Tyler H. Ruggles

Carnegie Institution for Science · Department of Global Ecology

A measurement of the H→ττ signal strength is performed using events recorded in proton–proton collisions by the CMS experiment at the LHC in 2016 at a center-of-mass energy of 13TeV. The data set corresponds to an integrated luminosity of 35.9fb−1. The H→ττ signal is established with a significance of 4.9 standard deviations, to be compared to an e...

Electricity usage (demand) data are used by utilities, governments, and academics to model electric grids for a variety of planning (e.g., capacity expansion and system operation) purposes. The U.S. Energy Information Administration collects hourly demand data from all balancing authorities (BAs) in the contiguous United States. As of September 201...

Wind and solar energy technologies are, by their nature, variable. Variations in resource availability, based on weather patterns, occur on intra-day to inter-annual time scales. Many energy system models optimize over a single year of input weather and electricity demand data. Energy system planners need increased understanding of the variability...

Resource adequacy, or ensuring that electricity supply reliably meets demand, is more challenging for wind-and solar-based electricity systems than fossil-fuel-based ones. Here, we investigate how the number of years of past weather data used in designing least-cost systems relying on wind, solar, and energy storage affects resource adequacy. We fi...

This perspective investigates the impacts of disparate energy disruptions during Winter Storm Uri, which in 2021 caused severe power outages across the state of Texas leading to numerous deaths and billions of dollars of damage to property and infrastructure. The paper focuses on the potential injustice along ethnic lines in the distribution of pow...

In contrast to battery storage systems, power-to-hydrogen-to-power (P-H2-P) storage systems provide opportunities to separately optimize the costs and efficiency of the system’s charging, storage, and discharging components. The value of capital cost reduction relative to round-trip efficiency improvements of P-H2-P systems is not well understood i...

A stylized macro-scale energy model of least-cost electricity systems relying only on wind and solar generation was used to assess the value of different storage technologies, individually and combined, for the contiguous U.S. as well as for four geographically diverse U.S. load-balancing regions. For the contiguous U.S. system, at current costs, w...

Wind droughts, or prolonged periods of low wind speeds, pose challenges for electricity systems largely reliant on wind generation. Using weather reanalysis data,we analyzed the global distribution of and trends in wind droughts using an energy deficit metric that integrates the depth and duration of wind droughts. We identified regions with high p...

The power supply from solar and wind generators is not only inherently variable but also prone to failure due to rare-weather related events, i.e., hailstorms, icing. Current system sizing strategies often consider system reliability or resilience but rarely consider them simultaneously. Here, we proposed a sizing approach for an off-grid power sys...

It remains a significant technical and economic challenge to fully power large-scale grids with intermittent renewable energy (RE). Meanwhile, due to the rapid decrease in the cost of RE power generation technologies in recent years, the number of real-world implementations and studies dedicated to the optimal capacity sizing of renewable off-grid...

We employed an idealized macro-energy system model to examine how the value of unidirectional and bidirectional charging electric vehicles (EVs) varies with EV penetration and mix of electricity generators. We find that EVs can help wind and solar-based electricity generation systems to be less costly by making better use of power that would otherw...

Policies in the US increasingly stipulate the use of variable renewable energy sources, which must be able to meet electricity demand reliably and affordably despite variability. The value of grid services provided by additional marginal capacity and storage in existing grids is likely very different than their value in a 100% variable renewable el...

Solar photovoltaics, with sufficient power generation potential, low-carbon footprint, and rapidly declining costs, could supplant fossil fuel uses and help produce lower-cost net-zero emissions energy systems. Here we used an idealized linear optimization model, including free lossless transmission, to study the response of electricity systems to...

Wind and solar photovoltaic generators are projected to play important roles in achieving a net-zero-carbon electricity system that meets current and future energy needs. Here, we show potential advantages of long-term site planning of wind and solar power plants in deeply decarbonized electricity systems using a macro-scale energy model. With weak...

We employed a bottom-up modeling framework to examine a set of scenarios to generate insights on the techno-economic and environmental implications of increasing levels of EV penetration using Nigeria as a case study. Results indicate that, despite having a natural gas-dominated electricity system, the deployment of EVs can support the decarbonizat...

Electricity systems worldwide are transforming from relying almost exclusively on firm, predictable generation (e.g., fossil, nuclear, and large hydropower) towards incorporating more variable generation (e.g., wind and solar PV). In these systems, the electric load minus generation from variable resources is known as the “residual load.” The peak...

Wind and solar photovoltaic are projected to play important roles in achieving a net-zero-carbon electricity system that meets current and future energy needs. Here, we show potential advantages of long-term site planning of wind and solar power plants in deep decarbonization scenarios for electricity systems. We use a macro-scale energy model to f...

Electric sector capacity expansion models are widely used by academic, government, and industry researchers for policy analysis and planning. Many models overlap in their capabilities, spatial and temporal resolutions, and research purposes, but yield diverse results due to both parametric and structural differences. Previous work has attempted to...

Hundreds of gigawatts of renewable technologies, such as wind and solar, need to be installed to reach a zero-carbon electricity system that meets current and future energy needs. Locations of new installations are typically chosen based on wind and solar availability to maximize facilities’ capacity factors. Here, we show that this is not always t...

Variable, low-cost, low-carbon electricity that would otherwise be curtailed may provide a substantial economic opportunity for entities that can flexibly adapt their electricity consumption. We used historical hourly weather data over the contiguous U.S. to model the characteristics of least-cost electricity systems dominated by variable renewable...

As reliance on wind and solar power for electricity generation increases, so does the importance of understanding how variability in these resources affects the feasible, cost-effective ways of supplying energy services. We use hourly weather data over multiple decades and historical electricity demand data to analyze the gaps between wind and sola...

Reliable and affordable electricity systems based on variable energy sources, such as wind and solar may depend on the ability to store large quantities of low-cost energy over long timescales. Here, we use 39 years of hourly U.S. weather data, and a macro-scale energy model to evaluate capacities and dispatch in least cost, 100% reliable electrici...

A bstract A search for the standard model Higgs boson produced in association with a W or a Z boson and decaying to a pair of τ leptons is performed. A data sample of proton-proton collisions collected at $$ \sqrt{s} $$ s = 13 TeV by the CMS experiment at the CERN LHC is used, corresponding to an integrated luminosity of 35.9 fb ⁻¹ . The signal str...

We present a deep learning, computer vision algorithm constructed for the purposes of identifying and classifying charged particles in camera image sensors. We apply our algorithm to data collected by the Distributed Electronic Cosmic-ray Observatory (DECO), a global network of smartphones that monitors camera image sensors for the signatures of co...

The total area of silicon in cell phone camera sensors worldwide surpasses that in any experiment to date. Based on semiconductor technology similar to that found in modern astronomical telescopes and particle detectors, these sensors can detect ionizing radiation in addition to photons. The Distributed Electronic Cosmic-ray Observatory (DECO) uses...

Solid-state camera image sensors can be used to detect ionizing radiation in addition to optical photons. We describe the Distributed Electronic Cosmic-ray Observatory (DECO), an app and associated public database that enables a network of consumer devices to detect cosmic rays and other ionizing radiation. In addition to terrestrial background rad...

A search for a heavy scalar boson H decaying into a pair of lighter standard-model-like 125 GeV Higgs bosons hh and a search for a heavy pseudoscalar boson A decaying into a Z and an h boson are presented. The searches are performed on a data set corresponding to an integrated luminosity of 19.7 fb−1 of pp collision data at a centre-of-mass energy...

Camera image sensors can be used to detect ionizing radiation in addition to optical photons. In particular, cosmic-ray muons are detected as long, straight tracks passing through multiple pixels. The distribution of track lengths can be related to the thickness of the active (depleted) region of the camera image sensor through the known angular di...

In 2014 the number of active cell phones worldwide for the first time surpassed the number of humans. Cell phone camera quality and onboard processing power (both CPU and GPU) continue to improve rapidly. In addition to their primary purpose of detecting photons, camera image sensors on cell phones and other ubiquitous devices such as tablets, lapt...

The Colorado College Energy Audit and Retrofit Program is a non-profit organization that teaches students the science and mechanics involved in energy audits and retrofit work through service–learning and community-based research projects. This approach represents a “win–win” scenario where the college contributes to maximize learning and minimize...