Case study: Catalysis & electrochemistry for decarbonization — a city or utility pilot and the results so far

In 2023, the Port of Antwerp-Bruges launched one of Europe's most ambitious electrochemical decarbonization pilots, deploying a 2.5 MW proton exchange membrane (PEM) electrolyzer coupled with a novel carbon dioxide conversion reactor to produce methanol from captured industrial CO2 and green hydrogen. The project, known as the Antwerp@C Electrochemical Conversion Pilot, represented a critical test of whether catalytic CO2 reduction could operate reliably at semi-industrial scale while maintaining economic viability under real-world grid conditions. After 18 months of continuous operation, the pilot has generated over 1,200 metric tons of e-methanol, reduced net CO2 emissions by approximately 2,800 metric tons, and delivered a set of technical and economic lessons that are reshaping how European ports and chemical clusters approach electrochemical decarbonization.

Why It Matters

Heavy industry accounts for roughly 21% of global greenhouse gas emissions, with the chemical sector alone responsible for approximately 925 million metric tons of CO2 annually. Unlike power generation or passenger transport, industrial chemistry cannot simply electrify its way to zero emissions. Many chemical processes require specific molecular feedstocks, carbon-containing intermediates, or high-temperature catalytic environments that electricity alone cannot replably substitute. This is where catalysis and electrochemistry become indispensable: they offer pathways to replace fossil-derived feedstocks with renewable alternatives while maintaining the molecular outputs that downstream manufacturing depends on.

The European Union's Carbon Border Adjustment Mechanism (CBAM), which entered its transitional phase in October 2023, imposes carbon costs on imported goods including chemicals, fertilizers, and steel. By 2026, importers will need to purchase CBAM certificates reflecting the embedded carbon content of these products. This regulatory shift fundamentally alters the economics of electrochemical conversion. Production routes that were previously 40-60% more expensive than fossil alternatives now face a narrowing cost gap as carbon prices rise toward the EUR 80-100 per metric ton range projected by the European Commission for 2027-2030.

Port authorities and chemical clusters occupy a unique position in this transition. They concentrate large volumes of industrial CO2, have access to shipping infrastructure for product distribution, and can aggregate renewable electricity procurement across multiple tenants. The Antwerp pilot was designed specifically to test whether this concentration advantage translates into viable electrochemical production at a scale relevant to commercial operations.

Key Concepts

Proton Exchange Membrane (PEM) Electrolysis splits water into hydrogen and oxygen using electricity passed through a solid polymer membrane. PEM systems offer faster response times and higher current densities than traditional alkaline electrolyzers, making them better suited to operation with intermittent renewable electricity. The Antwerp pilot selected PEM technology specifically for its ability to ramp between 10% and 100% of rated capacity within seconds, enabling direct coupling with variable wind generation from North Sea offshore farms.

Catalytic CO2 Reduction to Methanol uses copper-zinc-aluminum oxide catalysts (or increasingly, novel copper-indium or copper-gallium formulations) to combine hydrogen with carbon dioxide at elevated temperatures (220-280 degrees Celsius) and pressures (50-80 bar). The reaction is thermodynamically favorable but kinetically limited, meaning catalyst selectivity and activity determine both conversion efficiency and product purity. Traditional industrial methanol synthesis uses syngas derived from natural gas; the electrochemical route substitutes green hydrogen and captured CO2, producing chemically identical methanol with dramatically lower lifecycle emissions.

Carbon Capture Integration in industrial clusters typically draws CO2 from concentrated point sources such as ethylene crackers, ammonia plants, or power-from-waste facilities. The Antwerp pilot captures CO2 from a nearby ethylene oxide production facility operated by BASF, where exhaust streams contain 95-99% pure CO2, eliminating the need for expensive post-combustion capture equipment. This integration model reduces the total energy penalty of the carbon capture step from 3-4 GJ per metric ton (typical for dilute flue gas capture) to less than 0.5 GJ per metric ton.

Power-to-X describes the broad category of processes that convert renewable electricity into chemical energy carriers or industrial feedstocks. E-methanol, e-ammonia, and e-kerosene represent the primary Power-to-X products under commercial development. The Antwerp pilot focuses on e-methanol because of its immediate market applications: maritime fuel blending under IMO 2030 targets, chemical feedstock for formaldehyde and acetic acid production, and wastewater treatment applications in Flemish municipalities.

The Pilot: Design and Implementation

The Antwerp@C pilot emerged from a consortium of seven partners: the Port of Antwerp-Bruges (infrastructure and permitting), BASF (CO2 supply), Siemens Energy (PEM electrolyzer), Johnson Matthey (catalyst development), Fluxys (gas distribution), the University of Leuven (process modeling), and the Flemish Institute for Technological Research (VITO) for independent monitoring and verification.

Construction began in March 2022 on a brownfield site adjacent to BASF's Verbund facility, with first hydrogen production achieved in September 2022 and the methanol synthesis reactor reaching steady-state operation in January 2023. Total capital investment reached EUR 38 million, of which EUR 14 million came from the EU Innovation Fund and EUR 6 million from Flemish regional development grants.

The system architecture comprises three integrated modules. The electrolysis module houses a 2.5 MW Siemens Silyzer 300 stack producing up to 500 Nm3/hour of hydrogen at 99.999% purity. The CO2 conditioning module receives raw gas from BASF's ethylene oxide plant, removes trace contaminants (sulfur compounds and water), and compresses the purified CO2 to synthesis pressure. The methanol synthesis module uses a fixed-bed tubular reactor with Johnson Matthey's KATALCO 51-9S catalyst, modified with proprietary promoters to improve selectivity under the variable hydrogen feed rates inherent in renewable-coupled operation.

A critical design decision was the inclusion of a 4-hour hydrogen buffer storage system (a 150 m3 pressurized vessel at 30 bar) that decouples electrolyzer operation from methanol synthesis. This buffer allows the electrolyzer to track renewable generation profiles while maintaining steady-state conditions in the catalytic reactor, which performs poorly under rapid load changes. Without this buffer, catalyst deactivation rates would increase by an estimated factor of three, shortening catalyst replacement intervals from the target 18 months to approximately 6 months.

Measured Outcomes

After 18 months of operation (January 2023 through June 2024), independent monitoring by VITO documented the following performance metrics:

Metric	Target	Achieved	Notes
Methanol Production	1,500 t/yr	1,247 t/yr	83% of target; limited by electrolyzer downtime
System Availability	90%	82%	Membrane replacements and grid curtailments
CO2 Conversion Efficiency	95%	91.3%	Improved from 87% in first quarter
Specific Energy Consumption	10.5 MWh/t methanol	11.8 MWh/t	Higher than target due to part-load operation
Net CO2 Avoided	3,500 t/yr	2,814 t/yr	Based on displacement of fossil methanol
Catalyst Lifetime	18 months	14 months (projected)	Faster deactivation at low loads
Levelized Cost of Methanol	EUR 650/t	EUR 780/t	Electricity costs higher than projected
Water Consumption	12 L/kg methanol	13.4 L/kg	Within acceptable range

The production shortfall relative to targets was primarily driven by two factors. First, the PEM electrolyzer experienced three unplanned shutdowns totaling 47 days for membrane stack replacement, a rate higher than Siemens' warranty specifications. Second, grid curtailment events during periods of negative wholesale electricity prices (which occurred 312 hours in 2023, nearly triple the 2022 frequency) required the system to shut down because the renewable electricity purchase agreement did not include provisions for grid balancing services.

The economic performance, while above target cost, demonstrated a clear trajectory toward competitiveness. During the first six months, levelized methanol cost averaged EUR 920 per metric ton. Process optimization, improved electrolyzer management, and a renegotiated electricity contract reduced this to EUR 680 per metric ton in the final quarter of the monitoring period.

What Worked

The concentrated CO2 source proved to be the single most important cost advantage. By tapping a 95%+ purity stream from existing chemical production, the pilot avoided EUR 80-120 per metric ton in capture and purification costs that projects using dilute flue gas sources must bear. This finding has direct implications for project siting: electrochemical conversion installations should prioritize co-location with high-purity CO2 sources over proximity to renewable generation, since electricity can be transmitted via grid while CO2 transport remains expensive.

The hydrogen buffer storage system performed as designed, enabling the methanol reactor to maintain steady-state operation during 92% of operating hours despite electrolyzer output varying between 20% and 100% of capacity. This decoupling strategy reduced catalyst stress and improved product consistency, with methanol purity averaging 99.7% compared to the 99.5% specification.

The consortium governance model, while occasionally slow in decision-making, ensured that operational data and lessons were shared openly among partners. VITO's independent monitoring role prevented the optimistic bias that frequently distorts pilot project reporting. All performance data was published quarterly on the Port of Antwerp-Bruges transparency portal, enabling peer review and comparison with similar projects.

What Did Not Work

Electrolyzer reliability fell short of expectations. The PEM stack degraded faster than manufacturer projections, with voltage decay averaging 4.2 microvolts per hour compared to the warranted 2.5 microvolts per hour. Siemens attributed the accelerated degradation to the frequency of load cycling (averaging 8-12 significant ramp events per day) rather than cumulative operating hours. This finding challenges the assumption that PEM electrolyzers can seamlessly track renewable generation profiles without reliability penalties.

The electricity procurement structure created perverse incentives during periods of very low or negative wholesale prices. The fixed-price power purchase agreement (PPA) at EUR 52 per MWh did not allow the pilot to benefit from spot market prices that dropped below EUR 20 per MWh on 1,400 hours during the monitoring period. A more sophisticated PPA with hybrid fixed-floor and spot-market components would have reduced average electricity costs by an estimated EUR 8-12 per MWh.

Catalyst deactivation under variable load conditions remains an unresolved technical challenge. While the hydrogen buffer mitigated the worst effects, thermal cycling in the synthesis reactor during extended low-production periods (weekends and maintenance windows) accelerated sintering of the copper-zinc catalyst surface. Johnson Matthey is developing a next-generation catalyst formulation with improved thermal stability, but commercial availability is not expected before 2027.

Transferable Lessons

Lesson 1: Site selection should prioritize CO2 purity over renewable proximity. The economics of electrochemical conversion are more sensitive to CO2 capture costs than to electricity prices within typical European ranges. Projects should target industrial sites with concentrated CO2 streams (ethylene oxide, ammonia, bioethanol, cement kiln bypass) even if this requires grid-delivered renewable electricity rather than direct connection to wind or solar farms.

Lesson 2: Hydrogen buffer storage is not optional. Any electrochemical conversion system coupled with variable renewable electricity requires intermediate hydrogen storage to protect downstream catalytic processes. The optimal buffer size depends on the renewable generation profile and the catalyst's tolerance for load variation, but 2-6 hours of storage at rated production capacity represents a reasonable design range.

Lesson 3: Electrolyzer degradation under cycling loads requires contractual protection. Standard manufacturer warranties based on total operating hours do not adequately cover degradation caused by frequent load cycling. Procurement contracts should include cycle-count-based warranty terms and performance guarantees that account for real-world renewable generation variability.

Lesson 4: Regulatory carbon pricing transforms project economics. At prevailing EU Emissions Trading System prices of EUR 65-85 per metric ton CO2, the e-methanol cost premium over fossil methanol narrows to EUR 150-250 per metric ton. With CBAM fully operational and free allocation phasing out by 2034, the cost crossover point for e-methanol in European markets is projected between 2029 and 2032, assuming continued renewable electricity cost reductions.

Lesson 5: Municipal and port authorities can play catalytic roles. The Port of Antwerp-Bruges contributed no proprietary technology but provided essential enabling functions: permitting acceleration, infrastructure access, consortium coordination, and demand aggregation among port tenants for the e-methanol output. Other port authorities and municipal industrial development agencies should consider similar facilitator roles.

Action Checklist

• Assess available CO2 point sources within 25 km of potential project sites, prioritizing streams above 90% purity
• Evaluate electrolyzer technology options with specific attention to cycling degradation rates, not just rated efficiency
• Design hydrogen buffer storage sized for 2-6 hours of rated methanol production capacity
• Structure electricity procurement with hybrid PPA terms that capture value from low wholesale price periods
• Engage independent third-party monitors from project inception to ensure credible performance reporting
• Model project economics under multiple carbon price scenarios (EUR 50, 75, 100, and 125 per metric ton)
• Identify potential offtakers for e-methanol within the local industrial ecosystem before finalizing project scale
• Apply for EU Innovation Fund, Horizon Europe, or equivalent national funding programs during the front-end engineering phase

FAQ

Q: How does the cost of e-methanol from this pilot compare to conventional fossil methanol? A: Fossil methanol produced from natural gas in 2024 costs approximately EUR 300-400 per metric ton at European import terminals. The pilot's achieved cost of EUR 780 per metric ton (trending toward EUR 680) represents a premium of roughly 70-100%. However, when EU ETS carbon costs are applied to fossil methanol (approximately EUR 0.5-0.7 per kg CO2 embedded), the effective fossil methanol cost rises to EUR 500-600 per metric ton, narrowing the gap to 15-35%.

Q: Can this approach work with lower-purity CO2 sources like cement plants or power stations? A: Yes, but the economics change substantially. Capturing and purifying CO2 from cement plant flue gas (typically 15-25% CO2) adds EUR 60-100 per metric ton of captured CO2, while coal or gas power plant exhaust (4-12% CO2) adds EUR 80-130 per metric ton. These additional costs increase the levelized methanol price by EUR 120-250 per metric ton compared to the high-purity source used in Antwerp.

Q: What is the water consumption footprint of this process? A: The pilot consumed 13.4 liters of deionized water per kilogram of methanol produced, with electrolysis accounting for approximately 85% of total water demand. In water-stressed regions, this consumption rate may require desalination or water recycling integration, adding EUR 0.02-0.05 per kilogram to production costs.

Q: How scalable is this model beyond the pilot phase? A: The Port of Antwerp-Bruges has approved a Phase 2 expansion to 25 MW electrolyzer capacity with a target of 12,000 metric tons per year of e-methanol production by 2027. Engineering studies indicate that further scale-up to 100 MW (50,000 metric tons per year) is technically feasible using modular electrolyzer and reactor designs, with projected cost reductions of 25-35% from economies of scale. The primary scaling constraint is not technology but rather the availability of contracted renewable electricity at competitive prices.

Q: What regulatory approvals were required for the pilot? A: The pilot required environmental permits under the Flemish VLAREM framework (industrial emissions, water discharge, and noise), a Seveso III notification due to hydrogen storage volumes exceeding 5 metric tons, a grid connection agreement with transmission operator Elia, and product certification for the e-methanol under REACH chemical registration requirements. The permitting process took 14 months from initial application to operational authorization.

Sources

• Port of Antwerp-Bruges. (2024). Antwerp@C Electrochemical Conversion Pilot: 18-Month Performance Report. Antwerp: Port Authority Publications.
• International Energy Agency. (2025). The Role of E-fuels in Industrial Decarbonization. Paris: IEA Publications.
• European Commission. (2024). EU Innovation Fund: Results and Lessons from First Call Projects. Brussels: Directorate-General for Climate Action.
• Johnson Matthey. (2024). Catalyst Performance Under Variable Load Conditions: Field Data from Power-to-Methanol Operations. Catalyst Technical Bulletin No. 47.
• VITO. (2024). Independent Monitoring Report: Antwerp@C Electrochemical Conversion Pilot. Mol, Belgium: Flemish Institute for Technological Research.
• Siemens Energy. (2024). PEM Electrolyzer Degradation Analysis: Cycling vs. Steady-State Operation. Technical White Paper SE-2024-EL-07.
• BloombergNEF. (2025). Power-to-X Economics: European Market Outlook 2025-2035. London: Bloomberg LP.