Research ideas for 1 MW power station using propane generators and solar.

[Supervstech]

Hello all,

I hope this is the right subforum to post this thread in; discussion includes generators, solar panels, and large-scale inverters.

I'm looking into the feasibility of building a 1 MW power station and using grid power as backup.
I'd like to get a ballpark figure on costs before spending too much time digging deeper.

Our current power consumption is about 700-800 KW at peak, and our annual electric costs are about $225K.
I've estimated that if capital costs of such a system can be repaid in 10 years, including generator fuel, it's worth the investment.

The location in question is serviced by a poorly run electric company and we've found that the legs are very often out of balance, especially during the summer months, which is destroying the life of our motors and electrical equipment.

My initial thought is to buy 1 MW of solar panels (day) and 1 MW of propane generators (night).
Ideally, we'd have 3x 500 KW generators, 2x running in parallel simultaneously and 1x shut down for service (or as a backup) at any time.

I have not even begun searching for inverters of this size yet, and this is one of my main concerns.
Adding lithium batteries at this time seems prohibitive, unless someone has a good, economical storage alternative to propose.

Any thoughts, input, and ideas are welcome.

Thank you.

How Much Investment Do You Need For A Solar Farm? | Coldwell Solar

When it comes to alternative investment options to pick from outside of bonds and stock, the solar farm is one of the popular choices. We say this because it also...

coldwellsolar.com

From looking at this page it appears a 1MW plant would produce 1440MWh a year average, and profit around 43K, so the 4hour average daily production would likely cut your usage by 1/3 to 1/2 depending on operation times.
If you contacted tesla you might get a MWH of battery modules for another million... you might get enough from solar to eliminate your energy draw from the grid entirely...

Heck...
Add another MW of production and get PAID by the power company to produce power that will stabilize THEIR grid...

Assuming of course ya have 16 or so acres available...

 

[Skypower]

Who is John Galt?

I dono, and I shrug ?

 

[Millennium]

Otherwise very good conversation.

Also look up the big natural gas generators. If you are lucky enough to be near natural gas lines (they don't even need to be super big), you can just feed them natural gas and they crank out power. Lots of big units used in the oilfield to power electronic submersible pumps (ESPs). Company I work for has ~150 ESPs in the Permian basin sucking down 400-500 kW each. Many ran off generators. Some natural gas (burning natural gas that would otherwise be flared off), some diesel. They're designed for high reliability.

Let's run through the math for a Cat CG127-12 TA engine (used for electric generation and gas compression).

400 kW at 480V is 100% capacity so you'd need 2-3.

Fuel consumption at full load = 4906 SCF per hour (this shows at 905 BTU/cf, which is a bit below what usually comes out of pipelines). Going to use 1000 BTU/cf, which is a bit more realistic and easy for math purposes, so that's 4906/(1000/905) = 4439 SCF per hour x 24 = 106558 SCF per day. That's 107 Mcf (oil/gas uses M for thousand) per day. Current henry hub spot price is $3.07 per MMBTU. Since we used 1000 BTU per CF, that convienently results in the same price per MMBTU as MCF. So you're using 107 MMBTU * 3.07 $/BTU = $328.49 per day of gas. You're also generating 400 kW x 24 hours = 9600 kWh. That's a cost of $0.034 per kWh (3.4 cents per kWh).

You won't get spot pricing, but you'll get close to it at 100-300 mcf/day. Amortize the generator cost over X years and you're good to go. These generators are also commonly available for rental/lease if you want to test things out.

Also the efficiency goes up slightly as you back off from full load. If you run 3 of these at 83% each (3x333 kW = 1 MW), you'd be near peak efficiency.

Here's a list of CAT engines in this product line - https://www.cat.com/en_US/products/new/power-systems/oil-and-gas/land-production-generator-sets.html

Edit: there is a lot of interest in this area to burn natural gas to generate electricity in the oilfield to power bitcoin miners. The gas would otherwise be flared. Up to you to decide if that's a valuable venture or not (hint: the mined bitcoin has 2-3x the value of the generated electricity).

Thanks for this.
I was able to speak with our local NG supplier. Nearest main is about 11 miles from my location.
Rep. quoted me an approx. $4MM design and build out, which was a bit pricey. I could justify a quarter of that cost.
Propane can be delivered to my location, but it's about 4x the cost, I believe, for the same energy density.

 

[Millennium]

How Much Investment Do You Need For A Solar Farm? | Coldwell Solar

When it comes to alternative investment options to pick from outside of bonds and stock, the solar farm is one of the popular choices. We say this because it also...

coldwellsolar.com

From looking at this page it appears a 1MW plant would produce 1440MWh a year average, and profit around 43K, so the 4hour average daily production would likely cut your usage by 1/3 to 1/2 depending on operation times.
If you contacted tesla you might get a MWH of battery modules for another million... you might get enough from solar to eliminate your energy draw from the grid entirely...

Heck...
Add another MW of production and get PAID by the power company to produce power that will stabilize THEIR grid...

Assuming of course ya have 16 or so acres available...

I've got hundreds of unused acres, real estate is not an issue. My problem is that the power company does not "buy" back, but they'll take it for free.

A friend of mine recommended a hybrid system as well, where we produce about 50% of our own power, through solar and batteries, and use the grid for the balance of power needed. We'll see, stil researching solutions.

I need to look into Tesla MW batteries. They seemed expensive on the consumer side, although they may have better deals for commercial users.

 

[Supervstech]

I dono, and I shrug ?

It's a quote from the book atlas shrugged

In the book it's akin to saying that's the way it is...

 

[Supervstech]

I've got hundreds of unused acres, real estate is not an issue. My problem is that the power company does not "buy" back, but they'll take it for free.

A friend of mine recommended a hybrid system as well, were we produce about 50% of our own power, through solar and batteries, and use the grid for the balance of power needed. We'll see, stil researching solutions.

I need to look into Tesla MW batteries. They seemed expensive on the consumer side, although they may have better deals for commercial users.

That's crazy, when their production is weak and unstable that they wouldn't buy from. You.

 

[Millennium]

That's crazy, when their production is weak and unstable that they wouldn't buy from. You.

They can purchase more energy, but they're cheap.
Grid design and distribution has been a nightmare.
If they kept up with distribution over the years, they could have bought more power now from other energy providers and pass it on to the consumers.

One good piece of news is that I finally found the email to the Power Manager; I've sent him an email and received a reply.
He'll look into our situation on Monday. I'm hopeful this conversation could help resolve some of our issues.

 

[shadowmaker]

I need to look into Tesla MW batteries. They seemed expensive on the consumer side, although they may have better deals for commercial users.

Sunsynk 1MW battery is currently 99k£, including shipping container, climate control and fire extinguisher.

 

[SajgZi]

Thanks for this.
I was able to speak with our local NG supplier. Nearest main is about 11 miles from my location.
Rep. quoted me an approx. $4MM design and build out, which was a bit pricey. I could justify a quarter of that costs.
Propane can be delivered to my location, but it's about 4x the cost, I believe, for the same energy density.

Yep that's a bit far. For $4MM there are plenty of other, better options, including giant batteries and solar/wind to match. Not to mention the price of natural gas, even though there are supply/demand factors to keep the price relatively low, can be highly variable.

Batteryhookup.com has plenty of large-ish batteries in the $100/kWh range. I'd imagine if you contact them and say you need a few MWh, they'd be very interested in helping.

Realistically, and I haven't done the math on costs, in my mind the best option would be to build a battery with a couple hours of storage. Plan to use the grid to feed the battery. Use stackable/big inverters to do constant inversion from the battery. Get a couple propane gens to fire up if the outage is longer than X hours. Solar/wind to assist with not purchasing power from the grid.

Just did a search on google for "1 mwh battery" and a surprising number of results popped up, with prices and everything! $400k-ish, which is $400/kWh. The question is - how much do you want to DIY this to save $$$.

 

[50ShadesOfDirt]

Not being an EE, which is what I think you need, and furthermore, one who specializes in power plant design, I'd pursue the following:

1. implement large (diesel, propane) generators, of the class needed to meet power requirements
- this gets you going right now
- gens in this class are super reliable (1800rpm)

2. over time, replace (or at least augment) fuel-driven generation with solar-driven
- start to reduce fuel costs & generation periods with solar
- fuel generation is now there as a backup to solar, or extra capacity for high demand

It would take an EE to understand all the power requirements of your facilities, and one versed in power plant design to come up with a small private power generation scheme, to make sure it was all done right.

I have seen many large industrial firms augment their standard power-consuming practices with solar (and wind, where feasible).

What we do on a very small scale allows us to dump the power utilities ... equipment has gotten to that point, and we are our own power company now. I get to worry about all kinds of backups to the backups; luckily, I like doing this. I'd imagine this can scale up to 1MW, but an EE will need to guide that (IMHO) ... I'd start researching to see who else is dumping the utility companies, and how they are going about it.

Hope this helps ...

 

[Millennium]

Sunsynk 1MW battery is currently 99k£, including shipping container, climate control and fire extinguisher.

That's a great price for what you get. How can they afford staying in business? LOL!
What kind of warranty (years) and how many charge-discharge cycles is it rated for?

 

[shadowmaker]

That's a great price for what you get. How can they afford staying in business? LOL!
What kind of warranty (years) and how many charge-discharge cycles is it rated for?

Oh, and it seems to include gas detection system and inverter too for that price...

For more details you have to contact Sunsynk, but I'm quite sure Sol-Ark (US version of Sunsynk/Deye) will give you hard time to get these into US. At least it will be 2-3x more expensive... ?

Keith seems to be very exited about this stuff:

 

[Millennium]

Oh, and it seems to include gas detection system and inverter too for that price...

For more details you have to contact Sunsynk, but I'm quite sure Sol-Ark (US version of Sunsynk/Deye) will give you hard time to get these into US. At least it will be 2-3x more expensive... ?

Keith seems to be very exited about this stuff:

Just contacted Synsynk; I'm curious to see if they will sell their Innagator Container Batteries in the USA.

Here is the link to those units: https://www.sunsynkmobile.com/innagator
And here are the specs:

 

[peakbagger]

I designed and managed the building of small (1 to 8 MW) combined heat and power projects for several years for hospitals and manufacturers in Mass. In most cases, they were designed to cover the load in the facilities from on site generation (usually a natural gas engine or turbine) with the utility supplying what is called minimum import which means the plants could not export power to the grid. One particular customer was an electronics manufacture located on a big grid that had similar reliability issues. If they had off spec power it cost them a bundle in production and took a couple of days to start up again. Their load was around a 1 MW. They also had a 1.3 MWh Tesla battery in addition to natural gas generator. Controlling it all was a multimode inverter built by SEL (big name in power protection and electronics), the inverter would continuously monitor the grid and run at minimum import as when running in a CHP mode they could generate power and heat required for the facility for less than grid power (mass has very expensive power). If the grid power went out of spec, the plant wokld "island" into an off grid mode and would do it in matter of a couple of cycles so that the transfer was "bumpless"

In your case, you need a PV array, a multimode inverter and a big battery. You can get a federal tax credits or some type of preferential accounting for all three. SEL and Dynapower are two supplies of multimode inverters that I am aware of, there are others. These units are effectively a power utility in a box, they control the power quality and are programmed with lots of rules to make sure that when unusual situations occur that they respond correctly. Keep in mind that the utility acts like a big flywheel so that disturbances usually are dampened out somewhat, with a microgrid, small disturbances can cause big issues quickly. Variable speed drives are one source of small disturbances. My guess is the multimode inverter would run as microgrid but use utility power to charge the batteries, if the power goes out of spec, the battery stops charging. Its like a really big UPS.

If there is onsite generation you would need to file an interconnect application with your local utility. That is not cheap or easy (small solar folks like most of the readers of this forum get to play by simplified rules but its highly likely you need to play with the big boys). You have to pay your utility to do a interconnection study and make requirements that you have to follow to prevent your generation from harming their system. As long as you do not export (sell power to the utility) odds are you will need to run a specialized communications line called a DTT (Direct Transfer Trip) that allows them to isolate your production from the utility whenever they deem it necessary. If you want to export, its can get real expensive as much of the grid grid was not designed to have local generation intermittently pumping power into the grid adn the utility can charge you to do that upgrade, odds are its a "#3VO" at minimum and they charge you to upgrade their ancient substation. With a DTT trip you are off grid and your battery had better be sized big enough to carry all the load. Depending on your regional grid operator you may also need to have a separate communications line to the regional grid operator reporting out your production and it also has the option to shut off your generation from the grid. On most of my projects this was a $100 to $300K process and usually 18 months to 3 years in length. The only way around it is to have your plant completely isolated from the grid with locking transfer switch that the utility would need to open and close. Keep in mind that if you need to get the utility to turn on the switch you most likely set a one year demand charge for any power that you pay regardless of if you are buying any power. At one of my employers, they needed to test a piece of equipment and had to buy lots of powers for three days one year, their ongoing demand charges were more than their actual usage for the next 11 months.

In most, but not all cases, batteries on the grid are being encouraged and the interconnect aspect is "easier" but by the description of your utility they probably are not interested and capable of doing things on their end. Odds are they will require an interconnect application and a DTT circuit, maybe more.

Keep in mind if you have lots of large induction motors, your power factor probably is bad and any equipment you install has to have the capability of generating VARS to offset the induction loads, batteries can be real good at that but ideally you want to implement load control on your large motors so that they start staggered. Ideally you want to install a power quality meter on the plant for several months and determine you peak loads and VARS so that you can design properly sized system. Ideally once you have data, you can install some capacitor banks to improve power factor and consider putting some power management equipment on your starter sections to stagger large motor starts and possibly auto shed load if the batteries are getting low. BTW, most small multmodal equipment is set up for 480 volt 3 phase, they can go higher voltage but once the equipment goes over 600 volts, everything goes up in price big time. Same with batteries.