Propane VS Diesel in ~20-30kW generator ranges.

[Open Neutral]

They burn through a lot of it. At minimum, weekly exercising, at least one hour. Some under load, some not. They do test the fuel regularly.

They may get advantageous rates on an interruptible basis. IOW, when the grid has peak demand, they get a call from the utility or ISO [PJM, etc.] to load shed & move to their generator supply. That uses some fuel. But a lot vs. their inventory???

 

[GoldDigger]

Our local propane suppliers use a wireless level transmitter to tell their route trucks when you need fuel and offer a keep full service where you do need to pay attention to your usage.
But if you connect a generator to the tank they no longer offer that service. The usage is too high and unpredictable given the frequency at which they drive by to check the propane level.
And if you let the tank go empty (zero pressure) they add a $100 fee when refilling.

Sent from my Pixel 4a using Tapatalk

 

[Open Neutral]

The usage is too high and unpredictable given the frequency at which they drive by to check the propane level.

The services I've seen use a cell data transmitter so no drive-by is needed to know the level. In the NoCal case, that was impossible as there was no cell coverage there.

 

[tortuga]

Interesting, we found a local contractor in our area whom can pull the mechanical permit provide piping and sell the customer a customer owned tank.
We have been getting good feedback from that, as the customers are now not locked in to one delivery company and just pay COD.
We had one customer call and say the delivery company put their sticker on the tank, we told them to remove the sticker and put 'customer owned' on it , its their tank.

 

[Todd0x1]

Interesting, we found a local contractor in our area whom can pull the mechanical permit provide piping and sell the customer a customer owned tank.
We have been getting good feedback from that, as the customers are now not locked in to one delivery company and just pay COD.
We had one customer call and say the delivery company put their sticker on the tank, we told them to remove the sticker and put 'customer owned' on it , its their tank.

That's shady that the propane company put their sticker on the tank. That is likely to prevent other companies from filling it.

 

[petersonra]

That's shady that the propane company put their sticker on the tank. That is likely to prevent other companies from filling it.

I would not call it shady anymore than it is shady for an EC to put his sticker on a residential panelboard. It is called marketing.

 

[Todd0x1]

I would not call it shady anymore than it is shady for an EC to put his sticker on a residential panelboard. It is called marketing.

I bet its more than just marketing. I think propane companies wont fill a tank owned by a competitor.

 

[petersonra]

I bet its more than just marketing. I think propane companies wont fill a tank owned by a competitor.

nor should they.

 

[Todd0x1]

nor should they.

Right. So ABC propane puts their sticker on a customer owned tank, then customer calls XYZ propane to come out and upon arrival they see the ABC sticker and refuse to fill it.

 

[GoldDigger]

ABC may assert that they are just advertising their brand rather than claiming ownership of the tank, but that is not clear to other companies. Could be interference with freedom to contract and justify damages.

 

[retirede]

Right. So ABC propane puts their sticker on a customer owned tank, then customer calls XYZ propane to come out and upon arrival they see the ABC sticker and refuse to fill it.

Why would they refuse to make a sale?

Not saying you’re wrong, I just don’t understand why.

 

[brantmacga]

Why would they refuse to make a sale?

Not saying you’re wrong, I just don’t understand why.

I would guess it’s courtesy to not fill a tank they think a competitor owns; that’s part of the deal when you get the tank for no cost, the company that provides the tank has exclusive rights to service it.


Sent from my iPhone using Tapatalk

 

[Todd0x1]

ABC may assert that they are just advertising their brand rather than claiming ownership of the tank, but that is not clear to other companies. Could be interference with freedom to contract and justify damages.

Even just advertising is not ok, unless they obtained permission before placing the label. A car dealership that put their license plate frame on my vehicle when it was in for service had a rather unpleasant day.

 

[Coach Mike]

Beyond the fuel difference, you're also talking about a difference in engine technology - Spark Ignited (SI) vs. Compression Ignited (CI).
Most folks refer to these commonly as Gas and Diesel engines.

What has changed dramatically in the last 8 years or so is lower HP off-road engines have become subject to the EPA Tier 2 Gas and Tier 4 Final Diesel regulations. The key point here is the amount of emissions permitted is based upon the HP of the engine itself.

Most generators are small enough that DEF is not needed. DEF is used to reduce the NOx emitted during combustion to meet EPA allowable limits. NOx increases along with combustion temperatures and engine size. Over the road trucks have used DEF fluid for quite some time due to their large HP. The next set of vehicles affected were diesel equipped pickup trucks. When the regulations began affecting the HP ranges used in gensets, many manufacturers opted not to develop engines capable of meeting the requirements.

Diesel generators that are below 74HP (55kW mechanical x 80% generator efficiency ~ 44kW generator set) usually do not require DEF fluid and may not even need a Diesel Particulate Filter (DPF) but only a Diesel Oxidation Catalyst (DOC) which performs a similar function that the Catalytic Converter does on a gasoline engine. As an example, Kubota manufactures a few stand-by diesel units - their "GL" line - that come in 7, 11 & 14kW none of which requires DEF nor have a DOC or DPF.

Propane or Natural Gas models will require spark for combustion so these units are "gasoline" engines that have been converted to run on these other fuels in the same way forklifts have been available for years using LPG.

Now, one way manufacturers can keep costs per kW low, is to use a smaller engine running at higher RPM. Generally, the generators used in these applications come in either 2 or 4 pole arrangements. Reminding ourselves of the frequency/RPM relationship (RPM = (120 x f)/ # of poles) yields an engine RPM of either 3600 or 1800. Units are available in both speeds and both fuels/engine types in the market.

So while the initial cost per kW may be lower with a 3600 RPM unit, one must also consider several things about the unit life cost vs. the 1800 rpm model:

• Greater fuel consumption due to RPM;
• Increased noise levels;
• Accelerated wear and tear on engine components and the drivetrain vs. 1800 RPM units.

These factors can make the total life cost (i.e. acquisition plus operation plus maintenance costs) of the higher RPM unit greater.

Natural Gas units have an advantage in home standby applications where the home already has a supply for cooking or heating. In more remote areas, diesel or LPG would be preferred since refueling can be accomplished portably either through bulk delivery or exchanging smaller tanks.
Again, the costs to refuel would depend upon the engine RPM and should be taken into consideration when comparing models. Hopefully, the manufacturers being considered publish the fuel consumption per amount of load so a comparison can be made.

There are also some restrictions by locality on the type of fuel that may be utilized by the genset. This falls into the same category as that phrase in the NEC "or by the Authority Having Jurisdiction" so the consumer would be wise to check local regulations before purchasing a unit.

Moreover, LPG units will have additional components to allow the use of LPG vs. regular gasoline. These components are relatively reliable but do add a level of complexity above a gasoline powered engine. SI engines, by their very nature, also require additional systems and components for spark ignition which are not needed in CI engine applications. Finally, SI engines will most likely have an engine ECU but CI engines may not require an ECU to meet EPA limits unit they are above around 20hp (~12 kW genset).

So to sum up, when comparing models, I would recommend consider the following:

• Lifetime ownership costs;
  • Fuel Consumption rate at comparable load;
  • Wear and tear based upon engine RPM;
• Noise Levels;
• Restrictions in the local area;
• Complexity of the technology required to operate engine.

 

[retirede]

Beyond the fuel difference, you're also talking about a difference in engine technology - Spark Ignited (SI) vs. Compression Ignited (CI).
Most folks refer to these commonly as Gas and Diesel engines.

What has changed dramatically in the last 8 years or so is lower HP off-road engines have become subject to the EPA Tier 2 Gas and Tier 4 Final Diesel regulations. The key point here is the amount of emissions permitted is based upon the HP of the engine itself.

Most generators are small enough that DEF is not needed. DEF is used to reduce the NOx emitted during combustion to meet EPA allowable limits. NOx increases along with combustion temperatures and engine size. Over the road trucks have used DEF fluid for quite some time due to their large HP. The next set of vehicles affected were diesel equipped pickup trucks. When the regulations began affecting the HP ranges used in gensets, many manufacturers opted not to develop engines capable of meeting the requirements.

Diesel generators that are below 74HP (55kW mechanical x 80% generator efficiency ~ 44kW generator set) usually do not require DEF fluid and may not even need a Diesel Particulate Filter (DPF) but only a Diesel Oxidation Catalyst (DOC) which performs a similar function that the Catalytic Converter does on a gasoline engine. As an example, Kubota manufactures a few stand-by diesel units - their "GL" line - that come in 7, 11 & 14kW none of which requires DEF nor have a DOC or DPF.

Propane or Natural Gas models will require spark for combustion so these units are "gasoline" engines that have been converted to run on these other fuels in the same way forklifts have been available for years using LPG.

Now, one way manufacturers can keep costs per kW low, is to use a smaller engine running at higher RPM. Generally, the generators used in these applications come in either 2 or 4 pole arrangements. Reminding ourselves of the frequency/RPM relationship (RPM = (120 x f)/ # of poles) yields an engine RPM of either 3600 or 1800. Units are available in both speeds and both fuels/engine types in the market.

So while the initial cost per kW may be lower with a 3600 RPM unit, one must also consider several things about the unit life cost vs. the 1800 rpm model:

• Greater fuel consumption due to RPM;
• Increased noise levels;
• Accelerated wear and tear on engine components and the drivetrain vs. 1800 RPM units.

These factors can make the total life cost (i.e. acquisition plus operation plus maintenance costs) of the higher RPM unit greater.

Natural Gas units have an advantage in home standby applications where the home already has a supply for cooking or heating. In more remote areas, diesel or LPG would be preferred since refueling can be accomplished portably either through bulk delivery or exchanging smaller tanks.
Again, the costs to refuel would depend upon the engine RPM and should be taken into consideration when comparing models. Hopefully, the manufacturers being considered publish the fuel consumption per amount of load so a comparison can be made.

There are also some restrictions by locality on the type of fuel that may be utilized by the genset. This falls into the same category as that phrase in the NEC "or by the Authority Having Jurisdiction" so the consumer would be wise to check local regulations before purchasing a unit.

Moreover, LPG units will have additional components to allow the use of LPG vs. regular gasoline. These components are relatively reliable but do add a level of complexity above a gasoline powered engine. SI engines, by their very nature, also require additional systems and components for spark ignition which are not needed in CI engine applications. Finally, SI engines will most likely have an engine ECU but CI engines may not require an ECU to meet EPA limits unit they are above around 20hp (~12 kW genset).

So to sum up, when comparing models, I would recommend consider the following:

• Lifetime ownership costs;
  • Fuel Consumption rate at comparable load;
  • Wear and tear based upon engine RPM;
• Noise Levels;
• Restrictions in the local area;
• Complexity of the technology required to operate engine.

Very good summary.

The only counterpoint I would make is that in the case of most residential backup applications (which is the primary topic in this thread) it would be virtually impossible to run either an 1800 or 3600 RPM genset enough hours to approach the end of its useful life. It may die of old age before it wears out!

I’ve lived in my current home 22 years and have been without power perhaps a total of 10 hours.

May be a different story for folks living in area such as those prone to hurricanes. Even then, a week (150 hours) every few years....

 

[oldsparky52]

I’ve lived in my current home 22 years and have been without power perhaps a total of 10 hours.

May be a different story for folks living in area such as those prone to hurricanes. Even then, a week (150 hours) every few years....

And that is why I have a couple of small (1600W continuous) inverters to power my house enough to "get by" until the PoCo restores power after a hurricane. Last one (a couple of months ago) we were out for about 9 hours, the one before (a couple of years ago) we were out for 5 days.

The cost of a whole house standby generator is just too much for me for the benefit. Having a portable generator that would take care of the whole house (probably about 10KW) is not bad, but the fuel bill for 5 days would be rather large compared to my inverters.

 

[Coach Mike]

And that is why I have a couple of small (1600W continuous) inverters to power my house enough to "get by" until the PoCo restores power after a hurricane. Last one (a couple of months ago) we were out for about 9 hours, the one before (a couple of years ago) we were out for 5 days.

The cost of a whole house standby generator is just too much for me for the benefit. Having a portable generator that would take care of the whole house (probably about 10KW) is not bad, but the fuel bill for 5 days would be rather large compared to my inverters.

Very good summary.

The only counterpoint I would make is that in the case of most residential backup applications (which is the primary topic in this thread) it would be virtually impossible to run either an 1800 or 3600 RPM genset enough hours to approach the end of its useful life. It may die of old age before it wears out!

I’ve lived in my current home 22 years and have been without power perhaps a total of 10 hours.

May be a different story for folks living in area such as those prone to hurricanes. Even then, a week (150 hours) every few years....

Great points and I agree whole heartedly. Working for an engine distributor that designs its own line of gensets evokes this kind of response from me...it's a reflex....

I have a 3600 RPM small, single cylinder portable 7kW unit that I use in emergencies. It is not permanently attached and I do all my load management manually. That little unit is adequate to run two refrigerators, the 3 Ton AC unit on the ground floor of the house, microwave and several lighting loads. When the well pump needs to build pressure, I turn the AC off and then back on when the pump is finished. Since I have gas heat and stove, this size is adequate for my needs.

I don't trust the output for electronic devices so I do not attempt to operate TVs or computer network/equipment during outages...but we can keep our cell phones charged to stay informed. In the four years I've lived in this home, I've put just over 10 hours on it...most of that during one outage...but it's paid for itself by avoiding food spoilage costs.

One of the guys at our company cobbled together a 15kW, 1800 RPM diesel unit for use at his home. He can run his entire home with it and it's come in handy for him on a few occasions but, as you've both stated, he's put maybe 20 hours on it in the 5 years he's had it.

Most people do not have the technical ability of those in this group to use a small unit or inverters connected to the house electrical system for emergencies. For them, they either run extension cords to a portable unit or use a whole house unit - which is better because it is "automatic" and prevents them from sending power back upstream where the line workers are repairing the system. This is the customer the standby home market is serving so often they are selling more than is actually needed.

Additionally, infrequent use presents another set of issues such as the need for regular exercising of the unit to maintain its operational effectiveness and fuel storage/quality issues.

So, having been "recalibrated" by some of my colleagues here, I'd suggest the OP consider a portable unit that would have multiple uses beyond just the home standby system. In that case, he needs to insure he has an easy way to remove and reconnect the main bonding jumper on the portable unit depending upon whether he's using it as a home standby unit or as a portable power source. In my situation, I had to remove the jumper from my unit's distribution panel and created some small jumpers I can attach directly to the generator output when providing portable power.

I also installed an hour meter and a few cheap AC meters on the side of mine so I can monitor approximate current draw on each phase and system voltage as I want to keep it balanced best I can. Since I'm manually managing the loads, I marked my home panel so I know which phase serves each load.

 

[tortuga]

I'd suggest the OP consider a portable unit that would have multiple uses beyond just the home standby system.

Yeah good points the portable ones are an option, as I said the load being backed up is 20-30kW, not really an average home, perhaps a luxary home, so they would have to be trailers.
Or several portable generators for each site.

When the outage began here on Sept 7th due to the wild fires we had utilities cutting power to prevent more fires.

Explosion, sparks from power line preceded Oregon’s Holiday Farm fire, area residents say

The accounts may provide clues about the cause of one of Oregon’s largest wildfires, which remains under investigation.

www.oregonlive.com

Generators here racked up hours powering 20-30 kW loads such as convenience stores, water pumping, farms/ranches, refrigeration, cold storage, small medical clinics etc.
Places that do not require mandatory back up but have a 20-30kW load needing to be backed up are becoming a common request and prices are all over the map.
There are certain farm tasks that are time sensitive, so if say you harvested a field and you need to get the harvest processed or it rots.
Or Cold storage of dairy and meats etc.
We had a overloaded 20kW generator on a farm that got me thinking.

In that case, he needs to insure he has an easy way to remove and reconnect the main bonding jumper on the portable unit depending upon whether he's using it as a home standby unit or as a portable power source.

Can you elaborate on this?

 

[Coach Mike]

Wow...looks like that was a mess! And yes, in those cases, larger sets come into high demand pretty quickly.

Can you elaborate on this?

As far as the bonding jumper question, Mike Holt has a great guide on generators located here: NEC Genset Requirements

If you look at page 4, you'll see that the generator can only be bonded when it is a "Separately Derived System" meaning the neutral would need to be switched by the transfer switch. If your transfer switch does not do this OR if you use a 4 wire plug to connect your portable genset to power the structure (i.e. just the two Hot legs, Neutral & Ground), you must remove the bonding jumper on the genset.

Easy rule of thumb...there can only be ONE bond in an electrical system!

 

[mbrooke]

Yeah good points the portable ones are an option, as I said the load being backed up is 20-30kW, not really an average home, perhaps a luxary home, so they would have to be trailers.
Or several portable generators for each site.

When the outage began here on Sept 7th due to the wild fires we had utilities cutting power to prevent more fires.

Explosion, sparks from power line preceded Oregon’s Holiday Farm fire, area residents say

The accounts may provide clues about the cause of one of Oregon’s largest wildfires, which remains under investigation.

www.oregonlive.com

Generators here racked up hours powering 20-30 kW loads such as convenience stores, water pumping, farms/ranches, refrigeration, cold storage, small medical clinics etc.
Places that do not require mandatory back up but have a 20-30kW load needing to be backed up are becoming a common request and prices are all over the map.
There are certain farm tasks that are time sensitive, so if say you harvested a field and you need to get the harvest processed or it rots.
Or Cold storage of dairy and meats etc.
We had a overloaded 20kW generator on a farm that got me thinking.


Can you elaborate on this?

What happened when the 20kw overload?