Measurement and Analysis of bioenergy greenhouse gases: Integrating GHGs into LCAs and the UK Biomass Value Chain Modelling Environment (MAGLUE)

为了实现2020年可再生能源目标，英国将需要大量的生物质。DECC希望到2020年再增加20- 38 TWh的生物质发电，这将需要大约1200 - 2300万干吨生物质。这是一个巨大的材料量，其中绝大多数将作为颗粒从加拿大和美国进口，并在转换的燃煤发电厂燃烧。其他进口的液体燃料原料可能包括巴西的甘蔗乙醇和东南亚的棕榈油。英国并不是唯一一个希望使用更多生物质的国家。荷兰、比利时、丹麦和瑞典都预计将使用更多的木屑颗粒，例如，预计欧盟未来仅木屑颗粒的需求量就在2300万至8000万吨之间。英国的一个燃煤发电站希望每年获得高达1000万吨的生物质。如果英国想要大规模的生物质发电，很明显，发电机将需要成为跨大西洋木屑颗粒贸易的主要参与者。在这种需求增加的背景下，使用生物质作为能源在环境上是否可持续仍然存在很大的不确定性。任何类型的有管理的土地使用都可能产生碳“债务”--碳或其他温室气体向大气中的净损失，导致全球变暖。其他温室气体包括甲烷和氮氧化物。但是，量化生物能源作物相对于其可能取代的作物（有时称为反事实）的净影响并不简单。这导致了许多索赔和反索赔的商业利益，环保团体和学术界，对土地利用变化的生物能源系统的真实的温室气体的影响，仍然存在很大的分歧和controversies.The项目在这里描述的目的是解决这个有争议的问题-量化不同的土地利用过渡到生物能源作物的真实的温室气体平衡，为英国和进口的生物能源原料。我们将部署能够快速测量温室气体的先进仪器，以更好地了解此类系统中可能发生的温室气体排放的动态范围，包括耕地和种植以及添加肥料的时间。在数据收集之后，我们将通过对英国广泛的地理范围以及来自世界其他地区的生物质原料进行建模来扩展我们的分析。如果我们能够利用全球范围内的天气、土壤和相关作物的产量数据，我们使用的模型应该是可行的。这些系统中的温室气体数据通常用于开发排放因子，这些因子被输入到碳（或碳当量）成本的全生命周期评估（LCA）中，但过去这些数据往往未经验证。我们将评估过去数据的质量，通过我们的测量和模型活动，我们可以测试排放因子的有效性，以及如何通过我们的工作来改善它们，包括海外原料。最后，在一个联合项目中，我们开发了一个价值链模型，以优化英国生物能源的技术选择，这取决于如何定义成本，温室气体平衡和土地可用性。我们将运行这个模型，以确定最好的生物能源链，在温室气体平衡方面，为英国和测试方案（“如果”的问题），以确定有多少进口原料可能是可持续的未来。

To meet the 2020 renewable energy target the UK is going to need biomass, and lots of it. DECC has an aspiration for an additional 20-38TWh of biomass electricity by 2020 and this will require around 12-23 million dry tonnes of biomass. This is a huge quantity of material, the vast majority of which would be imported as pellets from Canada and the USA and burnt in converted coal fired power plants. Other imported feedstocks for liquid fuels might include Brazilian ethanol from sugar cane and oils from palm oil in Southeast Asia. The UK is not alone in wanting to use more biomass. The Netherlands, Belgium, Denmark, and Sweden all expect to use more, and estimates of future EU demand for wood pellets alone, for example, range from 23-80 million tonnes. One single coal power station in the UK is looking to source up to 10 million tonnes of biomass each year. If the UK wants biomass power on a large scale it is clear that the power generators will need to become major players in the transatlantic wood pellet trade. Against this background of increased demand, there remains significant uncertainty on whether the use of biomass for energy is environmentally sustainable. Any type of managed land use can incur a carbon 'debt' - a net loss of carbon or other greenhouse gases to the atmosphere that contributes to global warming. Other greenhouse gases include methane and the oxides of nitrogen. But quantifying the net impact of a bioenergy crop relative to what it might replace (sometimes called the counterfactual), is less than straightforward. This has led to many claims and counter-claims from commercial interests, environmental groups and academics, on the real greenhouse gas impact of land use change to bioenergy systems, where there still remains much disagreement and controversy.The project described here is aimed at addressing this controversial issue - quantifying the real GHG balance of different land use transitions to bioenergy crops, for both UK and imported bioenergy feedstocks. We will deploy sophisticated state-of-the-art instrumentation that is able to measure GHGs very rapidly, to gain a better insight into the dynamic range of GHG emissions that can occur in such systems, including when fields are ploughed and planted and when fertilisers are added. Following data collection, we will extend our analysis by modelling a wide geographical range across the UK and for biomass feedstock sourced from other areas of the world. The models we use should work if we can utilise available datasets, globally, for weather, soils and yield data of the range of crops of interest.The GHG data in such systems are usually used to develop emissions factors that are inputted into whole life cycle assessments (LCAs) of carbon (or C equivalent) costs, but these in the past have often been unverified data. We will assess the quality of past data and from our measurement and model campaigns we can test the effectiveness of emissions factors and how they might be improved from our work, including for overseas feedstocks. Finally, in an allied project we have developed a value chain model to optimise the technology options for the UK for bioenergy, depending on how cost, GHG balance and land availability are defined. We will run this model to identify the best bioenergy chains, in terms of GHG balance, for the UK and test scenarios ('what if' questions), to determine how much imported feedstock might be sustainable in the future.