Life cycle assessments (LCA) typically exclude spatial information in estimating the water consumption associated with a product, resulting in calls to improve regional detail to better reflect spatial variation. In response to these calls, we have compiled a spatially-resolved inventory of changes in water consumption associated with the coal-to-gas transition in Pennsylvania at the resolution of watersheds from 2009 to 2012. Results indicate that the total water consumption of the fuel extraction and power sectors in Pennsylvania increased by 7.6 million m³ (2 Bgal) over four years. At the state and watershed scales, we compare total water consumption for the coal-to-gas transition to a case where only the water consumed across two life cycle stages of electricity generation is considered – fuel extraction and use at the power plant to generate electricity. The results for the latter indicate that water consumption decreased by over 15.1 million m³ (4 Bgal). For both cases, watershed-level results showed water consumption generally increased in watersheds with growing shale gas activity or new natural gas capacity, while it decreased with diminishing coal-fired generation. Watershed-scale water consumption from 2009 to 2012 may be reversed from a net increase to decrease (and vice versa) when the total water consumption is compared to the water consumed specifically for life cycle stages of electricity generation, reinforcing the importance of further developing spatially-resolved inventories for LCA. Focusing on the water consumption associated with only electricity generation and its fuel use does not capture the full effects of fuel extracted for use in other sectors. We suggest that spatially-explicit inventories that include multiple life cycle stages should be a critical component in the development of more comprehensive, spatial LCA methodology. Spatial differentiation in inventories is necessary to adequately characterize watershed-level impacts that can be normalized over a functional unit. The approach can be used as a complementary assessment to LCA that can inform policy-makers and investors about where energy developments may pose additional risks to water supply and availability.

生命周期评估（LCA）通常在评估与产品相关的水消耗时会排除空间信息，因此需要改进区域细节以更好地反映空间变化。为了回应这些呼吁，我们编制了一个空间解析清单，列出了宾夕法尼亚州煤改气的水消耗量变化，该变化量取自2009年至2012年的分水岭。结果表明，燃料的总水消耗量宾夕法尼亚州的采掘和电力部门增长了760万m ³（2 Bgal）超过四年。在州和流域尺度上，我们将煤制气转换的总耗水量与仅考虑发电的两个生命周期阶段的耗水量（燃料提取和电厂的发电）相比较的情况进行了比较。对于后者的结果表明，水耗下降超过15100000米³（4 Bgal）。对于这两种情况，分水岭水平的结果表明，随着页岩气活动或新天然气能力的增加，流域的耗水量普遍增加，而随着燃煤发电量的减少，耗水量减少。如果将总耗水量与专门用于发电生命周期阶段的耗水量进行比较，则2009年至2012年流域规模的耗水量可能会从净增加量减少到减少量（反之亦然），从而强调了在空间上进一步发展的重要性-已解决的LCA库存。仅关注与发电有关的水消耗及其燃料使用并不能完全反映提取出来的用于其他部门的燃料的全部效果。我们建议，包括多个生命周期阶段的空间明晰的清单应成为开发更全面的空间LCA方法学的关键组成部分。为了充分表征可在功能单元上归一化的分水岭级影响，必须进行清单空间分异。该方法可以用作LCA的补充评估，可以使政策制定者和投资者了解能源发展可能在何处给水供应和可利用性带来额外风险的信息。