Bioenergy Plants Research Articles

ECONOMIC EFFECTIVENESS OF INVESTMENT IN BIOENERGETIC CULTURE GROWING IN THE ZONES OF FOREST OF UKRAINE

Introduction. One of the most promising areas of renewable energy development is the use of biomass energy. It contributes to the economy of traditional fuels and does not increase the global greenhouse effect. However, insufficient economic efficiency of obtaining energy from biomass under the current conditions necessitates the state's "paternalism" to the bioenergy industry. Purpose. The article aims to carry out an economic assessment of the effectiveness of investing in the cultivation of highly productive energy crops (giant miscanthus and energy willow) using modern technologies under the conditions of the Ukrainian forest-steppe. Method. The research was conducted during 2012-2016 on the basis of experimental energy plantations in Ternopil, Volyn and Kyiv oblasts. The assessment of the effectiveness of investment in bioenergy crops is based on a set of criteria: net discounted profit (NPV), investment profitability index (PI), internal rate of return (IRR), discounted payback period (DPP). Results. It has been established that on plantations of willow, the volume of dry biomass on average over the five-year period of research amounted to 27,3 t · ha-1, and to the miscanthus - 25,3 t · ha-1. Accordingly, the energy output per unit area was somewhat higher in energy willow (573.3 GJ · ha-1 versus 516.2 GJ · ha-1). Willow and miscanthus are characterized by high-energy coefficients compared with other bioenergy crops, which can reach values 54.3 and 55. It indicates the significant energy efficiency of investing in the cultivation of these crops. The analysis of the sensitivity of bioenergy projects has found out that the most significant NPV investment in the plantation of the miscanthus can be influenced by the volatility of the productivity of the crop, the price of biofuels and planting material, and for the willow plantation - fluctuations in the yield of biomass, its price and discount rate. The estimation of the investment efficiency in the bio-energy plantations of the miscanthus and willows has revealed the need to work out state programs of financial support for the creation of plantations of bioenergy crops and legislative mechanisms for their implementation.

An Investigation into the Effects of Risks and Risk Management of Bioenergy Projects

Risk is an important component in project management and plays a key role in securing project finance in renewable energy sector. As the amount of companies making investment in renewables grow, so do the inherent risks in the different stages of the projects. This study seeks to obtain information, which will help examine the risks associated with bioenergy projects and the methods used to identify, manage and reduce them. The study is conducted in the form of a survey with data being gathered using questionnaires. The results of this study shows that although when taken as a whole, policy and regulatory risk is the most significant risk associated with renewable energy projects, financial and environmental risks are the most important risks related to bioenergy projects. These suggest that financing, which is one of the key elements in maintaining, building and operating bioenergy plants faces substantial obstacles in managing it risks. Moreover, the study shows that insurance coverage and company-based risk management functions are the most important risk management tools for managing financial and environmental risks respectively. It is recommended that governments should strive to include bioenergy stakeholders in their policy development in order to integrate industry’s perspective into the process.

SUSTAINABLE FOREST-BASED BIOENERGY IN EURASIA

This study analyzes the Russian forest biomass-based bioenergy sector. It is shown that presently - although given abundant resources - the share of heat and electricity from biomass is very minor. With the help of two IIASA models (G4 M and BeWhere), future green-field bioenergy plants are identified in a geographically explicit way. Results indicate that by using 3.78 Mt (or 6.16 M m3), twice as much heat and electricity than is presently available from forest biomass could be generated. This amount corresponds to 3.3% of the total annual wood removals or 12% of the annually harvested firewood, or about 11% of illegal logging. With this amount of wood, it is possible to provide an additional 444 thousand households with heat and 1.8 M households with electricity; and at the same time to replace 2.7 Mt of coal or 1.7 Mt of oil or 1.8 G m3 of natural gas, reducing emissions of greenhouse gases from burning fossil fuels by 716 Mt of CO2-equivalent per year. A multitude of co-benefits can be quantified for the socioeconomic sector such as green jobs linked to bioenergy. The sustainable sourcing of woody biomass for bioenergy is possible as shown with the help of an online crowdsourcing tool Geo-Wiki.org for forest certification.

Redesigning a bioenergy sector in EU in the transition to circular waste-based Bioeconomy-A multidisciplinary review

The transformation of the energy systems encompasses technological, societal, cultural, economic, and environmental aspects and calls for a more important role for citizens and communities. Bioenergy systems are subjects to legal, technical, environmental, economic, and social settings. At the regional level, bioenergy can incorporate agricultural traditions and offer waste-management solutions. Many are the stakeholders, with different perceptions and sometimes, conflictual interests. This study is a multidisciplinary, comprehensive review of recently published papers, on legal, technical, economic, and environmental layers of the bioenergy. It highlights the role of bioenergy in the transition to a Circular waste-based Bioeconomy. Three dimensions of sustainability (environmental, economic, and social) were discussed and some thermodynamic (energy, exergy, emergy) and environmental indicators applied to bioenergy systems, were cited. Findings conclude that in the context of Circular Bioeconomy, global bioenergy sector may face challenges, due to the new demand for biomaterials from the same sources. Bioenergy sustainable pathways should be selected at the base of high efficiency, towards closing loops and in the concept of cascade and integrated biorefineries. At the regional level, bioenergy systems may be integrated with the cascade biorefinery models or can offer waste management solutions by stand-alone, tailor-made decentralized systems. In redesigning the bioenergy sector, local knowledge, public health, and community's resilience should not be neglected, while social-environmental benefits should be considered in addressing the viability of bioenergy plants. Social acceptance can be improved by a better understanding of the scientific and technical issues and by developing a broader consciousness of the planet and life.

Precision subsurface drip irrigation increases yield while sustaining water-use efficiency in Mediterranean poplar bioenergy plantations

Abstract Bioenergy production in poplar Short Rotation Coppice plantations (SRC) is strongly limited in drought prone areas due to the high crop water requirement. Appropriate scheduling of subsurface drip irrigation (SDI) could be a practice for ensuring adequate biomass production with reduced water inputs while maintaining high water-use efficiency. We tested SDI in a commercial SRC cultivated with the hybrid poplar clone Monviso under Mediterranean environmental conditions. We applied two irrigation treatments during the summer season, i.e. a control irrigation treatment with an average amount of 115 mm (CI) and a double irrigation treatment for an average amount of 239 mm (DI) over two growing seasons of the second triennial rotation. We analyzed tree growth, yield, shoot diameter increments (PDI) and carbon isotope composition (δ13C) in both litterfall and tree-rings. We also measured soil moisture at 10, 20, 30, 40, 60 and 100 cm soil depths to explore more efficient irrigation scheduling. The results showed that CI and DI recovered 23–49 and 43–90% of the April-September precipitation deficit over the two growing seasons, respectively. We observed higher yield increments in DI compared to CI, with mean yields of 11.4 and 20.4 Mg ha−1 for CI and DI respectively. DI significantly affected biomass quality (biomass allocated to shoots with greater dimensions); however, stem moisture and shoot basal density did not significantly change after the irrigation treatments. δ13C in tree-rings showed non-significant differences after CI and DI applications for two growing seasons. Congruently, the analysis of litterfall δ13C did not show significant differences comparing the two irrigation regimes. Thus, the isotopic analyses indicate a constancy of intrinsic water-use efficiency (iWUE), irrespective of the watering regime. We found significant positive linear relationships (R2 from 0.89 to 0.96) between PDI and soil moisture at 30 and 40 cm soil depths for both CI and DI when compared to the rest of the monitored soil layers. We suggest, therefore, the monitoring of soil moisture at 30–40 cm as a reference for scheduling irrigation practices during the growing season. In conclusion, DI significantly increased the overall plantation yield while sustaining the same iWUE observed in the deficit irrigation regime (CI).

An optimization study of a palm oil-based regional bio-energy supply chain under carbon pricing and trading policies

Biomass residues due to their low bulk density typically require frequent transportation from biomass plantations in rural areas to conversion bio-energy power plants. This issue contrasts with environmental protection strategies, especially when power plants are facing different carbon reduction policies that enforce them to emit less than a given specific carbon amount. Although several researchers have investigated bio-energy supply chains concerning environmental policies, the majority of studies have been devoted to strategic decisions over a single planning period. This paper presents a multi-period bio-energy supply chain under carbon pricing (carbon tax) and carbon trading (cap-and-trade) policies at the tactical planning level. A mixed-integer linear programming model was adopted to optimize the proposed regional oil-palm biomass-to-bio-energy supply chain planning model. The numerical results indicate that when carbon pricing is in place when carbon tax increases linearly, carbon emissions’ reductions have a nonlinear trend, whereas both cost increase and carbon emissions’ reductions have a relatively upward trend in the carbon trading scheme. This paper also presents the sensitivity analysis of the proposed model regarding cost, emissions’ generation and supply chain performance. Finally, the paper recommends several significant practical implications and policy-making insights for managers and policymakers.

Forest biomass power plant installation scenarios

Modern society is dependent on energy use in several ways. Due to environmental and strategic issues, biomass is emerging as an alternative for the diversification of energy sources worldwide. Forest biomass is abundant at Minas Gerais, Southeastern Brazil, but its usage for power generation remains a niche pathway yet to be exploited. The geographical planning of biomass energy production is of the utmost importance to guarantee the distribution of cheap and clean energy. This study presents a GIS-based methodology for prospecting forest biomass power plants in the Minas Gerais state, Brazil. First, applying fuzzy logic, suitable zones for biomass activity were identified by combining various environmental and social factors, along with the State road network infrastructure. For the second step, a location-allocation model was generated, which considered only the most suitable areas for plant development, spatial availability of raw materials, and the existing road network. Various scenarios were simulated with different numbers of bioenergy plants, using a capacitated location-allocation model, in order to consume half of the state forest biomass stock. The best locations and the optimum number of power plants were found by minimizing transport distances of raw material to the factories. This proposed methodology could be adapted for use in other countries.

Envisioning and implementing wood-based bioenergy systems in the southern United States: Imaginaries in everyday talk

Bioenergy development in the Southern United States was said to promise a future with renewable energy, energy independence, expanded wood markets, and rural development. We view this vision of wood-based bioenergy as a sociotechnical imaginary involving a future where energy and rural development needs are met using sustainably-harvested local resources. While this vision has led to bioenergy development, it has not been universally shared and counter-narratives have circulated. Local people receive multiple messages and have diverse experiences with bioenergy, which affect how they interpret the imaginary. We use cultural models to examine the extent and ways that elements of the national bioenergy imaginary occurred in everyday talk in three communities where bioenergy plants had recently been developed. We show how local people articulated, responded to, and altered the national bioenergy imaginary while simultaneously drawing on diverse experiences, values, and other important social discourses. While local people had limited opportunities to alter the national imaginary, they contested and diluted it in ways that indicated that they were not fully in support of the imaginary and the development it spurred. Ultimately, this may hinder bioenergy development.

Crop residue recycling for economic and environmental sustainability: The case of India

Abstract India is one of the key producers of food grain, oilseed, sugarcane and other agricultural products. Agricultural crops generate considerable amounts of leftover residues, with increases in food production crop residues also increasing. These leftover residues exhibit not only resource loss but also a missed opportunity to improve a farmer’s income. The use of crop residues in various fields are being explored by researchers across the world in areas such as textile composite non-woven making processes, power generation, biogas production, animal feed, compost and manures, etc. The increasing trend in addition of bio-energy cogeneration plants, increasing demand for animal feedstock and increasing trend for organic agriculture indicates a competitive opportunity forcrop residue in Agriculture. It is to be noted that the use of this left over residue isoften not mutually exclusive which makes measurement of its economic value more difficult.For example, straw can be used as animal bedding and thereafter as a crop fertilizer. In view of this, the main aim of this paper envisaged to know about how much crop residue is left unutilized and how best they can be utilized for alternative purposes for environmental stewardship and sustainability. In this context, an attempt has been made to estimate the total crop residue across the states and its economic value though data available from various government sources and a SWOT analysis performed for possible alternative uses of residue in India. This paper also discusses the successful case studies of India and global level of use of crop residues in economic activities. Over all 516 Mtonnes of crop residue was produced in 2014-15 in India among which cereals were the largest producer of crop residue followed by sugarcane. The energy potential from paddy rice straw crop residue was estimated as 486,955 megawatt for 2014-15 and similarly for coarse cereals it was 226,200megawatt.

Remote Sensing of Above-Ground Biomass

Accurate measurement and mapping of biomass is a critical component of carbon stock quantification, climate change impact assessment, suitability and location of bio-energy processing plants, assessing fuel for forest fires, and assessing merchandisable timber.[...]

Characterization of a novel thermo-stable lipase from endophyte Pseudomonas putida in Pistacia chinensis Bunge

A novel lipolytic enzyme-producing endophytic strain PC2 was successfully isolated from the seeds of an ideal bioenergy plant Pistacia chinensis Bunge. Based on the analysis of morphology and 16S rRNA sequence, bacterial strain PC2 was identified as a subspecies of Pseudomonas putida, therefore named as P. putida PC2. Whole-genome sequencing showed PC2 contained a 1224-nucleotide lipase gene (named lip-PC2) predicted to encode a 407-amino-acid protein. Purified lipases from both the original PC2 strain and heterologously expressed Escherichia coli were nearly 50 kD with specific activity of 9.48 U/mL. LIP-PC2 displayed the maximal activity at 50°C or pH 8.0, and maintained above 80% relative activity in the range of from 40 to 60°C or pH in the range of from 6.0 to 8.0, indicating thermostable and alkaline properties. Enzyme activity was enhanced by Mg2+, Na+ and Mn2+, but strongly inhibited by Cu2+, Zn2+ Co2+, EDTA as well as organic solvents and surfactants. Additionally, the analysis of amino acid sequence and structure indicated that LIP-PC2 was a novel member belonging to family I.3 of bacterial lipolytic enzymes and its catalytic triad was consisted of Ser-200, Asp-342 and His-374.

Fuel for thought

Fuel for thought

Characterisation and valorisation of biomass waste as a possible addition in eco-cement design

The use of biomass to generate energy has grown significantly in recent years in response to social awareness and renewable-based sustainability policies geared to conserving the environment and eradicating coal as a raw material in electric power production. The bioenergy industry also gives rise to by-products or waste, however, most of which are presently deposited in landfills. This study aims to characterise three types of biomass waste from Spanish bioenergy plants with a view to their valorisation as additions in the design of new eco-efficient cements with a lower clinker content. The focus is on the pozzolanicity of this waste and the hydration products formed in the biomass waste/Ca(OH)2 system. The findings show that irrespective of their nature, all three types of waste are apt for use in the cement industry or in concrete as supplementary cementitious materials.

Profitability potential for Pinus taeda L. (loblolly pine) short-rotation bioenergy plantings in the southern USA

The use of renewable resources is important to the developing bioenergy economy and short rotation woody crops (SRWC) are key renewable feedstocks. A necessary step in advancing SRWC is defining regions suitable for SRWC commercial activities and assessing the relative economic viability among suitable regions. The goal of this study was to assess the potential profitability, based on obtainable yield and economic feasibility; of Pinus taeda L. (loblolly pine) across 13 states of the southern USA. A process-based growth model, 3PG, produced estimated yields of P. taeda in terms of mean annual increment (MAI) that were evaluated as internal rate of return on investment (IRR) and land expectation value (LEV). Coastal areas (southeast Texas, southwest Louisiana, and northern Florida) have the highest potential MAI production ranging from 13.7 to 18.9Mgha−1yr−1. LEVs ranged from −1126 to 3111$ha−1 on upland sites and −2261 to 2341$ha−1 on lowland sites. IRR ranged from −0.3% to 14.2% on uplands and −2.9% to 10.4% on lowlands. On soils of the same textural class, LEV and IRR were higher on uplands relative to lowlands given lower site preparation costs, although the projected yield from upland soils are generally lower than those from lowland soils. The highest LEV and IRR were in northern Florida, southern Alabama, southern Georgia, and southern South Carolina. The lowest LEV and IRR were in Virginia and northern North Carolina. Spatially categorizing suitable lands in biological and economic terms can use geographic information system technology to advantage in combination with societal considerations to begin to answer sustainability questions as well as identify suitable sites for bioenergy plantations.

Green-house gas mitigation capacity of a small scale rural biogas plant calculations for Bangladesh through a general life cycle assessment.

Calculations towards determining the greenhouse gas mitigation capacity of a small-scale biogas plant (3.2 m3 plant) using cow dung in Bangladesh are presented. A general life cycle assessment was used, evaluating key parameters (biogas, methane, construction materials and feedstock demands) to determine the net environmental impact. The global warming potential saving through the use of biogas as a cooking fuel is reduced from 0.40 kg CO2 equivalent to 0.064 kg CO2 equivalent per kilogram of dung. Biomethane used for cooking can contribute towards mitigation of global warming. Prior to utilisation of the global warming potential of methane (from 3.2 m3 biogas plant), the global warming potential is 13 t of carbon dioxide equivalent. This reduced to 2 t as a result of complete combustion of methane. The global warming potential saving of a bioenergy plant across a 20-year life cycle is 217 t of carbon dioxide equivalent, which is 11 t per year. The global warming potential of the resultant digestate is zero and from construction materials is less than 1% of total global warming potential. When the biogas is used as a fuel for cooking, the global warming potential will reduce by 83% compare with the traditional wood biomass cooking system. The total 80 MJ of energy that can be produced from a 3.2 m3 anaerobic digestion plant would replace 1.9 t of fuel wood or 632 kg of kerosene currently used annually in Bangladesh. The digestate can also be used as a nutrient rich fertiliser substituting more costly inorganic fertilisers, with no global warming potential impact.

Functional differences in the microbial processing of recent assimilates under two contrasting perennial bioenergy plantations

Land use change driven alteration of microbial communities can have implications on belowground C cycling and storage, although our understanding of the interactions between plant C inputs and soil microbes is limited. Using phospholipid fatty acids (PLFA's) we profiled the microbial communities under two contrasting UK perennial bioenergy crops, Short Rotation Coppice (SRC) willow and Miscanthus Giganteus (miscanthus), and used 13C – pulse labelling to investigate how recent carbon (C) assimilates were transferred through plant tissues to soil microbes. Total PLFA's and fungal to bacterial (F:B) ratios were higher under SRC willow (Total PLFA = 47.70 ± 1.66 SE μg PLFA g−1 dry weight soil, F:B = 0.27 ± 0.01 SE) relative to miscanthus (Total PLFA = 30.89 ± 0.73 SE μg PLFA g−1 dry weight soil, F:B = 0.17 ± 0.00 SE). Functional differences in microbial communities were highlighted by contrasting processing of labelled C. SRC willow allocated 44% of total 13C detected into fungal PLFA relative to 9% under miscanthus and 380% more 13C was returned to the atmosphere in soil respiration from SRC willow soil compared to miscanthus. Our findings elucidate the roles that bacteria and fungi play in the turnover of recent plant derived C under these two perennial bioenergy crops, and provide important evidence on the impacts of land use change to bioenergy on microbial community composition.

Influence of endophytic root bacteria on the growth, cadmium tolerance and uptake of switchgrass (Panicum virgatum L.).

This study aimed to evaluate the effect of five cadmium-tolerant endophytic plant growth-promoting bacteria (PGPB) strains on the biomass and cadmium tolerance, and accumulation of the bioenergy plant switchgrass (Panicum virgatum L.) under cadmium (Cd)-contaminated conditions. Five bacterial strains (Bj05, Le14, Ps14, So02 and Bo03) that could tolerate up to 2000μmoll-1 CdCl2 with a high Cd-binding capacity were isolated from plants grown in Cd-contaminated soil. These strains could promote the growth of switchgrass in the presence of 20μmoll-1 CdCl2 . Under Cd stress, both the root and shoot length and biomass in two switchgrass cultivars, Alamo and Cave-in-Rock (CIR), increased significantly after treatment with PGPB (P ˂ 0·05). Of the five PGPB strains, Bj05 and Le14 most effectively alleviated the Cd-induced growth inhibition of Alamo plants. Interestingly, the five PGPB strains increased Cd tolerance and decreased the accumulation and translocation factor (TF) of Cdin switchgrass when grown in the presence of 20μmoll-1 CdCl2 . The Cd concentrations in roots and shoots of Alamo and CIR plants were significantly reduced (P˂0·05) compared with noninoculated plants. By 16S rRNA sequencing, these PGPB strains were classified as Pseudomonas putida Bj05, Pseudomonas fluorescens Ps14, and Enterobacter spp. Le14, So02 and Bo03. Inoculation with PGPB protects plants from the inhibitory effects of Cd, improves plant growth and decreases Cd concentration. These observations suggest that these strains could be used to promote growth and lower the bioavailability of Cd in switchgrass. These strains are potential candidates for the development of low Cd-accumulating switchgrass, particularly in areas of Cd contamination and pollution, and could be used efficiently for the bioremediation of contaminated soil.

Relationship between soil chemical composition and potential fuel quality of biomass from poplar short rotation coppices in Portugal and Belgium

Soil-woody biomass interactions are relevant for the productivity of bioenergy plantations and biomass quality. In this context, the main objective of this study was to evaluate and to quantify possible relationships between chemical variables of the soil and the produced biomass through a multivariate approach. This latter approach allows to overcome the complex issue of multi-collinearity among variables. Soil and woody biomass samples were collected from two poplar short rotation coppices in Santarém (Portugal) and in Lochristi (Belgium). The results from the analyses of those samples were integrated into three databases with soil, woody biomass and site plots as cases, and 23 physical and chemical properties as variables. The databases were subjected to a multivariate sequence of calculations, which included correlation, principal components, factorial and hierarchical clustering analyses. The calculations showed that the site plots and the woody biomass of genotypes in Lochristi were more homogeneous as compared to Santarém; they also confirmed the high interconnection between soil and woody biomass variables. The higher heating value of the woody biomass correlated well with the soil concentrations of P2O5, Mg, Ca, Na and organic C. Linear equations related the higher heating value to the most important soil and woody biomass variables. Finally, the results suggest that the annual monitoring of soil and biomass in SRC systems should be performed to optimize both productivity and woody biomass quality as a fuel.

Economic Analysis of Combined Geothermal and CO2 Storage for Small-Size Emitters

The CO2-DISSOLVED project proposes a different approach to CO2 Capture and storage by focusing on a cheaper solution targeting small industrial emitters such as a bio–energy plant. The capture part of the CO2-DISSOLVED system, designed and patented by Pi-Innovation [1] basically consists in injecting the fumes into a special storage well where CO2 would dissolve into the water within the well prior to its injection in a deep saline aquifer. This capture strategy makes mandatory to use a water/brine movement. Therefore, the CO2-DISSOLVED concept consists in coupling this CO2-brine dissolution technology to a geothermal loop with a hot brine production well for heat extraction and an injection well for re-injecting the cooled brine saturated with CO2[2]. This loop provides storage and heat for the processes of the emitting plant. Due to the limited amount of CO2 that can be totally dissolved in the geothermal loop (about 10 to 15 ton/h, typically), the CO2-DISSOLVED concept is well suited for small-size emitters.For a sugar beet refinery [3], the BECCS approach provides excellent environmental results with negative emission due to the production of the bioethanol. However, on the economic standpoint, the performance of the project was poor due to the small volume of emission stored that could not offset the CAPEX.Applying the CO2-DISSOLVED approach to the same plant, i.e. coupling CO2 capture with a geothermal loop, enables significant reductions both on the emissions, between 25 to 60%, and on the energy, between 5 to 30% depending on the assumptions compare to the no CCS case (i.e. currently operating conditions). As compared to the BECCS reference case (Laude et al., 2011), the CO2-DISSOLVED approach can achieve an emission reduction between 15 to 50% while the corresponding non-renewable energy consumption can be reduced by 5 to 30%.The CO2 emission reduction is bigger than the non-renewable energy consumption reduction because the first stages of compression for the CO2-DISSOLVED approach require significant compression energy. On the economic standpoint, to reach an emission reduction from 15% to 50% higher, the BECCS approach costs between 100% and 350% more than the CO2-DISSOLVED approach.The cost per ton of CO2 saved (stored + not emitted by the combustion due the use of geothermal energy) for the range of performance of the project is between 39 and 72 €2015/ton saved over a 30 year lifetime (at 6% WACC). This is still higher than the current CO2 price level in Europe. However, the project reduced natural gas consumption via the geothermal loop which significantly improves the economics of the project.The probabilistic distribution of the Net Present Value of this project ranges between – 5 MM€2015 and +20 MM€2015 with an average value of 8 MM€2015. This wide range is linked to the wide range of CO2 prices considered in the model (5 to 50 €/ton of CO2). It shows that the project can be reasonably profitable at 6% discount rate (WACC) for the average scenario. Considering the best efficiency scenario, the project can be profitable in the current market conditions.It is also interesting to mention that from 12.5 €/ton onward, the CO2-DISSOLVED project is worth doing as compared to a pure geothermal project. This shows that this approach should be seriously envisaged for future geothermal projects provided local conditions make the project technically feasible (CO2 sources and storage integrity).Even if this study is at a conceptual stage, the CO2-DISSOLVED approach seems really worth investigating for small CO2 sources. It can contribute to reduce CO2 emission at significantly lower cost than CCS. It is noteworthy to mention that very specific conditions have to be fulfilled to be able to develop a CO2-DISSOLVED project, such as CO2 availability, and subsurface favorable context (geothermal and storage). However, a previous study [4] demonstrated the existence of an actual potential of application of this technology in France, Germany, and the U.S.A.

Overexpression of Populus × canescens isoprene synthase gene in Camelina sativa leads to alterations in its growth and metabolism

Isoprene (2-methyl-1,3-butadiene) is a hemiterpene molecule. It has been estimated that the plant kingdom emits 500–750 million tons of isoprene in the environment, half of which results from tropical broadleaf trees and the remainder from shrubs. Camelina (Camelina sativa (L.) Crantz) is an emerging bioenergy plant for biodiesel. In this study, we characterized isoprene formation following a diurnal/nocturnal cycle in wild-type Camelina plants. To understand the potential effects of isoprene emission on this herbaceous plant, a gray poplar Populus×canescens isoprene synthase gene (PcISPS) was overexpressed in Camelina. Transgenic plants showed increased isoprene production, and the emissions were characterized by a diurnal/nocturnal cycle. Measurements of the expression of six genes of the plastidial 2-C-methyl-d-erythriol-4-phosphate (MEP) pathway revealed that the expression patterns of three key genes were associated with isoprene formation dynamics in the three genotypic plants. Conversely, dissimilar gene expression levels existed in different genotypes, indicating that dynamics and variations occurred among plants. Moreover, transgenic plants grew shorter and developed smaller leaves than the wild-type and empty vector control transgenic plants. Photosynthetic analysis showed that the CO2 assimilation rate, intracellular CO2 concentration, mesophyll conductance and contents of chlorophylls a and b were similar among PcISPS transgenic, empty-vector control transgenic, and wild-type plants, indicating that the transgene did not negatively affect photosynthesis. Based on these results, we suggest that the reduced biomass was likely a trade-off consequence of the increased isoprene emission.