How to Read China's Ultra-High-Voltage Transmission Projects: What the Channels Are For, How Much Renewable Power They Carry, How Their Tariffs Are Built, and What the 2025–2026 Rules Change

Short answer. China's ultra-high-voltage (UHV) channels are the backbone of long-distance transmission. The NEA counts 45 in operation — 24 DC and 21 AC — and puts national "West-to-East" capacity at 340 GW. Three questions get past the headlines: how much renewable electricity a given line actually carries (the NEA publishes this line by line for UHV DC), what policy requires of new channels, and how the line's tariff is set, because the tariff formula decides who bears the risk of an under-used line.

1. What the channels are for

The NEA's Electric Power Department described the 45 channels as an "electricity highway" running east–west and north–south, with 340 GW of West-to-East transmission capacity. Policy assigns them a clean-energy role. The 2030 carbon-peaking plan strictly controls the coal power built to accompany cross-regional renewable transmission and requires the renewable share on newly built channels to be in principle not lower than 50%. The 2024–2025 energy-saving plan calls for faster construction of outbound channels for large wind and PV bases and more cross-provincial capacity.

The NDRC/NEA December 2025 opinions on grid development keep that direction but add discipline: plan cross-provincial channels in an orderly way to serve "desert-Gobi-wasteland" and hydro-wind-solar bases, keep a reasonable pace while tackling corridor constraints, use market price signals to raise transmission efficiency and economics, steadily raise the clean-energy share carried and upgrade existing channels where feasible, all within a national structure of six regional synchronous grids. They also list R&D on large-capacity flexible (VSC) DC, islanded new-energy export and low-frequency transmission, and a pilot of long-distance export from a base with 100% new energy.

2. How much renewable power they carry

The NEA's 2024 renewable-power monitoring results (国能发新能〔2025〕92号) give the numbers. In 2024, 20 UHV DC lines carried 705.3 TWh, of which 400.8 TWh was renewable (up 22.2%), a 56.8% renewable share (up 4.3 points). State Grid's 16 lines carried 615.3 TWh at 50.5% renewable; China Southern Grid's 4 lines carried 90 TWh, all renewable.

The averages hide a wide spread. Line by line, 2024 renewable shares ran from 11.3% on 陕武直流 (33.9 TWh carried) — with 昭沂 at 17.4% and 灵绍 at 21.8% also low — to 100.0% on the four China Southern Grid lines; among State Grid lines the highest were 锦苏 (99.5%) and 建苏 (99.1%). 吉泉 carried the most (68.4 TWh) at 26.8% renewable. The figures are reported by the grid companies (rows 1–16 State Grid, 17–20 China Southern Grid). CNWattHub editorial method: when a project pitch says a UHV line "delivers clean power", look up that line in Table 6 of the monitoring results rather than relying on the national average.

3. How a UHV tariff is built

The NDRC's pricing method for cross-provincial special transmission projects (issued with 发改价格规〔2025〕1490号, in force from 1 January 2026 for 10 years, replacing the 2021 method) sets the rules. Special projects are inter-regional projects and intra-regional cross-provincial projects with relatively clear sending and receiving ends and a relatively fixed flow direction. A provisional price is set before commissioning and a formal price after final accounts, with periodic review; the tariff is a single per-kWh energy charge.

The price is set by the operating-period method: annual net cash flows are discounted at the equity IRR so that the whole operating period balances, and price = average annual revenue / [design transmission volume × (1 − pricing line-loss rate)]. For DC projects the design volume is design utilisation hours × rated capacity, with hours taken from the approval document or, if not specified, in principle 4,500 hours. Formal-price parameters are a 35-year operating period with straight-line depreciation, an equity IRR of no more than 5%, a 25-year loan term and an O&M rate of at most 2%; provisional prices assume equity of 20% of investment and a 2% O&M rate. CNWattHub arithmetic on that formula: a hypothetical 8 GW DC line priced at the 4,500-hour default has a design volume of 36 TWh a year, before line losses.

Two clauses allocate utilisation risk. Line-loss deviations are borne or enjoyed by the buyer monthly; revenue from actual hours above the priced hours goes 30% to the grid company and 70% to the NDRC to support cross-provincial export of new energy; and the price is adjusted if the project's function changes fundamentally, actual hours exceed design hours by 40% or more, or actual costs or revenue deviate seriously from those used in pricing. In inter-provincial spot trading, power routed over a second project because the cheapest path is full still pays the cheapest-path price, and temporary extra transmission over spare capacity may be priced at no more than the approved tariff.

4. What is changing

Both the pricing method and the grid opinions open the door to two-part or capacity-only tariffs for projects that mainly carry clean energy or provide interconnection. The pricing method alone also proposes exploring transmission-rights trading. Read together with the 50% rule for new channels and the NEA's line-level data, the direction is to tie channels more closely to clean-energy delivery and to market signals, while keeping a regulated return on the asset.

Reading table

Checklist

CNWattHub editorial method, not a sourced rule:

1. Identify the line by its official short name (e.g. 吉泉直流) and read its row in the latest NEA monitoring results.
2. For a new channel, ask how it meets the 50% renewable requirement and which bases supply it.
3. Ask for the approved design utilisation hours and whether the provisional or formal price applies.
4. Check whether the project is priced as a special project or within a regional or provincial network.
5. Watch for two-part or capacity tariffs, which shift volume risk away from the per-kWh charge.

Scope limits

National texts and NEA statistics only. No individual project approval was retrieved, so line capacities, lengths, investment and approved tariffs are not quoted; the 8 GW example is hypothetical. The 45 channels are not listed by the NEA source; the 20 DC lines are those in the 2024 monitoring results. AC UHV utilisation and DC transmission reliability indices are not covered. Not engineering or investment advice.