Energy-Intensive Industries Providing Ancillary Services: A Real Case of Zinc Galvanizing Process

TL;DR

The paper investigates whether a real zinc galvanizing furnace can provide grid-balancing services by upgrading to continuous power control. It develops a detailed 4th-order state-space model to describe the furnace as a thermostatically controlled load and formulates linear FCR and MILP-based mFRR bidding problems with full hindsight to bound potential profits. Results indicate that FCR yields meaningful net savings with a payback potentially under a year, while mFRR poses greater temperature-rebound risks and is less attractive for this single-state process. The study demonstrates tangible demand-side flexibility for industrial loads and offers design guidance on investments and bidding timelines, with implications for similar single-state processes across industries.

Abstract

Energy-intensive industries can adapt to help balance the power grid. By using a real-world case study of a zinc galvanizing process in Denmark, we show how a modest investment in power control of the furnace enables the provision of various ancillary services. We consider two types of services, namely frequency containment reserve (FCR) and manual frequency restoration reserve (mFRR), and numerically conclude that the monetary value of both services is significant, such that the pay-back time of investment is potentially within a year. The FCR service provision is more preferable as its impact on the temperature of the zinc is negligible.

Figures (11)

• Figure 1: Schematic of the zinc furnace.
• Figure 2: Top: Power consumption for lower and upper zones and the total consumption. Middle: Temperature and contactor switches in the upper zone. Bottom: The same for the lower zone.
• Figure 3: Decision making timeline and variables for bidding into FCR and mFRR markets of day $\rm{D}$.
• Figure 4: Cumulative operational cost of the zinc furnace in the period of January 2021 to July 2023 when participating in either FCR or mFRR market compared to the baseline (base cost) when no services are offered.
• Figure 5: Worst-case day in the period of January 2021 to July 2023 in terms of cumulative frequency deviation to 50 Hz. Top: total baseline operational power and FCR reserve capacity. Middle upper: wall temperature of upper and lower zones with and without (denoted as base) FCR market participation. Middle lower: operational power consumption of lower and upper zones as well as the total consumption with the baseline operational consumption in solid lines. Bottom: spot and FCR prices for the worst-case day.