A peer-reviewed modeling study published in Nature Communications Earth & System Sciences sizes a phased offshore carbon capture, utilization and storage (CCUS) network for the Guangdong–Hong Kong–Macao Greater Bay Area at roughly 2,178 km of optimized CO2 pipeline — 56.78% shorter than the ~5,040 km theoretical worst-case layout — serving 23 emission sources and seven offshore storage sites with a combined sink capacity the authors place in the hundreds of gigatonnes.

The study anchors the plan in a 2023 emissions inventory covering 21 prefecture-level cities plus Hong Kong and Macau. The region emitted approximately 883 Mt of CO2 in 2023, with the Pearl River Delta accounting for 430.65 Mt and western Guangdong 266.02 Mt — together 78.89% of the regional total. Zhanjiang (130.78 Mt) and Huizhou (125.37 Mt) were the largest single emitters, followed by Maoming (98.37 Mt) and Guangzhou (97.87 Mt). Under baseline projections aligned with China's 2030 peak and 2060 carbon-neutrality timeline, regional emissions rise from about 892 Mt in 2024 to roughly 952 Mt in 2030, then decline to about 713 Mt by 2060.

Where the CO2 goes

Onshore Guangdong offers limited sequestration potential because of faulted strata, so the model routes captured CO2 to two offshore basins. In the Pearl River Mouth Basin, four sags — Lufeng, Xijiang, Huizhou and Enping — hold an estimated 35.1 Gt of effective saline-aquifer storage at the P50 confidence level within the 800–3,500 m depth window. The Huizhou sag leads at 10.26 Gt, followed by Xijiang at 9.11 Gt. In the Beibu Gulf Basin, where average water depth runs only about 50 m, the Wushi sag holds 6.86 Gt (P50) and sits roughly 20 km from Zhanjiang's Leizhou Peninsula.

The model partitions sources and sinks into four zones, each consolidated at a cluster hub — Jieyang, Huizhou, Yangjiang and Zhanjiang — before pipeline delivery offshore. The Huizhou–Huizhou sag zone aggregates the most sources, 13 cities emitting ~468 Mt per year, over an optimized pipeline length of ~922 km. The Zhanjiang–Wushi sag zone connects only Zhanjiang and Maoming, ~229 Mt per year, over the shortest route at ~203 km. The Jieyang–Lufeng (~449 km) and Yangjiang–Enping (~603 km) zones carry ~93 Mt and ~92 Mt per year respectively.

The economics

Using cost curves from the China CCUS Development Report 2021 and an 8% discount rate, the authors project total regional project costs of RMB 228 × 10^10 at a 60% capture-efficiency scenario, RMB 152 × 10^10 at 40% and RMB 76 × 10^10 at 20%, against carbon-pricing revenue of RMB 250 × 10^10, 167 × 10^10 and 83 × 10^10 respectively. Net present values land at approximately RMB 22 × 10^10, 15 × 10^10 and 7 × 10^10, with profitability beginning around 2040 in all three scenarios.

Transport distance, not capture rate, drives the breakeven timing. The Zhanjiang–Wushi zone turns profitable first, in 2037; Jieyang–Lufeng follows in 2038, Yangjiang–Enping in 2039 and Huizhou–Huizhou in 2041 — the longest-haul zone and the only one to post a net loss over the full project life. When the model holds pipeline distance at a uniform 717 km, nearly all zones fail to achieve overall profitability across 2030–2060, consistent with prior research that caps economic cluster transport at roughly 800 km. Sensitivity analysis shows cumulative returns swing ±21.2% on a ±10% carbon-price move, versus ±6.0% for capture cost, ±4.0% for transport distance and ±1.2% for storage cost.

Enhanced oil recovery (EOR) carries the early, loss-making years. Suitable oil reservoirs across both basins offer only ~31 Mt of dedicated storage at the medium assessment — marginal against Guangdong's ~883 Mt annual emissions — but miscible flooding at WS17-2 could generate roughly RMB 3.8 billion in discounted oil revenue during route II's 2030–2036 deficit, subsidizing about 4% of cumulative profits over that interval. At XJ24-3, EOR revenue of about RMB 13.1 billion could cover 29% of route I's cumulative profits during its 2037–2040 deficit. The nominal carbon price reaches roughly 20 times its 2030 level by 2060.

The build schedule

The paper proposes a three-phase schedule. Phase I starts at Zhanjiang–Wushi in 2030, leveraging the shortest pipeline, a subsea link to the Leizhou Peninsula already built by China National Offshore Oil Corporation and partners for hydrocarbon service, and 2023 GDPs of 0.38 and 0.4 trillion RMB for Zhanjiang and Maoming. Phase II activates Huizhou–Huizhou after the first zone turns profitable in 2037. Phase III brings Jieyang–Lufeng and Yangjiang–Enping online around 2040.

Against a 2 °C-aligned burden-sharing estimate of 2.87 Gt of CCUS-based reductions for Guangdong by 2050 — 10.76% of national GDP prorated from China's 26.68 Gt CCUS allocation — the framework delivers 2.71 Gt cumulative reductions by 2050 in the low-attention scenario, 5.43 Gt at medium attention and 8.14 Gt at high attention. At P50 confidence, remaining saline-aquifer capacity after 2060 could sustain storage until around 2140 under high deployment.

All of this remains a modeled plan, not built capacity; the only operating asset cited is EP15-1, China's first offshore CCUS demonstration, in the Enping sag. The decision milestones are the five-year window to 2030 for a Zhanjiang–Wushi final investment decision and the carbon-price trajectory, the single most sensitive variable in whether the network's economics hold.