Cogeneration
Voltage dips have become
one of the least-discussed
risks facing modern industry.
Brief, almost always invisible, but enough to throw a production line into error. Voltage dips have become one of the least-discussed risks facing modern industry.
A production line stops. The lights stay on. PLCs throw alarms, inverters reset, a batch is scrapped. The energy meter has recorded nothing unusual, and the utility has no outage to report.
What happened lasted less than a second. A voltage drop of a few milliseconds, sometimes just a few grid cycles, but enough to throw an industrial plant’s automation into error.
Across Europe, these events are becoming more frequent. The growth of non-dispatchable renewables, the spread of distributed generation, and a grid originally designed for one-way flows are changing how the electrical system behaves. Blackouts make the news, but they are only the visible part of the problem. Below them sits a layer of continuous, very brief disturbances that never get counted as proper outages and that hit industrial users directly.
A voltage dip is a drop in voltage lasting anywhere from a few milliseconds to a few seconds. Invisible to the human eye. Almost always tolerable for an asynchronous motor already running. Not for a PLC, an inverter, a drive, or a control system.
The causes are often structural. The main one is automatic reclosing on the grid. When a fault occurs on a high- or medium-voltage line, such as a lightning strike, a tree falling on a conductor, or an earth fault, the protective breaker opens the circuit for a few hundred milliseconds and then attempts to reclose. If the fault is transient, service resumes and no one notices. If it’s permanent, the breaker recloses and reopens several times before finally locking out.
For the grid it’s a self-protection mechanism. For everything downstream, it’s a sequence of consecutive voltage dips that stresses every piece of electronics on site.
Other common causes: the start-up of large inductive loads upstream, faults at neighbouring sites, weather disturbances, oscillations from intermittent renewable sources.
The most sensitive processes are those that depend on precision, controlled temperatures, and heavy automation. Food processing, plastics, textiles, chemicals, pharmaceuticals. In all of these, a few milliseconds of voltage swing can shift process parameters enough to ruin an entire batch. The damage isn’t only electrical: it’s materials, time, and production rescheduling.
Continuous-process plants pose a different problem. Pumping, water treatment, desalination, wastewater: here a voltage dip stops the pumps and can trigger conditions that don’t clear when the system restarts, such as salt crystallisation or sediment building up in the pipes. Recovery means hours of manual cleaning and, in some cases, dismantling sections of the line.
With a true blackout the shutdown is predictable: there’s a protocol, the back-up generator starts if needed. With a voltage dip, none of that applies. The plant stops for something that officially never happened. Control systems can take hours to come back online: every PLC has to be restarted in the right sequence, every inverter reconfigured, every alarm reviewed to check whether it has caused damage downstream.
For many companies, this is where the line falls between a resilient plant and a fragile one: in the ability to absorb brief events without letting them propagate into the process.
There is no single solution. There are two, and they work best together.
The first is dynamic energy storage. A rotary UPS uses the kinetic energy of a spinning flywheel to cover transients: when grid voltage drops, the flywheel transfers its inertia to the generator and keeps power flowing long enough to ride through the event. Compared with a static battery UPS, it’s better suited to heavy industrial loads, has a long operating life, and doesn’t require maintenance on chemical components.
The second is on-site energy generation. A cogeneration plant covers a stable, predictable share of the site’s electrical demand and reduces grid exposure. Combined with dynamic storage, it allows for an energy architecture in which a grid voltage dip becomes a managed event rather than something the plant simply absorbs.
The point is the combination. Together they change the plant’s relationship with the grid: from passive consumer to a system with its own footing.
This is how MTM Energia has worked from the start: sizing cogeneration on real consumption and integrating it with the other technologies on site, including dynamic storage where power quality is a priority. Continuity is a consequence of the architecture.
