The Efficiency of the Solar Roof

A Tesla Solar Roof owner recently put out a video detailing how their system has allowed them to live for a whole year without paying for electricity.

Marques Brownlee is a YouTuber who runs a tech review channel. On July 28th, he posted a video entitled "Tesla Solar Roof Review: Was it Worth It?". In the video, Marques lays out the whole process he went through to get a Tesla Solar Roof installed, and how it worked.

The details themselves are very interesting, but the main point is that his Solar Roof system - coupled with a three-unit Powerwall setup - was able to produce and store enough electricity to power the home - and charge Brownlee's Tesla vehicle - for the whole year.

This was mostly achieved using local power credit programs. Almost every place has some sort of program that rewards users for producing more electricity than they need and feeding it back into the grid.

As it turned out, Spring and Fall were the best times for solar coverage for the area Marques lives. Summer heat brings not only more storms, but also more draw from the air conditioning unit - while winter months see very little sun at all - so don’t end up making much energy.

Solar cells can actually gain some power on cloudy days - anyone who gets sunburned on cloudy days can vouch for the Sun's ability to send UV radiation through the clouds.

But charging a Tesla vehicle takes a large portion of a home's power draw, and during the winter, the solar output just couldn't cover it all. Had Marques not owned an electric vehicle, he believes his home would have not needed help from the grid at all.

Regardless, Brownlee’s energy credits from earlier in the year more than paid for the small dips into the public power grid during the winter, so he still didn’t have to pay for anything - with the exception of a $5.75 service charge from the Grid management company that is, you can’t escape bureaucracy I guess.

Marques was also very excited at the prospect of Tesla vehicles gaining the ability to make use of bi-directional charging - having the vehicles able to take and give power to the home in cases of emergency. He said that his Model S is the rough equivalent to 7 or 8 Powerwall batteries once fully charged, and it would certainly help his system deal with low-power times if his car could act as another battery.

There were some problems of course - setting up a solar roof system isn’t cheap by any stretch, and so likely out of reach for even those of us wealthy enough to own homes these days. Marques paid about $121,000 for the system plus installation. This was brought down to just over $90k after tax rebates, but that’s about as much as a home’s down-payment in some places.

Marques said that he made the choice for a more expensive Tesla system so that everything in the home from his car to the roof tiles worked on the Tesla network - there were cheaper options, but his thought was that it’s best to go with hardware that can interface easily.

Aside from the hefty price tag, there was an over 8-month process to get the roof installed. Solar roof panels are not standard roofing materials, so paperwork needed to be filed with Brownlee’s local construction authority. Luckily, Tesla supplies Solar Roof customers with an advisor from the company who helps with all the local paperwork, which is a very good service.

So there’s some hurdles at setup for sure - but that’s true of every solar system for a home. The big takeaway from this story is that we’re at a point where we can say that not only is solar a functional option for powering a person’s home - but it’s getting to be a relatively affordable option - compared to what solar systems used to be priced at anyhow.

And that’s reflected in the amount of sales made for the product this year.

Like most of his products, CEO Elon Musk had high hopes for the Solar Roof after Tesla acquired Solar Cities in 2016. He had wanted to produce over 1000 roofs per week by 2019 - a goal which obviously didn’t happen. “Relatively Affordable” doesn’t mean “actually affordable” and so the product has been cancelled and re-activated in the intervening time.

But with energy bills increasing to unsustainable amounts, more and more people are buying Tesla’s energy products - from batteries to solar panels to full solar roofs. And Tesla’s plans to expand their production capabilities to take advantage of the US Inflation Reduction Act includes their solar and battery products.

And Marques did mention that those federal rebates are only getting larger - so if you do happen to own your own home, now might be a good time to see about adding some solar to your roof, and take some load off that ageing local power grid.