Techno-Economic Feasibility Analysis of Quantum Key Distribution for Power-System Communications

TL;DR

This paper addresses the challenge of securing power-system communications against quantum threats by developing an integrated techno-economic framework that evaluates QKD adoption alongside PQC. It introduces a stochastic model that links key demand, QKD key supply, buffering, and fallback policies, and defines Levelized Cost of Security (LCoSec) and Cost of Incremental Security (CIS) as normalized economic metrics. Through discrete-event simulations on IEEE 118-bus, 123-node, and 39-bus networks, the study demonstrates that Hybrid architectures (QKD+PQC) markedly improve availability and reduce tail SLA violations, especially for real-time services. The results show breakeven regions depending on fiber loss and buffer design, providing a reproducible decision tool for risk-aware, large-scale QKD deployment in resilient power grids.

Abstract

The accelerating digitalization and decentralization of modern power systems expose critical communication infrastructures to escalating cyber risks, particularly under emerging quantum computing threats. This paper presents an integrated techno-economic framework to evaluate the feasibility of Quantum Key Distribution (QKD) for secure power-system communications. A stochastic system model is developed to jointly capture time-varying key demand, QKD supply under optical-loss constraints, station-side buffering, and post-quantum cryptography (PQC) fallback mechanisms. Analytical conditions are derived for service-level assurance, including buffer stability, outage probability, and availability bounds. Building on this, two quantitative metrics, including the Levelized Cost of Security (LCoSec) and Cost of Incremental Security (CIS), are formulated to unify capital, operational, and risk-related expenditures within a discounted net-present-value framework. Using IEEE 118-bus, 123-node, and 39-bus test systems, we conduct discrete-event simulations comparing PQC-only, QKD-only, and Hybrid architectures across multiple topologies and service profiles. Results show that Hybrid architectures dominated by QKD significantly reduce key-outage probability and SLA shortfalls, achieving near-unit availability for real-time and confidentiality-critical services. Economic analyses reveal clear breakeven zones where QKD-enhanced deployments become cost-effective, primarily in metropolitan and distribution-level networks under moderate optical loss and buffer sizing. The proposed framework provides a reproducible, risk-aware decision tool for guiding large-scale, economically justified QKD adoption in future resilient power-system infrastructures.

Figures (9)

• Figure 1: Availability distributions with violin+box overlays. The x-axis is grouped by topology (Metro, Distribution, LongHaul) using shaded bands; within each group, classes are ordered as GOOSE, PMU, SCADA, M1--M5. Dashed horizontal lines indicate representative SLA targets.
• Figure 2: Ridgeline-style end-to-end delay densities for the Metro topology across representative classes (GOOSE, PMU, SCADA, M1); vertical dashed lines mark class-specific delay bounds.
• Figure 3: Top-20 stress nodes (selected by PQC median) out-of-key probability on a log scale; box summaries (5--95% whiskers) with beeswarm of per-run samples.
• Figure 4: Levelized Cost of Security (LCoSec) distributions by architecture, grouped into Metro, Distribution, and LongHaul bands. Violin shapes depict full distributions and box overlays show 5--95% whiskers.
• Figure 5: Equivalent annual cost (EAC) across architectures with a raincloud-style view (violin + box + jitter) and topology grouping.