State Portfolio Research Articles

Evaluating state tax revenue variability: a portfolio approach

This article develops a volatility model based on portfolio theory to examine state tax revenue variability. Unlike traditional parametric methods used to analyse state tax revenue variability, the portfolio approach allows the computation of a tax's share of total tax revenue that minimizes the overall variability in total state tax revenue given a state's portfolio of tax revenue sources. The model can thus be used to evaluate how closely a state's revenue portfolio is constructed to minimize variability in total state tax revenue. An empirical application of the model is conducted on a sample of US states. The volatility model presented here serves as a useful complement to parametric techniques that have been used to estimate tax revenue variability.

On the HYway—sustainable assets in Germany's energy state's portfolio

Historically, North Rhine-Westfalia (NRW), Germany's energy state with the heavily industrialized Ruhr area in its middle, provided coal and steel for the industrialization of the country in the late 18th and the 19th century, was key in the recovery process after WWs I and II, and stands today for the ongoing successfully pursued transformation process from carbonaceous energy raw materials to high-tech energy technologies. Step by step, prevailing energy policy has become energy technology policy! The state hosts Germany's partner in the development club for a hydrogen-based zero-CO 2 coal fired power plant, as well as the biggest PV production capacity in the country; it operates a significant share of Germany's almost 9 GW e wind parks, and runs a remarkable co-operative fuel cell development network of academia and industry. So far, the youngest baby is the rapidly growing hydrogen energy economy structure, consisting of hydrogen technologies for more or less all the links of the hydrogen energy conversion chain, particularly clean hydrogen production from fossil fuels, including CO 2 sequestration, or from renewable energy sources. Thus, the transformation process of NRW from coal and steel to solar- and hydrogen-based high-tech energy technologies seems exemplary for many historically similarly structured world regions. The paper tries to offer an insight into the build-up of hydrogen-based decarbonized, hydrogenated, and, thus, dematerialized energy markets. On the energy HYway, energy technologies have taken the lead. They provide more clean energy services at the back end of the energy conversion chain from less environmentally harmful and climate change risking carbonaceous energy raw material at its front end. They grant urgently needed exergetization (exergy=energy–anergy) of the nation's energy system, and, not least, they are preconditional for otherwise irrational energy sustainability: H 2 is the paving stone of the HYway's sustainable pavement!