In Europe, there is a sharp increase in reserve needs for coping with the variability introduced by a steadily increasing RES share in the generation. The big challenge is to extend the possibility of providing Ancillary Services (AS) – frequency and voltage control, congestion management, etc.) to entities connected to the distribution network.
All these issues have been addressed by the SmartNet European research project (http://smartnetproject.eu/), which aimed at comparing different TSO-DSO interaction schemes and different real-time market architectures with the goal of finding out which would deliver the best compromise between costs and benefits for the system. The objective of this three-and-ahalf year project (2016-2019) was to develop an ad hoc simulation platform which models all three layers (physical network, market and ICT), analysing three national cases (Italy, Denmark, Spain).

In addition to providing information on the main results obtained by the SmartNet project, this report include some information on the status quo of the procurement of ancillary services in selected countries. A questionnaire was formulated and distributed among the members of ISGAN Annex VI. The questionnaire contained the following questions:

• What system services are provided in your country (voltage regulation, frequency regulation, inertia, support to power quality…)
• Who is providing them (generators and/or loads?)
• Modalities to collect ancillary services: via markets, contracts, compulsory non-paid services… Please describe in detail.
• Are generators and/or loads located in distribution admitted to provide system services? If yes, how is TSO-DSO interaction carried out (please describe in detail)
• Are there plans from the national regulator to activate demand side management or to collect inputs from generators connected to distribution for the future? Which timeframe? Are pilot projects already active?

Solutions providing advances in flexibility are of utmost importance for the future power system.
However, flexibility is not a unified term and is lacking a commonly accepted definition. The flexibility term is used as an umbrella covering various needs and aspects in the power system which complicates the discussion on flexibility and craves for differentiation to enhance clarity.

ISGAN Annex 6 has dedicated an activity on flexibility with the intention to support an increased understanding of the flexibility concept, proposing categorisation of flexibility needs in the power system.

This activity resulted in several publications with contributions from parties in: Sweden, Austria, Canada, France, Germany, Italy, Norway, and Switzerland.

• The final results and conclusions of this activity were presented at a dedicated ISGAN Webinar, November 2019.

• In the Fact Sheet: Grid Evolved – Power System Flexibility, the condensed knowledge from this activity, with collaboration with Mission Innovation, was published for the 10th Clean Energy Ministerial in Vancouver, Canada, May 2019.

• In the Discussion Paper (DOI: 10.13140/RG.2.2.22580.71047), the full report is provided from this activity, including description of the flexibility categories: Flexibility for Power, Flexibility for Energy, Flexibility for Transfer Capacity, and Flexibility for Voltage.

• The Leaflet: Power system flexibility – the ability to manage change presents an executive summary of the discussion paper, giving a good insight into the work. This leaflet was published for the ISGAN Conference The future of electricity markets in a low carbon economy in Stockholm, Sweden April 2019.

• The Scientific paper: Flexibility to support the future power systems, based on the discussion paper, was published for the CIGRE Symposium in Aalborg, Denmark, June 2019.

The main objective of this report is to assess the future data exchange and ICT requirements concerning the interaction of distribution and transmission networks, by identifying key challenges that deserve attention.

This report is based on a questionnaire regarding the ICT aspects of TSO-DSO interaction. The questionnaire contained questions regarding technical aspects (e.g. technical connection points between TSO and DSO in the countries), regulatory aspects, flexibility markets, drivers and barriers for TSO-DSO interaction as well as experiences from projects and lessons learned. The questionnaire was sent to the Annex partners and nine responses were collected. In particular Belgium, Germany, Italy, Finland, Sweden, United States, China, India and Austria have sent comprehensive answers.

Due to the integration of renewable energy sources, the interaction between TSOs and DSOs gets more and more important to handle the high volatility of generation and unexpected load growth in power grids. Additionally, new market mechanisms and the connected flexibilities require a closer interaction between TSOs and DSOs.