Fuel cell systems like the zepp.X150, which power zepp’s stationary generator sets, convert hydrogen into electrical energy with an efficiency between 50% and 62%, depending on the operating point. The remaining energy is released mostly as thermal energy through the cooling circuit. In a standard power-only installation, this thermal output is considered waste heat and is dissipated into the surrounding air through radiators.
In a combined heat and power (CHP) setup, capturing and using this thermal energy pushes the overall system energy utilisation to over 90%. When that heat replaces electricity or natural gas that would otherwise be burned for heating, thermal integration creates direct operational savings that effectively subsidise the cost of hydrogen fuel.
A concrete industrial example
To see how this works in practice, consider a manufacturing facility planning an expansion. The plant currently has a contracted utility grid connection limit of 700 kW. Under normal baseline operations, the facility draws approximately 650 kW.
The expansion requires increasing total site capacity to 1.2 MW. A significant portion of this additional demand comes from turning on heavy machinery at the start of a batch process several times per day, creating peak power surges. Upgrading the site’s utility grid connection to supply the extra 500 kW is not an option in the short term, as regional grid congestion has pushed grid reinforcement wait times out by several years in many industrial hubs. Halting the expansion means turning down new business and losing market share.
Managing continuous load and peak surges behind the meter
Rather than putting expansion plans on hold, the facility installs a zepp.generator G500 set behind the meter to operate in parallel with the existing grid connection.
The generator set manages the facility’s expanded load profile in two ways:
During batch startup, heavy electric motors and heating elements create an immediate demand surge. The zepp.generator G500 delivers up to 500 kW of rated peak power to absorb these instant spikes. Its integrated battery system acts as a rapid-response buffer, handling the instantaneous loads without pulling extra power from the grid.
Once the batch process reaches a steady operational state, the additional demand levels off. The G500 settles into supplying up to 300 kW of continuous fuel cell power to cover the expansion line, using dips in power demand to recharge its integrated battery. Meanwhile, the existing grid connection continues delivering its baseline 700 kW, allowing the plant to maximise its draw of cheaper grid electricity while using hydrogen only to cover the deficit.
Turning heat into cost savings
The financial case becomes compelling when looking at the heating requirements of the plant. The batch process requires large volumes of hot water to wash one of its feedstocks. Normally, this water is heated from ambient temperatures using natural gas boilers.
The zepp.generator is developed to handle combined heat and power setups. The hot cooling water from the fuel cell circuit is routed through a heat exchanger directly into the factory process water feed.
Preheating the process water with captured fuel cell heat directly reduces the volume of natural gas required by the boilers. This creates an immediate reduction in monthly natural gas bills while simultaneously lowering the plant’s overall carbon footprint. Instead of treating decentralised power generation strictly as an added operational expense needed to bypass grid delays, the facility uses the captured heat to lower its primary fossil fuel expenses.
The bottom line
Evaluating zero-emission equipment only on its electrical output overlooks a significant opportunity for operational cost reduction. By deploying hydrogen generators to bypass grid limitations and piping the thermal output directly into existing process streams, industrial operators can unlock an additional energy efficiency gain.
