The global climate change challenge together with the volatility of the fossil fuel prices are pushing the society towards the renewable energy era. In addition, the global renewable energy sector is continuously pursuing to achieve the cost effectiveness of renewable energy power systems to deliver in a future a competitive price of electricity. The integration and management of the electricity coming from renewable energy sources into the grid is representing a big challenge to address, considering that by 2020 the 20% of the global renewable energy generation will be fed to the grid. Worldwide, the electricity generation coming from renewable sources is expected to reach 7000TWh, representing 26% of the total power capacity installed across the globe.
The Smart grid and its technology evolution to optimize its service quality, costs, operations and management is the key for an efficient use of renewable energy sources (RES) and distributed energy storage (DES). One of the goals of a smart grid is to promote active customer participation and decision making as well as to create the operation environment in which grid operators, electricity users and producers influence each other. Utilities can improve reliability through the demand response programs, adding distributed generation or energy storage at substations, and providing automated control to the grid. When the proportion of decentralized generation exceeds 15-20%, large fluctuations in frequency, grid voltage and power flow occur thus the grid can become unmanageable and lead to power outages.
With the wide spread introduction of renewable energy sources into traditional and smart grids, a new grid-stability challenge is being realized by grid operators, inverter and energy storage manufacturers. While renewable generation sources are increasingly playing a role in goals related to emission reduction, energy independence, and efficiency, they fall short in the proven grid-stability functionality offered by traditional synchronous generators. As a result, when the proportion of renewable energy sources in a grid is sufficiently high, the lack of stabilizing functionality, together with the intermittent nature of renewable generation devices, may cause large fluctuations in power angle, grid voltage and power flow. Such fluctuations can cause frequent disconnects of renewable sources – thus reducing yield, and, in more extreme situations, may lead to a cascade reaction and cause damages on both utility operations and on load-side equipment alike. These grid stability concerns limit the utilization of renewable generation in traditional grids, as well as in micro solar/ wind topologies, considering that all this has a very high cost for the electricity consumers and grid operators.
By the end of the project, we intend to develop an improved inverter which will allow higher volumes of renewable energy sources to be implemented to the grid while maintaining stability.
