This Cummins white paper examines the shift in data center onsite power systems from traditional emergency backup toward an active-standby model. It identifies decarbonization and shortages of grid capacity and transmission capability—particularly acute in Europe and North America—as the key drivers. The paper considers cleaner fuels and generation technologies, energy storage, fuel cells, and microgrid controls that could enable data centers to support the grid without moving to continuous onsite generation.
Key Takeaways
Grid constraints and decarbonization targets are reshaping the role of data center onsite generation: it should complement the grid rather than serve solely as emergency backup.
An active-standby model entails more operating hours for onsite assets in demand response and grid-support applications, but does not make them the data center's primary power source.
Switching to lower-carbon fuels, particularly HVO, is a direct route to reducing the carbon intensity of backup power.
The principal constraint on more frequent generator operation is regulation of critical emissions, especially NOx; near-term options include gas generators, improved engines, and exhaust aftertreatment systems.
BESS may be suitable where demand-response events have an appropriate duration; as the hydrogen ecosystem develops, fuel cells and hydrogen engines offer longer-term potential.
Key Figures
Share of global electricity consumption attributable to data centers
2–3 %
According to various sources cited in the document; an estimate of current global data center electricity consumption.
Author's tenure at Cummins
30 лет
Across engineering and technical marketing roles in the Power Generation business.
Bulletin edition
11/24
Bulletin 6511837, produced in the United States.
Practical Value for Data Center Owners
For data center owners and project teams, the paper provides a framework for assessing scenarios where grid capacity is constrained: a backup power plant can be designed as a controllable active-standby resource for mandatory demand response and grid support. During concept development and design, teams should compare expected grid-constraint durations, permissible operating hours, and NOx limits against the available asset mix—HVO- or gas-fueled generation, BESS, and, in the future, hydrogen—while providing microgrid controls for multiple sources. The paper also emphasizes that where grid capacity is available, onsite systems are not viewed as the preferred source of continuous prime power because of the operational burden involved.
The paper introduces FissionReady, a scheduler for data centers supplied by a multi-module small modular reactor (SMR) plant. It jointly manages the output of each reactor module, deferrable batch workloads, and grid purchases while accounting for fuel age, iodine-xenon dynamics, and reactivity margin. In simulations, the approach eliminates forced outages and missed batch-job deadlines while reducing water use and grid-electricity costs relative to a comparable baseline configuration.
Small Modular Reactors (SMRs)Data Center Power SupplyGeneration Load FollowingData Center Microgrids
Wärtsilä’s presentation examines the use of modular gas and dual-fuel power plants alongside energy storage to supply data centers, including AI workloads. It links constraints on grid connections to growing demand for primary onsite and off-grid generation, and cites several projects in Ireland and the United States. The material emphasizes capacity availability, modularity, part-load efficiency, lower water consumption, and the potential to transition to sustainable fuels over time.
Data center power supplyAI workloadsOnsite generationOff-grid data centers
This AVK and Wärtsilä Energy white paper examines constrained grid capacity as a major barrier to the expansion of European data centres, particularly facilities serving AI workloads. It proposes on-site microgrids combining dispatchable generation, BESS and renewables to accelerate site energisation before—or independently of—a grid connection. The paper compares power-system scenarios and four supply configurations for a representative AI data centre in terms of cost, reliability, land use and carbon footprint.
Data Centre Power SupplyAI Data CentresMicrogridsDispatchable Generation