Floating offshore wind is being considered in northern California as indicated by the Bureau of Ocean Energy Management's issuance of a lease consideration in the Humboldt Call Area. Humboldt County offers access to this enormous resource, but local electric load and transmission are limited. The potential impacts of offshore wind generators at three different scales were studied using a regional grid model of Humboldt County. Offshore wind generation was calculated using modeled wind speed data and 12-MW turbine specifications and integrated with projected load and historical generation. Offshore wind farms deployed in the Humboldt Call Area achieve annual capacity factors between 45% and 54% after losses and maintenance. Power output is variable between and within seasons, with full power output 30% of the time and no output approximately 20% of the time. Electricity from a 48-MW wind farm provides 22% of regional load with limited exports. A 144-MW wind farm serves 38% of local load, exporting 40% of its electricity with the extant 70-MW transmission capacity. A full build-out of 1836 MW would result in 88% curtailment with existing transmission. Across scenarios, offshore wind variability necessitates reliance on existing power plants to meet local demand in periods of low wind.

Around the world, nearly 1 billion people live without access to electricity, and about 840 million more live with unreliable and intermittent service from electric grids. For many of them, fossil fuel backup generators are the only source of power. But these machines offer a problematic, intermediate solution: their cost of operation is high, they fill neighborhoods and cities with noise pollution, and the exhaust is hazardous to health and the environment. Researched in partnership with the Schatz Energy Research Center at Humboldt State University and the International Institute for Applied Systems Analysis (IIASA) with support from the IKEA Foundation, the report, The Dirty Footprint of the Broken Grid, documents for the first time the economic, environmental, and health effects of fossil fuel generators, and calls for the rapid adoption of clean alternatives. This study explores fundamental questions about the scale and impacts of backup generators that have been largely unanswered beyond anecdote and local or regionally focused studies.

The Waste to Wisdom project was part of the Biomass Research and Development Initiative (BRDI) and funded by the Department of Energy (DE-EE0006297) at an amount of $5.8 million. Our interdisciplinary research team, consisting of academics, business professionals, and land managers, worked together for about four years (September 2013 to December 2017) to: 1) conduct field-based experiments to develop innovative tools and systems that improve the economics, accessibility, and production of quality feedstocks from forest residues, 2) develop and test stand-alone in-woods or near-the-forest biomass conversion technologies (BCTs) for the production of biochar, torrefied wood, and briquettes, and 3) perform analyses to evaluate the economic feasibility of commercial deployment of BCTs and to quantify the life cycle economic and environmental benefits of utilizing forest residues with BCTs for the production of bioenergy and bioproducts. The research papers presented in this Special Issue cover key aspects of the research efforts and findings made by the project team. We encourage the audience to visit the project web site (http://wastetowisdom.com/) to learn more about the team's research on feedstock development, biomass conversion technologies, and the financial and environmental benefits of utilizing forest residues for production of bioenergy and biobased products.

Two commercial biochar production machines - a single-auger unit and a larger dual-auger version - were operated to evaluate feedstock specifications, biochar quality, throughput rates, and emissions profiles. Biochar was produced from woody biomass feedstocks of various species, contamination levels, comminution methods, and moisture contents. Feedstocks with ash content exceeding 15% dry basis or moisture content exceeding 25% wet basis were observed to decrease fixed carbon content of biochar and to increase the labor effort required to operate the machine. The dual-auger version of the machine was able to process 380 kg h(-1) of biomass feedstock (dry basis) to produce 63 kg h-1 of biochar with a mean electricity demand of 4.5 kW. Average CO, propane, NOx, and SO2 emission rates from the flare of this machine were measured to be 160, 120, 51, and 43 g h(-1), respectively, with total particulate matter (PM), PM10, and PM2.5 emission rates of 380, 40, and 4.5 g h-1, respectively. Results from these experiments indicate that high-quality biochar can be produced from a variety of feedstocks, including forest residuals, as long as the ash and moisture content are within the specifications. Future research and development should focus on increasing the throughput of the machine, implementing an automated control system to reduce the operational effort, and improving safety and product consistency.

The Waste to Wisdom project was part of the Biomass Research and Development Initiative (BRDI) and funded by the Department of Energy (DE-EE0006297) at an amount of $5.8 million. Our interdisciplinary research team, consisting of academics, business professionals, and land managers, worked together for about four years (September 2013 to December 2017) to: 1) conduct field-based experiments to develop innovative tools and systems that improve the economics, accessibility, and production of quality feedstocks from forest residues, 2) develop and test stand-alone in-woods or near-theforest biomass conversion technologies (BCTs) for the production of biochar, torrefied wood, and briquettes, and 3) perform analyses to evaluate the economic feasibility of commercial deployment of BCTs and to quantify the life cycle economic and environmental benefits of utilizing forest residues with BCTs for the production of bioenergy and bioproducts. The research papers presented in this Special Issue cover key aspects of the research efforts and findings made by the project team. We encourage the audience to visit the project web site (http://wastetowisdom.com/) to learn more about the team’s research on feedstock development, biomass conversion technologies, and the financial and environmental benefits of utilizing forest residues for production of bioenergy and biobased products.

Mass absorption coefficient spectra were measured between lambda = 500 nm and 840 nm for nine forms of highly-absorbing carbonaceous aerosol: five samples generated from gas-, liquid-and solid-fueled flames; spark-discharge fullerene soot; graphene and reduced graphene oxide (rGO) crumpled nanosheets; and fullerene (C-60) assemblies. Aerosol absorption spectra were measured for size-and massselected particles and found to be dependent on fuel type and formative conditions. Flame-generated particles had morphologies consistent with freshly emitted black carbon (BC) with mass absorption coefficients (MAC) ranging between 3.8 m(2) g(-1) and 8.6 m(2) g(-1) at lambda = 550 nm. Absorption Angstrom exponents (AAE) - i.e. MAC spectral dependence e ranged between 1.0 and 1.3 for flame-generated particles and up to 7.5 for C-60. The dependence of MAC and AAE on mobility diameter and particle morphology was also investigated. Lastly, the current data were compared to all previously published MAC measurements of highly-absorbing carbonaceous aerosol. Published by Elsevier Ltd.

In rotating screw conveyors both the average and the distribution of the residence time influence the extent and the uniformity of the transformation. Experimenters have applied two distinct experimental approaches to obtain the residence time distribution of granular solids in longitudinal reactors: 1) measuring the mass flow rate of product at the exit from the reactor in response to a step change (either positive or negative) in the mass flow rate of feedstock into the reactor or 2) measuring the appearance of a tracer in the flow exiting the reactor in response to either a pulse or a step change addition of tracer in the inlet. We found that all three methods reveal residence time distributions that are approximately normal (i.e., symmetrical and bell-shaped), but the distribution estimated from the pulse input of tracer exhibited a long trailing tail that was not detectable in either the positive or negative step changes. Second, we demonstrated that a normal probability plot proved valuable in displaying and analyzing the residence time distribution obtained by the pulse addition of tracer. Finally, we observed that all three methods yielded mean residence times that consistently differed from the nominal values. The positive step change averaged 8% shorter, the pulse addition of tracer averaged 7% longer, and the negative step change averaged 60% longer.

An All Power Labs PP20 gasifier generation set (Berkeley, Calif.) was tested to evaluate its suitability for powering biomass conversion technologies (BCT) at remote forest operations sites. Feedstock of the species tanoak (Not-holithocarpus densiflorus), coast redwood (Sequoia sempervirens), and Douglas fir (Pseudotsuga menziesii) were tested at moisture contents of 15% and 25% (wet basis). The PP20 was connected to a load bank with five different load profiles designed to simulate possible BCT loads. Two parameters of power quality, voltage variability, and frequency deviation, were determined to be within acceptable limits. The unit also successfully powered a remote biochar operation in Branscomb, California. Emissions of the PP20, when compared to diesel generator regulations, would meet non-methane hydrocarbons (NMHC) and NOX requirements but exceed the CO emissions limits by a factor of ten. The CO emissions could be reduced by adding a catalytic converter. The results indicate that it is possible to use a PP20 unit to provide electric power for the highly variable loads of a BCT system.

A semi-mobile torrefaction and densification pilot plant was constructed in order to determine ideal operating conditions and evaluate briquette quality and throughput rate using forest residuals as the input feedstock. Experiments were conducted at various conditions with feedstock moisture content ranging from 4% to 25% (wet basis), reactor residence times of 10 and 20 min, and final product temperatures between 214 degrees C and 324 degrees C. Optimal operating conditions, evaluated based on throughput rate, specific electricity demand, torrefied briquette grindability, briquette volumetric energy density, and briquette durability, were identified to occur with a short residence time (10 min), low feedstock moisture content (<11% wet basis), and high final product temperature between 267 degrees C and 275 degrees C. These conditions were able to process 510 to 680 kg h(-1) (wet basis) feedstock with a dry mass yield of 79% to 84% to produce torrefied biomass with a higher heating value of 21.2 to 23.0 MJ kg(-1) (dry basis) compared to 19.6 MJ kg(-1) for the original biomass. Torrefied briquettes produced at these conditions had a neatly stacked packing density of 990 kg m(-3) and a volumetric energy density of 21,800 MJ m(-3). Their specific grinding energy was an average 37% of the energy required to grind a raw biomass briquette. These torrefied briquettes were more durable (94% DU) than raw briquettes (85% DU) directly following production, but were less durable after undergoing temperature and humidity fluctuations associated with long distance transportation (74% DU for torrefied and 84% DU for raw biomass briquettes). Results from this pilot plant are promising for commercial scale production of high quality torrefied briquettes and should lead to additional research and development of a torrefaction system optimized for a higher throughput rate at these conditions.

A rapid increase in the performance and quality of white LED light sources has changed the dynamics of electricity access in the last 10 years, reaching tens of millions of people with electric light who previously had no viable alternatives to fuel-based lighting, which is dangerous and expensive. Eliminating fuel-based lighting is a key public health, safety, social equality, and environmental opportunity that is now achievable. Technology advances in LEDs, other super-efficient appliances, solar photovoltaic generation, advanced batteries, and coordinating information technology systems have combined to significantly expand the reach of off-grid energy systems. With support and effort, it is plausible that small "pico-solar" and "solar home" systems could serve over a billion people within a generation, providing basic but highly valued services. Continued progress can be achieved with attention to continued improvements in technology, supporting a growing range of new businesses and enterprises in energy access markets, and synergy with broader human development effort around access to clean water, financial inclusion, and fair access to resources. (C) 2017 Academie des sciences. Published by Elsevier Masson SAS. All rights reserved.

A belt dryer and gasifier generator set were integrated into a biochar production plant to use process heat to dry biomass feedstock from forest residuals and to provide electric power to the plant using a side stream of dried biomass. Experiments were conducted to characterize the dryer throughput and drying capacity using process heat from a stack heat exchanger attached to the biochar machine flare. A matrix of tests was conducted at high and low flow rates for both the heat exchanger air flow rate (which varied the temperature and heat input to the dryer) and the residence time of feedstock in the belt dryer. Mean feedstock input moisture during dryer characterization was 45% and the mean moisture after exiting the dryer was 27%. The optimal test condition, providing the greatest water removal rate, was determined to have high air flow rate through the heat exchanger and short dryer residence time. This condition was used to demonstrate the integrated system for an 8-h production day. The integrated system dried incoming feedstock from 36% to 22% with a dryer throughput rate of 495 kg h-1 w.b. and an evaporation rate of 88.8 kg h-1, providing the necessary dry feedstock for the 20-kW gasifier generator set and the biochar machine, which produced 75 kg h-1 of biochar. This system required the operational effort of 0.92 labor hours per production hour. Results from this demonstration indicate that the integrated system provides key benefits in a biochar production operation including greater control of feedstock drying and the ability to operate without an external (non-biomass) source of fuel for electricity generation.

In 1990, 192 ARCO M75 photovoltaic (PV) modules were installed at the HSU Telonicher Marine Lab in Trinidad, California, 150 meters inland from the Pacific Ocean. Current-voltage (IV) tests were performed on each module prior to the array's construction in 1990 [1] and then again in 2001 [2], 2010 [3], and most recently in 2016 after the array was decommissioned. After 25.5 years, 188 of the original 192 modules remained operational. Over their lifetime, the modules' maximum power at the normal operating cell temperature (NOCT) declined by an average 21.6% with a degradation rate of 0.85% per year. The average degradation rate grew from 0.4%/year in the first 11 years to 0.81%/year after 20 years to 0.85%/year after the total 25.5 years.

Since 2010, the World Bank Group’s Lighting Africa program has comprehensively analyzed and documented the rapid evolution of the off-grid solar devices and services market. The 2010 and 2012 market trends reports become touchstones for the industry, just as the 2016 edition is expected to be. This third incarnation captures the rapid evaluation that is happening in the market, and is a collaboration between Lighting Global (the World Bank Group’s expanded platform to support the global market) and Bloomberg New Energy Finance, in partnership with the Global Off-Lighting Association (GOGLA). This report is also the first to substantially characterize the diverse investment community that is now focusing on the sector and the instruments being deployed to provide the capital necessary to realize the industry potential. The main findings of the report were first presented at the fourth international Off-Grid Solar Lighting Conference in Dubai in 2015, where the emergence of a rapidly maturing industry could be witnessed first-hand. The energized assembly included, for the first time, commercial investors inspired by the wave of entrepreneurial, technological advances, and a business model innovation. This report provides them with an introduction to a promising sector, just as it provides the companies seeking capital to understand the concerns, limitations, and perspectives with which these investors approach the industry.

Plug-in electric vehicles (PEVs) represent a substantial opportunity for governments to reduce emissions of both air pollutants and greenhouse gases. The Government of India has set a goal of deploying 6-7 million hybrid and PEVs on Indian roads by the year 2020. The uptake of PEVs will depend on, among other factors like high cost, how effectively range anxiety is mitigated through the deployment of adequate electric vehicle charging stations (EVCS) throughout a region. The Indian Government therefore views EVCS deployment as a central part of their electric mobility mission. The plug-in electric vehicle infrastructure (PEVI) model-an agent-based simulation modeling platform -was used to explore the cost-effective siting of EVCS throughout the National Capital Territory (NCT) of Delhi, India. At 1% penetration in the passenger car fleet, or similar to 10 000 battery electric vehicles (BEVs), charging services can be provided to drivers for an investment of $4.4 M(or $440/BEV) by siting 2764 chargers throughout the NCT of Delhi with an emphasis on the more densely populated and frequented regions of the city. The majority of chargers sited by this analysis were low power, Level 1 chargers, which have the added benefit of being simpler to deploy than higher power alternatives. The amount of public infrastructure needed depends on the access that drivers have to EVCS at home, with 83% more charging capacity required to provide the same level of service to a population of drivers without home chargers compared to a scenario with home chargers. Results also depend on the battery capacity of the BEVs adopted, with approximately 60% more charging capacity needed to achieve the same level of service when vehicles are assumed to have 57 km versus 96 km of range.

Highly efficient direct current (DC) appliances have the potential to dramatically increase the affordability of off-grid solar power systems used for rural electrification in developing countries by reducing the size of the systems required. For example, the combined power requirement of a highly efficient color TV, four DC light emitting diode (LED) lamps, a mobile phone charger, and a radio is approximately 18 watts and can be supported by a small solar power system (at 27 watts peak, Wp). Price declines and efficiency advances in LED technology are already enabling rapidly increased use of small off-grid lighting systems in Africa and Asia. Similar progress is also possible for larger household-scale solar home systems that power appliances such as lights, TVs, fans, radios, and mobile phones. When super-efficient appliances are used, the total cost of solar home systems and their associated appliances can be reduced by as much as 50%. The results vary according to the appliances used with the system. These findings have critical relevance for efforts to provide modern energy services to the 1.2 billion people worldwide without access to the electrical grid and one billion more with unreliable access. However, policy and market support are needed to realize rapid adoption of super-efficient appliances.

Market spoiling stemming from information asymmetry has slowed the adoption grid-independent technologies that replace fuel-based lighting in the developing world. End users typically first experience lighting technology innovations via flashlights. The rapid emergence of inexpensive LED flashlights is a potentially good advancement in this regard, as LED lighting can be longer-lived, have higher initial light output, and be more energy-efficient than incandescent. However, our laboratory tests and end user interviews indicate that these products often fall far short of advertised performance levels and typically fail after a few months of use. Our study of purchasing decisions by 23 Kenyan market traders given an opportunity to purchase warrantied LED lamps found that prior experience with inexpensive LED flashlights significantly reduced their probability of purchasing (p = 0.0028). As additional evidence of consumer skepticism, in a large statistical survey, we also find that willingness to pay increases significantly once an LED lighting product is directly handled and tested by the end user. If LED lighting is to achieve its potential as a superior substitute for fuel-based lighting, effective policy measures are needed to remove the information asymmetry between expected and actual performance. One such measure, independent testing and certification, has measurably increased the quality of products available in the off-grid lighting marketplace.

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We evaluated the uptake of grid-independent LED lighting among night vendors in two small Kenyan towns during the “early days” of the solarLED market. The methods we used combine social geography with energy and technology analysis to understand LED lighting adoption patterns in the context of a market that is getting its fi rst exposure to LED technology, a situation that is repeating itself in villages and towns across the developing world. Of 23 night vendors to whom we offered LED lanterns at realistic market prices, 14 (61 %) opted to purchase. We identifi ed wide variations in baseline kerosene fuel use, signifi cant fl uctuations in the pricing of kerosene, an only partial degree to which kerosene was displaced, the value of highfrequency utilization information derived from embedded data loggers, consumer willingness to pay for improved lights, and signifi cantly confounding effects of market spoiling due to prior experience with low-quality LED products. In a likely response to signifi cant reductions in kerosene prices during the trial period, a non-adopter control group increased