Experimental investigation and assessment of renewable energy integration into the grid

A recent issue of increasing public focus is the need for robust, sustainable and climate friendly power transmission and distribution systems that are intelligent, reliable and green. Current power systems create environmental impacts as well as global warming due to utilisation of fossil fuels, especially coal, as carbon dioxide is emitted into the atmosphere. In contrast to fossil fuels, renewable energy offers alternative sources of energy which are in general pollution free, technologically effective and environmentally sustainable. It is therefore a fundamental concern today to be able to bring higher percentages of renewable electricity into the energy mix due to the variable nature of many of these resources. The intermittent nature of power output from renewable energy sources, in particular wind and solar, introduces potential technical challenges that affect quality of power observed including voltage fluctuation, power system transients and harmonics, reactive power, switching actions, synchronisation, long transmission lines, low power factor, storage system, load management, and forecasting and scheduling. Therefore, the major aim of this research study on the “Experimental investigation and assessment of renewable energy integration into the grid” is to investigate the strategic impacts of integrating renewable energy sources with the grid, including analysis of the potential barriers and possible deployment integration issues of renewable energy into the grid so as to develop a clean-energy system for a sustainable future. The study was divided into five major sections. Firstly, a feasibility study was undertaken to analyse the potentialities of renewable energy sources in Australia, in particular wind and solar energy. The second part of the study predicted the availability and characteristics of variable wind speed and solar radiation as well as typical variations of energy production from renewable sources for adequate management of the power systems with large-scale renewable energy integration. This part also explored the usefulness of integrating renewable energy sources with the power systems, analysing the benefits and outcomes for a typical Australian power network within the subtropical climate of Central Queennsland. From the feasibility study, it can be evident that Australia has significant potential for renewable energy generation that reduces the cost of energy generation and global warming significantly. Forecasting model predicts the solar radiation and wind speed as well as possible energy generation from solar and wind sources in advance in the Capricornia region that can be used by the grid operators for grid management purposes. The major objective of the study is to investigate the strategic impacts of integrating renewable energy sources into the grid. Initially, rigorous experimental analysis was conducted using the Commonwealth Scientific and Industrial Research Organisation (CSIRO) Renewable Energy Integration Facility. Once experimental analysis was performed, a power system model that mimicked the experimental setup was developed using the power system design and analysis simulation tool PSS SINCAL to investigate the strategic impacts of renewable energy integration into the grid. However, to investigate the impacts of large-scale integration of renewable energy sources into the grid, a section of Ergon Energy’s Distribution Network was developoed, in particular the Rockhampton power network. It can be evident from the experimental analysis that integration of solar photovoltaic (PV) energy introduces harmonics and voltage fluctuations into the network and the level of these impacts increases with the increase of solar PV energy utilisation. Similar findings were also perceived from the simulation analyses. Model analysis clearly indicated that large-scale integration of renewable sources, in particular solar PV and wind, into the grid causes uncertainties in the power network due to the intermittent nature of these sources and the level of impacts that exceeded the regulatory standard defined by the local distribution network service provider (DNSP) for some of the studied case scenarios. The major adverse impacts are voltage regulation, overloading of transformers, poor power factor regulation and current and voltage harmonic distortion into the network which require to be reduced to provide a smooth power supply to the customers. Finally, the study explores possible mitigation measures to reduce the potential adverse impacts listed above and it was observed that integration of optimised STATCOM and energy storage improves the overall power quality of the power network as it enhances voltage regulation and improves power distribution and transformer utilisation and reduces total harmonic distortion of the power network. This vital study will be offered a path toward significant environmental improvement which will assist to reduce global warming and CO2 emissions substantially. This study will also be helpful for the power utilities and communities to develop a climate-friendly sustainable power system for the future.