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There is concern that mercury (Hg) in coal combustion by-products might be emitted into the environment during processing to other products or after the disposal/landfill of these by-products. This perception may limit the opportunities to use coal combustion by-products in recycle/reuse applications and may result in additional, costly disposal regulations. In this program, CONSOL conducted a comprehensive sampling and analytical program to include ash, flue gas desulfurization (FGD) sludge, and coal combustion by-products. This work is necessary to help identify potential problems and solutions important to energy production from fossil fuels. The program objective was to evaluate the potential for mercury emissions by leaching or volatilization, to determine if mercury enters the water surrounding an active FGD disposal site and an active fly ash slurry impoundment site, and to provide data that will allow a scientific assessment of the issue. Toxicity Characteristic Leaching Procedure (TCLP) test results showed that mercury did not leach from coal, bottom ash, fly ash, spray dryer/fabric filter ash or forced oxidation gypsum (FOG) in amounts leading to concentrations greater than the detection limit of the TCLP method (1.0 ng/mL). Mercury was detected at very low concentrations in acidic leachates from all of the fixated and more than half of the unfixated FGD sludge samples, and one of the synthetic aggregate samples. Mercury was not detected in leachates from any sample when deionized water (DI water) was the leaching solution. Mercury did not leach from electrostatic precipitator (ESP) fly ash samples collected during activated carbon injection for mercury control in amounts greater than the detection limit of the TCLP method (1.0 ng/mL). Volatilization tests could not detect mercury loss from fly ash, spray dryer/fabric filter ash, unfixated FGD sludge, or forced oxidation gypsum; the mercury concentration of these samples all increased, possibly due to absorption from ambient surroundings. Mercury loss of 18-26% was detected after 3 and 6 months at 100 F and 140 F from samples of the fixated FGD sludge. Water samples were collected from existing ground water monitoring wells around an active FGD disposal site (8 wells) and an active fly ash slurry impoundment (14 wells). These were wells that the plants have installed to comply with ground water monitoring requirements of their permits. Mercury was not detected in any of the water samples collected from monitoring wells at either site. A literature review concluded that coal combustion byproducts can be disposed of in properly designed landfills that minimize the potentially negative impacts of water intrusion that carries dissolved organic matter (DOM). Dissolved organic matter and sulfate-reducing bacteria can promote the transformation of elemental or oxidized mercury into methyl mercury. The landfill should be properly designed and capped with clays or similar materials to minimize the wet-dry cycles that promote the release of methylmercury.

This paper describes the economically optimal adoption and operation of distributed energy resources (DER) by a hypothetical California microgrid (μGrid) consisting of a group of commercial buildings over an historical test year, 1999. The optimization is conducted using a customer adoption model developed at Berkeley Lab and implemented in the General Algebraic Modeling System. A μGrid is a semiautonomous grouping of electricity and heat loads interconnected with the existing utility grid (macrogrid) but able to island from it. The μGrid minimizes the cost of meeting its energy requirements (consisting of both electricity and heat loads) by optimizing the installation and operation of DER technologies while purchasing residual energy from the local combined natural gas and electricity utility. The available DER technologies are small-scale generators (<500 kW), such as reciprocating engines, microturbines, and fuel cells, with or without combined heat and power (CHP) equipment, such as water and space heating and/or absorption cooling. By introducing a tax on carbon emissions, it is shown that if the μGrid is allowed to install CHP-enabled DER technologies, its carbon emissions are mitigated more than without CHP, demonstrating the potential benefits of small-scale CHP technology for climate change mitigation. Reciprocating engines with heat recovery and/or absorption cooling tend to be attractive technologies for the mild southern California climate, but the carbon mitigation tends to be modest compared to purchasing utility electricity because of the predominance of relatively clean central station generation in California.

Graphene has been used as an electrically tunable material for switchable devices. A large area fabrication of Al-doped ZnO/Al2O3/graphene/Al2O3/gold/silicon device was enabled by a spin-processible hydrophilic mono-layer graphene oxide. The graphene was obtained directly from graphene oxide during the atomic layer deposition without other extra steps. A significant shift of Raman frequency up to 360 cm−1 was observed from graphene in the fabricated device, indicating a structural change in graphene. The absorption from the device was tunable with a negative voltage applied on the Al-doped ZnO side. The generated absorption change was sustainable when the voltage was off and erasable when a positive voltage was applied. The sustainability of tuned optical property in the graphene under investigation can lead to a design of device with less power consumption and many other applications.

An analysis was made of siting issues in the coastal zone, one of the nation's most critical natural resource areas and one which is often the target for energy development proposals. The analysis addressed the changing perceptions of citizens toward energy development in the coastal zone, emphasizing urban communities where access to the waterfront and revitalization of waterfront property are of interest to the citizen. The findings of this analysis are based on an examination of energy development along New Jersey's urban waterfront and along the Texas-Louisiana Gulf Coast, and on redevelopment efforts in Seattle, San Francisco, Boston, and elsewhere. The case studies demonstrate the significance of local attitudes and regional cooperation in the siting process. In highly urbanized areas, air quality has become a predominant concern among citizen groups and an influential factor in development of alternative energy facility siting strategies, such as consideration of inland siting connected by pipeline to a smaller coastal facility. The study addresses the economic impact of the permitting process on the desirability of energy facility investments, and the possible effects of the location selected for the facility on the permitting process and investment economics. The economic analysis demonstrates the importance of viewing energymore » facility investments in a broad perspective that includes the positive or negative impacts of various alternative siting patterns on the permitting process. Conclusions drawn from the studies regarding Federal, state, local, and corporate politics; regulatory, permitting, licensing, environmental assessment, and site selection are summarized. (MCW)« less

Quantification of the trade-offs among greenhouse gas (GHG) emissions, yield, and farmers’ incomes is essential for proposing economic and environmental nitrogen (N) management strategies for optimizing agricultural production. A four-year (2017–2020) field experiment (including four treatments: basic N fertilizer treatment (BF), suitable utilization of fertilization (SU), emission reduction treatment (ER), and high fertilization (HF)) was conducted on maize (Zea mays L.) in the North China Plain. The Life Cycle Assessment (LCA) method was used in this study to quantify the GHG emissions and farmers’ incomes during the whole maize production process. The total GHG emissions of BF, SU, ER, and HF treatments in the process of maize production are 10,755.2, 12,908.7, 11,950.1, and 14,274.5 kg CO2-eq ha−1, respectively, of which the direct emissions account for 84.8%, 76.8%, 74.9%, and 71.0%, respectively. Adding inhibitors significantly reduced direct GHG emissions, and the N2O and CO2 emissions from the maize fields in the ER treatment decreased by 30.0% and 7.9% compared to those in the SU treatment. Insignificant differences in yield were found between the SU and ER treatments, indicating that adding fertilizer inhibitors did not affect farmers’ incomes while reducing GHG emissions. The yield for SU, ER, and HF treatments all significantly increased by 12.9–24.0%, 10.0–20.7%, and 2.1–17.4% compared to BF, respectively. In comparison with BF, both SU and ER significantly promoted agricultural net profit (ANP) by 16.6% and 12.2%, with mean ANP values of 3101.0 USD ha−1 and 2980.0 USD ha−1, respectively. Due to the high agricultural inputs, the ANP values in the HF treatment were 11.2%, 16.6%, and 12.4% lower than those in the SU treatment in 2018–2020. In conclusion, the combination of N fertilizer and inhibitors proved to be an environmentally friendly, high-profit, and low-emissions production technology while sustaining or even increasing maize yields in the North China Plain, which was conducive to achieving agricultural sustainability.

Abstract As a type of solid waste, the used cigarette filters (UCF) were utilized to produce ester-rich bio-oil via a cleaner production process, namely, microwave-assisted pyrolysis (MAP). The pyrolysis efficiency was significantly enhanced owing to the high heating rate under MAP conditions with assistance of microwave absorber silicon carbide (SiC) in reactor and adding methanol into N2 carrier gas. Compared with the traditional tubular muffle furnace heating method yielding 0% of bio-oil, the MAP heating method obtained 29.17% of bio-oil from UCF. The bio-oil yield from UCF increased from 29.17% to 46.71% due to the introduction of methanol. Results of the gas chromatography/mass spectrometry showed that esters were the main components in the bio-oils (over 40%), especially of methyl acetate (over 12%). The aromatic compounds of phenols and polycyclic aromatic hydrocarbons (PAHs) were also produced from the MAP of UCF. The bio-char from MAP of UCF exhibited the mesoporous property (e.g., over 500 m2/g of specific surface area). It is expected to produce over 350000 metric tons ester-rich bio-oil if the proposed technology can be scaled up globally. It will be a preeminent contribution for the conversion of UCF to the cleaner production and our environments.

This Methodology Booklet provides a comprehensive review and methodology guiding principles for constructing energy efficiency indicators, with illustrative examples of application to individual countries. It reviews work done by international agencies and national government in constructing meaningful energy efficiency indicators that help policy makers to assess changes in energy efficiency over time. Building on past OECD experience and best practices, and the knowledge of these countries' institutions, relevant sources of information to construct an energy indicator database are identified. A framework based on levels of hierarchy of indicators -- spanning from aggregate, macro level to disaggregated end-use level metrics -- is presented to help shape the understanding of assessing energy efficiency. In each sector of activity: industry, commercial, residential, agriculture and transport, indicators are presented and recommendations to distinguish the different factors affecting energy use are highlighted. The methodology booklet addresses specifically issues that are relevant to developing indicators where activity is a major factor driving energy demand. A companion spreadsheet tool is available upon request.

The findings of a literature review on the environmental concerns and associated control methods of geothermal energy utilization are presented. The document introduces the environmental problems associated with geothermal energy utilization; assesses the current status of control methods; references appropriate environmental documents; and identifies areas where additional environmental research is needed. The review attempts to consolidate current understanding of the environmental impact of geothermal energy development. Approximately 180 reports written by authors in industry, government and academia have been reviewed in the areas of air emissions, surface and subsurface liquid discharges, solid wastes, noise, subsidence, and induced seismicity.