Sustainable, Affordable and Viable Compressed Air Energy Storage (SAVE-CAES)

SAVE-CAES项目旨在开发大规模的长期能源存储，使英国能够主要（甚至可能完全）使用可再生能源。这种能源储存必须是可负担的、可持续的和大规模的。压缩空气储能（CAES）有潜力满足所有这些至关重要的标准。开发这样的储能系统可能是阻碍英国到2050年实现“净零排放”的最大挑战。英国周围的海上风能是未来英国零碳电力系统的重要资源。如果我们开发所有可能想象到的区域，英国海上风能每年可以产生大约2000TWh的电能——比我们目前一年消耗的电量多5倍以上。当然，从现在到2050年，用电量将会增加——可能从每年350TWh增加到每年1000TWh。然而，我们完全可以利用风能发电。太阳能也将在为英国的净零排放提供动力方面发挥关键作用，但有一些直截了当的原因，为什么它在未来只能提供大约20%的电力。其中最强烈的与季节性有关：仲夏平均每天的太阳能是仲冬平均每天的9倍，然而我们在冬季的能源需求高于夏季。令人高兴的是，风也是季节性的，它通常在仲冬的平均一天提供的能量是仲夏的平均一天的2.3倍。核能也将发挥一定作用。对于这一作用有多重要，人们意见不一，但这对于理解或证明这项研究计划并不重要。让一个国家主要依靠不灵活的低碳能源提供动力的关键问题是，需求和供应必须匹配，而需求相对“缺乏弹性”。这意味着电力成本的微小变化对耗电量的影响非常小。到2050年，我们将为我们的电能支付多少的定量评估表明，不到一半将由产生实际单位电能的直接成本组成。更大的成本将与提供灵活性——匹配供应和需求的能力——有关。不同的研究人员预测的比例不同，但一致认为灵活性成本将占主导地位。CAES是英国最有前途的一套可选方案，用于在数十小时-可能长达100小时的时间内存储大量（风能或太阳能）能源。CAES有潜力将良好的性能（高达70%的往返效率）与相对较低的成本（< 2英镑/千瓦时）相结合。世界上有两个不同的电网规模的储能工厂储存压缩空气，一个在德国的Huntorf，另一个在阿拉巴马州的McIntosh，然而，这些工厂也储存化石燃料。许多评论员犯了一个严重的错误，即根据这些来推断CAES可能做什么。SAVE-CAES项目旨在应用基础工程科学来确定一个设计良好的CAES工厂在没有化石燃料添加的情况下可能会做什么。SAVE-CAES是一个充满新奇的项目。加压空气将被储存在离岸或海岸的盐穴中。该项目将探索利用压力空气的等压储存和浓缩盐水（盐水）的管理来调节压力。它还将探索超高压空气储存（每立方米洞穴的最佳价值）。它还将探索在空气再膨胀过程中利用相对温和的地热能的潜力，以及一些风力涡轮机可能直接部署为最后一级压缩机，为储能系统充电的可能性。

Project SAVE-CAES is all about developing large-scale long-duration energy storage that will enable the UK to be powered largely (and possibly completely) from renewables. That energy storage must be affordable, sustainable and large-scale. Compressed air energy storage (CAES) has the potential to meet all these critically-important criteria. Developing such storage is probably the biggest single challenge standing in the way of "Net-Zero" for the UK by 2050. Offshore wind around the UK is a remarkable resource for a future zero-carbon UK electricity system. If we were to exploit all of the area that could feasibly be imagined, UK offshore wind could produce about 2000TWh of electrical energy every year - more than 5 times greater than the amount of electricity we presently consume in one year. Electricity usage will increase, of course, between now and 2050 - possibly increasing from ~350TWh each year to ~1000TWh annually. However, it is perfectly feasible that we can generate all of this electricity from wind.Solar power will also play a key role in powering the Net Zero UK but there are straightforward reasons why this will provide only about 20% of our power in the future. The strongest of those has to do with seasonality: solar on an average day in mid Summer is 9 times higher than on an average day in mid Winter, however our energy demand in Winter is higher than that in Summer. Happily the wind is also seasonal and it typically delivers 2.3 times more energy on an average mid-Winter day than it does on an average mid-Summer day. Nuclear power will also have some role. Opinions differ on how substantial that role will be but that is not very important for the purposes of understanding or justifying this research proposal. The key problem with having a country powered largely from inflexible low-carbon sources is that demand and supply must be matched and demand is relatively "inelastic". This means that proportionately small changes in the cost of electricity have very small influence on how much electricity that is consumed. Quantitative assessments of how much we will be paying for our electrical energy by 2050 suggest that less than half will be made up of the direct cost of generating the actual units of electrical energy. The larger cost will be connected with providing the flexibility - the ability to match up supply and demand. Different researchers predict different proportions, but the consensus is that flexibility costs will be the dominant ones.CAES is one of the most promising sets of options available in the UK for storing very large quantities of (wind or solar) energy over periods of tens of hours - possibly up to 100 hours. CAES has the potential to combine good performance (upwards of 70% round-trip efficiency) with relatively low costs (<£2/kWh). There are two different grid-scale energy storage plant which store compressed air in the world - one at Huntorf in Germany and the other in McIntosh, Alabama - however, these plants also store fossil fuel. Many commentators make the serious mistake of extrapolating from these to estimate what CAES can possibly do. Project SAVE-CAES sets out to apply fundamental engineering science to determine what a well-designed CAES plant without fossil fuel addition could possibly do.SAVE-CAES is a project filled with novelty. Pressurised air will be stored in salt caverns that are either offshore or at the coast. The project will explore the use of isobaric storage of the pressurised air and the management of concentrated brine (salt-water) for pressure regulation. It will also explore ultra-high-pressure air storage (for best value per cubic metre of cavern). It will also explore the potential for exploiting relatively mild geo-thermal heat during the re-expansion of the air and the possibility that some wind turbines might be deployed directly as last-stage compressors for charging the energy stores.