Coupling direct air capture (DAC) with methanol production is a technically attainable opportunity for CO₂ capture and utilisation (CCU). The process, known as power-to-methanol (PtM), consumes large amounts of renewable electricity for water electrolysis and DAC. However, the time-variability of renewable power remains a major challenge. Here, we consider erecting a wind farm as part of a PtM facility and propose using four parallel reactors to adjust the methanol production according to daily wind power generation, which we model for 90 onshore and offshore locations with real-world data. Batteries and reserve storage of compressed H₂ and CO₂ allow methanol production during near-zero availability of wind power. We investigate different operation strategies, aiming to either minimise the reserve storage or maximise production, ultimately finding minimised storage as more cost-effective. The resulting selling price of methanol from a plant powered by an onshore wind farm is $1400 per tonne, rising to $2200 for offshore wind power because of higher farm installation costs. However, with a well-located wind farm, coupled with improvements to DAC, electrolysis, and catalysts, the selling price falls as low as $300 per tonne of methanol, reaching parity with fossil fuel-derived methanol. Purchasing stable grid power for PtM avoids issues of intermittency, and results in a lower methanol selling price of $960 per tonne, falling to $340 with process improvements. However, life cycle assessment (LCA) shows the global warming potential (GWP) of the grid-based cases is no better than producing methanol from natural gas; whereas, wind-powered DAC-PtM delivers net-negative GWP between −760 and −1240 kg_CO2eq. per t_MeOH, demonstrating successful CCU.

中文翻译：

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管理甲醇可持续生产中可再生能源的间歇性，并结合直接空气捕获


将直接空气捕获 (DAC) 与甲醇生产相结合是 CO ₂ 捕获和利用 (CCU) 技术上可实现的机会。该过程被称为电力转甲醇 (PtM)，消耗大量可再生电力用于水电解和 DAC。然而，可再生能源的时间变化仍然是一个重大挑战。在这里，我们考虑建立一个风电场作为 PtM 设施的一部分，并建议使用四个并联反应器根据每日风力发电量调整甲醇产量，我们使用真实世界数据对 90 个陆上和海上地点进行了建模。电池和压缩 H ₂ 和 CO ₂ 的储备存储允许在风电可用性接近于零的情况下生产甲醇。我们研究了不同的运营策略，旨在最小化储备存储或最大化产量，最终发现最小化存储更具成本效益。由此产生的由陆上风电场供电的工厂的甲醇售价为每吨 1400 美元，由于风电场安装成本较高，海上风电的甲醇售价升至每吨 2200 美元。然而，凭借地理位置优越的风电场，再加上 DAC、电解和催化剂的改进，甲醇的售价可低至每吨 300 美元，与化石燃料衍生的甲醇持平。为 PtM 购买稳定的电网电力可以避免间歇性问题，并导致甲醇售价降低至每吨 960 美元，随着工艺改进，甲醇售价降至 340 美元。 然而，生命周期评估（LCA）显示，并网案例的全球变暖潜势（GWP）并不比天然气生产甲醇好；而风力驱动的 DAC-PtM 每吨 _MeOH 的净负 GWP 介于 -760 至 -1240 kg _CO2eq. 之间，证明了 CCU 的成功。