Abstract Chemical process electrification and renewable energy integration facilitate one another along the pathway towards a greener industry. However, integrating intermittent and variable renewable power into large-scale chemical processes, which conventionally are preferred to operate at a steady-state with a constant load, could lead to prohibitive costs if intermittency is addressed solely by energy storage. Here, we consider the concept of a flexible chemical process which can operate with a variable load throughout the year while meeting a specified annual production target. Using methanol production via carbon dioxide hydrogenation as a case study and by means of process conceptual design and optimisation, we investigate how the over-sizing of flexible process units and the introduction of intermediate storage in the chemical process offer the possibility to improve the overall performance of systems. The impact of the characteristics of renewable power is also explored by performing the analysis using meteorological data from two locations dominated respectively by wind and solar energy. This study shows clear potential benefits of process flexibility when the renewable energy supply is highly variable and is to achieve a high level of penetration. For a 100% renewable production, the introduction of flexibility reduces the levelised cost of methanol by approximately 21 and 34% for the two case study locations, respectively. The cost attribution reveals further insights into the origin of the economic advantages through examining the comparative costs of chemical production, energy generation, intermediate product storage and renewable energy storage. The learning from this work suggests that incorporating process flexibility through a holistically optimised design of energy storage and chemical production has the potential to offer an economically viable route to large-scale green chemical production through renewables-enabled electrification.

中文翻译：

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电力转化为甲醇：工艺灵活性在将可变可再生能源整合到化工生产中的作用

摘要 化学过程电气化和可再生能源整合在迈向更绿色产业的道路上相互促进。然而，将间歇性和可变的可再生能源整合到大规模化学过程中，如果仅通过能量存储解决间歇性问题，通常倾向于在稳定状态下以恒定负载运行，可能会导致成本过高。在这里，我们考虑了灵活的化学过程的概念，该过程可以在全年以可变负载运行，同时满足指定的年度生产目标。以二氧化碳加氢制甲醇为例，通过工艺概念设计和优化，我们研究了灵活工艺单元的超大尺寸和化学工艺中中间存储的引入如何提供提高系统整体性能的可能性。通过使用分别以风能和太阳能为主的两个地点的气象数据进行分析，还探讨了可再生能源特性的影响。该研究表明，当可再生能源供应高度可变且要实现高渗透率时，流程灵活性的潜在好处显而易见。对于 100% 可再生生产，灵活性的引入使两个案例研究地点的甲醇平均成本分别降低了约 21% 和 34%。通过检查化学品生产、能源生产、中间产品存储和可再生能源存储的比较成本，成本归因揭示了对经济优势来源的进一步洞察。从这项工作中获得的经验表明，通过能源储存和化学品生产的整体优化设计来整合工艺灵活性，有可能为通过可再生能源电气化实现大规模绿色化学品生产提供一条经济可行的途径。