Many commercial and utility-scale solar projects installed at the beginning of the solar construction boom are celebrating their 10th birthday around the year 2020. But instead of something to revel, this milestone is a nuisance for many project owners given that the string inverters on these systems are nearing their average 15-year lifespans.
In a new report, Wood Mackenzie estimated that approximately 4.2 GWDC of global solar assets will run into premature failures in 2020, with the annual total jumping to 36 GWDC in 2025.
The big question is — are project owners adequately prepared for the O&M necessary to handle an influx of expired inverters between now and 2025?
The monitoring conundrum
In the study, Wood Mackenzie found the basic scope of solar O&M contracts cover very few basic maintenance activities.
Silvia Blumenschein-Schütz, CEO of solar monitoring provider Solar-Log, has found a similar theme in conversations with project owners. She recalls an EPC approaching her at a solar tradeshow in early 2020, saying he was thinking about adding monitoring to his portfolio of about 10,000 projects. She mentioned it would be helpful to also add monitoring hardware to the inverters to collect more comprehensive performance data, and he bristled at the thought of having to visit every site to install them.
“I said, ‘Don’t you go out there one time per year?’ And he looked at me and said, ‘I don’t see a need for that,'” Blumenschein-Schütz said. “If you just talk about the typical residential/commercial/industrial sector, I think we would all be surprised to learn how many sites are not properly monitored yet. People don’t know that they are losing a lot of money, and how easy it is to get back into that business to make money on the long term.”
There are plenty of options in the solar monitoring space. The technology continues to advance to alert project owners of failures or maintenance requirements with greater accuracy. But many asset owners still aren’t investing in it.
Solar-Log chief marketing officer Anne Nelson said more education is needed to show project owners the importance of monitoring.
“O&M and the idea of selling services is a relatively new topic when we’re talking about the solar market,” Nelson said.
Many first-generation solar projects were installed without monitoring, so project owners likely have no way of knowing if those aging inverters are working properly.
“When we talk about the amount of money that would be lost, especially if an inverter dies on site and is completely undetected, even a small drop means a big financial loss, but if the inverter completely dies, that’s a lot of money lost,” Nelson said. “So a lot of plant owners, if they knew that, would be totally willing to invest in having a service provider come out and add monitoring so that they can detect and protect this investment that’s supposed to last 20 to 25 years, much after the lifetime of the inverter.”
Most new inverters come with built-in monitoring options, but when sites have multiple inverter brands due to replacements over the years, monitoring is best performed by one neutral third-party system.
“I really believe it’s so important to have a neutral inverter-agnostic monitoring platform, because when we’re talking about older plants, if you have to swap out components that are not matching the brand that’s already on site, how do you monitor that unless you have a neutral system that can connect all of the different components regardless of which brand or model it is?” Nelson said.
Logistical considerations for inverter maintenance
Another issue for project owners and O&M companies is that all inverters won’t fail at the same time, costing more money for multiple one-off truck rolls to sites.
“You’re not going to be able to be super-efficient about this because they’re all going to be a bunch of one-offs and failing at different times,” said Derek Chase, CEO of O&M provider SunSystem Technology. “If you’re able to aggregate all of these and then make a mass purchase and schedule them all really smoothly with dense routes, you could really reduce the cost of all this. But nobody’s going to be that proactive — they’re just going to wait for one to go off and another one to go off. Somehow, somebody’s got to see the bigger picture here and try to aggregate all this stuff together.”
SunSystem is working on pioneering such an aggregation with Palmetto Solar for the residential solar segment. The O&M company was struggling to organize sales and financing logistics for all the individual homeowners needing inverters fixed. SunSystem decided to partner with financier Palmetto Solar to aggregate all the individual, non-leased PPA customers and sell them new inverters, service and maintenance through Palmetto’s existing financing plan. That way, residents aren’t looking at one staggering bill for an inverter replacement.
But inverter maintenance for the larger-scale solar market is more complicated. Chase thinks many asset owners still view O&M as an afterthought. He also thinks there should be more inspections to ensure systems are safe throughout their lifespans.
“There’s not even a standard and there’s no enforcement of any of this, so that’s what I think makes it be an afterthought. [Owners think], ‘Hey, whatever, if something happens we’ll figure it out,’ rather than, ‘If I don’t do this, an inspector might show up and shut our plant down and that would be bad news,'” Chase said.
Inverter manufacturer preparedness
Chase also has concerns about whether string inverter manufacturers are prepared to handle the influx of inverters approaching their 15-year lifespans that require maintenance or replacement.
When SunSystem has to troubleshoot an inverter, Chase first calls the manufacturer to verify the unit is actually dead and the warranty is out of play. Then he sees if there are any monetary breaks if the unit is replaced with that company’s product vs. switching brands.
Unfortunately, many inverter companies from the early 2010s are no longer in business. The inverter market has always been volatile, with high-profile company exits and acquisitions happening almost every year. Even if the original manufacturer is still in business, 10-year-old inverters most likely are out of warranty.
For those companies still around, SunSystem’s team of 170 technicians has found that calling a manufacturer to help diagnose specific inverter issues can take up to an hour.
“If you multiply that by 170 technicians, plus whatever other technicians are out there from different companies, the amount of just sheer on-hold time from a labor cost standpoint is crazy,” Chase said.
He thinks inverter manufacturers should either scale-up their customer service workforce or offer digital solutions that allow technicians to submit return merchandise authorization requests through an app or similar streamlined process.
String inverter manufacturer CPS America has heard the customer service issues from O&M technicians and is working on solutions to streamline the process. The company uses RingCentral to route calls and has a goal for a human representative to answer the phone 90% of the time.
CPS also launched an Authorized Service Provider training program in early 2020 to help O&M techs learn specifics about its inverter line to help them troubleshoot in the field by themselves. The training is virtual and also offered at the company’s Texas headquarters, which helps O&M techs form relationships with CPS workers.
“The inverter companies are squeezed and under pressure. Not every inverter company has enough resources to be able to answer the phone all the time,” said Ed Heacox, general manager of CPS America. “One way to help make sure good service is available is to anticipate it and get the relationships in place in the region.”
CPS has warehouses full of refurbished spare inverter models available for O&M technicians to swap with failed units. But as 2025 gets closer and old units start reaching end-of-life en masse, that stockpile will eventually run out.
“In addition to checking with suppliers like us on readiness to support the field, another diligence some companies are going through is thinking ahead to, well, what’s a reasonable retrofit of an old site to a modern inverter?” Heacox said.
He expects retrofitting to grow in popularity as the original inverter fleet ages, whether it’s replacing old central inverters with string, replacing 600-V inverters with 1,000-V or higher, or other configurations.
SunSystem’s Chase said typically the most affordable solution in the case of string inverter failures would be to swap with another string inverter, but systems may have more longevity if the old string inverters are swapped in favor of new technology like string inverters with optimizers, or even microinverters. It may also be an opportune time to add storage to projects.
“One thing that I always tell everybody — if you’re going to get a new inverter [or] make any investments — your first dollars need to go toward a monitoring system,” Chase said.
Detecting that an inverter is down in the first place is crucial as early inverters inch closer to their 15-year lifespans.
“We’re 10 years in now. It’s a perfect time to go back to your original customer base and say, ‘Hey, you could be losing money, let’s take a look at the system. Let’s install adequate professional monitoring so we can detect these issues,'” said Nelson.