FuelCell Energy 1.25 MW Block System (formerly SureSource 1500)

FuelCell Energy's 1.25 MW carbonate system, renamed from SureSource 1500 and restated down from 1.4 MW

FuelCell Energy 1.25 MW Block System (formerly SureSource 1500) is one of 12 fuel cells tracked in the SecondWatt catalogue, each with specifications, lead times and indicative secondary-market pricing.

FuelCell Energy 1.25 MW Block System dossier: the SureSource 1500 rename and rating restatement, carbonate specs, carbon capture, and inspection guidance.

The SureSource brand is retired. FuelCell Energy's current product is the 1.25 MW Block System, transitionally still labelled the 1500 fuel cell system on the platform page, and the legacy URL for the 1500 now resolves to the Block System page with no SureSource string anywhere on it. The rating changed with the name: the historical SureSource 1500 was a 1.4 MW plant, and the current system is rated 1,250 kW. That is a 10.7% restatement with no published explanation, and the identical 10.7% appears on the 3000 line. The consequence for a listing is precise. Installed hardware from roughly 2015 to 2024 physically carries a 1.4 MW nameplate, while the same product line sold new today is marketed at 1,250 kW. A listing that says 1.4 MW SureSource 1500 is not necessarily misdescribed; it is a legacy nameplate, and it should not be corrected downward without inspecting the plate. Current published specifications, dated September 2025: 1,250 kW at 480 VAC and 60 Hz, 50% electrical efficiency LHV and 85% total with heat recovery, 3.1 MMBtu/h of heat on natural gas, fuel input of 9.5 MMBtu/h at 9,250 SCFH, natural gas or 0 to 100% biogas or blends up to 50% hydrogen, NOx and CO at 0.01 lb/MWh, a 58 by 42 by 20 foot envelope, 62 dBA at 30 feet and 3.9 gpm of water in against 2 gpm discharged. The molten carbonate architecture reforms methane internally at roughly 650 degrees C, which is why there is no external reformer to inspect.

Why it matters

Molten carbonate is the only commercial stationary fuel cell technology with inherent carbon capture: carbon dioxide from an external exhaust stream is fed to the cathode and transferred to the anode where it becomes far easier to separate, and the process adds power rather than consuming it. FuelCell Energy reports above 90% capture efficiency in laboratory testing. No solid oxide or phosphoric acid product offers an equivalent.

Who buys it

Universities, hospitals, wastewater and industrial sites that need baseload power with usable heat and full biogas capability, plus utilities procuring distributed generation under long-term power purchase agreements. Named microgrid references include the University of Bridgeport at 1.4 MW supplying roughly 80% of campus power and Santa Rita Jail paired with solar and battery storage.

Role in the data center

Baseload on-site generation with recoverable heat for absorption cooling, deployed as the constituent module of larger blocks rather than as a standalone data hall supply.

Key specifications

Technical summary

Rated output: 1,250 kW net AC at 480 VAC, 60 Hz Legacy nameplate: 1,400 kW as SureSource 1500 on hardware built through roughly 2024 Electrical efficiency: 50% LHV; total 85% LHV with heat recovery Heat output: 3.1 MMBtu/h on natural gas; 3.3 MMBtu/h on biogas Fuel input: 9.5 MMBtu/h, 9,250 SCFH natural gas or 15,640 SCFH biogas Fuel flexibility: natural gas, 0-100% biogas, and blends up to 50% hydrogen Emissions: NOx and CO 0.01 lb/MWh; SOx and PM10 negligible; CO2 886 lb/MWh electric-only Dimensions: 58 ft x 42 ft x 20 ft (17.7 x 12.8 x 6.1 m); 62 dBA at 30 ft Water: 3.9 gpm consumption against 2 gpm discharge; ambient minus 20 to 120 degrees F Standards: ANSI/CSA FC-1, NFPA 70, UL 1741, IEEE 1547, California Rule 21, CARB 2007 and 2013

Pricing and availability

Trend: up Lead time, new: Initial 30 MW delivery began inside the year of contract signature on the Fit Energy agreement.

Lifecycle and maintenance

Carbonate systems are designed around a 25 to 30 year system life with stack modules replaced inside it, at a 5-year target cell design life on legacy modules and 7 years on current production. The manufacturer publishes a 10% to 15% decrease in power and efficiency across the life of a module, and the legacy 3000 datasheet expressed the same thing as an efficiency band falling from 49% to 44% LHV. Balance of plant therefore outlives three to five module generations, which is why value concentrates in module age rather than plant age. Long-term service agreements run up to 20 years and include module exchange, and the agreement permits a new or a used replacement module.

Common failure points

• Stack module end of life — Modules carry a 5-year legacy or 7-year current target cell design life and then need a maker exchange
• Electrolyte loss — Molten carbonate is lost over long exposure through volatilization of alkali chlorides
• Service agreement transferability — Without a transferable agreement the asset cannot be exchanged, serviced or warranted by anyone
• Sulfur and halide contamination — Testing at 5 ppm H2S produced rapid power loss, and organic sulfides and halides remain unsolved
• Second-life modules — The maker may fit a new or used replacement module, so a refurbished plant can hold aged stacks
• Long start-up — A cold unit is not a same-day restart and no published start duration exists

Procurement channels

Direct from FuelCell Energy, predominantly as generation under a long-term power purchase agreement rather than as equipment. The one transferable form is the project company: FuelCell Energy sold the Trinity College 1.4 MW project to OnSite Partners with a 15-year service agreement attached.

Regional notes

North American 480 VAC and 60 Hz product certified to ANSI/CSA FC-1 with CARB 2007 and 2013 compliance. Air permits and interconnection are site-level and do not travel with the equipment even though the product certification does.