The use of graphical pinch analysis for visualizing water footprint constraints in biofuel production

A graphical pinch approach for analysis of water footprint constraints on biofuel production systems is presented. The technique is based on the composite curve method which was originally developed for carbon-constrained energy planning, which is extended in this paper based on the underlying similarities of source-sink allocation problems. The pinch analysis approach enables limiting water footprint conditions to be identified, and provides insights that are useful for planning the large-scale cultivation of biofuel crops. An illustrative case study based on the bioethanol program of the Philippines is solved using the proposed approach.     

Land and water requirements of biofuel and implications for food supply and the environment in China

The increasing thirst for energy to fuel its fast growing economy has made China keen to explore the potential of modern form of bioenergy, biofuel. This study investigates the land and water requirements of biofuel in China with reference to the government biofuel development plans for 2010 and 2020. The concept of land and water footprints of biofuel is applied for the investigation. The result shows that the current level of bioethanol production consumes 3.5–4% of total maize production of the country, reducing market availability of maize for other uses by about 6%. It is projected that depending on the types of feedstock, 5–10% of the total cultivated land in China would need to be devoted to meet the biofuel production target of 12 million metric tons for the year 2020. The associated water requirement would amount to 32–72 km³ per year, approximately equivalent to the annual discharge of the Yellow River. The net contribution of biofuel to the national energy pool could be limited due to generally low net energy return of conventional feedstocks. The current biofuel development paths could pose significant impacts on China's food supply and trade, as well as the environment.     

Water: A key resource in energy production

Water and energy are the key resources required for both economic and population growth, and yet both are increasingly scarce. The distribution of water takes large amounts of energy, while the production of energy requires large amounts of water in processes such as thermal plant cooling systems or raw materials extraction. This study analyzes the water needs for energy production in Spain according to the energy source sector (electricity, transportation or domestic) and process type (extraction and refining of raw materials or thermal plant use). Current and future water needs are quantified according to energy demand and technology mix evolution. Hypothetical scenarios that simulate the risks of promoting specific energy policies are also analyzed. Results show that the combination of energy resources used in Spain is projected to be more than 25% more water consumptive in 2030 than in 2005 under ceteris paribus conditions. Renewable energies are mixed in terms of their consequences on the water supply; wind power can reduce water withdrawal, while the biofuels production is a water-intensive process.     

Coproduct market analysis and water footprint of simulated commercial algal biorefineries

Algal biorefinery-based integrated industrial sector is getting increased attention in United States as a sustainable way of producing biofuel, high value products and feed ingredients. However, coproduct market analysis and water footprint (WFP) of algal biorefineries need to be studied before large scale deployment and adoption of this strategy. This article highlights the coproduct market and WFP analysis of two simulated algal biorefineries. The market analysis of primary product (biodiesel) and coproducts (algal meal (AM), omega-3 fatty acids (O3FA), glycerin) from these biorefineries showed that there is clear market for AM and O3FA up to certain level, there after diversification for other coproducts is desirable. Challenges include, vigorously finding new market and sectors to integrate the products and coproducts. Hence, comprehensive assessment of coproduct market and coproduct diversification among the biorefinery to meet the local needs and to avoid market glut by excessive production of single coproduct is needed. Our analysis also showed the clear advantages for multiproduct paradigm to attain high operational profit and to sustain initial industry developmental phase with clear return on investment. Our WFP analysis showed that algal biodiesel production requires 23–62 L MJ⁻¹ of energy produced and our calculations showed that the energy return on water invested (EROWI) for algal biodiesel at different scenarios ranged between 0.042 and 0.016 MJ. Coproducts market analysis and WFP of algal biorefineries with different production scenarios illustrated the new policy and regulatory needs for the sustainable development of an algal biofuel sector to meet liquid fuel needs.     

From riches to rags: Biofuels,media discourses,and resistance to sustainable energy technologies

This study aims to open the black box of resistance to sustainable energy technologies by analyzing (shifts in) media discourse. To this end, media coverage on biofuels in the Netherlands between 2000 and 2008 is analyzed by means of combining novel quantitative approaches with practitioner interviews. The quantitative analyses reveal the dynamics in the content of media discourse, but also its underlying structure in the form of two axes, each representing opposite socio-cognitive frames: ‘techno-economic vs. social–ecological’ and ‘regional vs. global’. In-depth interviews with key practitioners in the Dutch biofuels field support these finding and provide additional insights with regard to (a) perceived shifts in media coverage; (b) cognitive pluralism; (c) the politics involved; and (d) resistance in practice.     

The emerging liquid biofuel market in Argentina: Implications for domestic demand and international trade

While the world's transport energy matrix is still strongly linked to limited and heavily polluting fossil fuels, new markets are appearing for the production and use of alternative transport fuels, such as liquid biofuels. Due to an interconnected global economy, such markets today are developing on a global scale with actors looking to meet local as well as potential international demand. The aim of this paper is to describe and evaluate the emergence of markets for liquid biofuels in Argentina. It reveals that biodiesel production for international supply is likely to emerge in the short run (up to 2010), giving the opportunity to be switched back to local supply in the medium run (post-2010). It also suggests that a bioethanol market (demand and supply) does not seem to be likely in the short run, and it is highly uncertain in the medium run as the most influential actors oppose its development. On the other hand, the current constellations of the biodiesel market appear to leave many uncertainties regarding its sustainability, especially in regard to a limited role of small and medium sized enterprises, and a suitable and diversified biodiesel feedstock. Currently, the focus lies solely on (very) large-scale production of biodiesel derived from soybean oil for the export market.     

Ecological footprint accounting for energy and resource in China

Resource consumption of the Chinese society from 1981 to 2001 is represented by ecological footprint (EF) as an aggregate indicator. The debate, advances and implications of EF are investigated in detail. EF intensity is also provided to depict the resource consumption level corresponding to unit economic output. The results show that the EF per capita always exceeded the biocapacity and the EF intensity increased steadily over the study period. In addition, sectoral analysis for each EF component is also conducted. The appropriation in the global ecological sense of Chinese society with the second largest energy consumption in the world is therefore quantified and evaluated.     

The recent European biofuel debate as a case study in the politics of renewable energy

This study outlines a number of issues of a political nature, associated with the implementation of renewables, with the primary emphasis on the recent European push for the production of liquid biofuels. In recent years biofuels have been gaining increasing attention as a potential alternative to conventional automotive fuels. This potential has recently become an issue in the European Union (EU) with surplus agricultural land being considered for the production of energy crops. In this paper political issues at stake in the promotion of biofuel crops in the EU are examined. A critical analysis is made of the environmental claims put forward in defence of the promotion of these fuel crops and comparisons made with alternate woody biomass fuels. Contrasts are drawn between this case study and other examples of the implementation of renewables including the development of PV in the US and wind power in the UK. Conclusions are made regarding the impact of the issues thrown up on the future development of renewables.     

Integrating waste and renewable energy to reduce the carbon footprint of locally integrated energy sectors

Energy use continues to rise and with it the emissions of CO₂. Energy efficiency methods have been applied across sectors. Efficiency gains and energy use per manufactured unit have fallen, particularly in relation to the processing industry. Residential, work place, leisure, and service sectors still use large amounts of energy and produce large emissions of CO₂ despite efficiency gains. Successful strategies used in the processing industry for integrating energy systems, namely Total Site targeting, have been applied to locally integrated energy sectors. The method shows that it can be successfully applied to integrate renewables into the energy source mix and consequently reduce the carbon footprint of these locally integrated energy sectors.     

A multi-actor multi-criteria framework to assess the stakeholder support for different biofuel options: The case of Belgium

The multi-actor multi-criteria analysis (MAMCA) is a methodology to evaluate different policy measures, whereby different stakeholders’ opinions are explicitly taken into account. In this paper, the framework is used to assess several biofuel options for Belgium that can contribute to the binding target of 10% renewable fuels in transport by 2020, issued by the Renewable Energy Directive (RED). Four biofuel options (biodiesel, ethanol, biogas and synthetic biodiesel (also referred to as “biomass-to-liquid” or BTL)) together with a reference fossil fuel option, are evaluated on the aims and objectives of the different stakeholders involved in the biofuel supply chain (feedstock producers, biofuel producers, fuel distributors, end users, vehicle manufacturers, government, NGOs and North–South organizations). Overall, the MAMCA provided insights in the stakeholder’s position and possible implementation problems for every biofuel option. As such, it helps decision makers in establishing a supportive policy framework to facilitate implementation and to ensure market success, once they have decided on which biofuel option (or combination of options) to implement.     

The real time dynamic water transport investigation due to net water transport coefficient (NWTC) based on measurement of water content in the outlet gas in a PEFC

The present method is expanded from the previous research [1], based on the experimental water pressure in the anode and cathode outlet. The real time NWTC in cathode and anode are obtained. The general NWTC, the peak NWTC, and the average NWTC in start-up and shut-down are discussed. The results show that, firstly, the membrane absorbs water from cathode and anode in the start-up after the current turned on and discharges water to cathode and anode after the current turned off, which causes the dynamic NWTC far from the steady state value. Secondly, there is peak value for NWTC both for start-up and shut-down, the anode peak value is nearly independent on the current in start-up, and decreases (more water transport) with increase of the current in shut-down. The asynchronous appearance moment of the peak values in the cathode side and the anode side are obtained. The average NWTC in the time interval of start-up keeps the same trend as the steady NWTC with increase of the current in start-up, and more water is discharged from the membrane for high current in shut-down.     

Correlations of vaporization performance of conventional and biofuel sprays in a crossflow heated chamber

Pre-vaporization and pre-mixing are the two main features of LPP type of combustor that operate on liquid fuels. The pre-vaporization length scale is one of its most important design parameters. In this study, the goal is to put forward a simulation based correlation for fuel vaporization performance as a function of dimensionless parameters for crossflow type of injections. Two types of fuels are studied here: jet-A and one of its potential biofuel substitutes, RME. Different sets of spray simulations are considered for crossflow type of injections. Correlations are provided for both jet-A and RME's vaporization performance as a function of non-dimensional inlet air temperature, fuel/air momentum flux ratio and normalized spray traverse distance.     

焦化厂实行梯级用水降低水耗的实践

通过对焦化厂所用水水质和不同用水系统工艺特点的分析,制订焦化厂梯级用水制度,降低水耗30％;对水处理设备进行改进,稳定水处理药剂浓度;根据阻垢及缓蚀实验结果,确定适用于高氯离子浓度循环水系统的阻垢缓蚀剂。     

Heterogeneous photocatalysis: From water photolysis to applications in environmental cleanup

Water splitting and environmental cleanup are two active fields in heterogeneous photocatalysis, which are both closely related to the research in semiconductor photoelectrochemistry since the 1960s. The present review paper will attempt to describe some of the progress and resulting achievements in these two fields, and to briefly discuss the future prospects. We will cover the major developments worldwide but will highlight work carried out in Japan over the last several years.     

Small-scale production of straight vegetable oil from rapeseed and its use as biofuel in the Spanish territory

Biofuels nowadays are an important topic of study. The most significant point is the availability of bioethanol or biodiesel and their production from different raw materials. It is already known that large-scale production of first-generation biodiesel cannot be seen as an alternative to fossil fuels due to land requirements, competition with food, increase in fertilizer requirements and pressure on tropical forests among others. This fact does not necessarily apply to second-generation biofuels or small-scale niche productions. Straight vegetable oil (SVO) can be used directly in diesel engines with minor modifications. Our proposal is a small-scale SVO production system for self-supply in agricultural machinery. In this paper a model to provide SVO to local farmers in a specific area in Catalonia (Spain) is presented. We also present a discussion about the regulations to be changed in order to make possible the incorporation of SVO as engine fuel in diesel vehicles and a comparative analysis between the emissions of tractors fed with SVO and petrodiesel. Moreover, a quantitative economic analysis of modifying diesel engines and long-term operability costs are shown and a first-run economic analysis comparing the actual crop rotation with the proposed one and some alternatives is studied.     

The Honduran palm oil industry: Employing lessons from Malaysia in the search for economically and environmentally sustainable energy solutions

Honduras is actively seeking ways to expand its palm oil industry for the purpose of processing biofuels for both internal consumption and export. This would be a critical juncture for Honduras, presenting an opportunity to move beyond the export of basic agricultural commodities and a history of path dependency and weak economic indicators. In order to glean lessons on how to approach palm oil expansion in the most effective manner, I turn to the Malaysian case. Once impoverished, Malaysia expanded plantations, promoted technological innovation, and provided financial incentives and tax structures to develop one of the most sophisticated palm oil industries in the world. In this paper, the insights to be gleaned from the Malaysian case are organized into three key themes: Governance, Investing in Research and Human Capital, and The Environment. Recommendations for Honduras include: increased collaboration with funding bodies, NGOs and universities to foster research; fiscal policies that support the development of a domestic market; and key environmental controls to ensure sustainability in the long term. These insights offer practical and pragmatic solutions not only for Honduras, but also the wider community of small, tropical, developing nations seeking to develop a viable biofuels sector.     

PEM water electrolyzers: From electrocatalysis to stack development

Proton Exchange Membrane (PEM) water electrolysis can be used to produce hydrogen from renewable energy sources and can contribute to reduce CO₂ emissions. The purpose of this paper is to report on recent advances made in PEM water electrolysis technology. Results obtained in electrocatalysis (recent progresses made in low-cost electrocatalysis offer new perspectives for decentralized and domestic applications), on low-cost membrane electrode assemblies (MEAs), cell efficiency, operation at high current density, electrochemical performances and gas purity issues during high-pressure operation, safety considerations, stack design and optimization (for electrolyzers which can produce up to 5 Nm³ H₂/h) and performance degradations are presented. These results were obtained in the course of the GenHyPEM project, a 39 months long (2005–2008) research program supported by the European Commission. PEM technology has reached a level of maturity and performances which offers new perspectives in view of the so-called hydrogen economy.     

Federal policy documentation and geothermal water consumption: Policy gaps and needs

With U.S. geothermal power production expected to more than triple by 2040, and the majority of this growth expected to occur in arid and water-constrained areas, it is imperative that decision-makers understand the potential long-term limitations to and tradeoffs of geothermal development due to water availability. To this end, water consumption data, including documentation triggered by the National Environmental Policy Act (NEPA) of 1969, production and injection data, and water permit data, were collected from state and federal environmental policy sources in an effort to determine water consumption across the lifecycle of geothermal power plants. Values extracted from these sources were analyzed to estimate water usage during well drilling; to identify sourcing of water for well drilling, well stimulation, and plant operations; and to estimate operational water usage at the plant level. Nevada data were also compared on a facility-by-facility basis with other publicly available water consumption data, to create a complete picture of water usage and consumption at these facilities. This analysis represents a unique method of capturing project-level water data for geothermal projects; however, a lack of statutory and legal requirements for such data and data quality result in significant data gaps, which are also explored.     

空调冷冻水泵变频能耗特性的研究

通过分析冷冻水管路特性随空调负荷变化的特点 ,得出了计算空调冷冻水泵变频调速运行总能耗的一般关系式。研究表明 ,在中央空调系统中 ,由于冷冻水管路特性曲线随空调负荷而变化 ,在确定水泵变频调速运行的能耗时已不能直接应用泵的相似定律 ;变频冷冻水泵的能耗并不与转速或流量的三次方成正比 ,而是与空调负荷、空调用户的流量分配及空调用户的位置等有关。     

New optimized model for water temperature calculation of river-water source heat pump and its application in simulation of energy consumption

The energy consumption calculation plays an important role in the analysis of project economic and social benefits. In order to calculate energy consumption accurately, this research presents a water temperature of condenser inlet calculation model of river-water source heat pump unit. The feasibility and calculation error of the model had been analyzed. Additionally, the new water temperature calculation model had been validated via an engineering case. The results showed that the hourly water temperature in 24 h could be replaced by daily average water temperature due to little change of the daily water temperature change. In this case, the calculation error could be less than 5%. It is found that despite water temperature has many influenced factors, there is a remarkable relationship between the daily average water temperature and daily average outdoor dry bulb temperature by data analysis (R² ≈ 0.9). The influence of river sampling location on water temperature calculation of condenser inlet could be ignored due to slight temperature changes (within 0.15 °C). The method proposed in this paper met the engineering accuracy and provided a very effective method for the engineering calculation of energy consumption of water chilling unit.