SMA launches a DC-coupled grid-forming solar-plus-storage system
Serguey Asael Shinder2 min readSMA has launched a solar-plus-storage system in which grid-forming control covers the whole plant rather than just the battery. Its Australian subsidiary presented the product at All-Energy Australia in Melbourne on 27 October, Energy-Storage.news reported, and said the first markets will be Germany, Australia and the UK.
Most solar plants and batteries use grid-following inverters, which track the voltage and frequency of the grid. Grid-forming inverters set their own references and respond to disturbances in a way that resembles the spinning generators of coal and gas plants, which is why grid operators increasingly ask for them as conventional plants close.
In SMA's design the solar modules and the battery share one inverter connection on the direct-current side. When solar output is higher than the inverter can pass to the grid, that surplus would normally be clipped and lost; here it charges the battery for later dispatch. The package combines power conversion equipment, plant controls and engineering support, which SMA says spares developers the work of coordinating equipment from several suppliers. It uses silicon carbide semiconductors and quotes DC/DC conversion efficiency of up to 99.5%.
SMA says more than 10 GW of its solar and battery inverter capacity is connected in Australia, and that this year it has received approvals for more than 6 GW of grid-forming battery and hybrid projects in the National Electricity Market under clause 5.3.4A of the National Electricity Rules, the process that sets a project's technical performance standards. Its grid-forming inverters run at Origin Energy's 300 MW/650 MWh Mortlake battery in Victoria.
What it means
Grid-forming capability has so far been something added to standalone batteries. Putting it on the shared DC bus lets one connection provide both the energy shifting and the system-strength service that operators such as AEMO now prioritise. For developers in markets with strict connection rules, a single supplier for the whole plant is also a way to shorten the technical approval that often delays projects more than the hardware does.