Research

Existing accounting for generative AI generally stops at the model. This work extends it to the interface, where use is decided, and to storage, where output accumulates.

The model boundary in generative AI cost accounting Two zones separated by a dashed line labelled model boundary. Above the line sit training, a one-time cost per model, and inference, incurred on every prompt at scale. These are the stages existing research measures. Below the line sit the interface, where use is decided, and storage, where output accumulates. One arrow runs from the interface upward across the boundary into inference. A second runs from inference downward across the boundary into storage. MEASURED BY EXISTING WORK Training Once per model Inference Every prompt, at scale MODEL BOUNDARY Interface Where use is decided Storage Where output accumulates WHERE THIS WORK INTERVENES

Consumer generative AI moved from research prototype to everyday use in under four years, and its environmental cost scaled with that adoption. Research on that cost has matured in two stages. The first measured the carbon emitted while training a model. The second measured the energy consumed while running one. Both stop at the model boundary and treat the volume and character of use as given. This work extends the analysis past that boundary, to the interface where use is decided and to the storage where the output accumulates.

Inference is the technical term for what happens each time someone submits a prompt. The trained model processes the input, produces a response, and draws power for the duration. Because a model is trained once and then queried billions of times, inference is now the larger and faster-growing share of the total footprint. Data centres consumed roughly 415 TWh of electricity globally in 2024, about 1.5% of global supply, and that figure has grown at roughly 12% per year since 2017 on International Energy Agency estimates. A single image generation costs between 1.4 and 2 watt-hours by the estimates developed in this work, equivalent to running a 9-watt LED bulb for around ten minutes. That is a trivial amount per query and a consequential one at the volume consumer systems now process.

Two dimensions of that footprint remain underexamined, and both sit on the user's side of the model. The first is the interface. What a prompt costs is invisible at the moment it is sent, and the design conventions of consumer AI have been evaluated as usability and engagement problems rather than sustainability ones. The second is storage. Generated content draws power for as long as it is retained, platforms retain it by default, and no current assessment framework treats storage as a distinct environmental phase with its own measures.

The claim tested across this work is that the environmental cost of generative AI can be addressed at the interface, because the interface is where the use that drives it takes place. A controlled between-subjects study supports it. Participants who could see the energy cost of each prompt consumed measurably less than participants who could not, although visibility alone left a gap between what those participants knew and what they did. The storage burden had neither vocabulary nor metrics when this work began, so it is approached from the ground up: naming it, classifying it, and building the measures that make it reportable.

Energy and emissions at inference

This work establishes how much energy diffusion-based image generation consumes once it reaches consumer scale. The work was among the earliest peer-reviewed treatments of inference-phase cost in consumer generative AI, published when the field was still measuring training almost exclusively, and, as far as I have been able to establish, the first to frame mass adoption itself as the primary environmental risk. Producing the estimates meant assembling fragmentary public figures on active users, hardware, and output volume, because the operators of these systems do not publish what would be needed to calculate the answer directly. That absence is a finding in its own right, and it recurs across the rest of this research.

2023

Climate Implications of Diffusion-based Generative Visual AI Systems and their Mass Adoption

14th International Conference on Computational Creativity (ICCC 2023). Waterloo, Canada. With Steve DiPaola.

Most work on the environmental cost of machine learning measures training. This paper argues that consumer-facing image systems move the weight of the problem to inference, and produces preliminary estimates showing that mass adoption contributes considerably to global energy consumption. It closes by specifying exactly what developers would need to publish for anyone to calculate this accurately: daily active users, total daily output, processing hardware, and user location, since emissions per kilowatt-hour vary by grid.

Digital waste and overconsumption

Bytes held in a data centre draw power whether or not anyone looks at them again, and consumer generative AI produces them at a rate nobody is counting. Lifecycle assessments of these systems account for training and inference but treat storage as background load, so the content they generate has no place in the environmental ledger and no measures attached to it. This strand builds both. It names the behavioural pattern driving the volume, distinguishes the output a user commits to from the intermediate generations discarded on the way there, and converts the resulting burden into workflow-level metrics that a disclosure regime could require. Enterprise figures put storage energy intensity at roughly 46 kWh per terabyte per year, with around half of stored enterprise data never accessed after collection. Consumer-generated content carries none of the organizational incentives that keep enterprise data under review, so its accumulation rate, and its burden, may exceed that baseline considerably.

2026

Generative AI has a Slag Problem

IJCAI, 1st Workshop on Sustainability and Resource Efficiency of Artificial Intelligence (SuRE).

Iterative generation produces large volumes of intermediate output that users discard but systems keep. Borrowing from metallurgy, this paper names that residue AI slag and distinguishes it from AI slop, the low-value terminal content existing work describes. It proposes two metrics: Slag Rate, the proportion of a workflow that becomes residue, and Waste Stream Intensity, which converts retained slag into annual carbon equivalents. Applied to a real image workflow, the Slag Rate was 0.88, meaning 88% of generated outputs were never used.

2025

Responsible Data Stewardship: Generative AI and the Digital Waste Problem

arXiv:2505.21720.

Digital waste is stored data that consumes resources without serving a purpose. This paper introduces the term to the AI community and argues that indefinite storage of synthetic content is an ethical problem rather than merely a technical one, because it commits future generations to maintaining infrastructure they had no part in creating. It draws transferable practices from digital lean manufacturing and information lifecycle management, and sets out recommendations for researchers, developers, and organisations.

2023

Digital Overconsumption and Waste: A Closer Look at the Impacts of Generative AI

CVPR 2023, Ethical Considerations in Creative Applications of Computer Vision (EC3V) Workshop. Vancouver, Canada. With Steve DiPaola.

Survey evidence on why people use generative image tools and how much they produce, paired with what happened when participants were shown emissions data. The response was scepticism about the figures and pessimism about whether anyone else would change their behaviour, which is the finding that pushed the rest of this work toward design rather than education.

Sustainable GenAI design principles

The maximalist design of consumer generative AI is a cultural commitment rather than a technical constraint. Midjourney returns four images per prompt by default, and ChatGPT presents a perpetually available prompt field alongside a single-click regenerate button. Neither choice follows from anything about how the underlying models work. Technologies embed the values of the people who build them, so a different set of values would produce a different system, and this strand specifies what that alternative would commit to. Five principles collected under the heading of Slow AI each operate at two levels, the design change that implements the principle and the interpretive shift it asks of the user. The lineage runs back to Slow Technology, which argued in 2001 that systems built for reflection rather than efficient throughput serve their users differently. What each principle does is return a decision that frictionless defaults currently make on the user's behalf without surfacing it.

2026

Environmental Slow AI: Design Principles for Generative Systems

ICML 2026, Culture × AI Workshop: Evaluating AI as a Cultural Technology. Seoul, South Korea.

Midjourney returns four images per prompt by default and ChatGPT presents a perpetually available prompt field. These are value commitments, not engineering constraints. The paper sets out five design principles under the heading of Slow AI: restraint, sufficiency, selectivity over retention, material visibility, and friction as affordance. Each restores a decision that frictionless defaults removed silently. It also sketches a restraint rate metric, measuring how often a system recommends non-use where a conventional tool would serve better.

2025

Green User Interface Design for Generative AI Systems: Ensuring Data Generation and Energy Consumption Cognizance

ACM Celebration of Cascadia Women in Computing. Vancouver, Canada.

An early report on the interface that became U.ness, drawing on the literature on energy use indicators in household appliances, where relational and historical feedback have been shown to change behaviour and comparison against social norms has sometimes backfired. It sets the two research questions the later study answered: whether showing energy use, or showing kilobytes generated, reduces the number of prompts people send.

U.ness: a system that shows what it costs

U.ness is a locally-run, open-source generative AI system that displays what each prompt costs. It runs distilled language models through Ollama behind a browser interface built with Gradio, and its Energy Use Indicator reports per-prompt watt-hours, cumulative session energy, and a rolling A-to-E efficiency grade after every query. Nothing leaves the machine it runs on. The system addresses four dimensions of user agency that commercial platforms resolve on the user's behalf, namely access, data ownership, environmental cost, and operational control.

The system exists to test what published emissions data cannot settle, which is whether people change what they do when the cost is visible at the moment they act rather than reported in aggregate afterwards. A between-subjects study with fourteen participants found that they do. Participants who saw the indicator consumed roughly half the energy of the control group across an identical three-task workflow and submitted around eight prompts per session against the control group's fourteen, with no significant difference in how long the sessions ran. The sample is small and the tasks were short, so this establishes a behavioural signal worth pursuing rather than a population-scale effect.

The interviews qualified the finding. Participants valued the visibility but described the watt-hour figure as a measurement they had no way to act on, and asked for guidance rather than more numbers. That gap set the agenda for the work on prompting strategy as an energy variable, which measures what a user can actually change.

Two papers reporting this work are currently under submission. Restoring User Agency in Generative AI: Inference-Phase Energy Visibility introduces the system and reports the study described above. Rethinking Prompt Engineering Through an Energy Lens: An Empirical Study of LLM Inference Consumption measures per-query energy across seven prompting strategies, five task scenarios, and two inference modes, and supplies the evidence base for the guidance layer the next iteration of U.ness will carry.

Developed at the iViz Lab under the supervision of Steve DiPaola, with Rafael Arias Gonzalez.

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Past: visual perception, aesthetics, and stimulus design

Before moving to sustainability, my work examined how the visual properties of a stimulus determine a viewer's response, and how computational systems can be used to control those properties experimentally. Deep learning systems can produce images and videos that observers do not reliably distinguish from human-made artworks, which means a stimulus set can be built to an experimental specification rather than assembled from whatever existing works happen to approximate it. Control over the generator becomes control over the independent variable. The aesthetics studies used that leverage to test how the two processing streams of the visual system interact with aesthetic judgment, returning initial evidence that movement within a percept engages reflexive attention and lowers the judgment that follows.

A parallel line asked what the visual system extracts from images that never reach awareness, testing semantic priming from pictures rendered invisible by backward masking and by continuous flash suppression. The backward-masking condition did not replicate the priming effect reported in the earlier literature, a result worth stating plainly given how much of that literature rests on effects of this kind. A third line applied the same knowledge to design rather than measurement. Faces carry identity and emotional expression at the same time, so conventional anonymization removes both, and this work tested AI stylization as a way to obscure the first while preserving the second in research interview footage.

This research secured the multi-year funding that supported my doctorate. Its methods transfer directly to the work above, since an interface is also a stimulus whose properties shape behaviour, and the same experimental design, controlled stimulus construction, and behavioural measurement underwrite the U.ness study.

2024

Empathy through Aesthetics: Using AI Stylization for Visual Anonymization of Interview Videos

CHI 2024, EmpathiCH Workshop. With Ö. N. Yalçin and S. DiPaola.

2021

Exploring the Application of AI-generated Artworks for the Study of Aesthetic Processing

IEEE Fourth International Conference on Multimedia Information Processing and Retrieval (MIPR 2021). With S. DiPaola.

2020

Using an AI Creativity System to Explore how Aesthetic Experiences are Processed along the Brain's Perceptual Neural Pathways

Cognitive Systems Research, 59. With S. DiPaola.

2020

Aesthetic Judgments, Movement Perception and the Neural Architectures of the Visual System

Tenth Annual Meeting of the BICA Society. With S. DiPaola.

2020

Unconscious semantic priming from pictures under backward masking and continuous flash suppression

Consciousness and Cognition, 78. With T. Stein and F. van Opstal.