Summary of Key Points
In 2010, China built the world's first million-ton-scale coal-to-olefins plant (the Shenhua Baotou project) in an attempt to reduce its dependence on imported oil. This "non-petroleum route" (coal-to-CTO + purchased methanol for MTO production) expanded rapidly, accounting for 20.7% of the country's ethylene production capacity in 2019. However, due to market arbitrage that eliminated the cost advantage of MTO and dual-carbon policies restricting the expansion of coal-based routes, its share dropped to 13.9% by 2026. Meanwhile, the propylene production method using propane dehydrogenation (PDH) emerged as the winner due to its simplicity and efficiency, although it now relies on imported propane from the United States. While this route has alleviated short-term energy pressures, it highlights the complexity of energy security: the issue is not just about changing the source of raw materials but about balancing costs, policies, and global supply chains.
I. Why Build a "Second Route"? The Urgency Stemmed from Oil Dependence
Before 2010, almost all ethylene in the world was produced from oil: crude oil was refined into naphtha, which was then cracked to produce ethylene and propylene. China faced several critical challenges:
- Price Control: In 2008, oil prices soared to $147 per barrel, driving up naphtha costs, leaving China with no control over its own ethylene production costs.
- Insufficient Supply: The country's self-sufficiency rate for polyethylene was only 59.2%, with more than 40% relying on imports. This meant that prices were unaffordable during price increases, and inventory became a liability during price declines.
- National Conditions: China has abundant coal but limited oil resources, so turning to coal-to-olefins (which involves multiple conversion steps) was a viable alternative to avoid relying on oil.
In short, since the oil industry controlled the prices, China needed to find an independent production method, and coal proved to be the best choice.
II. How This Route Was Established and Then Declined? Market Arbitrage Eliminated the Advantage
After the success of the Baotou project, coal-to-CTO and methanol-to-olefins (MTO) processes gained momentum, accounting for 0.7% of ethylene production capacity in 2010 and rising to 20.7% by 2019 (with one ton of ethylene produced from each five tons of coal or methanol). However, the decline in their share after 2019 was not due to a slowdown in coal chemical production but rather a divergence between the two routes:
- CTO Survived: With its own coal mines, CTO could anchor its costs to domestic coal prices, and its operating rate was similar to that of the petroleum-based route (83% vs. 85.7% for steam cracking). This made it less vulnerable to price fluctuations.
- MTO Struggled: Using purchased methanol as a raw material meant high costs—initially, the gross profit margin was $276 per ton in 2010. As more plants adopted MTO, methanol prices rose along with ethylene prices, reducing the margin to $7 per ton by 2025, resulting in an operating rate of only 68%. MTO became a marginal production method that was activated only when market conditions were favorable.
The essence is that once a new route shows potential profitability, capital will flow in to eliminate any excess profits. The success of the CTO technology marked the beginning of MTO's decline.
III. Policy: A Boost at First, Then a Hindrance
Coal-to-olefins development was never purely market-driven; policy played a crucial role:
- Initial Support: The project was promoted as part of national energy security strategies, and local governments (such as those in coal-rich regions like Inner Mongolia and Ningxia) actively supported it, aiming to convert low-cost coal into high-value chemicals.
- Dual-Carbon Policies: After the introduction of dual-carbon targets in 2020, coal-to-olefins was classified as a high-energy-consuming industry, making it harder to obtain production permits. Energy consumption restrictions and increased methanol prices (by 84% in 2021) further impacted MTO.
While policies can influence expansion speed, they cannot change the economic viability of a route. Subsidies may boost initial growth, but cost constraints (like the $7 per ton profit margin) ultimately determine its sustainability.
IV. The Propylene Market: Why PDH Prevailed Over Coal-Based Methods?
There were three main propylene production methods: coal-to-olefins, MTO, and PDH. PDH emerged as the winner due to its simplicity:
- Low Complexity: PDH requires only one reaction to produce propylene from propane, making it more efficient and less capital-intensive (a fraction of the cost compared to coal-based methods).
- Cost Advantages: The U.S. shale gas revolution led to a sharp drop in propane prices, significantly reducing PDH's raw material costs.
- Inefficiencies of Coal-Based Methods: Coal-to-olefins involves multiple conversion steps and requires access to coal mines and water (which is scarce in some regions), making it more capital-intensive and less flexible.
PDH's success demonstrates that in volatile industries, lighter and more agile production methods are more resilient than those with higher theoretical costs but greater complexity.
V. The Irony of Energy Security: Changing Dependencies Doesn't Solve the Problem
The goal was to reduce reliance on Middle Eastern crude oil. However, the new propylene production method (PDH) still relies heavily on imported propane from the United States:
- Propane Dependency: China imports 84% of its propane needs, with 59% coming from the U.S. in 2024.
- Tariffs and Energy Policies: During trade tensions between China and the U.S., liquefied gas (which contains propane) became a target for restrictions, highlighting that the shift to coal-to-olefins did not completely eliminate oil dependence.
This shows that energy security is about more than just avoiding one type of import; it's about balancing dependencies, the degree of reliance, and the resilience of global supply chains. Changing one dependency does not necessarily increase security unless other factors are also addressed.
Final Insights:
- Profit Margins Disappear Once a Route Is Proven Feasible: Technological barriers may protect profits, but market arbitrage erodes them.
- Simplicity Wins: PDH's single-step process outperforms more complex methods.
- Consider the Overall Capacity: Although the share of coal-to-olefins has declined, its absolute capacity is still growing due to the faster expansion of petroleum-based routes.
- Energy Security Is About Diversity: It's not about avoiding all imports but about diversifying sources and ensuring supply chain resilience.
- Policy Shapes Entry, Market Determines Survival: Policies can support new technologies, but their long-term success depends on cost and profitability.
Next: The U.S. shale gas revolution has changed global energy costs. With the success of China's coal-to-olefins plants, they now face competition from cheaper alternatives like ethane. That's the subject of the next chapter.