1. Background and progress required beyond the state of the art
Improving the carbon footprint of the European electricity system by 2020 (and beyond) can be more costly than foreseen, due to distribution network problems induced by technical barriers which slow down and even prevent form the deployment of renewable generation and/or of demand response.
On the one hand, renewable energy integration requires adequate resources (wind, solar, biomass, hydro…) which are located in privileged areas, often far away from consumption sites and thus requiring costly network reinforcements. The need for robust and flexible distribution networks becomes of paramount importance in order to help reshaping production and consumption patterns, both at local and global levels, in coordination with transmission system operators.
On the other hand, more efficient energy uses will be required to meet the 2020 EU targets leading to large scale energy saving initiatives (like in the building sector) or the more widespread use of IT technologies (like smart metering) which will allow electricity consuming appliances to disconnect from the network, waiting for more advantageous tariffs.
Both trends - more renewables connected to distribution networks and more energy efficient applications reacting to real-time price signals - will lead to increased volatility in electricity generation and consumption, thus potentially stressing the networks at distribution and possibly transmission levels.
Finally, storage will be developed to compensate the possible temporal mismatch between renewable peak generation (depending on the availability of the resource) and peak demand. The development of electric vehicles, which may become dispersed electricity storage or generation units, will use electricity more smartly when combining residential and transportation requirements.
The growing integration of Distributed Energy Resources (DER) leads to fundamental changes in power generation systems. The impacts of DER on Distribution Networks are mainly due to the possible reversion of unidirectional flows under the influence of small DER units feeding in at medium voltage (MV) and low voltage (LV) levels of the network. The other challenge of integrating a large number of medium scale Distributed Generation units (renewables) in the Distribution Network is to maintain power quality (e.g. by avoiding or mitigating harmonic distortion and power oscillations). Since the existing grid was designed for unidirectional electricity flows only, there is a limited capacity to integrate intermittent generation sources. Increase the grid hosting capacity for intermittent renewable energy sources requires active, real-time, large scale integrated management of distributed generation.
To cope with these difficulties, specific DER and grid interfaces have to be developed. An ICT infrastructure for monitoring and control DER will allow for the active control of DER.
Different technologies for DER will also be key to facilitate their integration to the grid, such as better PV forecasts, new technologies to improve the observability of PV units, etc. The observability of the LV and MV network is a critical issue which has not been so far much addressed. First, the current observability of MV and LV networks is very limited: only few secondary substations are automated, and no monitoring of the LV networks exists. This situation leads to, in particular, little capacity to manage active elements connected to the network and thus to maximise the use of distributed generation units.
Finally, two complementary aspects need to be investigated:
The advent of distributed and variable generation based on renewables (solar and wind mainly) impacts directly the performance of the electrical networks: in addition to demand response and forecasting tools, energy storage can provide profitable solutions to balancing issues, as well as new options to address power quality and network losses management.
The challenge is to prove through large-scale demonstrations under real life conditions the potential of electricity storage (focusing on power and/or energy). Different small-scale storage technologies (such asthermal storage, electric storage , power-to-gas , hydrogen storage , electrochemical storage …) should be tested. Regulatory recommendations should be proposed so that network operators are given incentives to implement such technological solutions when appropriate, together with appropriate communication infrastructure .
Even though existing large-scale demonstration projects in Europe are expected to be launched for the transmission operators, research, development and demonstration are still needed at distribution level.
Additional questions are related to business models for storage: what should be the market model for distribution network storage (in particular, who should be the owner of storage devices), what should be the market model for residential storage, etc. Business models for storage should take into account the possible services provided by storage to the grid, such as ancillary services provided by storage, load shaping, islanding…
Next, tools for the simulation of storage systems should be developed to assess the optimal location and size of storage. In particular, the question of the choice of centralised or distributed storage systems needs to be answered.
The foreseen deployment of Electric Vehicles (EV) in Europe may have a significant impact on distribution grids (possible overloads and power quality issues like harmonics, voltage profiles). However, appropriate rules and incentives could turn this constraint into opportunity because of the possible services provided by EV charging to the grid.
First, there is a need to address the impact of different types of EV charging technologies on the power system (fast recharge, very fast recharge, inductive recharge). The development of smart EV charging solutions, such as the centralized management of electric vehicle recharge stations from grid secondary substations, should be explored.
Positive consequences of massive integration of EV could rely on several services provided by EV charging to the grid, such as a potential for load shaping and ancillary services linked with EV charging. Adequate market mechanisms for V2G (vehicle-to-grid) could provide incentives to promote optimized EV charging.
Developing and implementing tools and methods to analyse the consequences of the massive charging of electrical vehicles, should also be developed. The simulation of EV charging should be further explored.
REserviceS (Economic grid support from variable renewables) is the first study to investigate wind and solar based grid support services at EU level. It provides technical and economic guidelines and recommendations for the design of a European market for ancillary services, as well as for future network codes within the Third Liberalisation Package.
evolvDSO (“Development of methodologies and tools for new and evolving DSO roles for efficient DRES integration in distribution networks”) is a FP7 collaborative project funded by the European Commission. The project lasts 40 months (September 2013- December 2016) and is carried out by a Consortium of 16 partners coordinated by Enel Distribuzione.
E. Smart Grids Model Region Salzburg (SGMS)
Salzburg is one of the pioneers in Europe in developing smart energy networks. This is why it was chosen by the Austrian Climate and Energy Fund to be the first Smart Grids Model Region in Austria. Smart Infrastructure Salzburg is an intelligent energy system that creates a regionally differentiated balance between production and consumption, leading to the use of a high percentage of volatile renewable energies while preventing network congestion. Smart Grids Model Region Salzburg is supported by an interdisciplinary team from the energy sector. The goal is to create a holistic smart grid system called Smart Infrastructure Salzburg.
COTEVOS project (Concepts, capacities and Methods for Testing EV Systems and their Interoperability within the Smart Grids) aims to establish the optimal structure and capacities to test the conformance, interoperability and performance of the systems to be included in the Electric Vehicles (EV) smart charging infrastructure.