Publications (86)
Balancing Cost Savings and Import Dependence in Germany's Industry Transformation
Toni Seibold, Fabian Neumann, Falko Ueckerdt +1
Greenhouse gas emissions from the steel, fertiliser and plastic industries can be mitigated by producing their precursors with green hydrogen. In Germany, green production may be e…
On abelian and additive complexity in infinite words
Hayri Ardal, Tom Brown, Veselin JungiÄ +1
The study of the structure of infinite words having bounded abelian complexity was initiated by G. Richomme, K. Saari, and L. Q. Zamboni. In this note we define bounded additive co…
A General Language Assistant as a Laboratory for Alignment
Amanda Askell, Yuntao Bai, Anna Chen +19
Given the broad capabilities of large language models, it should be possible to work towards a general-purpose, text-based assistant that is aligned with human values, meaning that…
Red Teaming Language Models to Reduce Harms: Methods, Scaling Behaviors, and Lessons Learned
Deep Ganguli, Liane Lovitt, Jackson Kernion +33
We describe our early efforts to red team language models in order to simultaneously discover, measure, and attempt to reduce their potentially harmful outputs. We make three main…
Extracting Training Data from Large Language Models
Nicholas Carlini, Florian Tramer, Eric Wallace +9
It has become common to publish large (billion parameter) language models that have been trained on private datasets. This paper demonstrates that in such settings, an adversary ca…
Cascading Failures and Critical Infrastructures in Future Renewable European Power Systems
Maurizio Titz, Franz Kaiser, Johannes Kruse +8
The world's power systems are undergoing a rapid transformation, shifting away from carbon-intensive power generation to renewable sources. As a result, electricity is being transp…
Opening the black box of energy modelling: Strategies and lessons learned
Stefan Pfenninger, Lion Hirth, Ingmar Schlecht +21
The global energy system is undergoing a major transition, and in energy planning and decision-making across governments, industry and academia, models play a crucial role. Because…
Benefits from Islanding Green Hydrogen Production
Christoph Tries, Fabian Hofmann, Tom Brown
In wind- and solar-dominated energy systems it has been assumed that there are synergies between producing electricity and electrolytic hydrogen since electrolysis can use excess e…
On the means, costs, and system-level impacts of 24/7 carbon-free energy procurement
Iegor Riepin, Tom Brown
A growing number of public and private energy buyers are interested in 24/7 carbon-free energy (CFE) procurement, which means that every kilowatt-hour of electricity consumption is…
The role of Projects of Common Interest in reaching Europe's energy policy targets
Bobby Xiong, Iegor Riepin, Tom Brown
The European Union aims to achieve climate-neutrality by 2050, with interim 2030 targets including 55% greenhouse gas emissions reduction compared to 1990 levels, 10 Mt p.a. of a d…
Science drivers and requirements for an Advanced Technology Large Aperture Space Telescope (ATLAST): Implications for technology development and synergies with other future facilities
Marc Postman, Tom Brown, Kenneth Sembach +11
The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a concept for an 8-meter to 16-meter UVOIR space observatory for launch in the 2025-2030 era. ATLAST will allow a…
The M31 Velocity Vector. II. Radial Orbit Towards the Milky Way and Implied Local Group Mass
Roeland P. van der Marel, Mark Fardal, Gurtina Besla +5
We determine the velocity vector of M31 with respect to the Milky Way and use this to constrain the mass of the Local Group, based on HST proper-motion measurements presented in Pa…
Scaling Laws and Interpretability of Learning from Repeated Data
Danny Hernandez, Tom Brown, Tom Conerly +15
Recent large language models have been trained on vast datasets, but also often on repeated data, either intentionally for the purpose of upweighting higher quality data, or uninte…
Managing the Mismatch: The Role of Flexibility on the Path to a Carbon-Neutral Energy System
Julian Geis, Michael Lindner, Tom Brown
A rapid expansion of system flexibility is essential to integrate increasing shares of renewable energy into future energy systems. However, flexibility needs and technology-specif…
Bounds on Van der Waerden Numbers and Some Related Functions
Tom Brown, Bruce M. Landman, Aaron Robertson
For positive integers and , let be the minimum integer such that any -coloring admits a -…
Mitigating heat demand peaks in buildings in a highly renewable European energy system
Elisabeth Zeyen, Veit Hagenmeyer, Tom Brown
Space and water heating accounts for about 40% of final energy consumption in the European Union and thus plays a key role in reducing overall costs and greenhouse gas emissions. M…
Inverse methods: How feasible are spatially low-resolved capacity expansion modelling results when disaggregated at high spatial resolution?
Martha Maria Frysztacki, Veit Hagenmeyer, Tom Brown
Spatially highly-resolved capacity expansion models are often simplified to a lower spatial resolution because they are computationally intensive. The simplification mixes sites wi…
The Potential Role of a Hydrogen Network in Europe
Fabian Neumann, Elisabeth Zeyen, Marta Victoria +1
Electricity transmission expansion has suffered many delays in Europe in recent decades, despite its significance for integrating renewable electricity into the energy system. A hy…
A new method for deriving the stellar birth function of resolved stellar populations
Mario Gennaro, Kirill Tchernyshyov, Tom Brown +1
We present a new method for deriving the stellar birth function (SBF) of resolved stellar populations. The SBF (stars born per unit mass, time, and metallicity) is the combination…
Measuring Progress on Scalable Oversight for Large Language Models
Samuel R. Bowman, Jeeyoon Hyun, Ethan Perez +43
Developing safe and useful general-purpose AI systems will require us to make progress on scalable oversight: the problem of supervising systems that potentially outperform us on m…
The role of storage technologies throughout the decarbonisation of the sector-coupled European energy system
Marta Victoria, Kun Zhu, Tom Brown +2
We use an open, hourly-resolved, networked model of the European energy system to investigate the storage requirements under decreasing CO emissions targets and several sector-…
H and CO Network Strategies for the European Energy System
Fabian Hofmann, Christoph Tries, Fabian Neumann +2
Hydrogen and carbon dioxide transport can both play an essential role in climate-neutral energy systems. Hydrogen networks help serve regions with high energy demand, while excess…
REMIND-PyPSA-Eur: Integrating power system flexibility into sector-coupled energy transition pathways
Adrian Odenweller, Falko Ueckerdt, Johannes Hampp +8
The rapid expansion of low-cost renewable electricity combined with end-use electrification in transport, industry, and buildings offers a promising path to deep decarbonisation. H…
Broad Ranges of Investment Configurations for Renewable Power Systems, Robust to Cost Uncertainty and Near-Optimality
Fabian Neumann, Tom Brown
To achieve ambitious greenhouse gas emission reduction targets in time, the planning of future energy systems needs to accommodate societal preferences, e.g. low levels of acceptan…
The Benefits of Cooperation in a Highly Renewable European Electricity Network
David P. Schlachtberger, Tom Brown, Stefan Schramm +1
To reach ambitious European CO emission reduction targets, most scenarios of future European electricity systems rely on large shares of wind and solar photovoltaic power gener…
Are biofuel mandates cost-effective? -- an analysis of transport fuels and biomass usage to achieve emissions targets in the European energy system
Markus Millinger, Lina Reichenberg, Fredrik Hedenus +3
Abatement options for the hard-to-electrify parts of the transport sector are needed to achieve ambitious emissions targets. Biofuels based on biomass, electrofuels based on renewa…
Endogenous learning for green hydrogen in a sector-coupled energy model for Europe
Elisabeth Zeyen, Marta Victoria, Tom Brown
Many studies have shown that hydrogen could play a large role in the energy transition for hard-to-electrify sectors, but previous modelling has not included the necessary features…
Pursuing decarbonization and competitiveness: a narrow corridor for European green industrial transformation
Alice Di Bella, Toni Seibold, Tom Brown +1
This study analyzes how Europe can decarbonize its industrial sector while remaining competitive. Using the open-source model PyPSA-Eur, it examines key energy- and emission-intens…
Counter-intuitive behaviour of energy system models under CO2 caps and prices
Juliane Weber, Heidi Ursula Heinrichs, Bastian Gillessen +4
The mitigation of climate change requires a fundamental transition of the energy system. Affordability, reliability and the reduction of greenhouse gas emissions constitute central…
PyPSA-DE: Open-source German energy system model reveals savings from integrated planning
Michael Lindner, Julian Geis, Toni Seibold +1
Germany has set an ambitious target of reaching net zero greenhouse gas emissions by 2045. We explore how integrated cross-sectoral planning can reduce costs compared to existing n…
Skill Rating for Generative Models
Catherine Olsson, Surya Bhupatiraju, Tom Brown +2
We explore a new way to evaluate generative models using insights from evaluation of competitive games between human players. We show experimentally that tournaments between genera…
Mind the Temperature Gap: The Role of Pit Thermal Energy Storage in a Sector-Coupled Energy System with High-Temperature District Heating
Caspar SchauÃ, Amos Schledorn, Tom Kähler +3
Pit thermal energy storage (PTES) provides large-scale thermal storage capacity in district heating systems, supporting flexibility on both daily and seasonal scales. Most existing…
Meteorological conditions during Dunkelflauten in Germany: Characteristics, the role of weather regimes and impacts on demand
Fabian Mockert, Christian M. Grams, Tom Brown +1
Renewable generation from wind and solar power is strongly weather-dependent. To plan future sustainable energy systems that are robust to this variability, a better understanding…
Predictability and Surprise in Large Generative Models
Deep Ganguli, Danny Hernandez, Liane Lovitt +27
Large-scale pre-training has recently emerged as a technique for creating capable, general purpose, generative models such as GPT-3, Megatron-Turing NLG, Gopher, and many others. I…
Price Formation in a Highly-Renewable, Sector-Coupled Energy System
Julian Geis, Fabian Neumann, Michael Lindner +2
As variable renewable energy increases and more demand is electrified, we expect price formation in wholesale electricity markets to transition from being dominated by fossil fuel…
Spatio-temporal load shifting for truly clean computing
Iegor Riepin, Tom Brown, Victor Zavala
Companies with datacenters are procuring significant amounts of renewable energy to reduce their carbon footprint. There is increasing interest in achieving 24/7 Carbon-Free Energy…
The role of spatial scale in joint optimisations of generation and transmission for European highly renewable scenarios
Jonas Hörsch, Tom Brown
The effects of the spatial scale on the results of the optimisation of transmission and generation capacity in Europe are quantified under a 95% CO2 reduction compared to 1990 leve…
The Impact of Climate Change on a Cost-Optimal Highly Renewable European Electricity Network
Markus Schlott, Alexander Kies, Tom Brown +2
We use three ensemble members of the EURO-CORDEX project and their data on surface wind speeds, solar irradiation as well as water runoff with a spatial resolution of 12 km and a t…
PyPSA: Python for Power System Analysis
Tom Brown, Jonas Hörsch, David Schlachtberger
Python for Power System Analysis (PyPSA) is a free software toolbox for simulating and optimising modern electrical power systems over multiple periods. PyPSA includes models for c…
Technical Report on the CleverHans v2.1.0 Adversarial Examples Library
Nicolas Papernot, Fartash Faghri, Nicholas Carlini +23
CleverHans is a software library that provides standardized reference implementations of adversarial example construction techniques and adversarial training. The library may be us…
A Minimal Methanol Backstop for High Electrification Scenarios
Philipp Glaum, Fabian Neumann, Markus Millinger +1
Electrification of sectors such as land transport and building heating is a cost-effective pathway to deep decarbonization. However, some sectors still require energy-dense fuels -…
Constitutional AI: Harmlessness from AI Feedback
Yuntao Bai, Saurav Kadavath, Sandipan Kundu +48
As AI systems become more capable, we would like to enlist their help to supervise other AIs. We experiment with methods for training a harmless AI assistant through self-improveme…
Advanced Technology Large-Aperture Space Telescope (ATLAST): A Technology Roadmap for the Next Decade
Marc Postman, Vic Argabright, Bill Arnold +65
The Advanced Technology Large-Aperture Space Telescope (ATLAST) is a set of mission concepts for the next generation of UVOIR space observatory with a primary aperture diameter in…
WorkflowHub: a registry for computational workflows
Ove Johan Ragnar Gustafsson, Sean R. Wilkinson, Finn Bacall +12
The rising popularity of computational workflows is driven by the need for repetitive and scalable data processing, sharing of processing know-how, and transparent methods. As both…
The strong effect of network resolution on electricity system models with high shares of wind and solar
Martha Maria Frysztacki, Jonas Hörsch, Veit Hagenmeyer +1
Energy system modellers typically choose a low spatial resolution for their models based on administrative boundaries such as countries, which eases data collection and reduces com…
On Double 3-Term Arithmetic Progressions
Tom Brown, Veselin JungiÄ, Andrew Poelstra
In this note we are interested in the problem of whether or not every increasing sequence of positive integers with bounded gaps must contain a double 3-term arithme…
A validated high-resolution hydro power time-series model for energy systems analysis
Hailiang Liu, Gorm Bruun Andresen, Tom Brown +1
We expand the renewable technology model palette and present a validated high resolution hydro power time series model for energy systems analysis. Among the popular renewables, hy…
Import options for chemical energy carriers from renewable sources to Germany
Johannes Hampp, Michael Düren, Tom Brown
Import and export of fossil energy carriers are cornerstones of energy systems world-wide. If energy systems are to become climate neutral and sustainable, fossil carriers need to…
Principal Flow Patterns across renewable electricity networks
Fabian Hofmann, Mirko Schäfer, Tom Brown +3
Using Principal Component Analysis (PCA), the nodal injection and line flow patterns in a network model of a future highly renewable European electricity system are investigated. I…
Cost optimal scenarios of a future highly renewable European electricity system: Exploring the influence of weather data, cost parameters and policy constraints
David P. Schlachtberger, Tom Brown, Mirko Schäfer +2
Cost optimal scenarios derived from models of a highly renewable electricity system depend on the specific input data, cost assumptions and system constraints. Here this influence…
Discovering Language Model Behaviors with Model-Written Evaluations
Ethan Perez, Sam Ringer, KamilÄ LukoÅ¡iÅ«tÄ +60
As language models (LMs) scale, they develop many novel behaviors, good and bad, exacerbating the need to evaluate how they behave. Prior work creates evaluations with crowdwork (w…
Offshore power and hydrogen networks for Europe's North Sea
Philipp Glaum, Fabian Neumann, Tom Brown
The European North Sea has a vast renewable energy potential and can be a powerhouse for Europe's energy transition. However, currently there is uncertainty about how much offshore…
The Capacity for Moral Self-Correction in Large Language Models
Deep Ganguli, Amanda Askell, Nicholas Schiefer +46
We test the hypothesis that language models trained with reinforcement learning from human feedback (RLHF) have the capability to "morally self-correct" -- to avoid producing harmf…
Modeling Curtailment in Germany: How Spatial Resolution Impacts Line Congestion
Martha Frysztacki, Tom Brown
This paper investigates the effects of network constraints in energy system models at transmission level on renewable energy generation and curtailment as the network is being spat…
Linear Optimal Power Flow Using Cycle Flows
Jonas Hörsch, Henrik Ronellenfitsch, Dirk Witthaut +1
Linear optimal power flow (LOPF) algorithms use a linearization of the alternating current (AC) load flow equations to optimize generator dispatch in a network subject to the loadi…
Offshore Wind Integration in the North Sea: The Benefits of an Offshore Grid and Floating Wind
Philipp Glaum, Fabian Neumann, Tom Brown
Wind energy has become increasingly important for meeting Europe's energy needs. While onshore wind expansion faces public acceptance problems, for offshore wind the European Commi…
Transfer of Adversarial Robustness Between Perturbation Types
Daniel Kang, Yi Sun, Tom Brown +2
We study the transfer of adversarial robustness of deep neural networks between different perturbation types. While most work on adversarial examples has focused on and…
Long-Term Benefits of Network Boosters for Renewables Integration and Corrective Grid Security
Amin Shokri Gazafroudi, Elisabeth Zeyen, Martha Frysztacki +2
The preventative strategies for network security dominant in European networks mean that network capacity is kept free in case a line fails. If instead fast corrective action…
Flow-based analysis of storage usage in a low-carbon European electricity scenario
Bo Tranberg, Mirko Schäfer, Tom Brown +2
The application of the flow tracing method to power flows in and out of storage units allows to analyse the usage of this technology option in large-scale interconnected electricit…
Approximating Power Flow and Transmission Losses in Coordinated Capacity Expansion Problems
Fabian Neumann, Veit Hagenmeyer, Tom Brown
With rising shares of renewables and the need to properly assess trade-offs between transmission, storage and sectoral integration as balancing options, building a bridge between e…
The role of hydro power, storage and transmission in the decarbonization of the Chinese power system
Hailiang Liu, Tom Brown, Gorm Bruun Andresen +2
Deep decarbonization of the electricity sector can be provided by a high penetration of renewable sources such as wind, solar PV and hydro power. Flexibility from hydro and storage…
Training a Helpful and Harmless Assistant with Reinforcement Learning from Human Feedback
Yuntao Bai, Andy Jones, Kamal Ndousse +28
We apply preference modeling and reinforcement learning from human feedback (RLHF) to finetune language models to act as helpful and harmless assistants. We find this alignment tra…
Speed of technological transformations required in Europe to achieve different climate goals
Marta Victoria, Elisabeth Zeyen, Tom Brown
Europe's contribution to global warming will be determined by the cumulative emissions until climate neutrality is achieved. In this paper, we investigate alternative transition pa…
Dual theory of transmission line outages
Henrik Ronellenfitsch, Debsankha Manik, Jonas Hörsch +2
A new graph dual formalism is presented for the analysis of line outages in electricity networks. The dual formalism is based on a consideration of the flows around closed cycles i…
The Near-Optimal Feasible Space of a Renewable Power System Model
Fabian Neumann, Tom Brown
Models for long-term investment planning of the power system typically return a single optimal solution per set of cost assumptions. However, typically there are many near-optimal…
In-context Learning and Induction Heads
Catherine Olsson, Nelson Elhage, Neel Nanda +23
"Induction heads" are attention heads that implement a simple algorithm to complete token sequences like [A][B] ... [A] -> [B]. In this work, we present preliminary and indirect ev…
Modelling the High-Voltage Grid Using Open Data for Europe and Beyond
Bobby Xiong, Davide Fioriti, Fabian Neumann +2
This paper provides the background, methodology and validation for constructing a representation of the European high-voltage grid, including and above 200 kV, based on public data…
The role of photovoltaics in a sustainable European energy system under variable CO2 emissions targets, transmission capacities, and costs assumptions
Marta Victoria, Kun Zhu, Tom Brown +2
PyPSA-Eur-Sec-30 is an open-source, hourly-resolved, networked model of the European energy system which includes one node per country as well as electricity, heating, and transpor…
Transmission Expansion Planning Using Cycle Flows
Fabian Neumann, Tom Brown
The common linear optimal power flow (LOPF) formulation that underlies most transmission expansion planning (TEP) formulations uses bus voltage angles as auxiliary optimization var…
Roadmap to fault tolerant quantum computation using topological qubit arrays
David Aasen, Morteza Aghaee, Zulfi Alam +179
We describe a concrete device roadmap towards a fault-tolerant quantum computing architecture based on noise-resilient, topologically protected Majorana-based qubits. Our roadmap e…
Early decarbonisation of the European energy system pays off
Marta Victoria, Kun Zhu, Tom Brown +2
For a given carbon budget over several decades, different transformation rates for the energy system yield starkly different results. Here we consider a budget of 33 GtCO2 for the…
Heuristics for Transmission Expansion Planning in Low-Carbon Energy System Models
Fabian Neumann, Tom Brown
Governments across the world are planning to increase the share of renewables in their energy systems. The siting of new wind and solar power plants requires close coordination wit…
UV friendly T-parity in the SU(6)/Sp(6) little Higgs model
Tom Brown, Claudia Frugiuele, Thomas Gregoire
Electroweak precision tests put stringent constraints on the parameter space of little Higgs models. Tree-level exchange of TeV scale particles in a generic little Higgs model prod…
Price formation without fuel costs: the interaction of demand elasticity with storage bidding
Tom Brown, Fabian Neumann, Iegor Riepin
Studies looking at electricity market designs for very high shares of wind and solar often conclude that the energy-only market will break down. Without fuel costs, it is said that…
Optimal heterogeneity in a simplified highly renewable European electricity system
Emil H. Eriksen, Leon J. Schwenk-Nebbe, Bo Tranberg +2
The resource quality and the temporal generation pattern of variable renewable energy sources vary significantly across Europe. In this paper spatial distributions of renewable ass…
Energy Imports and Infrastructure in a Carbon-Neutral European Energy System
Fabian Neumann, Johannes Hampp, Tom Brown
Importing renewable energy to Europe offers many potential benefits, including reduced energy costs, lower pressure on infrastructure development, and less land-use within Europe.…
The impact of temporal hydrogen regulation on hydrogen exporters and their domestic energy transition
Leon Schumm, Hazem Abdel-Khalek, Tom Brown +4
As global demand for green hydrogen rises, potential hydrogen exporters move into the spotlight. However, the large-scale installation of on-grid hydrogen electrolysis for export c…
E-biofuels reduce the cost of achieving emissions targets in hard-to-electrify sectors
Yunlong Zhang, Markus Millinger, Fredrik Hedenus +2
Renewable liquid fuels are essential for achieving emissions targets for hard-to-electrify sectors such as aviation and shipping. While biofuels and synthetic e-fuels have been wel…
Approximations of additive squares in infinite words
Tom Brown
We show that every infinite word on a finite subset of must contain arbitrarily large factors which are "close" to being \textit{additive squares}. We al…
Accelerating fossil gas independence in Europe
Lukas Franken, Iegor Riepin, Tom Brown
Recent price shocks have prompted calls to curb Europe's dependence on fossil gas imports, but the cost of this goal, and the consumer protection it affords, remain uncertain. Here…
Shifting burdens: How delayed decarbonisation of road transport affects other sectoral emission reductions
Elisabeth Zeyen, Sina Kalweit, Marta Victoria +1
In 2022, fuel combustion in road transport accounted for approximately 21% (760 million tonnes) of CO2 emissions in the European Union (EU). Road transport is the only sector with…
PyPSA-Eur: An Open Optimisation Model of the European Transmission System
Jonas Hörsch, Fabian Hofmann, David Schlachtberger +1
PyPSA-Eur, the first open model dataset of the European power system at the transmission network level to cover the full ENTSO-E area, is presented. It contains 6001 lines (alterna…
Topology-based Approximations for Contingency Constraints in Power Transmission Networks
Amin Shokri Gazafroudi, Fabian Neumann, Tom Brown
It is crucial for maintaining the security of supply that transmission networks continue to operate even if a single line fails. Modeling security in power system…
Market Integration Pathways for Enhanced Geothermal Systems in Europe
Lukas Franken, Elisabeth Zeyen, Orestis Angelidis +2
Enhanced Geothermal Systems (EGS) can provide constant, reliable electricity and heat with minimal emissions, but high drilling costs and uncertain cost reductions leave their futu…
Testing Robustness Against Unforeseen Adversaries
Max Kaufmann, Daniel Kang, Yi Sun +9
Adversarial robustness research primarily focuses on L_p perturbations, and most defenses are developed with identical training-time and test-time adversaries. However, in real-wor…
Language Models (Mostly) Know What They Know
Saurav Kadavath, Tom Conerly, Amanda Askell +33
We study whether language models can evaluate the validity of their own claims and predict which questions they will be able to answer correctly. We first show that larger models a…