Three technological pilots to demonstrate different modalities to provide to ancillary systems to the system
The demonstration activities in SmartNet are aimed at proving that Distributeed Energy Resources (DER) can provide ancillary services to the TSO. For that purpose, three physical pilots will be implemented in field. Each pilot will demonstrate a different TSO-DSO coordination scheme, each of them will use the flexibility provided by different types of DER and each of them will focus on a different part of the ancillary services provision value chain. For a full complementarity also in terms of geographical scope, they will be carried out in Italy, Denmark and Spain.
The Italian pilot concentrates in the actual TSO-DSO interaction by defining, developing and demonstrating all the required information exchanges between both system operators.
The beautiful area of Ahrntal is located in the South Tyrol, in the Northern part of Italy. It is a mountainous area in the Alps, with periods of heavy rain fall and snow melting in spring, so very well suited for having hydro power plants. The good conditions for hydro power production and the heating requirements in winter resulted in some substations in the area having an important amount of DER connected, both in transmission and in distribution grids. As an example, the Molini di Tures substation has about 20 MW of hydro power connected at transmission level and another 40 MW at distribution level. Besides, there are some thermal generators and an increasing quantity of PV capacity being connected at distribution level. This increasingly contribution of DER production is making the power flow getting reversed, so that, except for the coldest months in winter, electricity is being flowing from distribution to transmission.
The aim of the pilot is to increase the visibility of the TSO (Terna) over generation and consumption in the network of the local DSO (Edyna) in order to anticipate the potential impact that such reverse flow may have in the transmission network. For that purpose different control units will be installed at the primary and secondary substations, in order to communicate and control with hydro power generators connected both at transmission and at distribution level. As a result, the TSO will have a more detailed and accurate vision of what is happening at distribution level.
Moreover, the devices to be installed also permit the remote operation of the generation units by the TSO, so that they can provide frequency regulation and voltage control services both from transmission and distribution to the TSO.
During the first half a year of SmartNet execution, the whole system architecture has been defined and the functional specification has been made. The data acquisition and monitoring system will be able to provide data every few seconds (2-4 seconds), so that security conditions can be evaluated every 5 seconds. In addition, the TSO will be able to collect the active and reactive power production per type of generation source every 20 seconds. Consequently, the TSO will have almost real-time information about grid status, DER production and the remaining flexibility capacity per type of DER in case balancing or frequency control services are to be requested.
The two manufacturers involved in the demonstration project (Siemens and Selta) are completing the technical specification of the system and the project has been presented to local authorities and to DER plant owners, most of which agreed to participate in the demonstration project.
The core activity in the Danish pilot is the use of price signals to control the electricity demand of swimming pools located in rental houses.
Novasol is a company dedicated to renting houses for vacation periods (either in summer, in weekends or in other usual vacation periods). These houses include an indoor swimming pool which uses an electric heating system to keep the water temperature within comfort ranges. Due to the high thermal inertial of the water mass contained in the pool, the time in which the pool is heated can be modified if the right incentives are in place.
A price-based control strategy will be tested in the demonstration project, so that the aggregator (Danske Commodities) will broadcast variable prices and the control devices for swimming pool heating systems will react to those prices by consuming more electricity when the price is low and stop consuming when prices rise. In particular, about 30 summer houses located in the same DSO (Nyfors) area will be included in the pilot.
Price variations may occur because wholesale market prices vary, but also because real-time grid conditions change. Both the TSO (Energinet.dk) and the DSO may have balancing or congestion problems in their networks, which can be solved if the electricity consumption pattern is modified. Therefore, the aggregator can use the flexibility of swimming pool heating systems to bid into the markets for ancillary services and get remunerated for helping the system.
However, the aggregator must be able to determine the prices to be sent to consumers, so that they react as the aggregator expects, while the aggregator can still make a profit from selling electricity to consumers. Although this is being investigated in the aggregation modelling activity, it is one of the mayor challenges to be solved to have a successful field implementation.
The other main challenge is to ensure that the ICT infrastructure is able to transfer all the information required by the different parties, which has been the main focus of this pilot in these first steps.
In particular, the functional and technical specifications of the ICT system have been made, finding that 2 main systems will be needed. One of them will be used for metering purposes and will be based on established standards. The other one will be needed to control the actuators of the thermostats in the swimming pools. Since the thermostats in the different houses are made by different manufacturers and have different technical characteristics, an ad hoc solution must be made with the aim of having a unique and scalable solution. This solution will be use a cloud-based system for data exchange and is still under construction.
However, a whole operational test of the solution has been made and results are very satisfactory. Now these solutions will be implemented in the first two real sites to continue the proof-of-concept testing and, if no particular difficulties are met, the full 30-site demonstration project will start its operations on the 1st of January.
The Spanish pilot will focus on demonstrating the ability of radio base stations and grid-connected electric vehicles (EVs) to provide frequency regulation and voltage control services which can be used by the DSO.
Mobile phone communication requires the existence of radio base stations to manage the information exchanges between phone users. With a view to ensure the continuous provision of the service, base stations are equipped with battery systems, which allow the station to keep on transferring data if there is a black out or a curtailment in the electricity supply. As the interruption of the electricity service is a very rare event in developed countries, the battery systems included in base stations can be used to get the station disconnected in purpose from the grid for providing ancillary services, while keeping the communication service working for mobile phone customers. That is to say, battery systems can be used by the owner of base stations (Vodafone) to provide demand response for the DSO (Endesa Distribución). As the provision of ancillary services is not the core business of communication companies, the actual provision of the service is more likely to be made through demand aggregators (Danske Commodities).
But not only demand response can provide ancillary services, EVs can also become an important actor for providing grid support services. Companies in general and electric utilities in particular are increasingly transforming their vehicle fleet from petrol or diesel based to electricity-powered transportation. These vehicles include the vehicles needed to solve or repair incidents in distribution networks, but also vehicles used for commercial purposes or even for the personal use of employees. These vehicles are parked and have their battery fully charged most of the time, so, if the appropriate incentives are provided, EV owners can let an EV aggregator (Endesa eMobility) discharge partially their battery in order to support the grid and charge it again when the DSO problems have been solved.
The pilot will simulate a local market, where both demand and EV aggregators offer flexibility to the DSO, with the aim of providing balancing, congestion management and voltage control. As a result, the pilot will demonstrate that the DSO can send activation signals to aggregators and that these can transfer those signals to flexible DER, so that the DSO sees the result of the activation orders in its distribution grid control system.
The communication systems will thus include two main steps: one between the DSO and aggregators and a second one between aggregators and DER. The communication system between the DSO and aggregators is expected to use standarised communication protocols and data models, so that all the participants in this regulated market have clear rules to participate. On the contrary, the communication systems between each aggregator and flexible DER, even if they are mostly based on standards, may include specific requirements by aggregators, so they still need to be completely defined.
The architecture of the system has been defined, while functional and technical specifications are expected to be ready by the end of the summer. Then, equipment purchase, testing and installation will be made in autumn to have the pilot in full operation by the 1st of January.