U.S. BIOMASS SUPPLY FOR ELECTRICITY GENERATION: CLIMATE POLICY IMPLICATIONS AND CARBON NEUTRALITY

This paper investigates three important energy and climate policy issues: (1) the availability of biomass for electricity generation (i.e., supply), (2) climate policy effects on this supply, and (3) the net greenhouse gas reduction when biomass is used for electricity generation. Using a detailed model of U.S. agriculture and forestry markets and land-use, that includes a broad and diverse set of biomass feedstocks, we evaluate competing potential sub-national and feedstock specific supplies of biomass for U.S. electricity generation. Our preliminary results suggest significant supply, with residues dominating at lower delivered energy prices, and dedicated crops significant at higher prices. Sub-national variation is dramatic and will affect generation siting and sustainability. We find displacement of food crops, but net forest land and cropland expansion. We also find that GHG policies could substantially increase the delivered cost of biomass; however, the implications for individual regions and feedstocks is non-uniform, with some supplies falling to zero and others increasing. Finally, we find that bioelectricity is not carbon neutral, but can be emissions reducing relative to coal generation, yield greater direct GHG benefits than biofuels, and even result in domestic indirect emissions reductions with incentives for forest based feedstocks.Agricultural and Food Policy, Environmental Economics and Policy, Land Economics/Use, Resource /Energy Economics and Policy,

A Survey of Empirical Research on Nominal Exchange Rates

We survey the empirical literature on floating nominal exchange rates over the past decade. Exchange rates are difficult to forecast at short- to medium-term horizons. There is a bit of explanatory power to monetary models such as the Dornbusch 'overshooting' theory, in the form of reaction to 'news' and in forecasts at long-run horizons. Nevertheless, at short horizons, a driftless random walk characterizes exchange rates better than standard models based on observable macroeconomic fundamentals. Unexplained large shocks to floating rates must then, logically, be due either to innovations in unobservable fundamentals, or to non-fundamental factors such as speculative bubbles. The observed difference in exchange rate and macroeconomic volatility under different nominal exchange rate regimes makes us skeptical of the first view. The theory and evidence on speculative bubbles, however, is not conclusive. We conclude with the hope that promising new studies of the microstructure of the foreign exchange market might eventually rise to insights into these phenomena.

Greenhouse Gas Emissions, Stabilization and the Inevitability of Adaptation: Challenges for U.S. Agriculture

Environmental Economics and Policy, Q1, Q54, Q58,

Spectral Variations in Early-Type Galaxies as a Function of Mass

We report on the strengths of three spectral indicators - Mg_2, Hbeta, and Hn/Fe - in the integrated light of a sample of 100 field and cluster E/S0 galaxies. The measured indices are sensitive to age and/or and metallicity variations within the galaxy sample. Using linear regression analysis for data with non-uniform errors, we determine the intrinsic scatter present among the spectral indices of our galaxy sample as a function of internal velocity dispersion. Our analysis indicates that there is significantly more intrinsic scatter in the two Balmer line indices than in the Mg_2 index, indicating that the Balmer indices provide more dynamic range in determining the age of a stellar population than does the Mg_2 index. Furthermore, the scatter is much larger for the low velocity dispersion galaxies, indicating that star formation has occurred more recently in the lower mass galaxies.Comment: 4 pages, 1 figure, 1 table, to appear in the Astrophysical Journal Letter

The Endogeneity of the Optimum Currency Area Criteria

A country's suitability for entry into a currency union depends on a number of economic conditions. These include, inter alia, the intensity of trade with other potential members of the currency union, and the extent to which domestic business cycles are correlated with those of the other countries. But international trade patterns and international business cycle correlations are endogenous. This paper develops and investigates the relationship between the two phenomena. Using thirty years of data for twenty industrialized countries, we uncover a strong and striking empirical finding: countries with closer trade links tend to have more tightly correlated business cycles. It follows that countries are more likely to satisfy the criteria for entry into a currency union after taking steps toward economic integration than before.

A Panel Project on Purchasing Power Parity: Mean Reversion Within and Between Countries

Previous time-series studies have shown evidence of mean- reversion in real exchange rates. Deviations from purchasing power parity (PPP) appear to have half-lives of approximately four years. However, the long samples required for statistical significance are unavailable for most currencies, and may be inappropriate because of regime changes. In this study, we re-examine deviations from PPP using a panel of 150 countries and 45 annual observations. Our panel shows strong evidence of mean-reversion that is similar to that from long time-series. PPP deviations are eroded at a rate of approximately 15% annually, i.e., their half-life is around four years. Such findings can be masked in time-series data, but are relatively easy to find in cross-sections.

Development of thermally stable phosphonitrile elastomers for advanced aerospace structures

Attempts to prepare low molecular weight, curable poly-(fluoroalkoxyphosphazenes) have been successful. Derivatization of /Cl2PN/n polymer with alkoxides gave functionally reactive terpolymers. These terpolymers could be crosslinked with polyisocyanates at room temperature. Attempts to control molecular weight have not been as successful. The effects of (Cl2PN)3 monomer purity, use of (Cl2PN)3,4 mixture, and early termination of the bulk polymerization of (Cl2PN)3 were studied briefly. Both low and high molecular weight polymers were obtained. Reaction of NH4Cl with PCl5 with subsequent heating to give chain extension gave either gels of oils with molecular weights of several thousand. The stabilization of poly-(fluoroalkoxyphosphazene) was investigated. The results generally were inconclusive, but acids were found to be deleterious while bases had little discernible effect. Improvements in stability by modification of end groups was inconclusive

Development of thermally stable phosphonitrile elastomers for advanced aerospace structures

Both high and low molecular weight, curable poly(fluoroalkoxy phosphazene) terpolymers were prepared. These terpolymers resulted from reaction of (Cl2PNn) polymer with alkoxides derived from CF3CH2OH and C3F7CH2OH, and an alkoxide derived from CH3CH(OH)C2H4OH. The terpolymers were crosslinked with polyisocyanates at room temperature. High molecular weight materials were converted into isocyanate prepolymers which as films underwent moisture cures at room temperature. Prepolymer solutions were stable for several days, and showed good adhesion. Also the effects of polymerization of (Cl2PN)3 were studied. Purified octachlorophosphazene, thiocyanate salts, or hydrogen chloride were employed in attempts to decrease molecular weight. Hydrogen chloride was found to be a good agent for preparation of low molecular weight poly(dichloro phosphazene)

A wireless multi-sensor subglacial probe: design and preliminary results

This paper introduces a new way to investigate in situ processes, the wireless multi-sensor probe, as part of an environmental sensor network. Instruments are housed within a 'probe' which can move freely and so behave like a clast. These were deployed in the ice and till at Briksdalsbreen, Norway. The sensors measure temperature, resistivity, case stress, tilt angle and water pressure and send their data to a base station on the glacier surface via radio links. These data are then forwarded by radio to a reference station with mains power 2.5 km away, from where they are sent to a web server in the UK. The system deployed during 2004/05 was very successful and a total of 859 probe days worth of data from the ice and till were collected, along with GPS, weather and diagnostic data about the system