75% of Australia’s 3.3 million rooftop solar systems likely to be underperforming

Some 75% of residential rooftop solar systems are not passing on the full extent of electricity bill savings they are capable of delivering.

That's because they are not working properly or because they are paired with the wrong retail energy deal.

Solar monitoring company Solar Analytics used data from its own pool of 35,000 customers, and from industry statisticians SunWiz, and found a significant number of Australia’s 3.3 million rooftop solar systems are likely to be underperforming.

Solar Analytics recommends using a solar monitoring system that is designed to detect system faults and get them sorted as quickly as possible. Their system also offers weekly updates on the best energy deal to optimise each household’s solar savings.

But for those who don’t have solar monitoring, and aren’t retired engineers, it can be easy to miss the signs of an underperforming solar system.

Stefan Jarnason, the co-founder and CEO of Solar Analytics, says it could take a regular household up to three months to notice even a major drop off in solar production reflected in their energy bill.

But in more marginal cases, some households might never notice that they are not saving as much as they could be if their system was working to its full capacity or paired with a better retail deal.

Jarnason says it's particularly difficult to know now because of two complicating factors.

"First is lots of people are working from home and seasons are changing – they might be changing how they use energy, so their energy use is more variable over the last year or two.

“The other [complicating factor] … is energy prices are going up and they’re about to go up by another 23% in July again.” he says.

It makes it hard for someone who sees their bill go up by $20 a month to paying $80 a month to know whether something is wrong, or they're on the wrong plan, or because the cost of energy has gone up.

Nevertheless, the extra savings that can be made from the early detection of faults, or through switching to better plans, can be far from marginal.

Solar Analytics estimates that using monitoring software to identify and fix any faults with your rooftop solar system faster can save an average rooftop PV owner $312 a year.

And being on the wrong electricity plan can cost a household an extra $400 a year or more.

‍

How do you know if you’re not getting the right bang for buck?

The best way is to invest in solar monitoring. There are a number of options available. Some solar retailers or solar inverter brands offer the service as part of the installation, or as a small added cost during installation.

Monitoring programs like Solar Analytics, are not generally free. Solar Analytics provides a software only option for their monitoring service, at $60 a year – and offfers a free 30-day trial first to try it out.

If you don’t have or don't want monitoring, the next best bet is to get your system serviced regularly, to make sure it’s working to its best capabilities.

And to check if you’re on the best retail plan, there’s always services like Energy Made Easy, a federal government site, or other state-based offerings.

‍

My solar is working, I’m on a good plan, but my bill’s still going up – what next?

“What solar customers want is a tiny bill,” says Stefan Jarnason, and he recommends a few ways to help that happen, including installing as much solar as possible.

“As an environmentalist, my advice is to cover your roof,” he says. “As a pragmatist, it’s put on as much as you can afford.”

Beyond this point, things aren't so black and white.

Jarnason says that, currently, only 10% of solar households will make a positive return on investment in a home battery.

However, that’s likely to jump to around 30% within months, as grid energy prices rise. In the longer term, the economics of installing a home battery is also expected to improve.

Solar Analytics provide a battery calculator which gives all the different sizes of batteries on the market, and recommends one based on current usage that gives the best return on investment. It also recommends a plan and outlines how much a household can be independent from the grid.

“We’re not pushing batteries. We have no stake in your getting a battery or not. What we’re doing is just giving you independent, unbiased, accurate information on what [a battery] would actually do for you.”

The next frontier for Solar Analaytics is hot water. They plan to set up a calculator to work out the cost benefit analysis for switching a customer from gas to electric.

From research done so far, Jarnason’s best estimates is that it makes good economic sense for two out of three people with gas hot water systems to switch to heat pumps.

‍

An economic rule of thumb for energy independence and decarbonisation

“Cover your roof with solar, get off the gas, add a battery, and then buy an electric vehicle. That’s the order of economic value for the typical person,” says Stefan Jarnason.

And if you drive more than 15,000km or 20,000km a year "get solar first, then get an EV, and then get off the gas and get a battery.”

‍

The original of this article was first published on One Step off the Grid. You can read it here.