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MPhil in Engineering for Sustainable Development

global challenges, engineering solutions

Studying at Cambridge


Aris Karcanias

Evaluation of Vanadium Liquid Battery for Renewable Energy Systems

Aris Karcanias

Evaluation of Vanadium Liquid Battery for Renewable Energy Systems

The power sector faces new challenges in light of the renewed emphasis for security of supply, the requirements to meet updated international agreements such as the Kyoto protocol and the implications of creation of the free energy market that encourages the increased role of Distributed Generation (DG). The role of the Renewable Energy Sources (RES) is becoming increasingly important, and there is an inherent need to increase the utilisation of any existing assets. The integration of large-scale RES and the increased role of DG create significant problems for power quality and reliability due to intermittency and the time scale differences between supply and demand.

Energy Storage (ES) systems emerge as crucial components in the integration of RES, and DG sources in the electricity system, and define a crucial technology for the implementation of the EU energy policy for incorporation of RES into the electricity system. They may contribute in the balancing of energy supply and demand, improvement of power quality and reliability delivery of cost-effective and reliable energy supply capable of coping with any variations in demand. Large ES devices introduce “buffers” in the distribution system and hold significant potential for “structural stabilization” of the distribution system, which may help to avoid undesirable effects such as “blackouts” that are recently becoming more frequent. Furthermore, ES technology offers new opportunities for more reliable and efficient distribution that matches supply with demand and opens up the market for new services in the energy sector. The emerging energy system is very complex, and addressing the challenging tasks of integration requires the use of control technology and addressing crucial open control problems.

Amongst the recent developments of electric ES technologies, one of the most promising for power systems applications are the flow batteries. The vanadium-based ‘redox flow’ system (VRB) is one of the flow batteries that is capable of separating the power and energy capacity, consisting of a deep cycling capability and a very long lifespan. In this project, we focus on the evaluation of the VRB system and examine its potential in RES integration and improvement of performance of Power system with increased use of DG. This type of ES system has the potential to be competitive in diverse markets, ranging from small-scale PV systems to medium or large wind farms, and finally, directly in the load centres of the grid for power quality applications.

The main objectives of the project are to:

• Identify the key issues of the RES sector and the needs for ES. Review ES alternatives and specify the technical- economic issues of integration of RES devices.
• Evaluate the status of VRB technology, its advantages and limitations with respect to similar technologies, and perform a market analysis and LCA (environmental) comparison of VRB with competing technologies.
• Examine the nature of the emerging energy paradigm of Distributed Energy Resources (DER), identify the role of ES in DER and specify the technological challenges and market opportunities.
• Define a range of open systems and control problems that are crucial for achieving RES integration.

The project provides an in depth analysis of the problems linked to the integration of RES technologies in the emerging energy system, which is subject to market deregulation and strict environmental rules. It shows that achieving sustainability, reliability and energy security requires an increased role of RES. This may be achieved through an appropriate deployment of the ES technology of the VRB type, as well as using control, and by addressing a multitude of challenging problems of the control type, enabling the optimal use of VRB technology within the DER system.