Are alternative energies a real alternative for investors?

Fossil fuels supply most of the energy we need for many functions but alternative energy global consumption is expected to increase in the future supported by great incentives, advances in technologies, and the depletion of fuel oil reserves. In that context, investors begin to consider the possibility of investing in the alternative energy sector using different assets such as the Exchange Traded Funds (ETFs). We evaluate the out-of-sample performance of four strategies using the returns and volatility forecasts from a VAR-ADCC approach. We provide evidence that Alternative Energy ETFs clearly outperform Energy ETFs and, therefore, they are a real alternative for investors. These findings are relevant not only for academics but also for active professional managers who can use this technique to add value to their investment strategies.     

Are plant lipases a promising alternative to catalyze transesterification for biodiesel production?

Interest in the production of biodiesel—a clean renewable fuel—is increasing worldwide. Industrial-scale processes currently being developed use homogenous and heterogeneous chemical catalysis processes that are highly efficient but require very pure reagents and complex product purification steps, or high temperature and pressure processing conditions. Enzymatic catalysis using plant lipases as biocatalysts is an alternative which, contrary to chemical catalysis processes, is simple to perform, at low investment cost, and therefore potentially easier to disseminate, especially in developing countries. Although microbial lipases have been extensively studied, little research has been focused on the use of plant lipases in biodiesel production. These latter lipases can, however, be readily extracted from the plant organs that contain them (seeds, bran or latex) and they are less expensive to use than microbial lipases. The aim of the present article was thus to review published research findings and outline the most advanced knowledge concerning alkyl ester production catalyzed by plant lipases. This work focuses mainly on the conditions for using plant lipases in certain synthesis reactions (biomass selection, preparation and purification of lipase extracts) and current knowledge on reaction parameters that affect the catalytic activity. Moreover, biodiesel production using plant lipases and ethanol instead of methanol certainly seems to be in line with the development of innovative environment-friendly technologies.     

Life cycle assessment of alternative energy types – including hydrogen – for public city buses in Taiwan

Human activities have exacerbated the global greenhouse effect, resulting in extreme climate changes that have caused disasters and food and water shortages in recent years. Transportation is one of the main causes of global greenhouse gas (GHG) emission. Therefore, policy makers must develop feasible strategies to reduce GHG emission. One of Taiwan's policy is to replace traditional diesel fuel urban buses with alternative energy buses. This paper uses a case study of city bus route No. 2 in Tainan City following the international standard ISO/TS 14067:2013 to measure the carbon footprint of different energy buses. The bus carbon footprints measured from high to low as: LNG buses, 63.14 g CO2e/pkm; traditional diesel buses, 54.6 g CO2e/pkm; liquefied petroleum gas (LPG) buses, 47.4 g CO2e/pkm; plug-in electric buses, 37.82 g CO2e/pkm, and hydrogen fuel cell buses, 29.17 g CO2e/pkm. If all urban area public buses in Taiwan were switched to hydrogen fuel cell buses, this would reduce CO2e footprint by 227,832.39 t annually. This reduction is equivalent to planting 22.78 million trees.     

Hydroprocessed vegetable oil as a fuel for transportation sector: A review

Renewable fuels produced from vegetable oils are an attractive alternative to fossil-based fuel. Different type of fuels can be derived from these triglycerides. One of them is biodiesel which is a mono alkyl ester of the vegetable oil. The biodiesel is produced by transesterification of the oil with an alcohol in the presence of a catalyst. Another kind of fuel (which is similar to petroleum-derived diesel) can be produced from the vegetable oil using hydroprocessing technique. This method uses elevated temperature and pressure along with a catalyst to produce a fuel termed as ‘renewable diesel’. The fuel produced has properties that are beneficial for the engine as well as the environment. It has high cetane number, low density, excellent cold flow properties and same materials can be used as are used for engine running on petrodiesel. It can effectively reduce NOx, PM, HC, CO emissions and unregulated emissions as well as greenhouse gases as compared to diesel. The fuel is also beneficial for the after-treatment systems. Trials in the field have shown that the volumetric fuel consumption of renewable diesel is higher than petrodiesel and nearly proportional to the volumetric heating value. The present review focuses on the hydroprocessing technique used for the renewable diesel production and the effect of different parameters such as catalyst, reaction temperature, hydrogen pressure, liquid hourly space velocity (LHSV) and H₂/oil ratio on oil conversion, diesel selectivity, and isomerization. The review also summarizes the effect; renewable diesel has on combustion, performance, and emission characteristics of a compression ignition engine.     

A solution to renewable hydrogen economy for fuel cell buses – A case study for Zhangjiakou in North China

Fuel cell vehicles fueled with renewable hydrogen is recognized as a life-cycle carbon-free option for the transport sector, however, the profitability of the H₂ pathway becomes a key issue for the FCV commercialization. By analyzing the actual data from the Zhangjiakou fuel cell transit bus project, this research reveals it is economically feasible to commercialize FCV in areas with abundant renewable resources. Low electricity for water electrolysis, localization of H₂ supply, and curtailed end price of H₂ refueling effectively reduce the hydrogen production, delivery and refueling cost, and render a chance for the profitability of refueling stations. After the fulfillment of the intense deployment of both vehicles and hydrogen stations for the 2022 Winter Olympics, the H₂ pathway starts to make a profit thereafter. The practices in the Zhangjiakou FCB project offer a solution to the hydrogen economy, which helps to break the chicken-egg dilemma of vehicles and hydrogen infrastructure.     

Are Feed-in Tariffs suitable for promoting solar PV in New Zealand cities?

Feed-in Tariffs (FITs) implemented by city councils in the USA have proven an effective means of stimulating installation of renewable-electricity generation capacity at a local level, and may also be effective for New Zealand cities. Though New Zealand has a high proportion of electricity generated renewably, this is mostly from centralized hydroelectricity plants. The suitability of city-level FITs for promoting solar photovoltaic panels in New Zealand is examined. Findings suggest that FITs, with rates obtained using the cost-of-generation method, could be implemented in New Zealand cities at rates comparable to those in successful FIT schemes internationally. The unique structure of New Zealand's liberalized electricity market, however, is likely to make financing FIT schemes at city-level more complex than the equivalent situation in the USA. Benefits of introducing such schemes will include the possibility for purchasers of solar PV systems to calculate returns on investment over the long term, and the streamlining of the grid connection process by reducing the number of authorities involved.     

Grasses for biofuels: A low water-use alternative for cold desert agriculture?

In arid regions, reductions in the amount of available agricultural water are fueling interest in alternative, low water-use crops. Perennial grasses have potential as low water-use biofuel crops. However, little is known about which perennial grasses can produce high quantity, high quality yields with low irrigation on formerly high-input agricultural fields in arid regions. We monitored biomass production, weed resistance, rooting depth, and root architecture of nine perennial grasses under multiple irrigation treatments in western Nevada. Under a low irrigation treatment (71 ± 9 cm irrigation water annually), cool-season grasses produced more biomass and were more weed-resistant than warm-season grasses. With additional irrigation (120 ± 12 cm water annually), warm- and cool-season grasses had similar biomass production, but cool-season species remained more weed-resistant. Among species within each grass type, we observed high variability in performance. Two cool-season species (Elytrigia elongata and Leymus cinereus) and one warm-season species (Bothriochloa ischaemum) performed better than the other tested species. Root depth was not correlated with biomass production, but species with deeper roots had fewer weeds. Abundance of fine roots (but not large roots) was correlated with increased biomass and fewer weeds. Both L. cinereus and E. elongata had deep root systems dominated by fine roots, while B. ischaemum had many fine roots in shallow soil but few roots in deeper soil. Cool-season grasses (particularly E. elongata, L. cinereus, and other species with abundant fine roots) may be worthy of further attention as potential biofuel crops for cold desert agriculture.     

Fuel cells for road transportation purposes — yes or no?

The issues surrounding the application of fuel cells for road transportation are evaluated. The advantages and disadvantages of the candidate fuel-cell systems and the various fuels are discussed, together with the issue of whether the fuel should be converted directly in the fuel cell or should be first converted to hydrogen on-board the vehicle. Developments in competing vehicles technologies, namely, internal-combustion-engined vehicles (ICEVs), pure-battery vehicles (EVs) and ICE–battery hybrid vehicles (HEVs) are reviewed. Finally, the impact of the introduction of fuel-cell vehicles (FCVs) on industry, and in particular on the oil and automotive industries, is examined. For FCVs to compete successfully with conventional ICEVs, it is concluded that direct-conversion fuel cells — using probably hydrogen, but possibly methanol — are the only realistic contenders for road transportation applications.     

Systematic approach for recognizing limiting factors for growth of biomethane use in transportation sector – A case study in Finland

In this paper, limiting factors for increased use of biomethane as a transportation fuel are studied. The aim of this research is to recognize and estimate the limiting factors for biomethane utilization in the transportation sector. The limiting factors are studied by using calculation models from Life cycle perspective and literature reviews. According to the results, the main limiting factors can be classified into the following categories: production potential, technology, economy or policy. For biomethane utilization in Finland, the main limiting factors seem to be the lack of distribution infrastructure in northern parts of the country and the uncertain economical feasibility for agricultural biomass producers and for vehicle owners. From the political perspective, the external costs for petrol operated vehicles are higher than for biomethane operated vehicles. Reductions from the external costs could be used by political decisions as a base to support the growth of biomethane in the transportation sector which could lead to GHG emission reductions. A similar systematic approach can also be used to study limiting factors for other transportation energy systems.     

The value chain of green hydrogen for fuel cell buses – A case study for the Rhine-Main area in Germany

As an immanent necessity to reduce global greenhouse gas emissions, the energy transition poses a major challenge for the next 30 years, as it includes a cross-sectoral increase of fluctuating renewable energy production, grid extension to meet regional electricity supply and demand as well as an increase of energy storage capacity. Within the power-to-gas concept, hydrogen is considered as one of the most promising solutions.The paper presents a scenario-based bottom-up approach to analyse the hydrogen supply chain to substitute diesel with fuel cell buses in the Rhine-Main area in central Germany for the year 2025. The analysis is based on field data derived from the 6 MW power-to-gas plant “Energiepark Mainz” and the bus demonstration project “H₂-Bus Rhein-Main”. The system is modelled to run simulations on varying demand scenarios. The outcome is minimised hydrogen production costs derived from the optimal scheduling of a power-to-gas plant in terms of the demand. The assessment includes the energy procurement for hydrogen production, different hydrogen delivery options and spatial analysis of potential power-to-gas locations.     

What role for microgeneration in a shift to a low carbon domestic energy sector in the UK?

Domestic energy use accounts for more than a quarter of CO₂ emissions in the UK. Traditional approaches to energy reduction look at direct emissions savings, and recommend insulation and efficiency as more cost-effective than microgeneration. However, microgeneration has indirect, ‘soft’ benefits and could play a significant role in emissions reduction. Current uptake of microgeneration in the UK is low, with various barriers—economic, technical, cultural, behavioural and institutional—both to uptake and to maximising energy and emissions savings once installed. Subsidies and spreading information alone do not guarantee maximising uptake, and even if successful, this is not enough to maximise savings. The industry focuses on maximising sales, with no incentives to ensure best installations and use; householders do not have access to the best information, and user behaviour does not maximise energy and emission savings. This is related to a broader state of socio-technical ‘lock-in’ in domestic energy use; there’s a lack of connection between personal behaviour and energy consumption, let alone global climate change. This suggests that a major cultural–behavioural shift is needed to reduce energy/emissions in the home. Transition theory and strategic niche management provide insights into possible systemic change and a suitable framework for future policies, such as supporting a variety of radically innovative niches, both technological and social. Microgeneration, properly employed, has the potential to play a part in such a transition by increasing awareness and energy literacy and empowering people to seriously engage in energy debates as producers, as well as consumers, of energy. This deeper understanding and heightened responsibility are crucial in a shift toward bottom-up emission-reducing behaviour change and better acceptance of top-down energy-saving policy measures, as part of a new domestic energy paradigm. The implications for policy are that, as well as supporting the technologies, it needs to support existing niches and to develop new niche experiments. Policy needs to consider how to promote empowerment and responsibility and support or even develop new energy sector models; this will involve a range of stakeholders and multiple governance levels, not just national incentive schemes.     

Biodiesel via supercritical ethanolysis within a global analysis “feedstocks-conversion-engine” for a sustainable fuel alternative

The challenges in reducing the world's dependence on crude oil and the greenhouse gas accumulation in the atmosphere, while simultaneously improving engine performance through better fuel efficiency and reduced exhaust emissions, have led to the emergence of new fuels, with formulations blending petrodiesel, biodiesel, bioethanol and water in various proportions. In parallel, the sustainability of the new biofuel industries also requires to maintain a high level of biodiversity while playing on techno-diversity, using a variety of resources that do not compete with edible crops (nor by using arable land for energy crops or food crops for energy production) and flexible conversion technologies satisfying the eco-design, eco-energy and eco-materials criteria. In addition, it would be relevant to consider blending ethyl biodiesel, instead of methyl biodiesel, with petrodiesel, particularly if the fuel formulation is completed with bioethanol (or even water). The supercritical ethanolysis of lipid resources to produce ethyl biodiesel is a simple but efficient route that should have the potential to satisfy the sustainability criteria if analyzed holistically. Therefore, this review focuses specifically on the production of ethyl biodiesel via triglyceride supercritical ethanolysis within a global analysis “feedstocks-conversion-engine”. The scientific and technical bottlenecks requiring further development are highlighted by emphasizing (i) the kinetic and thermodynamic aspects (experiments and modeling) required for the process simulation, the results of which aim at securing the life cycle assessment, first at the process level and then at the fuel level; (ii) the proposals to improve the supercritical process performance in terms of eco-material and eco-energy; (iii) the impacts of ethyl vs. methyl biodiesel fuels and of biodiesel–ethanol–petrodiesel blends (with or without water) on the diesel engine emissions and performance; (iv) the technological flexibility of the supercritical process allowing its conversion toward production of other key products. Finally, built on the state-of-the art review, a new R&D direction combining supercritical ethanolysis of lipids with the addition of CO₂, glycerol recovery, and cogeneration, according to the biorefinery concept, is proposed and discussed.     

Are energy statistics useful for making energy scenarios?

One can measure “energy quantities” – e.g. joules, BTU, quads – but only at a given scale and within a specific narrative about energy conversions at the time. Therefore, at the moment of generating aggregate indicators, the arithmetic summing of assessments of energy quantities referring to different scales and narratives is meaningless. This paper addresses epistemological problems typical of energy accounting, which are at the moment tackled by acknowledging the existence of unspecified “qualitative differences” among different energy forms – e.g. a joule of electricity has more “value” than a joule of coal. Three energy forms referring to different scales and narratives about energy conversions are relevant for national accounting: Primary Energy Sources (PES), Energy Carriers (EC), and End Uses (EU). We critically examine the usefulness of current energy statistics in relation to this distinction. The conventional linear representation – flow chart – based on a single scale and a single quantitative accounting confuses the three semantic categories and entails an important loss of information. Finally, we illustrate an innovative scheme for energy accounting across hierarchical levels that: (i) addresses the autocatalytic nature of energy transformations; (ii) provides a multi-scale quantitative representation; and (iii) preserves the semantic distinction between relevant energy forms (PES, EC, and EU).     

Direct rebound effect for urban household in China—an empirical study

Household sector has become one important target sector on which the Chinese government implements its energy-saving and emission reduction policies. Improving energy efficiency is the primary method adopted by the Chinese government for energy conservation. However, its real energy-saving effects would be affected greatly owing to energy rebound effects. In this paper, we set up a Linear Approximation of the Almost Ideal Demand System (LA/AIDS) model to estimate the direct rebound effect for urban households in China, and real energy conservation effect of improving energy efficiency is also obtained. The assessment of the rebound has a lot of uncertainty, and therefore, exact figures are hard to determine. The results show that energy rebound for Chinese urban household is approximately 66%. In this regard, the Chinese government could not accomplish the energy conservation target through improving energy efficiency only. Policy supplements like energy pricing reform are also needed.     

Life cycle greenhouse emissions of compressed natural gas–hydrogen mixtures for transportation in Argentina

We have developed a model to assess the life cycle greenhouse emissions of compressed natural gas–hydrogen (CNG–H₂) mixtures used for transportation in Argentina. The overall fuel life cycle is assessed through a well-to-wheel (WTW) analysis for different hydrogen generation and distribution options. The combustion stage in road vehicles is modeled using the COPERT IV model. Hydrogen generation options include classical steam methane reforming (SMR) and water electrolysis (WE) in central plants and distributed facilities at the refueling stations. Centralized hydrogen generation by electrolysis in nuclear plants as well as the use of solar photovoltaic and wind electricity is also considered. Hydrogen distribution options include gas pipeline and refrigerated truck transportation for liquefied hydrogen. A total number of fifteen fuel pathways are studied; in all the cases the natural gas–hydrogen mixture is made at the refueling station. The use of WE using nuclear or wind electricity appears to be less contaminant that the use of pure CNG.     

Hydrogen transportation in Delhi? Investigating the hydrogen-compressed natural gas (H-CNG) option

Given the success of Delhi’s CNG vehicle program, energy stakeholders are now investigating a transition to hydrogen-compressed natural gas (H-CNG) blends in the city. Past research has shown H-CNG can reduce tailpipe emissions of both criteria and greenhouse gas pollutants relative to diesel, CNG, and gasoline [1], [2] and [3]. However, an unanswered question is how Delhi will satisfy the potential hydrogen demand in a sustainable manner. We conduct a techno-economic assessment of hydrogen production from gasification of the three most abundant agricultural residues near Delhi - rice straw, cotton stalk, mustard stalk - and find these residues could provide the city with up to 270,700 metric tons per year of hydrogen. This quantity far exceeds what is needed to run all existing CNG vehicles on 18%-82% H-CNG blends. The cost of each step of the biohydrogen supply chain is calculated and the total cost is estimated at 149.6 rupees ($3.39) per kg. Lastly, we show that the price of H-CNG at the pump would be roughly equivalent to CNG on a per mile basis.     

Scope-Oriented Thermoeconomic analysis of energy systems. Part I: Looking for a non-postulated cost accounting for the dissipative devices of a vapour compression chiller. Is it feasible?

The authors of the main thermoeconomic methodologies developed in the last two decades have recently focused their efforts on the analysis of dissipative devices, i.e. those components whose productive purpose is neither intuitive nor easy to define. Coherent and unanimously accepted cost structures have been identified for dissipative components, while ambiguities still exist as concerns the cost allocation principles to be adopted. Being this aspect evidently cost-influencing, accurate analyses focused on the subjectivity of results are needed. This paper is structured in two parts. In the Part I an in-depth study of some critical issues arising from the thermoeconomic analysis of a 1.5 MW_c industrial chiller is presented. The attention is focused on the role of the condenser and the throttling valve (considered as a limit condition for an expander with very low isentropic efficiency); marginal analyses performed on the condensation pressure and the isentropic efficiency of the expander provided elements to assess the rational of the cost allocation principles. Attempting to refugee any cost allocation criterion based on postulates, the concept of Scope is identified as a possible non-arbitrary basis for cost allocation in dissipative devices; consequently, a new topology is defined, abandoning the conventional classification between dissipative and productive units, toward a new distinction between Product Makers and Product Takers functions. The proposed approach is applied to the cost accounting of the examined chiller, revealing inadequate and less explicative than the conventional thermoeconomic approaches due to its “intrinsically differential” nature. In the Part II of this paper the proposed approach will be applied to an Optimization problem, revealing very flexible and insightful.     

Is there a space for additional renewable energy in the Norwegian power system? Potential for reduced global emission?

This paper presents the results of a Norwegian power system analysis. An energy system analysis model based on linear programming is used for modelling and optimisation. The analyses cover a number of scenarios where the studied system is subjected to changes by introducing other renewable energy sources, energy conservation measures and measures to promote renewable energy. The study shows that due to a combination of cheap hydropower and high investment costs, it is quite difficult for new generation units to be profitable. This is also true during periods of low precipitation where the system tends to survive on imported power instead of investing in new generation units. However, this does not apply to energy conservation measures that easily enter the system. On the other hand, biomass based CHP, wind power and wave power could be viable if measures are introduced to promote their use. Most of the scenarios show a high potential for reducing global emissions.     

Are fluctuations in coal consumption transitory or permanent? Evidence from a panel of US states

This short communication investigates whether or not US coal consumption follows a stationary process by examining coal consumption for the 50 US states over the period 1982–2007. Employing several panel unit root and stationarity tests with endogenously determined structural breaks, the results indicate that coal consumption is integrated of order zero. Thus, energy conservation policies oriented towards the reduction of coal consumption will only have short-term effects.