Private solar power storage systems can relieve the grid
The range of battery storage systems for photovoltaic installations is growing dynamically. The benefits offered by these storage systems for both solar system operators and the entire energy system were therefore discussed by solar and storage experts in December 2013 in Frankfurt am Main. Their conclusion: Decentralised solar power storage systems in private households could provide one of the few functioning business models for stationary battery storage systems for the foreseeable future.
“With the PV Benefitproject, we are for the first time comprehensively investigating the benefits that can be provided by storing solar power – not just in commercial terms for system operators but also for the grid, economy, environment and entire energy system,” explains Professor Bernd Hirschl from the Institute for Ecological Economy Research (IÖW). “Since the prices for battery systems are sinking, it is becoming increasingly difficult for commercial storage systems to offer system services for electricity grids on the basis of short-term contracts. The yield produced by the self-consumption of photovoltaic power, on the other hand, provides decentralised storage systems in private households with a stable revenue model while at the same time considerably lowering the capital costs. They ought soon to become financially worthwhile without subsidies,” adds Professor Dirk Uwe Sauer, a storage expert at the Institute for Power Electronics and Electrical Drives (ISEA) and head of the research project.
Utilising solar power storage systems to serve the grid
In the ideal case, decentralised solar power storage systems not only ensure that as much self-generated electricity can be used at home as is possible, and therefore that less electricity has to be subsidised through the Renewable Energy Sources Act (EEG), it also means that “the storage systems can also relieve the electricity grids and thus limit the necessary expansion of the grid,” explains Dr. Ralf Puffer from the Institute for High Voltage Technology (IFHT). How that can succeed was discussed by the experts in terms of the possible impacts that photovoltaic installations and storage systems could have on both the grid and the grid development costs. The central key in this regard is provided by the so-called “grid-serving operating strategies”, which, however, could conflict with the interests of the system operators to maximise their self-consumption. “However, the incentives that are necessary to ensure that PV system owners also operate their storage systems so that they serve the energy system and the grid are still unclear and are currently being investigated by us,” adds Sauer.
The “PV Benefit” project is being funded by the German Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety until May 2015. Further details are provided by the project business card and the “PV Benefit” project website.