*Novelty of the Paper*

The novelty of this research lies in the complex long-term optimization of a distribution system using RES sizing and allocation simultaneously, ES sizing and allocation and energy curtailment. Furthermore, the technical aspects of distribution system operation such as generation and consumption profiles, power flows, power losses or voltage levels are included.

The above-listed objectives can be obtained by the allocation of DG which can be carried out in several ways, including versatile types of variables. The significant majority of optimisation methods focus on the DG sizing and placing only [9,17–19,22,25,36,37]. Some methods also consider the selection of the DG type [3,7,20,22,23,31,38] but none of the mentioned methods combine the allocation of RES and ES or the allocation of RES and energy curtailment.

Optimization can be carried out for different time horizons and with different time resolutions. Most of the papers present methods optimising the DG structure for a single moment, omitting the dimension of time [2,5,8–11,17–19,22,23,25,36,39–41]. This static approach does not allow us to include crucial aspects of daily demand changes or intermittent RES generation, which are included in the presented paper. In papers where intermittent RES generation is included—[4] and [7]—there is a lack of long-time planning.

In papers [3,7,20,42,43], which present methods for long-time planning, no distribution system costs were minimized.

Most of the research already performed focuses on technical aspects, such as power line constraints [16] or nodal voltage limits, and only a few of them include economic aspects such as investment and O&M costs [17,23] or total cost of energy [19,22]. Only one of the papers reviewed includes different types of loads connected to considered systems [9]. This is another novel aspect of the paper that combines technical and economic aspects of distribution system operating, including different types of loads and generation units also.

Research also exists which combines the allocation of renewable energy sources and energy storages in the distribution system [44–46]. Other papers describe different approaches to energy curtailment: Turning off generation sources [47], limiting generation to a constant level [48], generation constraints adapted to technical constraints [49] or proportional generation reduction for the whole analyzed period [50]. None of the mentioned papers, however, combine the allocation of RES and ES or the allocation of RES and energy curtailment. Furthermore, none of the papers compare which distribution development strategy is more efficient.
