Predrag Djapic

Taking an active approach

The United Kingdom is leading Europe in its power market reforms and is currently engaged in addressing issues of DG integration through development of innovative approaches to network planning, operation, regulation, and pricing. This article draws on these recent advances to explore active management technologies, developing regulatory arrangements for network operation, and new commercial opportunities emerging from the low-carbon climate change agenda. It explores the changing role of the distribution system operator (DSO) in response to increasing penetration of DG and identifies the transitions currently taking place in the United Kingdom toward integration of DG that has wider implications for extrapolation across Europe.

Whole-Systems Assessment of the Value of Energy Storage in Low-Carbon Electricity Systems

Energy storage represents one of the key enabling technologies to facilitate an efficient system integration of intermittent renewable generation and electrified transport and heating demand. This paper presents a novel whole-systems approach to valuing the contribution of grid-scale electricity storage. This approach simultaneously optimizes investment into new generation, network and storage capacity, while minimising system operation cost, and also considering reserve and security requirements. Case studies on the system of Great Britain (GB) with high share of renewable generation demonstrate that energy storage can simultaneously bring benefits to several sectors, including generation, transmission and distribution, while supporting real-time system balancing. The analysis distinguishes between bulk and distributed storage applications, while also considering the competition against other technologies, such as flexible generation, interconnection and demand-side response.

Assessing the Contribution of Distributed Generation to System Security

The UK Government has set targets for renewable energy plant to be achieved by 2010, and by 2020. A significant proportion of this generation will be connected to distribution networks. One important technical issue is what contribution can this new generation make to distribution network security. Recently, a methodology for updating the existing security standard has been developed to account for the new generation technologies. This paper presents the main features of this methodology for assessing the security contribution from distributed generation, and describes numerical studies showing the effects of various parameters

Transmission Investment and Pricing in Systems with Significant Penetration of Wind Generation

In this paper we demonstrated that wind generation tends to drive less transmission investment than conventional generation. Two transmission planning approaches are analyzed in this paper focusing on the security and economics as being key drivers for investing in transmission. We demonstrated that it will not be appropriate to treat wind power as conventional generation in security assessments, as wind is a predominantly an energy source with relatively low capacity value. We also show that wind and conventional generation should share transmission capacity and hence avoid unnecessary and non optimal transmission network reinforcements. However, current approach to access and pricing does not support this efficient operation of the system.

Strategic Assessment of Alternative Design Options for Multivoltage-Level Distribution Networks

This paper presents a methodology for assessing the performance of alternative design strategies for multivoltage-level distribution networks. The key feature of the proposed methodology is its ability to reproduce realistic network topologies and lengths, as calibrated against real distribution networks. Through year-round power flow analysis and optimization processes, the proposed approach allows comprehensive network studies to be carried out for the decision makers to investigate the sensitivity to different parameters and to draw more robust conclusions than those reached through a specific network study. The output metrics used for comparison of network performance are overall network cost, network losses, and reliability, which represent the three most crucial network performance indicators in network design. The validity of the developed models was demonstrated through the investigation of alternative distribution network design for a real medium voltage (MV) network in the U.K. This investigation includes quantitative performance evaluation and comparison between a four-voltage-levels design (e.g., 132 kV/33 kV/11 kV or 6.6 kV/0.4 kV) with three-voltage-levels network arrangements (e.g., 132 kV/11 kV/0.4 kV or 132 kV/20 kV/0.4 kV) and comparison between the peak demand-driven network design versus the optimal loss inclusive network design.

Value of integrating Distributed Energy Resources in the UK electricity system

Continuous connection of Distributed Energy Resources (DER) technology on a “fit and forget” basis may lead to inefficiently low utilization of generation and network assets. In order to mitigate this effect, a reappraisal of the technical, regulatory, and commercial frameworks that shape decisions on future network design, investment, operation, and pricing are required. The transition of distribution network operation from passive to active would facilitate cost effective integration of DER and an efficient evolution towards a low carbon electricity system. In this context, this paper summarizes the results from a range of quantitative studies on the UK electricity system that have been carried out to assess the benefits of active management of distribution networks.