Biogas Electricity Research Articles

Study on the Supply and Demand Balance of Large-Scale Biogas Project Funds Based on System Dynamics

With the application and promotion of large-scale biogas project, economic analysis and evaluation of large-scale biogas project are particularly important. However, the benefits of biogas project embodied in the economic, social, ecological, and many other aspects have dispersion, which leads to production decisions in a gray state and investment in conformity. In this paper, Great Northern Wilderness beef cattle industry in Heilongjiang province is taken as an example for large-scale biogas electricity generation project. The supply and demand of funds in project operation are analyzed quantitatively by using system dynamics theory so as to do study and perform optimal analysis comprehensively on the economics of biogas project, and to explore the effective scheme of improving the proportion of income against cost. This study can provide scientific guidance for evaluating the construction and operation of large and medium-scale biogas project objectively and lay a solid theoretical foundation for the commercial operation in biogas industry.

The Co-benefits of Biogas From the Palm Oil Industry in Long-term Energy Planning: A Least-Cost Biogas Upgrade in Thailand

Thailand has set a large target of alternative energy share in final energy consumption and CO2 mitigation. The answer to this challenge is to take advantage of the crude palm oil (CPO) industry. Thailand is the world's fourth-biggest CPO producer. To increase the competitiveness of the CPO industry and to conserve the environment at the same time, cleaner technology is introduced to biogas projects in the palm oil industry. In this study, the biogas upgrading process complied with the subsidy in long-term planning is presented. This study uses a market allocation least-cost energy system as an analytical tool. The alternative cases considered are the co-benefits of subsidy to the biogas upgrading project, which complies with the target of the total electricity generation from biogas up to 60 MW in 2012. The results shows that green gas under subsidy is accounts for approximately 44.91 million m3 in 2012 and increased to 238.89 million m3 in 2030. Total biogas electricity generation will be 2.19 and 3.15 TWh respectively. The cumulative CO2 emission during 2012–2030 will be reduced in the range of 1.37 to 2.17 million tons.

A regional model for sustainable biogas electricity production: A case study from a Finnish province

A regional model for sustainable biogas electricity production was formulated and tested for a Finnish province, North-Savo. By using the model the aim was to support decision making for reducing greenhouse gas (GHG) emissions and increasing renewable energy (RE) production in the studied region in the biogas electricity production system. The system boundary of the model included transportation of waste, biogas production, heat and electricity production, as well as the delivery of heat and digestate to the end users. When electricity production was maximized in the studied region, the electricity production and GHG emissions were 20GWh/year and 24kt/year of CO2 equivalent, respectively. When GHG emissions were minimized, the electricity production and GHG emissions were 20GWh/year and 23kt/year of CO2 equivalent, respectively. By producing electricity of 20GWh/year, the maximum GHG reductions were roughly 74% of the theoretical maximum GHG emissions of 90kt/year of CO2 equivalent in both cases. The regional electricity production potential of 20GWh/year was only 21% of the maximum electricity production potential of 94GWh/year. The locations of biogas plants, regional relative GHG emissions, potential feedstocks and regional electricity production were optimized in both cases in the studied region.

Ökonomische Bewertung des Erneuerbare Energien Gesetzes zur Förderung von Biogas

AbstractThe Renewable-Energy-Source-Act (EEG) promotes German biogas production in order to substitute fossil fuels, protect the environment and prevent climate change. In this paper we quantitatively analyse the EEG-reform in 2008. Results imply that the reform contributes to an expansion of biogas electricity generation and thus to substitution of fossil fuels. However, subsidies, land and transport emissions per unit of electricity produced increase. An alternative analysis shows that an EEG with tariffs independent from plant-types would provide the highest subsidy-efficiency, lower land requirements and higher transport emissions compared to EEG before its reformation.

Reliability-based life cycle assessment for future solid waste management alternatives in Portugal

This paper presents a study related to the application of the reliability-based life cycle assessment (LCA) to assess different alternatives for solid waste management in the Setubal peninsula, Portugal. The current system includes waste collection, transport, sorting, recycling, and mechanical and biological treatment (MBT) by means of aerobic treatment and landfill. In addition, some future expansion plans are discussed. The proposed 18 alternatives were examined with respect to six impact categories based on a customized life cycle inventory (LCI). All the alternatives are designed to comply with the targets prescribed in the Packaging and Packaging Waste Directive and the Landfill Directive. These 18 alternatives were eventually assessed by using the reliability-based LCA methodology with respect to some uncertain parameters and scenarios. The results show that solutions based on anaerobic digestion at the MBT followed by energy recovery are the most advantageous options. Overall, recycling may help to avoid most environmental impacts. Alternatives which treat massively biodegradable municipal waste are also competitive. In addition to the recycling options, electricity production is also an influential determinant which affects the results. The uncertainty analysis focused on testing different energy-from-waste options (like landfill and MBT biogas electricity production) and different recycling substitution ratios. Such a quantitative analysis is proved effective to confirm the reliability of the LCI in the study. In order to improve the sustainability of the solid waste management (SWM) system, final suggestions may concentrate on the closure of aerobic MBT, the enhancement of anaerobic digestion MBT treatment, and the maximization of energy recovery from high calorific fractions of the waste streams. However, the option of stabilized residue applications cannot be encouraged at this stage, especially due to the absence of Portuguese regulations to control the quality of organic products issuing from biological treatment units.

Technoeconomic analysis of an integrated microalgae photobioreactor, biodiesel and biogas production facility

As fossil fuel prices increase and environmental concerns gain prominence, the development of alternative fuels from biomass has become more important. Biodiesel produced from microalgae is becoming an attractive alternative to share the role of petroleum. Currently it appears that the production of microalgal biodiesel is not economically viable in current environment because it costs more than conventional fuels. Therefore, a new concept is introduced in this article as an option to reduce the total production cost of microalgal biodiesel. The integration of biodiesel production system with methane production via anaerobic digestion is proved in improving the economics and sustainability of overall biodiesel stages. Anaerobic digestion of microalgae produces methane and further be converted to generate electricity. The generated electricity can surrogate the consumption of energy that require in microalgal cultivation, dewatering, extraction and transesterification process. From theoretical calculations, the electricity generated from methane is able to power all of the biodiesel production stages and will substantially reduce the cost of biodiesel production (33% reduction). The carbon emissions of biodiesel production systems are also reduced by approximately 75% when utilizing biogas electricity compared to when the electricity is otherwise purchased from the Victorian grid. The overall findings from this study indicate that the approach of digesting microalgal waste to produce biogas will make the production of biodiesel from algae more viable by reducing the overall cost of production per unit of biodiesel and hence enable biodiesel to be more competitive with existing fuels.

Greenhouse gas and energy balance of dairy farms using unutilised pasture co-digested with effluent for biogas production

Greenhouse gas (GHG) emissions from New Zealand dairy farms are significant, representing nearly 35% of New Zealand’s total agricultural emissions. Although there is an urgent need for New Zealand to reduce agricultural GHG emissions in order to meet its Kyoto Protocol obligations, there are, as yet, few viable options for reducing farming related emissions while maintaining productivity. In addition to GHG emissions, dairy farms are also the source of other emissions, most importantly effluent from milking sheds and feed pads. It has been suggested that anaerobic digestion for biogas and energy production could be used to deal more effectively with dairy effluent while at the same time addressing concerns about farm energy supply. Dairy farms have a high demand for electricity, with a 300-cow farm consuming nearly 40 000 kWh per year. However, because only ~10% of the manure produced by the cows can be collected (e.g. primarily at milking times), a maximum of only ~16 000 kWh of electricity per year can be produced from the effluent alone. This means that anaerobic digestion/electricity generation schemes are currently economic only for farms with more than 1000 cows. A solution for smaller farms is to co-digest the effluent with unutilised pasture sourced on the farm, thereby increasing biogas production and making the system economically viable. A possible source of unutilised grass is the residual pasture left by the cows immediately after grazing. This residual can be substantial in the spring–early summer, when cow numbers (demand) can be less than the pasture growth rates (supply). The cutting of ungrazed grass (topping) is also a useful management tool that has been shown to increase pasture quality and milk production, especially over the late spring–summer. In this paper, we compare the energy and GHG balances of a conventional farm using a lagoon effluent system to one using anaerobic digestion supplemented by unutilised pasture collected by topping to treat effluent and generate electricity. For a hypothetical 300-cow, 100-ha farm, topping all paddocks from 1800 to 1600 kg DM/ha four times per year over the spring–summer would result in 80 tonnes of DM being collected, which when digested to biogas would yield 50 000 kWh (180 GJ) of electricity. This is in addition to the 16 000 kWh from the effluent digestion. About 90 GJ of diesel would be used to carry out the topping, emitting ~0.06 t CO2e/ha. In contrast, the anaerobic/topping system would offset/avoid 0.74 t CO2e/ha of GHG emissions: 0.6 t CO2e/ha of avoided CH4 emissions from the lagoon and 0.14 t CO2e/ha from biogas electricity offsetting grid electricity GHGs. For the average dairy farm, the net reduction in emissions of 0.68 CO2e/ha would equate to nearly 14% of the direct and indirect emissions from farming activities and if implemented on a national scale, could decrease GHG emissions nearly 1.4 million t CO2e or ~10% of New Zealand’s Kyoto Protocol obligations while at the same time better manage dairy farm effluent, enhance on-farm and national energy security and increase milk production through better quality pastures.

The application of a Delphi technique in the linear programming optimization of future renewable energy options for India

The role of renewable energy resources in developing countries has increased considerably over the last decade. Technological developments are so advanced that the renewables can be conveniently substituted for commercial energy sources. The extent to which renewable energy could be substituted in the commercial energy scene in respect of environment and social impact is discussed in this paper. An optimal renewable energy mathematical (OREM) model will be developed for the substitution of renewable energy sources in India over the years 2010–11, 2015–16 and 2020–21. It is a linear programming model, which allocates optimal renewable energy sources for different end-uses such as lighting, cooking, pumping, heating, cooling and transportation. The model was developed with the objective of minimizing cost/efficiency ratio based on social acceptance, reliability, demand and potential constraints. The model predicts that around 25% of the total energy consumed will be from renewable energy sources by the year 2020–21. It was found that at optimal condition, for lighting end-use, solar PV and biogas electricity conversion could be used to an extent of 520 and 750 PJ , respectively. Similarly, the optimal renewable energy sources for other end-uses were determined by running OREM model. The potential for biomass, biogas, firewood and ethanol were varied in the model and different renewable energy distribution patterns were obtained. When the potential of these resources are increased in the model, the contribution of solar energy systems would decrease as they are expensive. Sensitivity analysis was conducted to validate the OREM model. The coefficient of sensitivity has been obtained for the variation of renewable energy demand, social acceptance and potential of renewable energy sources. Sensitivity analysis revealed that the OREM model is very sensitive with regard to variation of different parameters in the model. This model can be used in the formation of energy strategies in India.

State of the biomethanation development in the Chinese stock-farms

The development of Chinese rural areas and the raising of people's living standards increase the demand for energy supplies, quantitative as well as qualitative. Because of its advantages, biogas production is already used in 5 million households to cover everyday-life energy needs. About 20000 households use biogas produced in stock-farms and distributed through small biogas power stations or electricity stations. The annual biogas production potential from animal wastes could cover the energy needs of over 100 million households but research work is still needed to be done to find suitable designs for large-scale biomethanation development in stock-farms.