SolarEdge and SMA’s launches of inverters compatible with Tesla’s Powerwall and LG Chem’s new range mark a “growing trend” towards higher voltage batteries for residential PV systems, an IHS analyst has said.
Marianne Boust, a principal analyst on power technologies with the research firm, told Energy-Storage.News this morning that she anticipated that higher voltage batteries, already used in the EV industry and typically 250-450V, “will eventually be commonly used in the stationary energy storage market as well”.
This week, SolarEdge, which along with Fronius was one of the first two inverter makers with Powerwall-compatible products available, confirmed that LG Chem’s RESU10H and RESU7H batteries can also be used with Storedge, SolarEdge’s energy storage solution for PV self-consumption. Meanwhile, SMA’s Powerwall-compatible Sunny Boy Storage 2.5 solution was launched into the UK market this week, having already been available in Germany since April. Sunny Boy Storage will also be available in Europe and Australia soon, according to SMA.
SMA’s AC-coupled solution can be integrated into a new or existing solar PV system, whereas SolarEdge’s Storedge includes a DC optimised inverter and can be used in both DC- and AC-coupled settings. SolarEdge also claims that Storedge reduces voltage to a “safe level upon AC shutdown”. Boust described this “small DC/DC converter to reduce voltage at the consumer connection point” as a competitive advantage for SolarEdge’s product.
SMA emphasised the “flexibility” that its combination of AC-coupling and high voltage could enable, especially for retrofit installation and has aimed it at households still on high existing feed-in tariffs as well as for new PV system owners who want to maximise self-consumption. SolarEdge meanwhile touted the ability of its energy management systems to manage both solar and storage and said existing SolarEdge systems can be adapted to fit the new product set.
'High voltage shift is not a one-off announcement'
“We see the shift towards high-voltage batteries as a growing trend and not just a one-off announcement, although low-voltage batteries are likely to retain a large market share,” IHS’ Marianne Boust said.
“Currently the majority of the residential storage market is driven by 48V products – with the exception of Japan – as it’s safer for the consumers. Furthermore 48V has been a standard in many industrial and telecom applications,” Boust said, adding that lead acid-based systems do not require the same internal safety measures as lithium and therefore use lower voltages.
According to Boust, storage makers and PV system integrators are increasingly considering higher voltage batteries for a number of reasons. Less cabling is needed – and therefore equipment costs are reduced – while conversion losses are also reduced.
Marianne Boust also said that the partnerships already seen between inverter and power electronics makers and battery or storage system suppliers are likely continue to be forged.
“These systems are likely to be driven via partnerships between PV inverters and battery manufacturers and products would be sold as integrated package like SolarEdge with Tesla.”
An SMA spokesman told Energy-Storage.News this morning that the company is expected to announce compatibility with further battery systems at next week’s Intersolar Europe show in Munich, Germany.
SMA's UK market prediction and 1995 PV system gets battery
In announcing the UK launch of Sunny Boy Storage 2.5, SMA’s UK head of sales predicted the UK residential storage market would number around 1,000 to 2,000 units this year, “due to limited availability of batteries”. SMA’s James Felstead said that beyond this modest number, the retrofit market for some 750,000 existing residential rooftop PV systems would be likely to dominate in the immediate future.
In related news, the SMA spokesman told Energy-Storage.News that the company’s first ever UK residential rooftop project, installed as an integrated solution in 1995 at an ‘Eco house’ in Oxford, England, has been fitted with an energy storage system that has over the past few weeks already saved about 30% of electricity costs through enabling self-consumption of solar and evening use of shifted PV power.