A consortium led by the Austrian Institute of Technology will soon publish results from the LEAFS (Integration of Loads and Electric Storage Systems into Advanced Flexibility Schemes for LV Networks) project to measure the impact of increased use of energy storage systems and load flexibility on low voltage power distribution grids.
The final report from LEAFS to be published this summer will present findings from a wide range of potential approaches to managing distributed energy resources and demand-response programmes. Technologies and operation strategies have been studied for the past three years where the local grid operator uses direct or indirect control of distributed flexibility, a central storage system and/or incentives to activate flexibilities from more than 100 customers in order to optimise the distribution grid infrastructure.
The research has flagged a potential concern that market-based algorithms to activate flexibility might trigger congestion problems if customer load is switched on at the same time, AIT senior research engineer Johannes Kathan tells Engerati. “It can cause significant higher power levels and in low voltage grid areas and equipment might be overloaded,” he says.
The LEAFS project looked at many different scenarios with varying levels of DSO control. In the base level the DSO sets operational boundary conditions (based on weather-dependant forecasts of solar PV supply) to avoid thermal overload or voltage band violations in localised areas. Depending on the available infrastructure the DSO is additionally able to transmit the market signal as an infrastructure provider. In the third concept the DSO has full control over the flexibility asset (a central storage system in this case) and take corrective action to actively improve grid quality.
A more significant impact on the grid can be caused by the load side, he says, as a larger flexibility potential is already available and will be expected in the future. Additionally, generators already have a comprehensive set of functions to avoid voltage band violations. However, the project has demonstrated that with different measures such as flexible energy tariffs a small economic benefit can be achieved for the customer – in best cases up to €200/year.
The project is funded by the Austrian Climate and Energy Fund within the programme Energieforschung 2014. Consortium partners include: AIT Austrian Institute of Technology (Project management), Fronius International, Siemens, Salzburg Netz, Netz Oberösterreich, Energienetze Steiermark, TU Wien (University of Technology Vienna) – Energy Economics Group, Energy Institute at the Johannes Kepler University (JKU) Linz, MOOSMOAR Energies.