Aggregating and Disaggregating Flexibility Objects

Abstract

In many scientific and commercial domains we encounter flexibility objects, i.e., objects with explicit flexibilities in a time and an amount dimension (e.g., energy or product amount). Applications of flexibility objects require novel and efficient techniques capable of handling large amounts of such objects while preserving flexibility. Hence, this paper formally defines the concept of flexibility objects (flex-objects) and provides a novel and efficient solution for aggregating and disaggregating flex-objects. Out of the broad range of possible applications, this paper will focus on smart grid energy data management and discuss strategies for aggregation and disaggregation of flex-objects while retaining flexibility. This paper further extends these approaches beyond flex-objects originating from energy consumption by additionally considering flex-objects originating from energy production and aiming at energy balancing during aggregation. In more detail, this paper considers the complete life cycle of flex-objects: aggregation, disaggregation, associated requirements, efficient incremental computation, and balance aggregation techniques. Extensive experiments based on real-world data from the energy domain show that the proposed solutions provide good performance while satisfying the strict requirements.

Aggregating energy flexibilities under constraints

“…We consider, based on [10], traditional aggregation of FOs to be the function that given a set of FOs returns an aggregated one, taking into account the time and amount flexibilities of the FOs. Given a set of FOs, there are different alignments respectively, the number of the aggregation results (AFOs) that can be produced is:…”

“…N (20, 1), [19,21] N (8, 1), [5,10] U {2, 4} U {3, 4}, U {1, 2} 0 HP (day) N (13, 1), [12,14] Table I.…”

“…We compare our techniques with Start Alignment (SA) aggregation [10] (see Section III-A where all the FOs are aggregated into one FO). We also use a Start Alignment with Grouping (SAG) aggregation technique where a grouping phase is used in advance [10]. Consequently, FOs with the same earliest start time and the same time flexibility are grouped together and SA is applied on each group.…”

“…Using traditional aggregation techniques [10], the FOs are aggregated resulting in aggregated FOs (AFOs). As illustrated in Figure 1, the four FOs 1 are aggregated into two AFOs 2 .…”

Balancing Energy Flexibilities Through Aggregation

“…Furthermore, aggregation that takes into account flexibilities with a flexoffer use case evaluation has been investigated in [19]. Scheduling aggregated flex-offers that only represent energy consumption and introducing aggregation as a pre-step of scheduling has been investigated in [18].…”