Germany, Kassel: Battery storage could enable around 150 GW of additional photovoltaic capacity to connect at 1,313 rural substations in Germany by improving utilisation of existing transformers, according to a study by Fraunhofer IEE.
The study, commissioned by German solar association BSW-Solar, examined substations connecting medium- and high-voltage networks with high shares of renewable generation. Researchers calculated theoretical potential for around 150 GW of additional PV capacity supported by 60 GW of battery storage.
The analysis used actual operating data from 20 transformers at 13 substations before extrapolating the findings to the larger group through similarity analyses.
The study found that many transformers reach their capacity limits only intermittently. Battery systems could absorb generation peaks when transformer loading approaches its limit and discharge the stored electricity later.
In the reference scenario, the combined installed capacity of existing renewable generation and additional PV reaches 200 % of a transformer’s rated capacity. Under this approach, average curtailment of the additional PV capacity was calculated at around 1 %.
The researchers stress that the estimated 150 GW does not represent verified, immediately available connection capacity. The study does not include detailed assessments of grid bottlenecks or the condition of upstream and downstream network sections.
Implementation would require substations, storage and PV systems to operate as an integrated system, with power flows monitored dynamically and batteries responding to actual transformer loading.
According to the study, better utilisation of existing transformer capacity could reduce or postpone some grid expansion measures.
Source: PV Magazine
