• Energy Research
• 15. Life on land close

Abstract Several environmental accounting methods exist to evaluate the rate of ecosystems resource exploitation and to strengthen the comparison among human production systems in terms of renewability and sustainable use of resources. However, their application rarely refers to the environmental work that is necessary to produce natural resources. The aim of this research is to advance the characterization of different wood biomass species by using the emergy principles and thus to estimate the geobiosphere work required to generate wood resources. The analysis has been conducted applying the classical emergy methodology and a recently developed life cycle-based embodied energy approach. This latter is implemented with the support of Life Cycle Assessment (LCA) principles and tools to disclose as a result vectors of Unit Embodied Energy Value ( UEEV → ) , composed by three components: the Embodied Solar, Tidal and Geothermal Energy. Differently from emergy evaluation, the life cycle-based embodied energy approach does not consider the baseline concept and the emergy algebra, but the Solar, Geothermal and Tidal sources are independently quantified, keeping them separated and not weighted. The present paper shows that the latter method can provide a consistent framework to trace and evaluate the primary provision of energy throughout the formation of resources. Regionalized UEVs (Unit Emergy Values) and ( UEEVs → ) have been obtained and compared with regard to Fagus spp., Quercus spp., Picea spp., Pinus spp., Pseudotsuga spp., Fraxinus spp., Populus spp., Castanea spp., and other grouped conifers (Larix spp., Cupressus spp. and Abies spp.) and other deciduous species (Carpinus spp., Betulus spp., Alnus spp. and Robinia spp.). The trend of output values per unit of resource species obtained by means of the two methods was very similar when looking at the Solar Embodied Energy contribution, meaning that this flow has the main direct (with the life cycle-based embodied energy approach) and indirect (with the emergy one) influence on the generation of wood biomass. Results obtained by means of both methods can fill out the life cycle of products based on wood biomass, providing the natural contribution to wood species formation and thus embedding this information in the technosphere processes.

Switchgrass (Panicum virgatum L.) is projected to become one of the main herbaceous, biofuel crops in United States. This status was the result of several years of research; much it sponsored by the United States Department of Energy (DOE). Literature documenting fundamental aspects of switchgrass taxonomy, genetics, breeding, management, physiology, and use is now available and form the basis for protocols to establish and manage the crop, as well as efforts to develop improved cultivars. Future improvement will include production of high yielding hybrids and the use of genomic and transgenic biotechnologies to enhance both productivity and chemical composition. Reducing bioconversion recalcitrance via reduction of lignin content is an example of projected future research in this area.

Because of the inevitable depletion of fossil fuels and the corresponding release of carbon to the environment, the global energy future is complex. Some of the consequences may be politically and economically disruptive, and expensive to remedy. For the next several centuries, fuel requirements will increase with population, land use, and ecosystem degradation. Current or projected levels of aggregated energy resource use will not sustain civilization as we know it beyond a few more generations. At the same time, issues of energy security, reliability, sustainability, recoverability, and safety need attention. We supply a top-down, qualitative model--the surety model--to balance expenditures of limited resources to assure success while at the same time avoiding catastrophic failure. Looking at U.S. energy challenges from a surety perspective offers new insights on possible strategies for developing solutions to challenges. The energy surety model with its focus on the attributes of security and sustainability could be extrapolated into a global energy system using a more comprehensive energy surety model than that used here. In fact, the success of the energy surety strategy ultimately requires a more global perspective. We use a 200 year time frame for sustainability because extending farther into the future would almost certainlymore » miss the advent and perfection of new technologies or changing needs of society.« less

Two federal policies—the protection of endangered species, and the rapid creation of renewable energy infrastructure—currently exist in significant legal tension. While both are important for the development of necessary sustainability, climate change induced by the continuous burning of carbon-based fuels likely poses a greater threat to endangered species than does the growth of commercial-scale renewable energy sites. This paper outlines several points of conflict between the two policies and subsequently considers the extent to which federal agencies responsible for renewable energy oversight and development possess “wiggle room” under the Endangered Species Act. A few recommendations for greater leeway are then offered. Consilience, No 14 (2015): Issue Fourteen: 2015

Recent growth in the wind energy industry has increased concerns about its impacts on wildlife populations. Direct impacts of wind energy include bird and bat collisions with turbines whereas indirect impacts include changes in wildlife habitat and behavior. Although many species may withstand these effects, species that are long-lived with low rates of reproduction, have specialized habitat preferences, or are attracted to turbines may be more prone to declines in population abundance. We developed a prioritization system to identify the avian species most likely to experience population declines from wind facilities based on their current conservation status and their expected risk from turbines. We developed 3 metrics of turbine risk that incorporate data on collision fatalities at wind facilities, population size, life history, species' distributions relative to turbine locations, number of suitable habitat types, and species' conservation status. We calculated at least 1 measure of turbine risk for 428 avian species that breed in the United States. We then simulated 100,000 random sets of cutoff criteria (i.e., the metric values used to assign species to different priority categories) for each turbine risk metric and for conservation status. For each set of criteria, we assigned each species a priority score and calculated the average priority score across all sets of criteria. Our prioritization system highlights both species that could potentially experience population decline caused by wind energy and species at low risk of population decline. For instance, several birds of prey, such as the long-eared owl, ferruginous hawk, Swainson's hawk, and golden eagle, were at relatively high risk of population decline across a wide variety of cutoff values, whereas many passerines were at relatively low risk of decline. This prioritization system is a first step that will help researchers, conservationists, managers, and industry target future study and management activity.

The use of woody biomass is being promoted across the United States as a means of increasing energy independence, mitigating climate change, and reducing the cost of hazardous fuels reduction treatments and forest restoration projects. The opportunities and challenges for woody biomass use on the national forest system are unique. In addition to making woody biomass usage pencil out, national forest managers must also navigate substantial public engagement and forest planning processes that add to the complexity of fostering woody biomass use opportunities on the national forest system. We report on the results of a survey of US Forest Service managers and staff members (n = 339) about the trends in, barriers to, and strategies for fostering woody biomass use on national forests and their surrounding communities. The results highlight the economic and market challenges as well as the need for a basket of policies focused on a broad array of strategies for biomass use.

Small passerines, sometimes referred to as perching birds or songbirds, are the most abundant bird group in the United States (US) and Canada, and the most common among bird fatalities caused by collision with turbines at wind energy facilities. We used data compiled from 116 studies conducted in the US and Canada to estimate the annual rate of small-bird fatalities. It was necessary for us to calculate estimates of small-bird fatality rates from reported all-bird rates for 30% of studies. The remaining 70% of studies provided data on small-bird fatalities. We then adjusted estimates to account for detection bias and loss of carcasses from scavenging. These studies represented about 15% of current operating capacity (megawatts [MW]) for all wind energy facilities in the US and Canada and provided information on 4,975 bird fatalities, of which we estimated 62.5% were small passerines comprising 156 species. For all wind energy facilities currently in operation, we estimated that about 134,000 to 230,000 small-passerine fatalities from collision with wind turbines occur annually, or 2.10 to 3.35 small birds/MW of installed capacity. When adjusted for species composition, this indicates that about 368,000 fatalities for all bird species are caused annually by collisions with wind turbines. Other human-related sources of bird deaths, (e.g., communication towers, buildings [including windows]), and domestic cats) have been estimated to kill millions to billions of birds each year. Compared to continent-wide population estimates, the cumulative mortality rate per year by species was highest for black-throated blue warbler and tree swallow; 0.043% of the entire population of each species was estimated to annually suffer mortality from collisions with turbines. For the eighteen species with the next highest values, this estimate ranged from 0.008% to 0.038%, much lower than rates attributed to collisions with communication towers (1.2% to 9.0% for top twenty species).

The Renewable Fuel Standard (RFS2) in the U.S. Energy Independence and Security Act of 2007 (EISA) sets annual volume targets for domestic renewable transportation fuel consumption through 2022, but allows for flexibility in the types of biomass used for biofuels and where and how they are grown. Spatially explicit feedstock scenarios for how the agricultural and forestry sectors can produce sufficient biomass to meet these targets have been developed by the U.S. Department of Energy (DOE), the U.S. Environmental Protection Agency (EPA), and the U.S. Department of Agriculture (USDA). Here we compare the models used to generate these scenarios and their underlying assumptions on crop yields, feedstock prices, biofuel conversion efficiencies, land availability, and other critical factors. We find key differences in the amount of land devoted to different biomass sources and their geographic distribution, most notably for perennial grasses. These different visions of land use and management for bioenergy in the U.S. are currently being used both for regulation and to set research funding priorities. Understanding the key assumptions and uncertainties that underlie these scenarios is important for accurate assessment of the potential economic and environmental impacts of RFS2, as well as for optimal design of future energy and agricultural policy.

Recent trends in renewable energy development in the United States (U.S.) show that new installed capacity of utility-scale solar energy has exceeded 30% of total installed capacity of all sources per year since 2013. Photovoltaic solar energy provides benefits in that no emissions are produced; however, there are potential impacts from photovoltaic solar development on birds that include habitat loss and potential for collision mortality. Only 2 papers in the peer-reviewed literature present fatality information from fatality monitoring studies at a photovoltaic utility-scale solar energy facility; however, more data exists in unpublished reports. To provide a more comprehensive overview of bird mortality patterns, we synthesized results from fatality monitoring studies at 10 photovoltaic solar facilities across 13 site-years in California and Nevada. We found variability in the distribution of avian orders and species among and within Bird Conservation Regions, and found that water-obligate birds, which rely on water for take-off and landing, occurred at 90% (9/10) of site-years in the Sonoran and Mojave Deserts Bird Conservation Region. We found that a cause of mortality could not be determined for approximately 61% of intact carcasses, and that approximately 54% of all carcasses were feather spots, introducing uncertainty into the interpretation of the fatality estimates. The average annual fatality estimate we calculated for photovoltaic solar (high-end estimate of 2.49 birds per megawatt per year) is lower than that reported by another study (9.9 birds per megawatt per year) that included one photovoltaic facility. Our results provide a summary of fatalities in bird conservation regions where the facilities are located, but expanding our conclusions to new regions is limited by the location of facilities with fatality monitoring data.

Nearly all western states lack comparative advantages for producing corn for ethanol and oilseeds for biodiesel. Despite this disadvantage, most western states have legislated incentives for production of biofuels. Unfavorable changes in price relationships, high transportation costs for imported feedstocks, and tight credit markets in 2008 and 2009 led to bankruptcies and plant closures at a disproportionate rate in the western biofuel industry. Policy makers in western states are advised to fund research and development for bioenergy and biofuel feedstocks in which they have a comparative advantage. These include forestry by-products, food processing and crop residues, and livestock wastes.