SolarPower Europe in Brussels.
In the United States, residential installations are not expected to return to previously forecast levels until 2025, according to Wood Mackenzie - and some say going online won't work for all, especially in some rural communities.
"It's a totally different culture," said Benjamin Mayer, vice president of marketing for SunBug Solar, which sells in the countryside of western Massachusetts. "If you are going to get traction in that community, you need to be there for a decade."