Activating current and future flexibility potential in the distribution grid...

Full presentation title: Activating current and future flexibility potential in the distribution grid through local energy markets.

Objectives and context

Increasing shares of small-scale volatile generation as well as additional peak demand through electric vehicles and heat-pumps challenges the stable operation of current and especially future distribution grids. In order to cope with these challenges, e.g. the overloading of lines, transformers or grid assets, several approaches to reduce peak feed-in and demand are possible. This could for example be the curtailment of variable feed-in or peak loads or activation of demand-side flexibility through time of use tariffs or other variable pricing schemes. Local Energy Markets (LEMs) are a promising alternative concept to combine various of these measures and activate untapped flexibility potential of the demand- and generation-side as well as storages.

Methods

In this paper we propose a LEM mechanism which is able to explicitly consider demand, generation and storage flexibility in the form of flexibility orders. This approach allows participants with an electric battery storage for instance to bring unused storage capacity to the market without being exposed to price forecast errors. The market matching process is formulated as a linear optimization problem is presented that, e.g., overcomes the risk that electric vehicles would all attempt to charge in hours with the lowest electricity price thus potentially overloading the distribution grid. 

Through the simulation of a concrete LEM in a rural region of Germany (Wildpoldsried, Allgäu region) with high renewable feed-in, we demonstrate the effects of the proposed LEM for the current situation and a future scenario with additional load through electric vehicles and heat-pumps.

Outcomes and Conclusion

The simulation shows that, compared to a business as usual case, the LEM provides peak-shaving of PV feed-in during midday as well as reduced peak demand through EVs of up to 26% of the load at the transformer. Untapped flexibility potential of electric storages and heat-pumps can be harvested already in the current system. In a future scenario, more severe peak demands through EV charging are distributed over a longer charging period at night. Moreover, we show that a participation in the LEM allows owners of flexible assets to additionally profit from the activated flexibility potential of their assets. Finally, we also show the market mechanism ensures that the limits set by the distribution grid operator are respected.