基于外部性收益的畜禽养殖场沼气工程补贴模式分析

以我国北方某沼气工程为例,按照业主自筹全部资金、2009年国家建设补贴标准和工程实际投资3种建设投资方式,对其现有经济性进行了分析,并提出了以外部性收益为依据对沼气工程进行补贴的两种模式。结果表明,外部性收益与沼气工程运行效果和沼气产量有直接关系,依据外部性收益对沼气工程进行补贴,可以显著提高沼气工程的经济效益,推动规模化养殖场沼气工程正常运行和发展。综合沼气工程投资者和社会利益考虑,业主自筹全部建设资金,按照工程实际运行的外部性收益给予补贴,既可保障工程的正常运营,又符合整体经济性。     

Household biogas development in rural China: On policy support and other macro sustainable conditions

As a fuel, rural biogas is a promising renewable energy source. Policy support is a key initial impetus for industry development. This study explores household biogas development in rural China based on policy support found in literature. Relevant policies, which mainly include directive and guiding policies, economic inspiring policies, research policies, market policies, and other constructive policies, are gradually issued. Moreover, the National People's Congress has enacted five relevant laws, including the Agricultural Law, Renewable Energy Law, Animal Husbandry Law, Energy Conservation Law, and the Act on the Development of Circular Economy. The Energy Law is currently under revision. Relational rules and regulations have also been formed in response to the national policies and laws, which have already produced significant effects. The development of rural household biogas in China is growing steadily, and the technology standard projects have been established. The number of household biogas digesters and biogas annual output in 2010 was double of that in 2005. The offered financial incentive increased from 47 million dollars in 2002 to 760 million dollars in 2011. Policy supports play an important role in rural biogas development. And thus, additional national policy supports are necessary in the fields of scientific research, technological development, and biogas use model.     

中外沼气产业政策浅析

本文在分析我国沼气产业发展现状的基础上,梳理了现有沼气产业政策及其在产业链各环节上的布局,并与沼气产业发达的欧盟地区的政策进行对比。分析结果显示,我国颁布法律鼓励发展沼气,制定发展规划,提出沼气的阶段性发展目标,出台经济扶持政策补贴原料利用、工程建设及终端应用,制定国家及行业标准规范产业发展,立法及扶持政策推动我国沼气跨入产业化发展阶段。但与欧盟地区的产品补贴力度大、范围广,减免税政形式多样,标准化和质量检验体系完善等特点的产业政策相比,我国沼气政策仍存在终端产品补贴力度不足、工程及装备标准认证体系滞后、市场监管及运营粗放等问题。基于此,提出转变沼气工程建设及产品补贴方式、加强沼气产业减税政策的执行力度、完善和统一沼气产业规范标准体系等建议。     

Economic efficiency of solar hot water policy in New Zealand

New Zealand has recently followed the path of several other countries in promoting solar hot water (SHW) systems in the effort to reduce greenhouse gas emissions, yet the economic efficiency of large-scale policies to encourage SHW remains a pressing question for policymakers. This paper develops an economic framework to examine policies to promote SHW in New Zealand, including the current information, training, and subsidy policy. The economic framework points to environmental, energy security, and average-cost electricity retail pricing market failures as motivation for SHW policy, with the global climate change externality the most important of these. The results indicate that domestic SHW systems are close to being financially attractive from a consumer perspective, but a more substantial subsidy policy would be necessary for SHW to appeal to a wider audience. Such a policy is far more likely to have positive net benefits than a policy of mandating SHW on all homes or all new homes in New Zealand, and could be justified on economic efficiency grounds under reasonable assumptions. However, this result reverses under an economy-wide carbon trading system that internalizes the environmental externality.     

The influence of using biogas digesters on family energy consumption and its economic benefit in rural areas—comparative study between Lianshui and Guichi in China

The construction of biogas digesters has improved the family energy consumption structure, promoted the development of livestock breeding and farm production in the countryside. Through the comparative study of the questionnaires filled out by individual families in Lianshui, Jiangsu Province and Guichi, Anhui Province, we figured out the different effects of biogas digesters in different areas on household energy consumption and their benefits to economy and environment.     

户用沼气池对农村家庭能源消费的影响--以江苏省涟水县为例

户用沼气池建设不但改变了农村家庭能源消费结构，还带动了农村养殖业、种植业的发展。通过对江苏省涟水县农村家庭能源消费和沼气池使用等相关问题的入户调查，定量研究了户用沼气池建设所产生的影响。证明户用沼气池的使用能提高家庭能源利用效率，减少能源消费量和化肥的使用量，有利于农作物秸秆的还田，提高农户的生活质量。     

A review of the biogas industry in China

This article presents an overview of the development and future perspectives of the Chinese biogas industry. The development of the industry has the potential to improve the rural environment and produce significant amounts of sustainable energy for China. Barriers to the development are the relatively weak environmental policies, imperfect financial policies and lack of long-term follow-up services. The rapid economic development of China has also seen a development in the scales of biogas plants constructed. Although the technology has been improved, this review has identified problems in the construction and operation of Chinese biogas plants, particularly in the efficiency of household systems. All levels of China's government acknowledge this and recent biogas projects have more focus on quality and less on the quantity. The intention is to gradually introduce stricter environmental policies, to provide better service systems, improve the financial policies that support the construction and follow-up service of biogas projects, promote the use of standardized engineering equipment and materials and standards for plant construction and production. This will promote the development of biogas projects at various scales further, and reduce the dependency on fossil fuels and emissions of greenhouse gases.     

我国农村沼气CDM项目开发的潜力分析

清洁发展机制能为我国的可持续发展带来新的契机。本文对农村大中型沼气工程和户用沼气池的减排温室气体的潜力作了定量的分析,认为农村沼气工程适合开发成CDM项目。CDM能给农村沼气工程带来发展的机遇,提供更宽的融资渠道和技术支持。最后对当前农村沼气CDM项目开发中存在的一些障碍进行了分析。     

Technical,economic and environmental assessment of household biogas digesters for rural communities

This study was carried out in response to the growing interest on household biogas digesters in Latin America, particularly in rural Andean communities. The aim was to compare the fixed dome and plastic tubular digester in terms of biogas production, cost and environmental impact, using the life cycle assessment methodology. Design and operational parameters, construction materials and implementation costs were based on our previous research and literature results for plastic tubular and fixed dome digesters, respectively. According to this analysis, the main advantage of the plastic tubular digester was its ease of implementation and handling, and lower investment cost compared to the fixed dome digester, which appeared to be more environmentally friendly.     

The impact of a household biogas programme on energy use and expenditure in East Java

Biogas has been promoted as a renewable, cleaner and cheaper energy source. While there are several initiatives promoting the use of biogas, credible analyses of its effects on the use of alternative energy sources and energy related expenditure are limited. This study uses panel data from households engaged in dairy farming in rural East Java to assess the impact of a household level programme, which promotes the construction of digesters that produce biogas, on energy use and expenditures. Both a difference-in-difference analysis and a pipeline comparison show that the use of digesters leads to a sharp reduction in energy related expenditures and a reduction in the use of firewood and liquefied petroleum gas. However, without subsidies, the payback period of between 11 and 14 years, albeit based only on reductions in energy costs accruing from investing in a digester, is perhaps too long to justify the investment.     

促进供暖能源转型的经济激励政策国际经验研究

在国内,补贴政策是促进清洁取暖发展的关键手段。目前,清洁取暖补贴政策尚缺乏针对性、精准性设计,清洁取暖市场化机制尚未建立,影响清洁取暖的可持续发展。为此,通过梳理英国、德国、丹麦等国家在供暖领域的能源转型方向、经济激励政策,分析政策实施效果,总结政策设计与实施经验,为国内清洁取暖的补助政策设计以及实施提供启发与借鉴。结果表明:基于市场化机制的经济激励政策在英国等国家供热能源转型中发挥了关键作用;以精准的补助政策设计确保政策科学有效;在经济激励政策之外,其他配套政策的设计协同促进政策效益最大化;在政策实施过程中,系统的监测与评估体系确保政策执行效果的有效监测,为政策调整提供有力证据;在有效的经济激励政策支持下,英国、德国、丹麦等国家供热能源转型成效显著。     

Evaluating benefits of low-cost household digesters for rural Andean communities

Low-cost household digesters are a promising appropriate technology which can help reducing the pressure on the environment due to deforestation and greenhouse gases emissions. The biogas and biofertilizer produced can alleviate poverty, by improving health conditions, increasing crops productivity and saving working time and burden for women and children. The aim of this study is to evaluate low-cost digesters technical, environmental and socio-economic impacts in rural communities of the Peruvian Andes, where a pilot project was developed during the last 3 years. Although the benefits are restricted by the performance of anaerobic digestion at high altitude, the results show that the digesters improve household living conditions and economy, while reducing environmental impacts. Biogas production covers around 60% of fuel needs for cooking, leading to 50-60% decrease in firewood consumption (i.e. deforestation) and greenhouse gases emissions; the annual income is increased by 3-5.5% due to fertilizer savings and potato sales. These values could be improved by enhancing digesters performance and the sustainability of the technology.     

Biogas production in low-cost household digesters at the Peruvian Andes

Low-cost tubular digesters originally developed in tropical regions have been adapted to the extreme weather conditions of the Andean Plateau (3000-4000 m.a.s.l.). The aim of this study was to characterise biogas production in household digesters located at high altitude, operating under psychrophilic conditions. To this end, two pilot digesters were monitored and field campaigns were carried out in two representative digesters of rural communities. Digesters’ useful volume ranged between 2.4 and 7.5 m³, and hydraulic residence time (HRT) between 60 and 90 days. The temperature inside the digester’s greenhouse ranged between 20 and 25 °C. Treating cow manure, a specific biogas production around 0.35 m³ kg_VS⁻¹ was obtained, with some 65% CH₄ in biogas. In order to fulfil daily requirements for cooking and lighting, biogas production should be enhanced without increasing implementation costs as not to impede the expansion of this technology at household scale. In this sense, HRT below 60 days and OLR above 1 kg_VS m⁻³ day⁻¹ should be investigated to decrease digesters’ volume (i.e. costs) and increase biogas production rate. The adaptation of conventional gas burners to biogas characteristics can also contribute in improving the efficiency of the system.     

When does decentralized production of biogas and centralized upgrading and injection into the natural gas grid make sense?

The production of biogas through anaerobic digestion is one of the technological solutions to convert biomass into a readily usable fuel. Biogas can replace natural gas, if the biogas is upgraded to green gas. To contribute to the EU-target to reduce Green House Gases emissions, the installed biogas production capacity and the amount of farm-based biomass, as a feedstock, has to be increased. A model was developed to describe a green gas production chain that consists of several digesters connected by a biogas grid to an upgrading and injection facility. The model calculates costs and energy use for 1 m³ of green gas. The number of digesters in the chain can be varied to find results for different configurations. Results are presented for a chain with decentralized production of biogas, i.e. a configuration with several digesters, and a centralized green gas production chain using a single digester. The model showed that no energy advantage per produced m³ green gas can be created using a biogas grid and decentralized digesters instead of one large-scale digester. Production costs using a centralized digester are lower, in the range of 5 €ct to 13 €ct per m³, than in a configuration of decentralized digesters. The model calculations also showed the financial benefit for an operator of a small-scale digester wishing to produce green gas in the cooperation with nearby other producers. E.g. subsidies and legislation based on environmental arguments could encourage the use of decentralized digesters in a biogas grid.     

陕西户用沼气池越冬使用技术研究

为了有效解决陕西省农村户用沼气池使用时间短的难题,结合陕西农村的实际情况,对传统沼气池的结构形式进行了改进,增加预处理池为沼气池提供热量,并对沼气池的池墙、进(出)料口进行保温,以达到增加冬季沼气池池温的目的。以榆林市为代表,通过理论计算、试验等手段,证明冬季最低室外温度条件下,沼气池产气率可以达到0.1 m3/(m3.d)以上,一口6～8 m3的沼气池就可以满足一个普通农户一天的炊事用气要求。     

Trace element requirements of agricultural biogas digesters during biological conversion of renewable biomass to methane

The availability of trace metals as micro-nutrients plays a very significant role on the performance and stability of agricultural biogas digesters, which are operated with energy crops, animal excreta, crop residues, organic fraction of municipal solid wastes or any other type of organic waste. The unavailability of these elements in biogas digesters is probably the first reason of poor process efficiency without any other obvious reason, despite proper management and control of other operational and environmental parameters. However, trace metal requirements of biogas digesters operated with solid biomass are not often reported in literature. Therefore, the aim of this article is to review the previous and current literature about the trace metal requirements of anaerobic biogas digesters operated with solid organic substrates for production of methane.     

自动回流破壳(PVC)沼气池的构造与建造

针对我国传统户用沼气池存在的诸多问题,采用PVC塑料材料设计、建造了一种自动回流破壳沼气池。文章介绍了沼气池的构造、工作原理及结构性能,详述了建造该沼气池的操作过程。     

Socio-economic hurdles to widespread adoption of small-scale biogas digesters in Sub-Saharan Africa: A review

The unsustainable use of fossil fuels has led to increased awareness and widespread research on the accessibility of renewable energy resources such as biogas. Biogas is a methane rich gas that is produced by anaerobic fermentation of organic material. Despite its potential to replace biomass in Africa, where over 70% of the households use wood fuel and agricultural waste for cooking, biogas technology has not been adopted by Sub-Saharan African countries compared to their Asian counterparts. This paper examines the socioeconomic constraints to adoption of biogas in Sub-Saharan Africa and explores factors that could enhance adoption of the technology. These include standardization and quality control, as well as an approach of integrated farming using biogas and slurry. The article recommends mobilization of local and external funds to promote biogas, use of ready to use funds such as the Clean Development Mechanisms in overcoming the initial construction costs of biogas units, and formation of user and disseminator associations to reduce costs by joint procurement and linkage to finance. It further advocates the promotion of multiple uses of biogas for purposes other than cooking and lighting. It is expected that widespread adoption of the technology could lead to self-sufficiency in household energy provision for cooking. This would facilitate environmental management and economic development in Sub-Saharan Africa.     

A model-based analysis of biomethane production in the Netherlands and the effectiveness of the subsidization policy under uncertainty

Biomethane is a renewable alternative to natural gas. It has the potential to increase the sustainability of the energy system and to help deal with supply problems. However, several factors make the future of biomethane production complex and uncertain, such as resource availability, demand, capacity installation, profitability and the competition between the biomethane and electricity sectors for sharing the available biogas and biomass resources. In this research, we study the dynamics of the Dutch biomethane production and analyze the effects of subsidization policy with a system dynamics model. The policy is tested under uncertainty with respect to three conflicting objectives, namely maximizing production and emission reduction, and minimizing costs. According to the results, the subsidization is crucial to develop biomethane production, and the performance of the policy is enhanced in terms of robustness and of meeting all three objectives satisfactorily when the policy is implemented for a long time, with relatively low subsidy prices. Besides, the subsidization policy is found to be most vulnerable to the producers’ uncertain investment response to profitability. In future research, different policy options such as subsidizing other biomass-based renewable energy options and policies affecting the biomethane demand can be tested.     

Prospective application of farm cattle manure for bioenergy production in Portugal

Biogas is a promising renewable fuel, which can be produced from a variety of organic raw materials and used for various energetic purposes, such as heat, combined heat and power or as a vehicle fuel. Biogas systems implementation are, therefore, subjected to several support measures but also to several constraints, related with policy measures on energy, waste treatment and agriculture. In this work, different policies and policy instruments, as well as other factors, which influence a potential expansion of Portuguese biogas systems are identified and evaluated. The result of this analysis shows that the use of the cattle manure for biogas production is still far from its potential. The main reason is the reduced dimension of the Portuguese farms, which makes biogas production unfeasible. Various options are suggested to increase or improve biogas production such as co-digestion, centralized plants and modular plants. Horizontal digesters are the most suitable for the typical Portuguese plant size and have the advantage of being also suitable for co-digestion due to the very good mixing conditions. Mesophilic anaerobic digestion due to a more robustness, stability and lower energy consumption should be the choice. The recent increase in the feed-in tariffs for the electricity production based on anaerobic digestion biogas is seen as a political push to this sector.