Robust transmission and distribution networks are a critical part of Asia’s transition to a renewables-based, decentralized grid. Rather than simply the deployment of renewable generation, the integration of these assets is the single biggest concern facing the industry across Asia, according to this year’s Black & Veatch 2022 Asia Electric Report.
The rapid growth of solar power in Vietnam between 2019 and 2020, for example, holds important lessons for the rest of Asia. Installed solar capacity leapt from hundreds of megawatts to 16.8 gigawatts, representing approximately a quarter of the nation’s grid capacity.
However, without supportive enhancements to the grid and transmission network, Vietnam Electricity (EVN) reportedly restricted power by a total of 365 million kilowatt hours after grids in the central provinces of Ninh Thuan and Binh Thuan were overloaded in 2020 with further curtailments occurring in 2021.
With wind and solar resources often located far from existing transmission lines, alongside other factors such as the expansion of distributed energy resources (DERs) and increasing bidirectional flows, Asia’s transmission and grid systems need more investment to manage a successful energy transition.
Renewable Integration a priority
In the eyes of the 2022 survey respondents, underinvestment in transmission is one of the top three threats to reliable grid operations and performance. This is joined by insufficient energy storage capacity, which can play a critical role in stabilizing a grid with intermittent renewable energy generation; and government policies, an answer which could be attributed to the considerable policy debates around decarbonization, which occurred in the lead up to COP 26, coinciding with the timing of the survey.
In addition, one in four respondents admitted they were not confident in the performance and resilience of their transmission and distribution systems.
Expanding and investing in higher quality transmission and distribution systems will be required to improve the efficiency, resiliency and reliability of supply and balance the variability of renewable sources. Reliable grids that can support the growth of decentralized power will help to optimize generation and enhance grid stability.
Key transmission expansion strategies will include deploying interconnection lines, interconnection substations, and switching facilities in areas with high potential for renewable generation to allow seamless connection to the grid.
When appropriately deployed, these facilities will help to manage some of the challenges with renewable generation related to lower inertia and lack of dynamic reactive power capability while also facilitating integration with the collector substations that accompany each largescale renewable development.
Upgrading transmission presents challenges
Expanding transmission networks, however, is complex. The respondents identified land acquisition and right-of-way (ROW) access as the biggest challenge to improving transmission. While a typical solar farm may take six to nine months to develop, high-voltage transmission lines often take years to deploy and can be severely delayed by land issues.
Technologies such as composite core conductors or advanced tower designs can help mitigate and address potential land issues. An example of an advanced tower design technology includes Breakthrough Overhead Line Design (BOLD), which can maximize power transfer on existing ROW by replacing old transmission lines with smaller-footprint, higher-capacity BOLD lines. BOLD technology is ideal for long distance and intercountry connections where high-voltage AC interconnections are viable.
Noteworthy also from the findings is that poor understanding of transmission’s integral and rising role in balancing the electric system comes in second ahead of policy, permitting and financing concerns. There is a clear need to increase awareness among government and other public stakeholders around the role of transmission in improving the effectiveness of renewable integration and achieving a successful energy transition.
Regional electric industry leaders shared that over the next five years, their top investment focus will be in advanced system control devices that improve grid stability and operations such as Flexible Alternating Current Transmission Systems (FACTS).
FACTS enable better control of power flow from Congested parts of the grid to less-congested portions. FACTS devices such as static compensators (STATCOMs) are also critical to furnish the dynamic reactive power needs with integration of large blocks of renewable injections.
This is especially true with the onshore interconnect facilities associated with offshore wind projects. Load control devices that better balance generation and revamping existing substations were other high priority investment areas identified by Asian electricity leaders.
As Asia, like many other regions of the world, repowers its power industry, better planned and designed transmission systems are key to the decarbonization journey. Addressing voltage and frequency variability and grid code requirements effectively across the grid will reduce system losses, conserve energy and manage peak demand.
Operational complexities of grids are shifting from large power plants near the point of power consumption to more distributed and intermittent renewable plants and Distributed Energy Resources (DERs). These dynamics call for Asia’s electricity industry to re-evaluate transmission and distribution systems and conduct more advanced and interconnected planning and design across these systems.
Partnering with industry leaders experienced with every aspect in the lifecycle of projects from early financing through to commercial operation will be key to expanding Asia’s transmission networks for renewable integration success.