65 research outputs found
The political economy of electricity system resource adequacy and renewable energy integration: A comparative study of Britain, Italy and California
The need to integrate growing shares of variable renewable resources, like solar and wind, into the power system has initiated a new wave of resource adequacy policy reforms. Securing adequate resources on the system, particularly flexible and peak capacity, is indeed crucial for ensuring long-term grid reliability amid increased supply variability. While extensively explored from a techno-economic perspective, the political economy drivers and implications of these changes are frequently overlooked. Yet, power system evolution is not merely shaped by logics of techno-economic optimisation, it is also inherently political, rooted in specific liberalisation histories, political and institutional settings.
This paper contributes to the literature by conducting a comparative political economy analysis of recent resource adequacy reforms in Britain, Italy, and California. It explores how differences in the technical and political economy contexts of these jurisdictions affected their strategies for securing resource adequacy capacity and investment between 2013 and 2021. Conclusions draw on the analysis of over 134 policy documents and 53 in-depth interviews with power system stakeholders.
All jurisdictions introduced significant changes in resource adequacy policy, including explicit out-of-market mechanisms to remunerate resource adequacy capacity. The energy transition is thus reconfiguring state-market relations in the power sector, even in traditionally liberal countries. However, variation exists in the scope of reform, mechanism designs, policy trade-offs, and technological outcomes. This stems from context-specific political priorities, state-market relations, national and multi-level governance arrangements, market structures and stakeholder interests. This has important implications for power sector governance, as discussed in this paper
TU Tau B: The Peculiar 'Eclipse' of a possible proto-Barium Giant
TU Tau (= HD 38218 = HIP 27135) is a binary system consisting of a C-N carbon
star primary and an A-type secondary. We report on new photometry and
spectroscopy which tracked the recent disappearance of the A-star secondary.
The dimming of the A-star was gradual and irregular, with one or more brief
brightenings, implying the presence of nonhomogeneities in the carbon star
outflow. We also present evidence that the A-star is actively accreting
s-process enriched material from the carbon star and suggest that it will
therefore eventually evolve into a Barium giant. This is an important system as
well because the A-type star can serve as a probe of the outer atmosphere of
the carbon star.Comment: 9 pages, 9 figures, 4 tables, a number of amateur observatories made
significant contributions to this research. Paper accepted for publication in
The Astronomical Journa
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
A Focus on Atrial Fibrillation in Scotland: A report by the Cross-Party Group on Heart Disease and Stroke
No abstract available
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