Problem

Our customer EWE NETZ has some of the highest penetration levels of renewable generation in Germany. Previous regulation meant that they are responsible for upgrading the network to accommodate and passing on the cost of these upgrades to consumers. As well as increasing costs to consumers, the timescales to construct upgrades are not in line with DER customer expectation therefore they are faced reputational risk with DER customers as well as retail customers. Existing regulation allows them to curtail and compensate renewable generation in certain circumstances (e.g. overload) based on real time measurements and with compensation of DER customers. Since the so-called 3% rule in Germany (legally permitted by the German EnWG 2017; meanwhile expanded to 5% by EU’s Clean Energy Package 2019) it’s allowed to use curtailment without former legally required network expansion.

Solution

This curtailment is today manually carried out by SCADA operator in discrete active power blocks (0%, 30%, 60% or 100%). Since compensation payments are further increasing the cost of energy for retail consumers of EWE NETZ, Strata Grid is being used to deliver dynamic real-time curtailment for more efficiency and reduces the burden on the SCADA operator. Strata Grid monitors critical grid locations by available measurements and implements minimal real-time curtailment actions when flexibility services cannot be procured or other network events occur. Strata Grid delivers the ‘Red’ light of the traffic light concept which ensures no detrimental impact to network reliability from relying on flexibility solutions.

Result

Strata Grid successfully passed over 35 small-scale laboratory-tests in a comparison test with other vendors in the enera project (www.energie-vernetzen.de). The solution is currently in integration in all the existing utility systems of EWE NETZ and is moving to field trial ahead of roll-out.