Key Takeaways
- Rehlko (formerly Kohler) generators span from 60 kW to over 4 MW in the KD Series, covering edge deployments through hyperscale data centers.
- A published data center case study confirms deployment of the 2000REOZMD, a 2000 kW model with a permanent-magnet pilot exciter for strong load response.
- The KD1800-F demonstrates 100% rated load acceptance in one step per ISO 8528-5 and HVO fuel approval for sustainability targets.
- Selection must address not only kW rating but also load-step capability, emissions compliance, paralleling architecture, and lifecycle service access.
- For mission-critical sites, generator evaluation should extend beyond the spec sheet to controls integration, fault tolerance, and how the supplier packages support services.
Direct Answer
Rehlko data center generators offer a broad diesel backup power portfolio engineered specifically for high-reliability applications. The KD Series—with models from 60 kW to over 4 MW—is positioned for data center standby duty, hospitals, and other critical facilities where power quality and uptime are non-negotiable. The line includes industrial units confirmed for 100% one-step load acceptance and compatibility with hydrotreated vegetable oil (HVO) fuel, which matters for operators tracking Scope 1 emissions reductions.
Buyers should evaluate Rehlko options against three hard constraints: the site’s required standby rating under actual ambient conditions, the generator’s demonstrated load-step and transient performance, and the supplier’s ability to support the entire power train—engine, alternator, controls, and switchgear—as one coordinated system. This guide walks through the decision criteria, relevant product evidence, and practical steps to build a defensible RFQ.
Decision Factors When Evaluating Rehlko Data Center Generators
Power Rating and Duty Cycle: Match the Real Operating Point
Data center generator selection must start with a clearly defined operating scenario—standby vs. prime power, site altitude, ambient temperature, and voltage/frequency requirements all affect real-world output. Rehlko’s KD Series covers a wide range, but claiming a 2000 kW generator without qualification is misleading.
What to verify:
- Standby rating (ESP) vs. prime rating (PRP) under ISO 8528-1.
- Derating curves for your specific site altitude and maximum ambient temperature.
- Voltage drop and frequency recovery under block loading of UPS and cooling systems.
In a documented case study, Rehlko supplied model 2000REOZMD as a 2000 kW diesel generator for a data center, featuring a brushless alternator with a permanent magnetic pilot exciter for excellent load response Case Study: Data Center Application. This configuration points to good voltage control during large block loads—important when a data center transfers from utility to emergency power.
Load-Step Capability and Transient Response
Data centers load generators in aggressive steps as UPS batteries recharge and cooling restarts. A generator that cannot accept a large block load without excessive frequency or voltage dip will fail commissioning or cause protective relay trips.
The KD1800-F specification sheet reports 100% rated load acceptance in one step per ISO 8528-5 criteria Industrial Generator Set – KD1800-F Fuel Consumption …. This is a stringent performance class (G3 or better) that many data center designs require. Confirm this rating applies to your specific model and, critically, at your site’s operating conditions.
Emissions, Fuel, and Sustainability Requirements
Emissions compliance is increasingly a showstopper rather than a preference. Rehlko states that KD Series generators are engineered to deliver low particulates and NOx levels POD solutions for Data Center. Additionally, the KD1800-F is approved for HVO fuel per EN15940, enabling operators to reduce carbon intensity without engine modifications.
Evaluate against these constraints:
- Local EPA Tier 2/3 or equivalent emissions tier.
- Fuel logistics and runtime: does the site need 24, 48, or 72-hour fuel autonomy?
- Sustainability goals: HVO compatibility supports net-zero roadmaps.
System-Level Integration: Controls, Paralleling, and Switchgear
A generator set is only one component. Data center projects require seamless integration with medium-voltage switchgear, automatic transfer switches (ATS), and paralleling controls. Rehlko’s data center power solutions page emphasizes system-level packaging, including power system controls, paralleling switchgear, and aftermarket support Reliable Backup Power Solutions for Data Centers.
When comparing suppliers, ask:
- Does the vendor supply the complete power train or only the engine/alternator?
- Can the controls integrate with the building management system and EPMS?
- What is the factory witness-testing protocol for fault scenarios?
Technical or Selection Table
| Criterion | What to Check | Why It Matters | Rehlko Evidence / Guidance |
|---|---|---|---|
| Standby kW Rating | Verify ESP rating at site temperature and altitude | Undersized units fail during worst-case conditions | KD Series spans 60 kW to >4 MW Rehlko’s all-new KD Series™ 60-600 kW generators set … |
| Alternator Performance | Brushless, PMG exciter, 2/3-pitch winding class | Short-circuit support and nonlinear load handling | 2000REOZMD documented with PMG exciter Case Study: Data Center Application |
| Load Acceptance | % rated kW in one step per ISO 8528-5 | Prevents voltage/frequency collapse during transfer | KD1800-F: 100% one-step load acceptance confirmed Industrial Generator Set – KD1800-F Fuel Consumption … |
| Emissions Compliance | EPA Tier, EU Stage, local air-quality rules | Permitting risk and project delays | KD Series: low particulates and NOx POD solutions for Data Center |
| Fuel Flexibility | Diesel and HVO capability | Carbon reporting and future fuel strategy | KD1800-F: HVO per EN15940 Industrial Generator Set – KD1800-F Fuel Consumption … |
| Paralleling & Controls | Integrated switchgear, controller protocol | Reliability during multi-unit operation | Rehlko offers system-level controls and paralleling switchgear Reliable Backup Power Solutions for Data Centers |
| Service Access | Local distributor, parts availability, SLA terms | Mean time to repair impacts uptime Tier rating | Confirm with supplier for your project location |
| Noise Constraints | dB(A) at property line, enclosures available | Municipal ordinances and community agreements | Confirm with supplier; specify silent or containerized enclosures if required |
RFQ / Selection Checklist
Before issuing an RFQ for Rehlko data center generators, compile the following project-specific data. Missing items lead to inaccurate proposals and commissioning failures.
Site Conditions
- Project altitude (meters above sea level).
- Maximum ambient temperature (°C).
- Humidity and corrosive environment classification.
- Seismic zone and wind-load requirements.
Load Profile
- Total steady-state kW (IT load plus cooling and auxiliary).
- Largest motor or UPS block load in kVA and starting method.
- Power factor of combined load at transfer point.
- Allowable voltage dip and frequency dip during load steps.
Configuration Requirements
- Generator rating: Standby (ESP) or Prime (PRP).
- Voltage and frequency (e.g., 480V 3-phase 60 Hz).
- Enclosure type: open-skid, weatherproof, sound-attenuated, containerized.
- Paralleling requirements: number of units, load-sharing control architecture.
- Fuel type: standard diesel or HVO.
- Runtime at full load without refueling (hours).
Compliance & Certification
- Emissions tier (EPA, EU Stage, local rule).
- UL 2200 or equivalent listing required?
- ISO 8528 G2 or G3 performance class for voltage/frequency regulation.
- Seismic certification and IBC compliance, if applicable.
Lifecycle Support
- Factory witness test required?
- Commissioning supervision and load-bank testing.
- Service-level agreement: response time, parts depot location.
- Remote monitoring and alarm integration with BMS/DCIM.
FAQ
How does the 2000REOZMD perform in a data center backup scenario?
A published case study confirms the 2000REOZMD was deployed as a 2000 kW diesel generator for a data center. The unit’s brushless alternator with permanent magnetic pilot exciter supports stable voltage during load changes, and the overall system achieved the reliability the facility required Case Study: Data Center Application.
Can Rehlko KD Series generators run on biodiesel or HVO?
The KD1800-F is approved for HVO fuel per EN15940 Industrial Generator Set – KD1800-F Fuel Consumption …. For other models in the KD Series, confirm HVO or biodiesel compatibility directly with the supplier, as approval may vary by engine variant.
Does Rehlko supply the entire power system or just the generator?
Rehlko offers system-level packaging including generator sets, power system controls, paralleling switchgear, and aftermarket support Reliable Backup Power Solutions for Data Centers. This can simplify procurement and single-point responsibility, but verify the exact scope for your project—switchgear and medium-voltage integration may still require separate project coordination.
What emissions tier do KD Series models meet?
KD Series generators are engineered for low particulates and NOx POD solutions for Data Center. Confirm the exact EPA tier or EU stage certification for your selected model and the configuration required to meet local permit conditions.
Conclusion
Rehlko’s KD Series diesel generators represent a credible foundation for data center standby power from edge to hyperscale. Published evidence confirms deployment at 2000 kW, 100% single-step load acceptance on the KD1800-F, and HVO fuel compatibility—all directly relevant to data center procurement teams.
The real selection challenge is not whether Rehlko can manufacture a suitable generator, but whether the specific model, configured for your site’s conditions and integrated with your switchgear and controls, can pass commissioning under realistic load steps. Use the RFQ checklist to force detailed answers on rating conditions, transient performance, and service capability. Where product data is missing, demand supplier confirmation rather than extrapolating from similar models or generic engineering assumptions.
