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Advanced methodology and tools taking advantage of storage and FLEXibility in transmission and distribution grid PLANning

Periodic Reporting for period 1 - FlexPlan (Advanced methodology and tools taking advantage of storage and FLEXibility in transmission and distribution grid PLANning)

Reporting period: 2019-10-01 to 2021-03-31

In the last years, we are assisting to a high-speed deployment of Renewable Energy Sources (RES) in electric Transmission and Distribution (T&D) grids as well as to an increased penetration of Distributed Energy Sources (DER) in distribution grids. These phenomena are making grid planning activities more and more complex and affected by a high level of uncertainty.
Grid investments are capital intensive and infrastructures lifetime spans over several decades. Due to widespread RES and DER deployment, the generation and load scenarios upon which the cost-benefit analyses for new grid infrastructures are based are continuously and rapidly changing. As a consequence, when a new line is commissioned, the technical-economic benefits it was initially supposed to provide could prove significantly lower than expected.
Additionally, building new lines meets more and more hostility from the public opinion, which makes planning activities even longer and affected by uncertainties.
Variable flows from RES are generating a new type of intermittent congestion which can sometimes be better compensated by resorting to system flexibility: in many cases, an investment in a new line/cable would not be economically justified.
On this pathway, the FlexPlan project aims at establishing a new T&D grid planning methodology considering the opportunity to install new storage devices as well as to perform a flexible exercise of some loads located in selected grid nodes as an alternative to building new lines. Local compensation of RES generation spikes could allow to reduce the amount of congestion the grid is exposed to with a less expensive and less environment-impacting intervention.
FlexPlan aims at providing the following contributions:
• development of a new methodology and of a new tool optimizing T&D planning by considering the placement of new storage devices as well as the flexible exercise of some loads in selected grid nodes as an alternative to traditional grid planning;
• application of this methodology to perform a grid planning analysis over six European regional cases by considering both the mid- and the long-term (2030, 2040, 2050) in one only optimization process. In addition, pan-European scenarios are run as well, in order to establish consistent border conditions for all 6 regional cases;
• elaboration of regulatory guidelines aimed at providing National Regulatory Authorities with indications on the opportune regulation to be adopted for maximizing the benefits that can be obtained with the new grid planning methodology. These guidelines will be built by considering the potential role of flexibility and storage as a support of T&D planning, resulting from the outcome of the six regional cases.
During the first project period (from month M1 till M18), the whole modeling framework has been set and first prototypes have been created for the two main tools (the planning tool and the pre-processor). Those prototypes, which implement, for the moment, only part of the functionalities, have started their complex validation process by availing themselves of a set of reduced scale models. Such models are also indispensable for validating specific aspects of the modeling framework. Due to this, it was decided to give much emphasis to the creation of small scale models and their number and ambition has grown beyond what is described in Annex I of the Grant Agreement.
In parallel, scenario storylines have been set for the project, by adopting as a reference the three scenarios described in the ENTSO-E Ten-Year Network Development Plan 2020 and by extending them to the year 2050. The extra-high voltage network was provided by ENTSO-E for all covered countries, except for the Nordic region for which the ENTSO-E model doesn’t include grid details. Beyond the extra-high voltage of the Nordic Countries, the full sub-transmission grid layer was re-created on the basis of information drawn from Open Street Map as well as internal know-how of the project beneficiaries. This grid layer is important also because it constitutes the tie between the extra-high voltage section and the distribution grids. The methodology to model distribution grids has also been set during P1: due to the huge extension of real distribution systems, including the full extent of them would be too demanding both from the computational point of view and in consideration of the amount of requested data, usually not publicly available. Therefore it was chosen to elaborate equivalent “synthetic” distribution networks having the same characteristics as the real ones because synthesized by starting from statistics on real networks. Additionally, nodal data were collected for both the generators and loads included in the six regional cases.
During P1, pan-European scenarios were elaborated as well in order to provide a consistent set of border conditions for the six regional cases.
Finally, a thorough analysis on the present regulation trends at EU level was carried out as a first stage towards the elaboration of the final regulatory guidelines: the current EU legislative provisions have been analyzed alongside with position papers of the main stakeholders. Beyond constituting a first step towards the elaboration of the planning guidelines, this activity has been key for setting a realistic background for the methodological framework and the scenarios elaborated by the project.
The new planning methodology elaborated by FlexPlan will provide T&D grid operators not only with a new more efficient methodological framework but also with a complete set of planning tools already tested on real-size cases and an evaluation the technical-economic advantages the new planning methodology could achieve based on the analysis of six real-size cases covering most of the EU region.
The FlexPlan planning tool will be made available in open access format and upon request. So, tool testing will be possible for external System Operators (SOs) and stakeholders. A specific task will also be devoted to study an ergonomic graphic user interface, in order to foresee a working approach similar to that used by SOs. After the end of the project, the consortium members will remain available to discuss with SOs and other stakeholders possible customization requests in case the new tool meets their interest.
On their side, National Regulatory Authorities could take profit of the Regulatory Guidelines which will be elaborated in the final stage of the project in order to draw a complete analysis of barriers and enablers of the new planning methodology as well as a suggestion of the most efficient regulatory framework to implement it in the most efficient way.
Storage resources owners and flexible loads could elaborate new business cases taking profit of the opportunities opened by the new planning methodology.
Additionally, an enhanced availability of flexibility resources in strategic network nodes can contribute to increase the maximum level of penetration of RES, thus contributing to system decarbonization.
All customers could profit of lower infrastructure investment costs, resulting in a reduction of their electricity bill.