Converting existing transmission corridors to HVDC is an overlooked option for increasing transmission capacity

Abstract

A changing generation mix and growing demand for carbon-free electricity will almost certainly require dramatic changes in the infrastructure and topology of the electricity system. Rather than build new lines, one way to minimize social opposition and regulatory obstacles is to increase the capacity of existing transmission corridors. In addition to upgrading the capacity of high-voltage alternating current (HVAC) lines, we identify a number of situations in which conversion from HVAC to high-voltage direct current (HVDC) is the least-cost strategy to increase the capacity of the corridor. If restricted to the existing right-of-way (ROW), we find DC conversion to be the least-cost, and in some cases the only, option for distances of >200 km or for increases of >50% capacity. Across all configurations analyzed, we assess HVDC conversion to be the lower-cost option at >350 km and >50% capacity increases. While we recognize that capacity expansion through HVDC conversion may be the optimal solution in only some situations, with future improvements in the cost and performance of solid-state power electronics, conversion to HVDC could be attractive in a growing set of circumstances.

The Value of Inter-Regional Coordination and Transmission in Decarbonizing the US Electricity System

“…Transmission lines typically require permits from multiple federal agencies and from each state and local jurisdiction within their path; 67 the multi-party benefits of transmission make cost allocation difficult; 68 and like any type of energy infrastructure, transmission can engender local opposition. 69 There are a number of strategies for streamlining the planning, permitting, and construction of new inter-state transmission to overcome such barriers: increasing utilization of existing transmission rights-of-way through reconductoring of existing lines, increasing line voltage, or adding additional circuits; 70 converting existing AC transmission corridors to DC; 71 implementing federally identified transmission corridors; 72 and building social acceptance through public engagement 73 or community ownership 74,75 could accelerate and reduce the cost of transmission expansion and power-system decarbonization. While innovation in long-duration energy storage and nuclear power has the potential to reduce system costs, all zero-carbon systems modeled here deploy substantial capacities of wind and PV (>670 GW in all cases and >2,200 GW in the base case), demonstrating the importance of near-term deployment of available technologies in the pursuit of urgent climate targets.…”

Orderly retire China's coal-fired power capacity via capacity payments to support renewable energy expansion

“…Information on the transmission costs and losses for the 12 th Five-Year period released were obtained from the China Electric Power Planning and Engineering Institute and China Renewable Energy Engineering Institute (NBS, 2018). Capital costs for transmission lines vary with line power capacity, distance, and location (Reed et al, 2019).…”

Low Frequency AC Transmission Upgrades with Optimal Frequency Selection

“…The most common example of multi-frequency systems is high voltage DC (HVDC) transmission lines embedded in an AC grid. Advantages of HVDC include increased power transfer capacity and control of power flow [2]- [4] and ability to transfer power between interconnections that are not synchronized [5]. These benefits have prompted the development of existing and planned installations of HVDC in Europe [6], [7], in the US [8]- [11] and across the world [12]- [14].…”