Biomass energy in Western Europe to 2050

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Biomass energy in industrialised countries—a view of the future

Net energy and cost benefit of transparent organic solar cells in building-integrated applications

Net energy benefits of carbon nanotube applications

Net energy and cost benefit of phthalocyanine and heptamethine transparent photovoltaics in commercial buildings

Core Ideas Annual crops produced a third more biomass and three times as much ethanol as perennials. Perennial crops used half as much nitrogen fertilizer as annual crops. Grain from most annual crops enhanced ethanol production per unit of biomass. Sweet sorghum produced substantially more ethanol than all other crops. Sorghum yielded more biomass and potential ethanol than corn in hot, dry years. Although energy crops could eventually supply a growing portion of cellulosic biofuel feedstocks, long‐term comparisons of annual and perennial crops are rare. An experiment was established in 2007 near Manhattan, KS, to compare biomass productivity and ethanol yield of perennial and annual crops. Perennial crops included three C4 grasses: switchgrass (Panicum virgatum L.), big bluestem (Andropogon gerardii Vitman), and miscanthus (Miscanthus sacchariflorus). Annual C4 crops were corn (Zea mays L.) in two rotations: continuous and rotated with soybean [Glycine max (L.) Merr.]; and five types of sorghum [Sorghum bicolor (L.) Moench]: photoperiod sensitive, sweet, dual purpose (grain and biomass), brown mid‐rib, and grain; all rotated with soybean. Annual crops produced 7 Mg ha−1 yr−1 more biomass than perennial crops throughout 11 yr, with sweet sorghum exceeding 22 Mg ha−1 yr−1, and 12 m3 ha−1 yr−1 of ethanol. Biomass yield of miscanthus approached 14 Mg ha−1 yr−1, essentially the same as for several annual crops but with half as much fertilizer nitrogen. Annual ethanol production from miscanthus and switchgrass was 3.6 m3 ha−1 yr−1, half as much as that of several annual crops that produced similar biomass yields. Big bluestem consistently produced the least biomass and ethanol, less than 7 Mg ha−1 yr−1 and 1.7 m3 ha−1 yr−1, respectively. Rotated corn averaged 7.1 m3 ha−1 yr−1 of ethanol. Eleven years of results indicate that annual corn and sorghum crops as well as perennial grasses such as miscanthus and switchgrass could play a role as potential bioenergy feedstocks in diversified production systems.

Perennial bioenergy crops may enhance microbial community structures due to their extensive root system compared to annual crops. However, the long-term effect of perennial bioenergy crops receiving different N fertilization rates on microbial community structures is not well defined. We evaluated the 11-year effect of perennial bioenergy crops with various N fertilization rates as well as an annual crop with the recommended N rate on soil microbial properties in 2019 and 2020 in the US northern Great Plains. Perennial grasses were intermediate wheatgrass, IWG (Thinopyrum intermedium [Host] Barkworth and Dewey), and switchgrass, SG (Panicum virgatum L.), with N fertilization rates of 0, 28, 56, and 84 kg N ha−1, and the annual crop was spring wheat, WH (Triticum aestivum, L.) with 80 kg N ha−1. The total fungal phospholipid fatty acid (PLFA) proportion and fungal/bacterial ratio were significantly lower under annual spring wheat than perennial grass (SG). Increased N fertilization rate linearly increased Gram-positive bacterial PLFA proportions and the Gram-positive/Gram-negative bacterial ratio for IWG in 2020 but decreased the PLFA proportions of arbuscular mycorrhizal fungi (AMF) for both perennial bioenergy crops in all years. The proportions of AMF neutral lipid fatty acid and Gram-negative bacterial PLFA were greater for SG (0.432 and 0.271, respectively) than IWG (0.339 and 0.258, respectively), but actinomycetes and the Gram-positive/Gram-negative bacterial ratio were greater for IWG (0.160 and 1.532, respectively) compared to SG (0.152 and 1.437, respectively). Microbial community structures varied with perennial bioenergy crops, N fertilization rates, and perennial vs. annual crops. This study showed how perennial crops favored fungal growth and how annual crops enhanced bacterial growth impacting soil biological health.

Carbon and water dynamics of a perennial versus an annual grain crop in temperate agroecosystems

Evaluation of the environmental performance of sc-Si and mc-Si PV systems in Korea

<p>Bioenergy crops are expected to provide biomass to replace fossil resources and reduce greenhouse gas emissions. In this context, their effect on soil carbon sequestration is of primary importance. There is a wide range of candidate crops including perennial C4 crops or annual crops but their impact on soil organic carbon (SOC) stocks remain very uncertain as shown by the wild variability in published experimental results.</p><p>In this study, we measured the changes in SOC stocks under perennial (miscanthus and switchgrass), semi-perennial (fescue and alfalfa) and annual (triticale and sorghum or maize) bioenergy crops managed with two N fertilisation rates. The experiment called “Biomass & Environment” is located in northern France on a deep loamy soil (Haplic Luvisol) and was set up in 2006. The soil was sampled at the start of the experiment, in 2011-2012 and again in 2018 (0-60 cm, 5 layers). SOC stocks were calculated at equivalent soil mass and δ<sup>13</sup>C was systematically measured and used to calculate changes in new and old SOC stocks. In 2018, the SOC distribution in different soil particle-size fractions was also characterized for some treatments.</p><p>After 12 years, there was a large increase in SOC concentration (+7.6 g kg<sup>-1</sup> on average) under perennial crops in the surface layer (≈ 0-5 cm) but a slight decrease in deeper layers. Changes in δ<sup>13</sup>C also showed that more than half of the new SOC accumulated in the surface layer. In addition, the additional SOC storage in the first layer was found in coarse organic fractions (50-200 and 200-2000 μm) but also in the more stabilised 0-50 μm fraction. SOC concentration under semi-perennial crops increased in the two first layers (≈ 0-20 cm), from 10.2 g kg<sup>-1</sup> in 2006 to 11.6 g kg<sup>-1</sup> in 2018 on average and slightly decreased below. Under annual crops, a decrease in SOC concentration was observed in all layers and particularly in the third layer (≈ 20-33 cm). There was no significant effect of the N fertilisation. Over the old ploughed layer (≈ 0-33 cm), SOC stocks increased between 2006 and 2018 under perennial and semi-perennial bioenergy crops (by 3 and 2 t C ha<sup>-1</sup> on average respectively) and decreased by 7 t C ha<sup>-1</sup> on average under annual crops.</p><p>This study show that different bioenergy crops can have contrasted impacts on SOC stocks but also on SOC distribution in the soil profile.</p>

Residues remaining after the harvest of crop and forestry products are being proposed as a substantial energy source for the nation. An estimated 22 percent of the residues might be utilized, providing a renewable source of high-grade energy with the potential of supplying 1 percent of the current U.S. gasoline consumption as ethanol or 4 percent of the total electrical energy used. These net energy benefits are limited by high energy costs to collect, transport, and process the residues. Environmental threats include soil erosion, water runoff, and nutrient loss.

A field study was conducted during rabi season of 2013–14 in ten farmers’ fields of Joladarasi, K. Veerapur and Chellagurki villages of Bellary district in Karnataka, India to evaluate the improved chickpea variety JG11 with micronutrients application on yield, economics and energy flow in Vertisols. Adopting JG11 chickpea variety and application of micronutrient mixture at 5 kg ha-1 during winter season increased the grain and straw yields by 26% and 31%, respectively over A1variety cultivated by farmers without application of micronutrients. Application of micronutrients alone produced 9% higher yields in JG11 and A1. Greater gross and net returns with higher B:C ratio was observed with cultivation of JG11chickpea variety and application of micronutrients. Energy flow results revealed that smaller input energy through micronutrients application and cultivation of JG11variety produced higher total output energy and net energy benefit (NEB). The NEB per ha varied from 15966 MJ in control plots to as high as 22546 MJ in micronutrients applied plots with JG11 cultivation. Greater average energy use efficiency (EUE) of 3.57, energy productivity (EP) of 0.106 and lesser specific energy (SE) of 9.62 were observed with JG11 cultivation and applied with micronutrients compared to the control plots. Correlation studies indicated the positive and significant correlation of grain yield with net returns, B:C ratio, NEB, EUE and EP. In conclusion higher chickpea yields, profit and energy gains can be achieved by cultivating JG11 variety with micronutrients application at 5 kg ha-1 in the Vertisols of Bellary region during winter season.

Bioenergy crops are expected to provide biomass to replace fossil resources and reduce greenhouse gas emissions. In this context, changes in soil organic carbon (SOC) stocks are of primary importance. The aim of this study was to measure changes in SOC stocks in bioenergy cropping systems comparing perennial (Miscanthus × giganteus and switchgrass), semi‐perennial (fescue and alfalfa), and annual (sorghum and triticale) crops, all established after arable crops. The soil was sampled at the start of the experiment and 5 or 6 years later. SOC stocks were calculated at equivalent soil mass, and δ13C measurements were used to calculate changes in new and old SOC stocks. Crop residues found in soil at the time of SOC measurements represented 3.5–7.2 t C ha−1 under perennial crops vs. 0.1–0.6 t C ha−1 for the other crops. During the 5‐year period, SOC concentrations under perennial crops increased in the surface layer (0–5 cm) and slightly declined in the lower layers. Changes in δ13C showed that C inputs were mainly located in the 0–18 cm layer. In contrast, SOC concentrations increased over time under semi‐perennial crops throughout the old ploughed layer (ca. 0–33 cm). SOC stocks in the old ploughed layer increased significantly over time under semi‐perennials with a mean increase of 0.93 ± 0.28 t C ha−1 yr−1, whereas no change occurred under perennial or annual crops. New SOC accumulation was higher for semi‐perennial than for perennial crops (1.50 vs. 0.58 t C ha−1 yr−1, respectively), indicating that the SOC change was due to a variation in C input rather than a change in mineralization rate. Nitrogen fertilization rate had no significant effect on SOC stocks. This study highlights the interest of comparing SOC changes over time for various cropping systems.

Purpose – This study aims to investigate the impact of total primary energy consumption and CO2 emissions on the economic development in 16 emerging countries. Design/methodology/approach – The panel model was used taking the period 1980-2008. Findings – The results showed that a long-run relationship is present between total primary energy consumption, CO2 emission, and economic development in the countries under investigation. It was also found that both total primary energy consumption have a positive causal relationship with the economic development and other economic aspects playing an important role in achieving high economic performance with the consequence of higher pollution. Practical implications – The main recommendation of this study is to increase their investment and government spending on green energy projects to increase the share of green energy out of their total energy consumption. This can be considered a good solution for their energy woes. Originality/value – Different from the previous studies, it was also found that total primary energy consumption have a positive causal relationship with the economic development and other economic aspects playing an important role in achieving high economic performance with the consequence of higher pollution. In addition, there are a number of countries that had not investigated before.

Staple crops, which have large amounts of carbohydrates, proteins, and/or fats, provide the bulk of calories in people's diets. Perennial plants, which can be productive for many years without the need for replanting, can produce staple foods and environmental benefits, but their agronomic and nutritional properties haven't been considered synthetically in comparison to annual staples. Here we offer a framework to classify perennial staple crops according to their nutritional categories and cultivation status. We assemble literature to report on the yield potential of 51 perennial staple crops, only 15 of which are well-characterized in existing global datasets. We show the extent and distribution of perennial staple crop production in relation to annual crop types, calculate the carbon stocks they hold, and analyze their nutritional content for three macronutrients and nine micronutrients. We found that most perennial staple crops are regional crops (not globally traded) that grow in the subtropics to tropics. At least one perennial staple crop in each of the five nutritional categories has yields over 2.5 t/ha, in some cases considerably higher, competitive with and in many cases exceeding those of nutritionally comparable annual staples. Perennial staple crops only comprise ~4.5% of total cropland. They hold a modest ~11.4 GtC above and below ground, less than one third of the anthropogenic carbon-equivalent emissions for the year 2018, but more than the ~9 GtC held by the same amount of annual cropland. If linear growth in land under perennial staple production continues to 2040, and replaces only annual cropland, an additional ~0.95 GtC could be sequestered. Many perennial crops also had competitive macronutrient density and yield (per unit area) compared to annual staples; moreover, specific perennial staples are abundant in specific micronutrients, indicating that they can be a nutrient-dense part of diets, unlike the most ubiquitous annual staple crops (corn, wheat, rice) that do not appear in the top 85th percentile for any of the nine micronutrients analyzed. Transition of land and diets to perennial staple crops, if judiciously managed, can provide win-win solutions for both food production and ecosystems.