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Photovoltaic (PV) solar energy generating capacity has grown by 41 per cent per year since 2009 1 . Energy system projections that mitigate climate change and aid universal energy access show a nearly ten-fold increase in PV solar energy generating capacity by 2040 2 , 3 . Geospatial data describing the energy system are required to manage generation intermittency, mitigate climate change risks, and identify trade-offs with biodiversity, conservation and land protection priorities caused by the land-use and land-cover change necessary for PV deployment. Currently available inventories of solar generating capacity cannot fully address these needs 1 – 9 . Here we provide a global inventory of commercial-, industrial- and utility-scale PV installations (that is, PV generating stations in excess of 10 kilowatts nameplate capacity) by using a longitudinal corpus of remote sensing imagery, machine learning and a large cloud computation infrastructure. We locate and verify 68,661 facilities, an increase of 432 per cent (in number of facilities) on previously available asset-level data. With the help of a hand-labelled test set, we estimate global installed generating capacity to be 423 gigawatts (−75/+77 gigawatts) at the end of 2018. Enrichment of our dataset with estimates of facility installation date, historic land-cover classification and proximity to vulnerable areas allows us to show that most of the PV solar energy facilities are sited on cropland, followed by aridlands and grassland. Our inventory could aid PV delivery aligned with the Sustainable Development Goals. A global inventory of utility-scale solar photovoltaic generating units, produced by combining remote sensing imagery with machine learning, has identified 68,661 facilities — an increase of over 400% on previously available asset-level data —  the majority of which were sited on cropland.

The third-generation upgrade to the receiver on the South Pole Telescope, SPT-3G, was installed at the South Pole during the 2016–2017 austral summer to measure the polarization of the cosmic microwave background. Increasing the number of detectors by a factor of 10 to ∼ 16 , 000 required the multiplexing factor to increase to 68 and the bandwidth of the frequency-division readout electronics to span 1.6–5.2 MHz. This increase necessitates low-thermal conductance, low-inductance cryogenic wiring. Our cold readout system consists of planar thin-film aluminum inductive–capacitive resonators, wired in series with the detectors, summed together, and connected to 4K SQUIDs by 10 - μ m -thick niobium–titanium (NbTi) broadside-coupled striplines. Here, we present an overview of the cold readout electronics for SPT-3G, including assembly details and characterization of electrical and thermal properties of the system. We report, for the NbTi striplines, values of R ≤ 10 - 4 Ω , L = 21 ± 1 nH , and C = 1.47 ± . 02 nF . Additionally, the striplines’ thermal conductivity is described by k A = 6.0 ± 0.3 T 0.92 ± 0.04 μ W mm K - 1 . Finally, we provide projections for cross talk induced by parasitic impedances from the stripline and find that the median value of percentage cross talk from leakage current is 0.22 and 0.09 % from wiring impedance.

The third-generation South Pole Telescope camera is designed to measure the cosmic microwave background across three frequency bands (centered at 95, 150 and 220 GHz) with ∼  16,000 transition-edge sensor (TES) bolometers. Each multichroic array element on a detector wafer has a broadband sinuous antenna that couples power to six TESs, one for each of the three observing bands and both polarizations, via lumped element filters. Ten detector wafers populate the detector array, which is coupled to the sky via a large-aperture optical system. Here we present the frequency band characterization with Fourier transform spectroscopy, measurements of optical time constants, beam properties, and optical and polarization efficiencies of the detector array. The detectors have frequency bands consistent with our simulations and have high average optical efficiency which is 86, 77 and 66% for the 95, 150 and 220 GHz detectors. The time constants of the detectors are mostly between 0.5 and 5 ms. The beam is round with the correct size, and the polarization efficiency is more than 90% for most of the bolometers.

Methane emissions associated with the production, transport, and use of oil and natural gas increase the climatic impacts of energy use; however, little is known about how emissions vary temporally and with commodity prices. We present airborne and ground-based data, supported by satellite observations, to measure weekly to monthly changes in total methane emissions in the United States' Permian Basin during a period of volatile oil prices associated with the COVID-19 pandemic. As oil prices declined from ∼ USD 60 to USD 20 per barrel, emissions changed concurrently from 3.3 % to 1.9 % of natural gas production; as prices partially recovered, emissions increased back to near initial values. Concurrently, total oil and natural gas production only declined by ∼ 10 % from the peak values seen in the months prior to the crash. Activity data indicate that a rapid decline in well development and subsequent effects on associated gas flaring and midstream infrastructure throughput are the likely drivers of temporary emission reductions. Our results, along with past satellite observations, suggest that under more typical price conditions, the Permian Basin is in a state of overcapacity in which rapidly growing associated gas production exceeds midstream capacity and leads to high methane emissions.

We present a measurement of gravitational lensing over 1500 deg\\(^2\\) of the Southern sky using SPT-3G temperature data at 95 and 150 GHz taken in 2018. The lensing amplitude relative to a fiducial Planck 2018 \\(\\Lambda\\)CDM cosmology is found to be \\(1.020\\pm0.060\\), excluding instrumental and astrophysical systematic uncertainties. We conduct extensive systematic and null tests to check the robustness of the lensing measurements, and report a minimum-variance combined lensing power spectrum over angular multipoles of \\(50

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