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Initial Tesla partners include utilities, inverters and sales channels

Since Tesla Energy's battery system launches last week, partners and collaborators including Sunrun, SolarCity, Edison International, Fronius and SolarEdge have all provided further details. Image: Tesla.
More details have emerged on inverters for Tesla’s new home battery system, to be made by Fronius and SolarEdge, while the EV-maker's energy storage will be installed at demonstration and commercial projects for US utility Edison International.

US residential installer Sunrun, which operates mostly on a no-money down, third-party leasing model, will also partner with Tesla on sales of the Powerwall home battery system.

In Tesla’s announcement last week, CEO Elon Musk unveiled Powerwall for homes in 7kWh and 10kWh sizes, as well as larger batteries for commercial customers and bigger still for utility-scale systems, from 500kWh to 10MWh-plus, in 100kWh ‘blocks’.

Initial sales partnerships with sustainable home improvement retailer Treehouse and Vermont utility company Green Mountain Power were announced, as were inverter partners Fronius and SolarEdge.

US company Fronius’ Symo Hybrid inverter can couple Powerwall and residential PV together, with the inverter able to control both in a newly installed system. The Fronius inverter can be AC-coupled to ‘retrofits’ – in other words adding Powerwall to an existing system – or it can be DC-coupled to replace the existing inverter.

According to a statement from Fronius yesterday, the Fronius inverter will be rolled out initially to Germany, with other European markets and then Australia to follow.

Meanwhile, Israel’s SolarEdge, also named as an initial partner, has an inverter solution for Powerwall scheduled to launch by the end of this year. Like the Fronius Symo Hybrid, SolarEdge, which made its in name in PV by specialising in power optimisers, says its inverter will be capable of managing both PV array and battery.

“Tesla’s collaboration with SolarEdge unites leading organizations in two rapidly-growing industries – solar energy and energy storage – to bring homeowners a more cost-effective and integrated energy generation, storage, and consumption solution,” JB Straubel, Tesla’s CTO, said.

Utility interest

Meanwhile, California utility holding company Edison International will implement Tesla energy storage systems at residential, commercial and large industrial scale, both commercially and for demonstration projects.

Edison International’s main regulated utility subsidiary Southern California Edison (SCE) will deploy Tesla residential powerpacks to a number of customers that already have rooftop solar.

The utility’s vice president Ron Litzinger said last Friday that the two companies are seeking to “help create a market” for energy storage, with the demonstration projects in particular to be used to test the use case for batteries for providing grid-balancing demand response. While not many details have been revealed as yet, it is likely that this will entail aggregation, in other words connecting a large number of customer-sited batteries together. There will also be a demonstration programme for commercial and large industrial customers.

Customers who participate in the SCE demonstration may be given rebates on their electricity bills, while findings from the trial will hopefully help to bring down battery costs and provide new revenues from the devices. Both programmes are expected to begin during this year.

In addition, SoCore Energy, Edison International’s unregulated electricity business, which installs rooftop solar, will deploy an 800kWh system at one California cinema and a 1,200kWh system at another. Operating on a commercial basis, the battery systems will charge with off-peak electricity at night for use during the day.

Elsewhere, AEE Solar, a distributor of PV equipment and a subsidiary of Sunrun, will add Tesla’s Powerwall to its range of product offerings across the US. Tesla also already has a well known and long-standing partnership with another big residential installer, SolarCity. Musk serves as chairman of SolarCity’s board of directors.

“…limiting growth potential”

The announcements seem to begin to address some of the initial questions raised by analysts and industry commentators in the immediate wake of Musk’s press appearance last Thursday evening.

Energy storage analyst Dean Frankel of Lux Research said that the battery costs announced by Tesla starting at around US$350 per kWh for a residential system and around US$250 for utility-scale batteries were cheap. However, Frankel raised questions over the company’s supply chain, saying that Tesla would be “limiting its growth potential” without creating scaled production and supply of inverters and other power electronics. Frankel also said that installation costs and availability of financing for Powerwall systems could also be a limiting factor.

“Cheap cells made in the Gigafactory are only part of the puzzle. Unlike electric vehicles, in stationary batteries there is more of a relative cost contribution coming from power electronics, software, and installation,” Frankel said.

“Without more vertical integration – and perhaps even some acquisitions and Gigafactory-like efforts dedicated to inverters – Tesla is limiting its growth potential here.”

Similarly, Edison International’s proactive stance on energy storage and solar deployment, as well as Tesla’s partnership with Green Mountain Power, could be taken as an indication that some utilities have been following the growing case for solar-plus-storage sounding a death knell for conventional utilities’ business models and may be beginning to act accordingly.

Many, including leading financial institutions Barclays and Morgan Stanley, have forecast over the past year or so that the twin technologies pose a disruptive challenge to existing electricity markets, with some media outlets dubbing the phenomenon the “utility death spiral”.

However, some prominent solar companies including SolarCity and SunPower have told PV Tech Storage in the recent past that while the utilities’ business models may required significant rethinking, there are not many solar companies that believe PV system owners could completely “go it alone” and comfortably live without the grid in most regions of the developed world.

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