摘要
目前全世界生物质能源消费量占能源总供应量的１５ ％ 左右，由于各国气候、土地利用情况不同，生物质能源生产及利用水平差别也很大。如美国、瑞典、巴西、芬兰、丹麦、波兰和英国等已走在世界前列。经大量试验发现有２ 类能源植物比较有前途，它们分别是短期轮作矮林（ＳＲＣ） 和禾本科能源作物（ ＨＥＣ） 。食品生产与生物质能源生产之间没有冲突，生物质能源生产及利用有利于环境保护、人类健康和全球性气候变暖的减缓。生物质能源生产及利用正由传统的薪柴收集和直接燃烧的方式，迅速向能源作物集中生产和生物质能源现代化转换方向发展。
Bio-energy currently constitutes 15% of the world total energy consumption but its use in different countries varies greatly in respect of climate,land availability and economic development. In developed countries,bio-energy usage is relatively low (e.g. N. America 4%, Europe 4%, former USSR 3%), whereas regions with rural economies are more dependant on both natural and cultivated sources of bio-energy (e.g. S. America 26%, Asia 44%,rural China 80%, undeveloped parts of Africa 90%). Most countries have plans for the future expansion of bio-energy usage, but it is in the developed world that the greatest potential exists for substitution of fossil fuels.In Brazil and the USA, bio-ethanol is generated on a large scale utilising waste from sugar cane production, and contributes to reducing their-dependence on fossil fuels for motor vehicles. In northern Europe(Scandinavia, Poland), bio-energy resources from forestry residues, again a waste material, are very large but the extent of its utilisation and the conversion technology employed varies greatly, being the best developed in Sweden and Denmark. In the U.K., bio-energy use is currently low (1%) but has been stimulated by the Non Fossil Fuel Obligation policy. In rural China, domestic usage of bio-fuels (harvested wood, animal dung, and bio-gas) for cooking and heating, is high (80%).Two categories of energy crops, short-rotation coppice (SRC) and herbaceous energy crops (HEC), are the most promising. High-yielding hybrid varieties-of willows, poplars and eucalypts (SRC) have yielded up to 50 oven dry tonnes (ODT) ha-1y-1 in trials but average crop yields of 12 ODT ha-1y-1 are expected to be economically viable. The grasses Miscanthus and Panicum (both C4 plants) are the most promising HECs in areas with a relatively long growing season.Literature studies indicate that the apparent competition for available land between food production and biomass crops will not inhibit their expansion.In the developed countries, recent increases in food productivity per capita and the requirement for land to be taken out of food production (Set Aside in the E.U.), makes land available for bio-energy crops. In developing countries large areas of degraded or desertified land exist which could be rehabilitated for energy crops more readily than to agriculture. For many poor countries the need to produce bio-energy crops for domestic use is almost as acute as the need for food crops. Problems of hunger arise from socio-economic factors and poor distribution of food rather than the absolute lack of available land for food production.Being CO2 neutral, bio-energy crops can contribute to global warming mitigation, increase local bio-diversity and facilitate restoration of degraded land. SRC is also used for bio-filtration of waste waters and natural waters, to the benefit of environmental quality.Utilisation of biomass for energy is progressing rapidly from traditional collection and burning of firewood, towards a sustainable energy economy employing modern technologies for conversion of bio-energy crops both to heat and electricity.
出处
《宁夏农林科技》
1999年第5期5-8,16,共5页
Journal of Ningxia Agriculture and Forestry Science and Technology
关键词
生物质能源
土地利用
环境保护
Bio-energy
Biomass crops
Land Use
Environment Conservation.
