Methanol Fuel Cell or Solar vs diesel generator 3

[PetroBob]

We're considering a methanol fuel cell or perhaps solar panel system as alternative to a diesel generator for a remote site. The power is required for a small amount of instrumentation (eg pond level control, etc), hence only a small load. For larger loads we'd use a diesel generator. But it seems inefficient and a poor environmental design to run this large diesel generator all the time to provide power for the instrumentation.

What experience do folks have with methanol fuel cells or solar panel units for industrial application? Which of these would you recommend the most for this application? We need the system to be rugged and reliable. Can anyone suggest good suppliers for equipment suited to industrial application? (Preferably North American based.)

Thanks!

 

[racookpe1978]

DO you care if the facility only has power 6 hours of the day "most" of the time?

Solar power only gives you part of the nameplate power on clear days between 9:00 AM and 15:00 PM.
Cloudy days, you getr less. Not zero.zero, but less.
rainy days, you "maybe" 15 - 20% of what you'd get no a clear day. Maybe.
Snow days? likely zero for the next 4 days, maybe longer.
Ice? Likely zero for that day, and for the next three days also. (If highly sloped, it "might" slide off earlier.

So, you need 5x the area of solar you "think" you want on a clear day just to get juice to a battery for the on-service 6 hours plus accumulating the power to go to stored energy for the next 18 hours. Then you have process all of that power to a battery capable of your worst case delay plus a margin plus the conversion efficiency into a battery plus the conversion efficiency back out of a battery. 60% to 80% if you are lucky with new batteries. Be ready to swap batteries regularly.

You can stretch your generator fuel by running daylight hours on solar. Morning, evening and night on generator, with the generator as a backup for daylight.

 

[MortenA]

I assume that its charging batteries and that a (fairly large) diesel generator is rater in-efficient here?

If you have access to lift gas could you then consider a gas fuel cell?

Best regards

Morten

 

[MJCronin]

These solar and fuel cell alternatives sound way too elaborate and expensive. Periodic maintenance must be considered

How about a little gasoline or propane fueled generator sized for home service ?

The smallest are available in a 5-10kW size.... several vendors offer these.

GENERAC is only one vendor....

http://www.generac.com/

MJCronin
Sr. Process Engineer

 

[ScottyUK]

Propane would be a good choice because it is relatively clean, performs well at low temperatures, and doesn't suffer the aging problems of other fuels.

Would you consider a system with a substantially over-sized cranking battery which provides both engine starting and power to your load? The engine would need to run for half a day to re-charge the battery but perhaps only once a week depending on what you mean by 'low power' for the load and how big you make the battery capacity. I say half a day because most batteries recharge at their C/10 rate so it takes about 12 hours or so to replenish the battery.

There will be a trade-off between generator size, battery capacity, and run-time between charging cycles to find a sweet spot where you minimise cost of the overall system. You could separate the starting battery from the load battery, but small VRLA batteries have short and unpredictable lives where a shared system might allow you to justify use something better like a flooded ni-cad.

 

[LittleInch]

The first thing you need to do is look very closely at your loads and wheter you can reduce any by having less signals, using low consumption equipment etc etc. Think Appollo 13 whn they needed to reduce their loads to make the batteries last and you're on the right track. Far too many times when I've had a similar issue at remote locations with very simple / rarelty used bits of kit, there has simply been too little thought put into reducing the loads and coming up with a satisfactory daily consumption.

Only then can you assess whether solar / wind etc will satisfy your needs or not. I've used Solar for many systems with batteries or stored energy such as hydraulkic accumulators with a lot of success. Any liquid fuel system will need to be replaced on a regular basis.

Many wellhead systems are very rugged and solar powered, but as said - minimise your power load first and question everything that are "standard" when connected to the mains, but not required when you're generating it yourself.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[PetroBob]

Thanks very much Racookpe, Morten, MJCronin, Scotty and LittleInch for the advice. This is very helpful. The site only has a water storage pond & associated pumps, level control, liner leak detection, etc. Wellheads are many kilometres away and are outside our design scope. That's good advice to minimise power requirements thus making solar more reasonable. It sounds like solar or perhaps propane are the preferred options to investigate for low level continuous power for control systems. LittleInch, can you recommend any suppliers of solar equipment for this type of industrial application?

 

[LittleInch]

If your pump is operating for anything more than a few hours or is only very low power, Solar is likely to end up being a big area, but depends where you are in the world. You need local suppliers who understand these things.

At the end of the day its all about total energy per day that makes the difference.

My motto: Learn something new every day

Also: There's usually a good reason why everyone does it that way

 

[MartinLe]

Would a hybrid system make sense? Solar to power sensors, control system, communication with off-site, Diesel or similiar to power the pump when it's needed? Depends of course on the load, but I assume the pump is >1kW and the rest is <<1kW.