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Smart Micro-Grids

Low-voltage distribution grids are experiencing an increasing proliferation of small-power energy sources (mostly PV units) owned by domestic end-users (prosumers, i.e., at the same time producers and consumers). The current regulations enforce prosumers to feed their generated energy into the grid, and to disconnect if the grid parameters (voltage, frequency) outgo a given interval. These simple rules, however, misbehave in a situation, as the one currently experienced in Italy, where the installed PV power amounts to 15 GW and exceeds 6% of the total energy production. A smarter and more efficient management of the large amount of micro-flows powered by prosumers cannot be further deferred and must be approached by a radical innovation of the operation codes in low-voltage distribution grids.

Our smart micro-grid research program addresses this problem, by first equipping prosumers with energy storage capability and, second, by extending the control features of the inverters incorporated in the distributed generators. Accordingly, with an incremental investment, each prosumer can benefit of: modulation of generated and consumed power along the day, to take advantage of hourly tariffs; uninterruptible supply of domestic loads, even in case of grid failure; improved stabilization of local voltage; capability to feed power on-demand, based on request conveyed by the smart meter. 

In fact, the project goals are even more ambitious, because it aims to develop know-how and technologies enabling energy and data networking among the prosumers of a residential community. The result is the smart micro-grid, which allows the sharing of resources among the entire community, the trusted operation of the micro-grid, and the aggregation of prosumers so as to empower their role versus other players of the electrical market (DSO, utility, traders, etc.). This gives rise to a new paradigm (the Internet of Energy) whereby communities of prosumers implement peer-to-peer resource sharing, define common visions and strategies, organize themselves at various levels of aggregation, and play an authoritative role in the electrical market.

The expected benefits for end-users and, more generally, for the society and the environment are relevant, and fully consistent with the “Horizon 2020” strategy of the European Union. The easy and flexible integration of renewable sources and storage devices, together with a pervasive use of upfront ICT and power electronics technologies, will considerably reduce carbon footprint, increase energy efficiency, allow savings for end-users and distributors, improve quality and reliability of electrical services, and lead to a better exploitation of the electrical infrastructure. Moreover, the ICT platform developed in the project will spur new services to the customers and new roles and market shares also for public administrations, utilities, traders, DSOs and territorial bodies.

The scientific and technical partnership behind the project owns the know-how and expertise necessary to lead the project to success. The developed technologies will be implemented and experimented on a powerful testing facility and in the field, thanks to the support of territorial boards.

The wide consensus and support from municipalities, utilities, customer associations, bodies and companies in the field of building management and environment-friendly design, demonstrate the social and environmental impact of the project.

Specific objectives of the smart micro-grid research program

1) Local Energy Optimization: optimization of the energy consumption/production within the end user premises with the aid of local energy storage units (e.g., lithium batteries).

IMPACT: better exploitation of the energy that is locally produced by renewable energy sources, e.g., photovoltaic (PV), through the optimal management of energy storage units, will lead to the smoothing of power absorption from the grid, economic savings for the end-users and reduction of distribution losses.

2) Global Optimization: synergistic optimization of the energy resources distributed across the micro-grid. Distributed algorithms will orchestrate the amount of active/reactive power provided by the end-users to achieve load balancing, reduction of distribution losses, reactive and harmonic compensation and voltage stabilization.

IMPACT: this optimization will result in an enhanced hosting capacity, voltage stability and distribution efficiency, without requiring changes in the distribution infrastructure.

3) Implementation of a Communication Infrastructure (CI) allowing communication among the Power Interfaces installed at the end-user premises. This CI shall provide advanced data security functionalities to preserve data integrity and provide secrecy and authentication. In addition to the standard communication between utility servers and end-users, our CI will provide advanced "horizontal" communication, whereby end-users within the same micro-grid will also exchange messages. The adoption of PowerLine Communication (PLC) and wireless technologies will drastically reduce the cost of installation, removing the need of a dedicated deployment for the communication infrastructure.

IMPACT: the CI is the fundamental brick upon which objectives 1) and 2) are based. Besides, the CI enables the implementation of new business and interaction models between end-users and the electric utility, the opportunities offered by this go even beyond the reach of this project.

4) Design and implementation of a new family of power converters for residential grids: these will include the Energy Gateways (EGs), i.e., the power management units interfacing each prosumer with the grid, and the Utility Interface (UI), i.e., the power management unit interfacing each micro-grid with the utility at the point of power delivery. EGs will be in charge of implementing the primary control of the micro-grid and managing all local energy sources, including power generators (PV, wind, fuel cell, etc.) and energy storage devices (battery) and will be engineered to allow retrofitting of existing generation systems (e.g., PV panel/inverter) by upgrading the existing plants with a properly devised battery/inverter unit, which will be capable of providing active/reactive power injection into the micro-grid. The Utility Interface will integrate ancillary functions to improve the operation of the micro-grid as a whole (reactive, unbalance and distortion power compensation; secondary control of the micro-grid; grid-forming and black start operation).

IMPACT: the new power converters will allow the distributed optimization of energy resources in the micro-grid, and will implement the optimizations illustrated in 2).

Please visit also our SmartGrid Research website