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A graph showing cost breakdown of Ganti's project

BYOP: Bring Your Own Power

House in California turns into a real-life test bed for a smart, renewable, and affordable energy grid.

Perhaps there is no better personification of the idiom to “practice what you preach” than Vish Ganti, director of Strategy & Business Development at AutoGrid.

AutoGrid builds enterprise data software to help utilities, electric retailers, renewable energy project developers, and energy service providers deliver on the promise of a smart, renewable, clean, and affordable energy grid. Ganti took the company’s mission to heart as he set about turning his new house in East Bay, California, into a real-life test bed for just such a smart, renewable and affordable grid — one that uses rooftop solar and residential storage (Tesla Powerwalls) to make Ganti’s home essentially “energy neutral” — he uses only as much or less than he takes from the grid.

Along the way, Ganti said he also “secret shopped” an AutoGrid partner, Swell Energy, and used his own experiences to promote a new Swell Energy-AutoGrid partnership designed to help other California homeowners become “energy independent” themselves.

It all started when he bought the house in 2017. The 1500-sq ft detached single-family home came with one important feature that gave Ganti a slight jump-start on his energy independence quest — it came with a 5-kW standard photovoltaic (PV) system with 20 roof-mounted solar panels commissioned in August 2016.

“One of the attractive things about this house was the fact that it was fully upgraded with energy-efficient products,” Ganti recalled. “I knew right out of the gate that this house will allow me to apply my background in energy, internet of things (IoT), and technology to do some pretty cool stuff.”

That “pretty cool stuff” started with the house’s solar PV system, but Ganti quickly added an assortment of smart IoT devices such as programmable thermostats, Energy-Star rated appliances, dimmable LEDs, room sensors, and a 240-V Level 2 EVSE charger for his Chevy Volt.

“I researched about home automation gateways (HAN devices) on Amazon and found a few different options under US$100,” Ganti noted. “I picked Samsung SmartThings as my platform of choice, primarily for its developer friendly options and high-quality radios. It came out of the box with support for Zigbee, Z-Wave Plus, Wi-Fi enough to get the ball rolling.”

Once that ball started rolling, Ganti was on to the next step in his home energy planning — onsite local storage. “Traditionally, you start with the energy efficiency steps,” Ganti said. “Smart thermostats. Sensors. Next you get solar and the third step is storage. I was just able to bypass the solar as the house already had it when I bought it.”

Prior to selecting his batteries, Ganti did a full energy analysis of his house. Among the highlights were that his average daily energy production from the solar panels was 28 kWh, most of which was not used (beyond a base load of 250 W that was “always on”). His draw spiked in the mornings and at the end of the work day, as would be expected, and he said his usage actually mimicked the classic CAISO “Duck Curve” wherein the house’s demand swung from 4 kW during daytime solar plus 4 kW as EV charging kicked in, a spread of 8 kW. The monthly peak demand level was also under 8 kW, and so he set out to find storage units that would handle that 8-kW load to cover worst-case scenarios. Ganti settled on two Tesla Powerwalls.

Ganti's daily home load curve as charted at the start of project

Ganti’s Daily Home Load Curve as charted at the start of his project, showing typical spikes in the early morning hours and end of the work day.

All About the Money

At this stage of his design, Ganti had gotten plenty of bang for his buck without putting up much bucks again, the solar panels were in when he bought the house, and even qualified him for a preferred rate from local utility Pacific Gas & Electric Co. (PG&E) since the solar panels had been commissioned in 2016. Now, though, with storage being added to the mix, Ganti was going to have to part with some capital temporarily.

Ganti estimated his gross project costs to add storage came to US$21,820. Tesla would want its money up front, but Ganti took advantage of a California program called PACE, which allowed him to embed the capital cost into his annual tax bills. Using PACE financing, Ganti was able to “loan” most of the US$20,000 he needed, to be paid back as he applied for, qualified for, and later received state and federal tax incentives that would cover most of the cost.

In the end, Ganti received a California Self Generation Incentive (SGIP) payment of nearly US$9820, covering 43% of his capital costs, a US$5811 Federal Investment Tax Credit (ITC) to cover another 27% of the cost (his system qualified because it married solar plus storage), as well as a preferred early adopter discount of about US$2500 (another 11% of the cost) from Swell Energy, the company he admitted to “secret shopping” and that he chose to handle his installation.

The end result is that Ganti now pays only a US$10-per-month connection fee to remain on the system and be able to use grid power when needed as well as wheel it back out to PG&E when his solar panels generate more than the house can use. He’s on a net-metering plan with PG&E but doesn’t think he’s paid anything (beyond the monthly connection fee) for energy for over a year now. He’s proud of the fact that not only is he saving on his own energy bills, but is also doing his small part to cut carbon emissions. And for Ganti, the opportunity to piece together his own independent energy program contained tremendous appeal.

That said, he cautions it is not for everyone. “It took about six months for the state to approve my application for the SGIP incentive,” Ganti said. “By and large that will still be the case with anyone trying this on their own. Then you have the Federal ITC, which is another application process. If you to use PACE or some other financing program, you have to find and apply to that.”

Ganti also ran into a potential problem with Tesla. While waiting for his Powerwalls to be delivered, the battery maker had begun shipping most of its new production to Puerto Rico to help in the Hurricane Maria aftermath and ongoing rebuild of distribution there.

“In my case,” Ganti quipped, “Puerto Rico got in the way. So, anything can happen.”

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