The energy transition has resulted in fundamental changes to the energy market. Among other things, the focus is on the use of renewable energies and their integration into the existing supply while maintaining grid stability. In the liberalized energy market in Germany, the Electricity Grid Charges Ordinance, which came into force in 2005, specifies the method by which the respective grid usage charges are determined. Individual grid charges for high-load time windows and peak loads, which industrial grid customers must take into account in their calculations, are playing an increasingly important role. As a rule, medium-sized and larger companies with high electricity consumption are managed by the energy supply companies as special contract customers and are subject to power metering, which records electricity consumption in 15-minute time windows.

The annual performance price

Electricity suppliers must provide the maximum amount of energy that a company requires. The provision of this capacity is paid for via a so-called annual capacity price - even if it is only called up during certain periods. The annual capacity price is based on the peak load that occurs in a 15-minute time window and is recorded by a meter in the corresponding measuring interval. This peak load as the maximum measured electricity consumption in this time window is used as the measured active power for calculating the demand charge. The demand charge for the relevant billing period is applied if the agreed basic energy consumption is exceeded in an agreed period. For this purpose, the maximum 15-minute output in kilowatts measured in the contractually agreed period is multiplied by the demand charge in euros per kilowatt and year. Depending on the peak load, this can result in considerable additional costs. If the consumption peaks are reduced, the costs also fall.

Reduce the performance price

Active load management with the shutdown of non-critical consumers is not possible in every industrial application: in chemical processes or industrial production processes, it is often not possible to optimize consumption or even switch off energy-intensive consumers.

This is where an energy storage solution, such as that offered by Socomec, comes into its own. Here, load peaks are fed from a specially integrated energy storage system without recourse to the energy supplier.

Electricity storage and the EEG

In Germany, the Renewable Energy Sources Act (EEG) has so far hindered the use of electricity storage solutions due to the double burden of the EEG surcharge. This serves to reimburse the grid operators for the difference between the feed-in tariff for the generation of renewable energy and the lower price for the sale on the electricity market. It is paid by the end consumer. In the case of storage, the surcharge may be due twice: when storing and when withdrawing, provided the stored electricity is not fed back into the grid.

Since the beginning of 2017, the new version of the EEG - the EEG 2017 - has improved the situation by exempting storage facilities that are operated for self-supply, for example, from the double charge. The EEG surcharge is waived for storage losses and for injection to the extent that it is paid for the electricity withdrawn from storage. Proof is provided by recording all electricity volumes.

Know your own load profile

The basis for capping peak loads is the recording and evaluation of energy consumption, for example with the 'Diris Digiware' measurement solution from Socomec.

© Socomec

This elimination of the double levy paves the way for storage solutions for peak load capping in Germany. The prerequisite for using this method is knowledge of the individual load profile. A basis for the application of the energy storage solution is therefore the analysis of the causes of electricity consumption:

First of all, those responsible for planning or operations management must determine how much energy is requested and consumed in the company and when. This is done using a measuring device with power measurement. In order to record consumption accurately, the operator must ensure that the metering solution monitors the electricity consumption of as many consumption-intensive points in the company as possible. Only then is further evaluation possible, providing information on the extent of load overruns and indications for reducing and optimizing electricity consumption. By implementing suitable measures to reduce peak loads, companies can then reduce their annual electricity costs.