I for IMCEI

Every month, the graphs and curves of the index measuring industrial electricity consumption illustrate much more than technical data: they let us listen to the “heartbeat” of the Italian economy. The IMCEI (Monthly Industrial Electricity Consumption Index) prepared and published by Terna actually acts as a point of reference for analysts, institutions, and businesses, providing a tool that can shed light on trends in Italy’s main sectors of production.
From iron and steel to transport and from chemicals to food, there are a total of 9 industrial sectors under ISTAT’s (Italian National Institute of Statistics) ATECO2007 classification which can be considered “energy-intensive”. The term refers to businesses which access electricity by connecting directly to the transmission grid and therefore to the infrastructure managed by Terna, without going through a distributor. Every variation in electricity consumption tells a story of rising or falling production, of systems coming to a halt or starting up again, and of industrial processes undergoing transformations to reduce emissions and consumption.

An indicator that measures the Italian industry. But what exactly is the IMCEI? First of all, it’s an adimensional index; i.e., it allows us to compare data using different units of measurement, taking the year 2021 as base 100. It is prepared by Terna based on national electricity grid withdrawal data, taken from a sample of around one thousand energy-intensive businesses. These industrial customers from key sectors in Italian manufacturing consume vast amounts of energy: cement, lime and gypsum; iron and steel; chemicals; engineering; transport; food; paper; ceramics and glass; and non-iron metals. Month after month, the index provides a snapshot of trends in industrial electricity consumption, offering an early indicator of economic developments in Italy, usually expressed through the Industrial Production Index (IPI).
Moreover, IMCEI now also provides insight into structural changes in the production system, recording the progressive electrification of industrial processes, the introduction of digital and energy efficiency technologies, and the effect of the transition towards renewable sources.

In 2025, the IMCEI was driven by the iron and steel sector and by engineering. According to Terna’s data, Italian electricity demand in 2025, which came to 311.3 billion kWh, was characterised by two different trends: the first part of the year showed negative variations, followed by a recovery thanks in part to growth in industrial consumption. In fact, the IMCEI reveals that the recovery in the second part of the year allowed 2025 to close with just a slight overall downturn (-0.7%), despite the drop-off during the earlier months. Specifically, the sectors which ended 2025 on a positive figure were iron and steel; engineering; cement, lime and gypsum; and food. On the other hand, the sectors of non-iron metals; chemicals; transport; paper; and ceramics and glass all shrank. In more detail, the IMCEI showed percentage negative values in all months during the first part of 2025 — with the exception of May — compared to the same months of 2024, particularly February, April, and August. A gradual recovery began in September, and 2025 came to an end with four consecutive positive months (with December reaching +9.5%).

The evolution of the IMCEI over the years. At first, the monthly industrial electricity consumption index — which began at the instigation of the then-Ministry of Economic Development — used a small sample of measurements for withdrawals under the responsibility of the distributors. Later, the method of measurement changed. Since 1 January 2017, ARERA (the Italian Regulatory Authority for Energy, Networks and the Environment) has entrusted Terna with the responsibility for measuring all the electricity drawn from the transmission grid via TIME (the Integrated Text on Electricity Measurement). Therefore, the IMCEI has been “fuelled” directly using the measurements officially taken by Terna for almost 10 years now. In that time, the energy-intensive customers whose consumption Terna measures, as described, have doubled from around 530 to about 1,000. This means that both the precision and the speed of the index have improved over the years. In fact, Terna is now able to validate the measurements by the second-third working day of the month following the one for which the data were collected. In simple terms, Terna can provide all the measurements for the previous month at the start of each new month. And this is no longer a simple sample of measurements sent by the distributors, but the entire scope of measurements for Italian customers connected to the high and extra-high-voltage grid.

A key to understanding economic trends. Collecting data for the IMCEI allows Terna to monitor the behaviour of individual sectors while also tracking, for example, their reactions to external shocks. This made it possible to verify the nation’s response to the pandemic and the post-pandemic recovery in 2020 and 2021 in particular; and, more recently, to tensions surrounding energy prices caused by the wars between Russia and Ukraine and in the Middle East. These data help us to take the pulse of the nation’s economic circumstances more quickly and easily.
But analysing electricity consumption data also makes it possible, for example, to see how certain sectors are already benefiting from decarbonisation thanks to plans for the modernisation of systems and the integration of high-efficiency electricity systems, or because they have invested more in new production technologies.

The grid as a factor enabling the energy transition
Behind the IMCEI numbers is the story of the Italian electricity grid, one of the most complex and highly interconnected in Europe. The grid is more than a simple physical infrastructure: it is the platform which enables industrial competitiveness, energy security, and the integration of renewables.
The capacity to transport energy efficiently and reliably, as well as to balance supply and demand at every instant, is what allows businesses to produce uninterruptedly, to innovate in their processes and to plan investments, including in electrification and digitisation.
With energy data having become the key to understanding the real economy, the IMCEI is also an informational tool provided by Terna to all its stakeholders.