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Because of concerns about global climate change, possible global oil depletion, and because of potential benefits for both urban air pollution and rural employment and industry, many countries both in and out of the Organization for Economic Cooperation and Development (OECD), are promoting liquid biofuels as a replacement for oil-based transport fuels, and global output is rising steadily. In fact, bioenergy use in general is promoted, and is expected to play a major role in climate change mitigation. But bioenergy use in general faces competition for resources such as land, water and fertiliser from the two other general biomass uses, food production and biomaterials. Ethically, food production should take precedence over the other two uses (and at present all bioliquids are made from foodstuffs), and using biomass for biomaterials will in many situations reduce greenhouse gas emissions more than using the same amount of biomass for energy. Where a given amount of biomass is available for transport energy use, it will usually produce more greenhouse gas reductions per vehicle-km if used to produce electricity rather than liquid biofuels. Finally, there is signs that internal combustion engine vehicles could be phased out in the coming decades. If so, liquid biofuels will be phased out along with existing oil-based transport fuels. In conclusion, except for specialist uses, liquid biofuels do not appear to have a long-term future.

The development of renewable energy sources (RES) is considered to be a key instrument in addressing climate change. However, different RES have different potential and economic feasibility depending on country-specific conditions and mitigation ambitions. Understanding the relative importance of each RES could help policymakers focus their efforts on the most promising options. In this paper, we focus on Ukraine and explore the potential of biomass use under two mitigation scenarios – with 68% and 83% of greenhouse gas emissions reduction in 2050 relative to the 2010 level. First, using the TIMES-Ukraine energy system model, we show that biomass would play a major role in the future climate mitigation. If constrained at the baseline scenario level (due to political or other reasons), mitigation costs would be substantially higher – by 14.0–19.6 B € or 10.8–14.3 €/tCO2-eq., over the 2020–2050 time frame. Second, we quantify the importance of each biomass source. We show that woody biomass and bioliquids are the most important biofuels under the high-ambition climate scenario, while biowaste and bioliquids play a key role in the lower ambition pathway. Finally, we analyse the current policy environment in the context of future biomass development and conclude with a set of policy recommendations toward the realization of the biomass potential in Ukraine. We believe that findings presented in the paper would be relevant not only for supporting the decision-making process in Ukraine, but could also provide useful insights for other countries with similar conditions.

In this study, the evaporation temperature behaviors of various liquids in silica and activated carbon pores were investigated, and applicability of bioliquid in coal pores was reported. In countries around the world, to reduce the potential carbon dioxide, solid phase biomasses, such as wood chips and pellets, have been mixed with coal to make fuel for coal-fired power plants. However, the liquid phase biomass (bioliquid) has a phase different from coal in atmospheric conditions and evaporates at a relatively low temperature. As a result, it has been difficult to use biomass in the existing coal-fired power plants due to a number of problems, such as fuel injection, the reduction of combustion efficiency in coal, spontaneous combustion, and the risk of explosion during drying. To address these challenges, evaporation behaviors of bioliquids were evaluated using silica and activated carbon that have various pores and surface characteristics. The impregnation of bioliquids was accelerated on a support that had the same hydrophilic or hydrophobic characteristics, and the evaporation temperature increased at the hydrophilic surfaces or in small pores. In addition, evaporation behaviors were assessed by filling bioliquids into coal pores that originated from ash and fixed carbon. These results increase understanding of coal pore characteristics and will enable better choices of bioliquids that can be used together with coal in the existing coal-fired power plants.

This study reports the results of a detailed analysis of 203 samples of bioliquid used as a substitute for heavy fuel oil in oil-fired power plants. Bioliquid is a mixture of various vegetable oils, animal fats and its byproducts. The heating value of bioliquid is approximately the same as that of heavy fuel oil; however, bioliquid has significantly less N and S components and exhibits better combustion reactivity. For a commercial electricity generation, demonstration tests firing bioliquid in 75, 90, and 100 MW oil-fired boilers were conducted, and the results were compared with those obtained by firing heavy fuel oil. Further, the impacts of bioliquid fuel characteristics on combustion and boiler operation were also investigated. During the bioliquid firing, the heat absorption in the furnace decreased and the furnace exit gas temperature increased in comparison to the heavy fuel oil firing. No serious problems occurred in the boiler operation, and NOx and SOx emissions remarkably decreased. With minor modifications on the fuel transfer system and atomization devices, bioliquid could successfully replace heavy fuel oil in the existing oil-fired boilers. The limited values for 18 fuel properties of bioliquid are suggested by considering the stable boiler operation and environmental safety.

Fast pyrolysis liquid or bio-oil has been used in engines with limited success. It requires a pilot fuel and/or an additive for successful combustion and there are problems with materials and liquid properties. It is immiscible with all conventional hydrocarbon fuels. Biodiesel, a product of esterification of vegetable oil with an alcohol, is widely used as a renewable liquid fuel as an additive to diesel at up to 20%. There are however limits to its use in conventional engines due to poor low temperature performance and variability in quality from a variety of vegetable oil qualities and variety of esterification processes. Within the European Project Bioliquids-CHP - a joint project between the European Commission and Russia - a study was undertaken to develop small scale CHP units based on engines and microturbines fuelled with bioliquids from fast pyrolysis and methyl esters of vegetable oil. Blends of bio-oil and biodiesel were evaluated and tested to overcome some of the disadvantages of using either fuel by itself. An alcohol was used as the co-solvent in the form of ethanol, 1-butanol or 2-propanol. Visual inspection of the blend homogeneity after 48 h was used as an indicator of the product stability and the results were plotted in a three phase chart for each alcohol used. An accelerated stability test was performed on selected samples in order to predict its long term stability. We concluded that the type and quantity of alcohol is critical for the blend formation and stability. Using 1-butanol gave the widest selection of stable blends, followed by blends with 2-propanol and finally ethanol, thus 1-butanol blends accepted the largest proportion of bio-oil in the mixture.

According to the renewable energy directive 2009/28/EC, the European Union Member States should increase by 2020 the use of renewable energy to 20% of gross final energy consumption and to reach a mandatory share of 10% renewable energy in the transport sector. This study aims to quantify the impact of 2020 bioenergy targets on the land use in the EU, based on the projections of the National Renewable Action Plans in four scenarios: Scenario 1. Bioenergy targets according to NREAPs; Scenario 2. Bioenergy targets according to NREAPs, no second generation biofuels; Scenario 3. Bioenergy targets according to NREAPs, reduced import of biofuels and bioliquids; Scenario 4. Bioenergy targets according to NREAPs, high imports of biofuels and bioliquids. This study also considers the credit for co-products generated from biofuel production. The analysis reveals that the land used in the EU for bioenergy would range between 13.5 Mha and 25.2 Mha in 2020. This represent between 12.2% and 22.5% of the total arable land used and 7.3% and 13.5% of the Utilised Agricultural Area (UAA). In the NREAPS scenario, about 17.4 Mha would be used for bioenergy production, representing 15.7% of arable land and 9.4% of UAA. The increased demand from biofuels would lead to an increased generation of co-products, replacing conventional fodder for animal feed. Considering the co-products, the land used for bioenergy would range between 8.8 Mha and 15.0 Mha in 2020 in the various scenarios. This represent between 7.9% and 13.3% of the total arable land used in the EU and 4.7% and 8.0% of the UAA. In the NREAPS scenario, when co-products are considered, about 10.3 Mha would be used for biofuels, bioliquids and bioenergy production, representing 9.3% of arable land and 5.6% of agricultural land. This study further provides detailed data on the impact on land use in each Member State.

The renewable energy directive (RED) of the EU sets mandatory targets for increasing the use of renewable energy in EU member states by 2020. The RED introduces sustainability criteria for transportation biofuels and other bioliquids in order to ensure that their increasing production does not cause serious environmental and social problems. Bio-oil production through fast pyrolysis is one technology under development. The aim of this paper is to explore whether bio-oil derived from logging residues in Finland meets the GHG performance criteria set by the EU. The pyrolysis reactor is assumed to be integrated with a combined heat and power production plant (CHP). Special attention is paid to uncertainty analysis. An emission reduction target of 60% as compared to the reference fuel is exceeded if the pyrolysis reactor and the CHP plant are considered as separate units, and changes in soil carbon balances are ignored. On the contrary, the particular target is not met using a 20-year time frame for changes in soil carbon balances. The results depend in large measure on the selection of parameters set and the interpretation of the definitions provided in the RED to set the system boundary for the pyrolysis reactor and the CHP plant.

Anaerobic digestion promotes a valorisation of residual and dedicated biomass of agricultural origin. The EU Directive 2009/28/CE mandates a minimum 35% saving in greenhouse gas (GHG) emission for biofuels and bioliquids. National legislations add further limits, such as a 70 km maximum distance in the supply of biomass for energy uses (Short chain support scheme in Italy). In order to assess if the substitution of fossil fuels with biogas complies with such obligations and which are the factors most influencing GHG savings, a simulation study was carried out on a digester fed by maize silage, as many plants built in the frame of the current incentives. A simplified balance was drawn between the CO2 emitted and saved by a 1000 kWel digester aimed for heat and electricity co-generation. The simulation output was the operational radius of feedstock supply and digestate disposal allowing a 35% CO2 saving in a standard scenario. A sensitivity analysis was also run by varying several traits concerning process efficiency, feedstock characteristics, logistic aspects, plus the amount of net thermal energy actually exploited and CH4 and N2O emissions from the stored digestate. The standard scenario involving a 35% CO2 saving allowed an operational radius of 192 km, almost three times as large as the maximum distance prescribed by the Short chain scheme. As an alternative, a 50% CO2 saving was possible at a radius of 70 km. Varying the process, feedstock and logistic traits by ±10% determined variations in the break-even distance associated with a 35% CO2 saving, ranging from ±20% (total solids; volatile solids; anaerobic biogasification potential; biogas CH4 content), to ±15% (energy efficiency), to only ±5% (CO2 emissions in the cropping phase; the carrying capacity of transport means). Actual heat utilisation and digestate GHG emissions, respectively set at 100% and 0% in the standard scenario, are traits with a high uncertainty in the normal practice. Therefore, a respective variation of −50% and +50% was adopted in the sensitivity analysis, determining in both cases a strong reduction (50%) of the break-even distance. In order to overcome the critical points represented by the amount of net thermal energy actually valorised and by GHG emissions from the stored digestate, special care is needed in planning biogas plants, in order to ensure a good utilisation of heat and recycle residual CH4 within the process.

The investigation of upgraded bio-fuels production processes was carried out via the development of efficient catalysts for oxy-organic hydrodeoxygenation (HDO) processes. It was found that Ni–Cu catalysts are more attractive than single Ni catalysts in HDO under mild conditions. Copper facilitates the nickel oxide reduction at temperatures lower than 300 °C. Moreover, copper prevents methanization of oxy-organics at 280–350 °C. The catalyst supports play also a key role in hydrotreatment of oxygen-containing compounds. Screening of catalyst supports showed that CeO 2 and ZrO 2 are most effective in the target processes because of possible additional activation of oxy-compounds on the support surface. The prepared catalysts have non-sulfided nature and can be used for upgrading of bioliquids with a low sulfur content.