Energy transition technology roadmap. Distinguishing hype from reality – 2020 strategic technological plan and business targets
Climate change and global warming in particular may be a controversial scientific theory, particularly in the US, but its growing impact on business is undeniable. The energy generation landscape, to begin with, is being disrupted by the growth of renewables; transport is witnessing the affirmation of the electric car, in its pure form or as a hybrid, and, most pervasive of all, the search for energy efficiency is creating new businesses – think for example smart metering or behind-the-meter distributed generation – and is modifying existing ones in a variety of ways. Our vision of the macrotrends shaping the energy transition is consistent with the narrative of Bloomberg New Energy Finance's New Energy Outlook, to which we make extensive reference in this overview.
Performance Analysis of a hybrid micro-grid in Somalia
This paper presents a data analysis of an islanded diesel-PV-battery system, placed in Somalia. Operation of each generator is observed, concerning the most relevant performance indicators. Analysis is carried out during the first 11 months of operation, from November 2015 to September 2016. Investigations are divided into two periods, according to a significant load variation due to the connection of a new distribution line to the power plant. Thus, a comparison on load demand sharing among generators is realized between the two periods. In conclusion, benefits in terms of fuel consumption, CO2 emissions and money savings are presented.
Distributed storage for provision of ancillary services to the main grid: project PRESTO
This paper presents the three-year PRESTO research project (2013-2015). PRESTO is a self-funded project developed by the Department of Energy of Politecnico di Milano in cooperation with FIAMM Storage, Elvi Energy and MCM Energy Lab (an Italian spin-off). Within the project, experimental tests and numerical simulations were performed in order to evaluate the effectiveness of an Energy Storage System (ESS) in the provision of ancillary services to the main grid. This paper focuses specifically on the experimental and numerical analyses carried out in the project to develop an innovative control law for the primary frequency regulation, able to maximize the performances of the regulating service and effectively manage the ESS state of charge.
Optimal Management Algorithm for Battery Energy Storage System Included in an Islanded Micro-Grid
This work proposes an optimization method for the management of a Battery Energy Storage System (BESS) integrated in an islanded Micro-Grid, including Renewable Energy Systems (RESs) and generators burning fossil fuels. The optimized control of the battery State of Charge (SOC) allows to get the BESS available as much as possible to support the RES power production, hence minimizing the use of fossil fuels. The optimization of the BESS is based on load demand and RES production forecast. The Optimization Algorithm that has been adopted is the Linear Programming, using the method of the Interior Point.
Control loops design in a grid supporting mode inverter connected to a microgrid
This paper deals with some design aspects of the control loops in a droop-controlled VSI connected to other inverters of greater ratings or to a strong grid, which sets the frequency. The design of a damping resistor in series with the AC filter capacitor is discussed and the impact of strong feedback between the output current and the capacitor voltage is investigated. Moreover, an analysis of the derivative droop coefficients is carried out through a simplified equivalent circuit.
Hybrid micro-grid experimental application in Tanzania
This paper is intended to introduce the project Energy4Growing that aims at studying and setting up a hybrid micro-grid to supply power to a school in rural Tanzania. It describes the results of the early project actions which concerned in: (i) analysing the actual school power supply system through locally metered data; (ii) developing the first step of a new electro-mechanical model which addresses the simulation of operation and dynamics within an off-grid power system; (iii) validating the new model. In particular the paper focuses on describing the development and the first step implementation of the new modelling approach which address: (i) voltage and frequency analyses over medium term period by means of simplified electromechanical models of power sources and power electronics, (ii) the analysis of different dispatch strategies and their consequence on voltage and frequency trends, (iii) the effects of dispatch strategies on the energy performances of particular components such as battery bank or dump loads. The new approach has also been applied in modelling the current school power supply system.
Technical Strategies for Voltage Power Regulation in LV Distribution Networks
We report the integration of a novel voltage regulation strategy in the inverter control algorithm for Dispersed Generation (DG) applications. The adoption of a decentralized voltage control based on local curves allows the voltage profile to be controlled at the Point of Common Coupling (PCC) of the generators and, therefore, the capacity of existing distribution networks to host more generation from renewables. The work is focused on a low voltage distribution network and both the reactive power modulation and the real power curtailment are considered in the proposed local strategy. Both numerical and experimental analysis are necessary in order to test and validate the proposed voltage control strategy. Firstly, the performances of the proposed control are tested by a numeral analysis and the impact on both the electrical system and the inverter apparatus is evaluated. Secondly, the benefit of the control strategy is analysed by experimental analysis in a test facility to verify the feasibility of voltage regulation in a real feeder.
Hybrid distributed generation system for a rural village in Africa
Nowadays the use of distributed generating systems, which use a renewable energy source, has experienced a fast development. Moreover, their intrinsic intermittent nature can be overcome using hybrid systems which combine more energy sources. This paper proposes the study and design of a hybrid generation system able to cover the energy needs of a school in a rural village in Africa (Tanzania), combining renewable and/or alternative sources and storage systems. The final results consist in the definition of an electric grid architecture suitable to interface renewable and energy needs in the most reliable way, exploiting advanced regulation and control techniques.
Harmonic Analysis of Output Filters for Grid Connected Converters in Battery Energy Storage Systems
Battery Energy Storage Systems, as well as many distributed generation systems, use voltage source inverter as interface with the grid. These converters require a filtering section to reduce current harmonics injected to the grid. Usually, harmonic filter is a series inductance connected between grid and inverter. Higher order filters can provide better harmonic attenuation at lower switching frequency and reduce filter size, with potential benefits for high power applications. This paper deals with the sizing and the frequency response of three different harmonic filters suitable to reduce the ripple in the grid current waveform. Dynamic simulations of a 100 kW Battery Energy Storage System highlight the better performance of high order filters.