PV inverter manufacturer Power One has said that energy storage is part of "its vision for the next step of the PV market".

The company showcased a selection of its products at the Ecobuild show in London this week, including a battery-based energy storage system for use in combination with PV.

The company’s new battery storage system REACT (Renewable Energy Accumulator and Conversion Technology), has been launched so far in Germany and Italy and consists of a 4.6kW single-phase grid-connected inverter coupled with a lithium-ion battery.

PV Tech spoke to Cesare Lancini, Power One’s product marketing manager for renewable energies at the show.

Lancini explained that the storage unit is not intended to enable total self-consumption or off-grid use. Instead REACT is designed to match the electricity production curve to the consumption curve as much as possible. According to Lancini, in a post-tariff world, products such as REACT will be more and more important in adding value and benefits to PV system use.

“It’s part of Power One’s vision for the next step of the PV market. At the moment in the UK for example, you still have the feed-in tariff, you are still earning money for generating electricity. In a mature market like Germany or Italy, [the removal of the tariff] has effected a change in the paradigm in the minds of people looking to own PV – they are not earning money, they are saving money.”

The PV inverter is matched with a 2kWh battery. According to Lancini the battery is 2kWh ‘effective’ because the actual size of the battery is 2.6kWh and only needs to be charged and discharged to 40%.

“The life cycle of the battery is the most critical and expensive component so we want to protect the life of the battery as much as possible. The battery will last 10,000 cycles. We are using lithium-ion batteries. It sounds silly but the best use of the battery is not to use the battery; a high portion of the cost of the system comes from the battery. We are still waiting for battery manufacturers' claim that the increasing volume of batteries supplied to the EV industry will bring down prices to come true. Mass production is the only way to reduce the price. So for now, the best use of the battery is not to use it!"

“Why choose 2kWh? Why not 1kWh and why not 10kWh? It’s a compromise between the extremely high cost of the battery – a 10kWh battery could cost 25,000 Euros and you will never pay that back for the system. So we ran simulations with environmental predictions and load profile and the trade-off, the optimum solution is between the cost and the benefit is 2kWh. However you can expand the battery pack by up to 6kWh.”

The company, which was acquired by industrial giant ABB last year, showed the REACT system alongside inverters such as the TRIO-5.8/7.5./8.5-TL-OUTD, a new three-phase inverter and the AURORA MICRO-0.25-I and AURORA MICRO-0.3-I micro-inverters for residential systems. The company also exhibited the string inverter range TRIO-27.6 and TRIO-20.0, suitable for large rooftop applications.

Sales manager David Lowen revealed to PV Tech at the show that the company is looking to pilot a large-scale installation with storage in the UK, although further details were not forthcoming at this stage with the idea still at the discussion stage.

According to Lowen, the company expect the large-scale storage market to pick up pace in the near future, as predicted by analysts including IHS.

Explaining the scope for energy storage use, Lowen said: “Put simply, some people are restricted by grid connection but not by how much land they’ve got. So, grid connection is only effective when the sun’s shining. So if you have 2MW of available grid connection and then put in 4MW of solar panels and 2MW of storage, you can store the energy and continue to use the 2MW grid connection through the night, feeding it back into the grid. I can’t tell you if that’s going to work but it’s something we are seriously looking at. Like all money matters, if the sums add up it’ll work, if they don’t add up, it won’t.”

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