GigaWatt-Hour Subsurface Thermal Energy storAge: Engineered structures and legacy Mine shafts: STEaM

英国最后一座深井煤矿于2015年关闭。煤炭管理局有17.7万个已知煤矿条目的记录。这项提案审查了利用废弃矿井以热能的形式跨季节储存被削减的风能的可能性。2020年，英国的风能削减费用为2.82亿GB：足够为125万个家庭供电，相当于每兆瓦时发电4 GB。仅在东艾尔郡就有120千兆瓦的“备用”电力。以前对保温店进行了研究，但受到规模和隔热需求的限制。淹水的矿井在英国大部分地区随处可见，但矿井内的储热机会从未被探索过。竖井周围的岩石是绝缘体，我们联合体的试点工作表明，随着岩石加热，热提取的效率在短短三年内显著提高。我们将研究利用刮风天的备用电力来加热废弃矿井的水的可行性，这些水在寒冷的日子通过热泵抽出进入家庭和企业。英国到处都是煤矿时代的矿井--我们想把地面上的这些洞变成热能储存库，以帮助平衡电网，并为家庭和企业脱碳。矿井的衬里是混凝土或砖块(有时是无衬砌的)。为了安全和有效地利用这些遗留的地下基础设施，我们需要了解加热矿井水对以下方面的影响：井筒内的水体可能是自然分层的，将包含可能导致污染或结垢的矿物；衬砌材料，在矿山关闭后的几十年里可能已经降解；对周围岩石和它们所含的水(在孔隙和裂缝中)的影响。我们将开发复杂的热-水力-化学-机械(THCM)耦合模型，其依据是我们从英国竖井的分析中开发的案例研究，以及从测试现场收集的数据。我们还将采取全系统的方法，考虑到这样一个项目的经济性，以及通过建设和运营场地产生的任何碳排放，如何在更广泛的能源系统中建立这样的能源储备。我们正计划在一个竖井中进行测试，以获取水和盖子材料的样本进行分析，然后监控热量的注入以验证我们的模型。我们提议建设的范例竖井是Barony煤矿，它曾经是苏格兰最深的煤矿。我们的项目合作伙伴东艾尔郡议会有资金在现场附近建造一个观察洞，它将为建模和观察我们的实验进展提供数据基线。这项工作的结果将适用于评估英国各煤田矿井现场的矿井储热资源、与利用该资源相关的任何风险，以及在当地能源系统中使用该资源的最佳方式。我们还将为更加熟知的从矿井中提取天然地热补给热量的概念提供有用的新数据；审议放弃目前开采的矿场以使其能够随时进行热能储存的最佳方式；制作一个井筒和周围岩体完全耦合的热能管理模型；并开发出第一个包括地下基础设施和地质在内的综合能源系统模型。

The last deep coal mine in the UK closed in 2015. The Coal Authority has a record of 177,000 known mine entries. This proposal examines the potential to use abandoned mine shafts for interseasonal storage of curtailed wind energy in the form of thermal energy. In 2020, wind curtailment payments in the UK were £282M: enough to power 1.25 million homes and equivalent to £4 per MWh of energy generated. There is 120GW of 'spare' electricity in East Ayrshire alone. Thermal stores have been studied previously but are limited by size and the need to insulate. Flooded mine shafts are ubiquitous across much of the UK, yet the thermal storage opportunity within shafts has never been explored. The rock mass around the shafts are insulators and pilot work by our consortium has shown that as the rocks heat up the efficiency of the heat extraction rises considerably in as little as three years. We will investigate the feasibility of using the spare electricity on windy days to heat up water in abandoned mine shafts, to be extracted on cold days by heat pumps into homes and businesses. The UK is peppered with mine shafts from the days of coal mining - we want to turn these holes in the ground into thermal stores to help balance the electrical grid and to decarbonise homes and businesses. Mine shafts were lined with concrete or brick (sometimes unlined). To safely and efficiently utilise this legacy subsurface infrastructure we need to understand the effect of heating up the water in the mine shafts on: the water body in the shaft, which may be naturally stratified and will contain minerals that could cause contamination or scaling; on the lining material, which is likely to have degraded in the decades since mine closure; on the surrounding rocks and the water they contain (in pores and fractures). We will develop sophisticated coupled thermal-hydraulic-chemical-mechanical (THCM) modelling informed by case studies we develop from an assay of the UK's shafts, as well as data collected from a test site. We will also take a whole-systems approach to looking at how such an energy store could sit within the wider energy system, taking into account the economics of such a project, and any carbon emissions generated through construction and operation of a site. We are planning a test at a site where we drill into a shaft to retrieve samples of water and capping materials for analysis, and then monitor the injection of heat to validate our models. The example shaft that we are proposing to work on is the Barony colliery, once the deepest in Scotland. Our project partners, East Ayrshire Council have funding for an observation hole close to the site that will provide a baseline of data for the modelling and for observing the progress of our experiment. The outputs of this work will be applicable for assessing the mine shaft thermal store resource at mine shaft sites across UK coalfields, any risks associated with utilising that resource, and the optimal way to use that resource within the local energy system. We will also provide useful new data for the more well-understood concept of extracting natural geothermally recharged heat from mine workings; for consideration of the best way to abandon active mines so that they are thermal storage-ready; produce a fully coupled THCM model of mine shafts and the surrounding rock mass; and develop the first integrated energy system model to include subsurface infrastructure and geology.