Utility Fuel Cell module

Looking for something else, I found this carbonate (high temperature) fuel cell system:
https://www.fuelcellenergy.com/wp-content/uploads/2017/02/Product-Spec-SureSource-1500.pdf

• 1.4 megawatt
• natural gas fueled, 10860/hr (181 scfm * 60)
• 47% efficiency
• ~700F (371C) exhaust
  • Heating or absorption cooling
• Water, in 4.5 gpm with surge to 15 gpm, discharge 2.25 gpm
• 107,000 lbs, largest skid 50,000 lbs

For a disaster area, this might be a feasible approach IF the roads can handle the load. However, barges and rail might be a better approach.

Bob Wilson

 

Gas turbine generators that exhaust into a steam generator are achieving combined ~60% efficiency:
Gas turbine - Wikipedia

Gas turbines can be particularly efficient when waste heat from the turbine is recovered by a heat recovery steam generator to power a conventional steam turbine in a combined cycleconfiguration.[37] The 605 MW General Electric 9HA achieved a 62.22% efficiency rate with temperatures as high as 1,540 °C (2,800 °F).[38] For 2018, GE offers its 826 MW HA at over 64% efficiency in combined cycle due to advances in additive manufacturingand combustion breakthroughs, up from 63.7% in 2017 orders and on track to achieve 65% by the early 2020s.[39]​

The other problem with this fuel cell is the cost per kWh is higher than wind generated:

• $3.32/1k cubic feet March (EIA)
• $36.05 natural gas to generate 1.4 megawatts for one hour
• $0.026/kWh (fuel cost after installation and does not include water and sulfur disposal/sale)
• Wind power, <$0.01/kWh (marginal cost after installation)

It is the same problem Prius owners have faced from the beginning:

• Capital costs - one time purchase higher than gas but approaching diesel premium
• Operational costs - fuel, oil, tires, insurance, e.t.c.

Prius owners pay more today so we can pay less for gas tomorrow. A plug-in hybrid owner, my Huntsville miles, ~90%, are half the cost of the gas miles.

Bob Wilson

 

Not just size, efficiency is also driven by having two heat engines. The high exhaust temperature of the gas turbine engine is enough that a steam generator can produce the rest of the energy. In contrast, the 700F (644K) exhaust temperature of the fuel cell modules makes extracting more energy difficult ... not impossible, just hard to scale.

BTW, Mercedes once looked at a Rankin cycle, a steam cycle, using a non-water fluid to extract heat from the exhaust pipe. My understanding they learned valuable lessons . . . don't do it.

Bob Wilson

 

I'm fairly calm about this because I stumbled across this June 8, 2018 article:
Steep Share Drop At FuelCell Energy Tied To Earnings Miss, Connecticut Energy Policy - Hartford Courant

. . . FuelCell Energy Inc. rebounded slightly Friday after falling more than 9 percent Thursday with the release of its second-quarter earnings that missed analysts’ expectations.

But the Danbury fuel cell manufacturer’s biggest share owner said Friday he believes investors are showing nervousness in advance of new state energy policy that previously did not favor fuel cells as part of Connecticut’s portfolio of low-emission energy.

FuelCell Energy posted an $18.2 million loss, or a loss of 23 cents per share, greater than the $12 million loss, or 15 cents per share, expected by analysts surveyed by Bloomberg.
. . . ​

I don't see them as driven by a goal beyond trying to not go broke. They had the Connecticut government pass a law so they could get 'parity' with wind and solar. Why do they need a State government bill to support their product?

So I looked at their product offering thinking it might apply to Puerto Rico and the specs don't add up. I could not come up with any credible scenario that made sense versus a megawatt, wind turbine and battery storage.

A carbonate fuel cell does away with having to reformulate hydrogen through steam reformulation, a lossy step. Yet the 47% efficiency just doesn't make sense along with the water requirement. I even considered a sea going barge and again, it didn't make sense.

The other 'lesson learned' is apparently this fuel cell approach does not scale well to smaller, vehicle sized units. I won't rule out that an aggressive designer might be able to make a 75kW, carbonated fuel cell but I won't be holding my breath. There are opposed piston engines that make more sense in weight and power density.

Bob Wilson

​

 

• 5 * 2.8 MW = 14 MW
• 14 / (14 + 15) ~= 48% of the power from fuel cell
• 15 / (14 + 15) ~= 52% from steam unit

Now IF the fuel cell had an efficiency of 30%, it would be easy to report the combined efficiency of 60%. But their specs claim the fuel cell is 47% efficient. This leads to a projected system efficiency of ~94% which is more than a little 'optimistic.'

Perhaps you can provide a source so I can follow-up?

The reason I ask is apparently using waste heat for HVAC is often used to improve system efficiency rating.

Interesting the Wiki reports "52%" so I checked their data sheet which claims "65%-53%." I'm OK with the "53% which appears to be LHV (Lower Heating Value) but wonder if "65%" is higher heating value. Regardless, I'm OK if the fuel cell exhaust is hot enough to generate more electricity. I'm just not getting an impression of a co-generation power unit. At "16 tons" each, to approach 1.4 MW, 5-6 units, 80-96 tons, 160,000-192,000. Also, I'm not seeing how they handle sulfur.

We agree. I'm thinking if there is a ready source of methane like a landfill or waste water treatment plant, it makes more sense than just flair gas or a diesel. I would also like to see sulfur handled (I grew up in Oklahoma with a lot of sour gas wells.) But their IPO looks to be in trouble:
Fuel Cell Company Bloom Energy Prepares For Market Debut - Bloom Energy (Pending:BE) | Seeking Alpha

Bob Wilson