739 research outputs found
Summary of lidar and star-photometer measurments in Ny-Alesund during the moon-photometer intercomparison campaign
star photometer and lidar measurements from Ny-Alesund in Feb. 2020 during the international moon photometer intercomparison campaign are presented
Germany's Solar Cell Promotion: Dark Clouds on the Horizon
This article demonstrates that the large feed-in tariffs currently guaranteed for solar electricity in Germany constitute a subsidization regime that, if extended to 2020, threatens to reach a level comparable to that of German hard coal production, a notoriously outstanding example of misguided political intervention. Yet, as a consequence of the coexistence of the German Renewable Energy Sources Act (EEG) and theEUEmissions Trading Scheme (ETS), the increased use of renewable energy technologies does not imply any additional emission reductions beyond those already achieved by ETS alone. Similarly disappointing is the net employment balance, which is likely to be negative if one takes into account the opportunity cost of this form of solar photovoltaic support. Along the lines of the International Energy Agency (IEA 2007:77), we therefore recommend the immediate and drastic reduction of the magnitude of the feed-in tariffs granted for solar-based electricity. Ultimately, producing electricity on this basis is among the most expensive greenhouse gas abatement options.Energy policy, energy security, learning effects
Measuring Energy Supply Risks: A G7 Ranking
The security of energy supply has again become a similarly hot topic as it was during the oil crises in the 1970s, not least due to the recent historical oil price peaks. In this paper, we analyze the energy security situation of the G7 countries using a statistical risk indicator and empirical energy data for the years 1978 through 2007.We find that Germany’s energy supply risk has risen substantially since the oil price crises of the 1970s, whereas France has managed to reduce its risk dramatically, most notably through the deployment of nuclear power plants. As a result of the legally stipulated nuclear phase-out, Germany’s supply risk can be expected to rise further and to approach the level of Italy.Due to its resource poverty, Italy has by far the highest energy supply risk among G7 countries.Herfindahl Index, Energy Supply Risk Indicator
Long-term decline of spring AOD in Ny-Alesund
The long-term decline of Arctic Haze, based on photometer measurments from AWIPEV is presented
Economic Impacts from the Promotion of Renewable Energy Technologies - The German Experience
The allure of an environmentally benign, abundant, and cost-effective energy source has led an increasing number of industrialized countries to back public financing of renewable energies. Germany's experience with renewable energy promotion is often cited as a model to be replicated elsewhere, being based on a combination of far-reaching energy and environmental laws that stretch back nearly two decades. This paper critically reviews the current centerpiece of this effort, the Renewable Energy Sources Act (EEG), focusing on its costs and the associated implications for job creation and climate protection. We argue that German renewable energy policy, and in particular the adopted feed-in tariff scheme, has failed to harness the market incentives needed to ensure a viable and cost-effective introduction of renewable energies into the country's energy portfolio. To the contrary, the government's support mechanisms have in many respects subverted these incentives, resulting in massive expenditures that show little long-term promise for stimulating the economy, protecting the environment, or increasing energy security.Energy policy, energy security, climate, employment
Lossless State Detection of Single Neutral Atoms
We introduce lossless state detection of trapped neutral atoms based on
cavity-enhanced fluorescence. In an experiment with a single 87-Rb atom, a
hyperfine-state-detection fidelity of 99.4% is achieved in 85 microseconds. The
quantum bit is interrogated many hundreds of times without loss of the atom
while a result is obtained in every readout attempt. The fidelity proves robust
against atomic frequency shifts induced by the trapping potential. Our scheme
does not require strong coupling between the atom and cavity and can be
generalized to other systems with an optically accessible quantum bit.Comment: 4 pages, 4 figure
The Nature of the Ny-Ålesund Wind Field Analysed by High-Resolution Windlidar Data
In this work we present windlidar data for the research village Ny-Ålesund located on Svalbard in the European Arctic (78.923°N, 11.928°E) from 2013 to 2021. The data have a resolution of 50 m and 10 min with an overlapping height of about 150 m. The maximum range depends on the meteorologic situation. Up to 1000 m altitude the data availability is better than 71%. We found that the highest wind speeds occur in November and December, the lowest ones in June and July, up to 500 m altitude the wind is channelled strongly in ESE to NW direction parallel to the fjord axis and the synoptic conditions above 1000 m altitude already dominate. While the fraction of windy days (v>10m/s) varies significantly from month to month, there is no overall trend of the wind visible in our data set. We define gusts and jets by the requirement of wind maxima v>2m/s above and below a wind maximum. In total, more than 24,000 of these events were identified (corresponding to 6% of the time), of which 223 lasted for at least 100 min (“Long Jets”). All of these events are fairly equally distributed over the months relatively to the available data. Further, gusts and jets follow different distributions (in terms of altitude or depths) and occur more frequently for synoptic flow from roughly a southerly direction. Jets do not show a clear correlation between occurrence and synoptic flow. Gusts and jets are not related to cloud cover. We conclude that the atmosphere from 400 m to 1000 m above Ny-Ålesund is dominated by a turbulent wind shear zone, which connects the micrometeorology in the atmospheric boundary layer (ABL) with the synoptic flow
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