Fossil fuel consumption in transportation system and energy-intensive sectors as the principal pillar of civilization is associated with progressive release of greenhouse gases. Hydrogen as a promising energy carrier is a perfect candidate to supply the energy demand of the world and concomitantly reduce toxic emissions. This article gives an overview of the state-of-the-art hydrogen production technologies using renewable and sustainable energy resources. Hydrogen from supercritical water gasification (SCWG) of biomass is the most cost effective thermochemical process. Highly moisturized biomass is utilized directly in SCWG without any high cost drying process. In SCWG, hydrogen is produced at high pressure and small amount of energy is required to pressurize hydrogen in the storage tank. Tar and char formation decreases drastically in biomass SCWG. The low efficiency of solar to hydrogen system as well as expensive photovoltaic cell are the most important barriers for the widespread commercial development of solar-based hydrogen production. Since electricity costs play a crucial role on the final hydrogen price, to generate carbon free hydrogen from solar and wind energy at a competitive price with fossil fuels, the electrical energy cost should be four times less than commercial electricity prices.

Hydrogen production from renewable and sustainable energy resources: Promising green energy carrier for clean development

Many definitions of food security exist, and these have been the subject of much debate. As early as 1992, Maxwell and Smith (1992) reviewed more than 180 items discussing concepts and definitions, and more definitions have been formulated since (DEFRA, 2006). Whereas many earlier definitions centered on food production, more recent definitions highlight access to food, in keeping with the 1996 World Food Summit definition (FAO, 1996) that food security is met when “all people, at all times, have physical and economic access to sufficient, safe, and nutritious food to meet their dietary needs and food preferences for an active and healthy life.” Worldwide attention on food access was given impetus by the food “price spike” in 2007–2008, triggered by a complex set of long- and short-term factors (FAO, 2009b; von Braun and Torero, 2009). FAO concluded, “provisional estimates show that, in 2007, 75 million more people were added to the total number of undernourished relative to 2003–05” (FAO, 2008); this is arguably a low-end estimate (Headey and Fan, 2010). More than enough food is currently produced per capita to feed the global population, yet about 870 million people remained hungry in the period from 2010 to 2012 (FAO et al., 2012). The questions for this chapter are how far climate and its change affect current food production systems and food security and the extent to which they will do so in the future (Figure 7-1).

Food security and food production systems

Plug-in vehicles can behave either as loads or as a distributed energy and power resource in a concept known as vehicle-to-grid (V2G) connection. This paper reviews the current status and implementation impact of V2G/grid-to-vehicle (G2V) technologies on distributed systems, requirements, benefits, challenges, and strategies for V2G interfaces of both individual vehicles and fleets. The V2G concept can improve the performance of the electricity grid in areas such as efficiency, stability, and reliability. A V2G-capable vehicle offers reactive power support, active power regulation, tracking of variable renewable energy sources, load balancing, and current harmonic filtering. These technologies can enable ancillary services, such as voltage and frequency control and spinning reserve. Costs of V2G include battery degradation, the need for intensive communication between the vehicles and the grid, effects on grid distribution equipment, infrastructure changes, and social, political, cultural, and technical obstacles. Although V2G operation can reduce the lifetime of vehicle batteries, it is projected to become economical for vehicle owners and grid operators. Components and unidirectional/bidirectional power flow technologies of V2G systems, individual and aggregated structures, and charging/recharging frequency and strategies (uncoordinated/coordinated smart) are addressed. Three elements are required for successful V2G operation: power connection to the grid, control and communication between vehicles and the grid operator, and on-board/off-board intelligent metering. Success of the V2G concept depends on standardization of requirements and infrastructure decisions, battery technology, and efficient and smart scheduling of limited fast-charge infrastructure. A charging/discharging infrastructure must be deployed. Economic benefits of V2G technologies depend on vehicle aggregation and charging/recharging frequency and strategies. The benefits will receive increased attention from grid operators and vehicle owners in the future.

Review of the Impact of Vehicle-to-Grid Technologies on Distribution Systems and Utility Interfaces

Maize (Zea mays), also called corn, is believed to have originated in central Mexico 7000 years ago from a wild grass, and Native Americans transformed maize into a better source of food. Maize contains approximately 72% starch, 10% protein, and 4% fat, supplying an energy density of 365 Kcal/100 g and is grown throughout the world, with the United States, China, and Brazil being the top three maize-producing countries in the world, producing approximately 563 of the 717 million metric tons/year. Maize can be processed into a variety of food and industrial products, including starch, sweeteners, oil, beverages, glue, industrial alcohol, and fuel ethanol. In the last 10 years, the use of maize for fuel production significantly increased, accounting for approximately 40% of the maize production in the United States. As the ethanol industry absorbs a larger share of the maize crop, higher prices for maize will intensify demand competition and could affect maize prices for animal and human consumption. Low production costs, along with the high consumption of maize flour and cornmeal, especially where micronutrient deficiencies are common public health problems, make this food staple an ideal food vehicle for fortification.

https://nyaspubs.onlinelibrary.wiley.com/doi/epdf/10.1111/nyas.12396

Global maize production, utilization, and consumption

Lead Authors: Marco Bindi (Italy), Sally Brown (UK), Ines Camilloni (Argentina), Arona Diedhiou (Ivory Coast/Senegal), Riyanti Djalante (Japan/Indonesia), Kristie L. Ebi (USA), Francois Engelbrecht (South Africa), Joel Guiot (France), Yasuaki Hijioka (Japan), Shagun Mehrotra (USA/India), Antony Payne (UK), Sonia I. Seneviratne (Switzerland), Adelle Thomas (Bahamas), Rachel Warren (UK), Guangsheng Zhou (China)

Impacts of 1.5°C Global Warming on Natural and Human Systems

Literature review—efficacy of various disinfectants against Legionella in water systems

The prices of some grain commodities more than doubled from March 2007 to March 2008. Increased food prices coincided with increasing global biofuel production, leading to speculation that biofuel production was responsible for the increased food prices. However, over the six-month period after March 2008, grain prices declined by 50% while biofuel production continued to increase. It is not possible to reconcile claims that biofuel production was the major factor driving food price increases in 2007–2008 with the decrease in food prices and increase in biofuel production since mid-2008. The available data suggests that record grain prices in 2008 were not caused by increased biofuel production, but were actually the result of a speculative bubble related to high petroleum prices, a weak US dollar, and increased volatility due to commodity index fund investments. Many factors converged in 2007–2008 to increase food and related commodity prices including increased demand, decreased supply, and increased production costs driven by higher energy and fertilizer costs. Disentangling these factors and providing a precise quantification of their contributions is a difficult, perhaps impossible, task. In 2008, several reports were published by governmental and international agencies that speculated on the cause of increased food prices worldwide. Taken together, the available analyses suggest that biofuel production had a modest (3–30%) contribution to the increase in commodity food prices observed up to mid-2008. The development of second-generation biofuels (e.g., cellulosic ethanol) which use non-food residual biomass or non-food crops should mitigate any future impact of biofuel production on food prices.

Impact of biofuel production and other supply and demand factors on food price increases in 2008

When expressed using volumetric concentrations (as is industry practice), the addition of relatively small amounts of ethanol or methanol (e.g., 10% by volume) to gasoline appears to result in disproportionately large, nonlinear increases in research octane number (RON) and motor octane number (MON). As a result, volumetric “blending octane numbers” are of limited value for estimating the octane number of alcohol−gasoline blends because they vary with alcohol content and base gasoline composition. We show that RON and MON increases with alcohol content are approximately linear when expressed using molar concentrations. Moreover, molar-based blending octane numbers are effectively equal to the octane numbers of the pure alcohols for most base gasolines. A limited dependence on gasoline composition was observed, namely, greater-than-predicted octane numbers for ethanol−gasoline blends with unusually high isoparaffin content. We suggest that octane numbers of methanol−gasoline and ethanol−gasoline blends can...

Octane Numbers of Ethanol− and Methanol−Gasoline Blends Estimated from Molar Concentrations

DDT is reductively dechlorinated to DDD and dehydrochlorinated to DDE; it has been thought that DDE is not degraded further in the environment. Laboratory experiments with DDE-containing marine sediments showed that DDE is dechlorinated to DDMU in both methanogenic and sulfidogenic microcosms and that DDD is dehydrochlorinated to DDMU three orders of magnitude more slowly. Thus, DDD does not appear to be an important precursor of the DDMU found in these sediments. These results imply that remediation decisions and risk assessments based on the recalcitrance of DDE in marine and estuarine sediments should be reevaluated.

https://science.sciencemag.org/content/sci/280/5364/722.full.pdf

Reductive Dechlorination of DDE to DDMU in Marine Sediment Microcosms

Reid vapor pressures (RVPs) were determined for alcohol−gasoline blends containing 5−85% by volume of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, i-butanol (2-methyl-1-propanol), and t-butanol (2-methyl-2-propanol). The results are compared to literature data. Most alcohols form near-azeotropic mixtures with hydrocarbons in gasoline that affect the vapor pressure of the blend in a non-ideal manner. In addition, vapor pressures of dual-alcohol blends with gasoline containing a range of ethanol and 1-butanol volume percentages were determined. We demonstrate a simple method to prepare dual-alcohol−gasoline blends with RVPs indistinguishable from that of the base gasoline. It may be advantageous to use alcohols in addition to ethanol in the form of dual- or multi-alcohol blends as these become available in larger scale in the future.

Sherry A. Mueller

Papers

Literature review—efficacy of various disinfectants against Legionella in water systems

Impact of biofuel production and other supply and demand factors on food price increases in 2008

Octane Numbers of Ethanol− and Methanol−Gasoline Blends Estimated from Molar Concentrations

Reductive Dechlorination of DDE to DDMU in Marine Sediment Microcosms

Vapor Pressures of Alcohol−Gasoline Blends