Need Help with Off Grid Power System

Boonies

New Member
We are off-grid in Southwest New Mexico. For the last 25 years we have used Hydro power with a backup generator for our electricity needs. Changes in weather patterns are causing our river to diminish. I do not think it would be out of the question for the river to completely stop flowing above ground some day. We need to upgrade our system so we are not exclusively reliant on the river and generator.

Power Consumption Profile:​

The hydro plant, as it is, produces 4.5 kW continuous power output. We have an electronic load manager system where you can assign a priority to certain loads and the manager will automatic turn lower priority loads on and off based on power availability. This effectively allows for higher average power consumption. Due to the nature of our operations here the load profile varies considerably over time and seasonally. Our overall consumption can be anywhere between 1.75 kW to very close to 4.5 kW continuous for weeks at a time. (The Load Manager makes it possible to operate close to 4.5 kW average consumption).

We have good sun exposure here so Solar Power is a possibility. Wind Power might be a possibility. Seems like some hybrid combination of Hydro/Solar/Wind might be the best solution. Does anybody have any ideas or suggestions on how to proceed with this project? Could anybody help, or know someone or some business or group who could help as a consultant on this project?
 

DCPower

New Member
Hi!

I run a hybrid solar / hydro system here, and have for 16 years. I sympathize re: the 20 year drought - though my watershed hasn’t dried out entirely, there’s about half the year around flow now compared to 16 years ago. The 2020 summer was kinda scary - but we made it by adding a few boulders and rocks to the intake diversion weir.

My average household load is about 400 watts, with short peaks to 5kW when making toast, coffee and the well pump runs to charge the pressure tank. My hydro is 1.3kW continuous, solar is 2kW but I have 7.2kW of inverter and 5 KWh of battery so it all works.

4.5kW continuous - whoa. That’s a lot of load. 108 kWh per day. Three times the USA “average.” When you’re talking solar, and battery, it’s a fairly large system.

Just for an example, using Albuquerque’s insulation data from NREL, you get 4.4 kWh per m^2 per day in December, so to recharge a 100 kWh battery you’d need about (highballing losses) 35kW of PV. That is 117 300W modules. I’d look at a solar-edge type of high voltage DC parallel array and 10 kW 240 VAC Inverter system, with a high voltage battery / charge controller - maybe fully integrated with an inverter / generator input (for the hydro) - there are several sources around for this type of design.

Obviously, if the hydro contributes reliably at a lower power level - the solar / battery can be adjusted lower. That’s just worst case solar PV only - and the battery provides no multiple cloudy day backup at 109 kWh.

>>>> Load shedding is the key to solar / battery living. <<<<

Wind? If you can stand living there, it probably isn’t a good wind site. Wind requires 12-27 mph velocity to operate. No more, no less. If you put your hand a foot from your mouth and blow as hard as you can, that’s a 12 mph wind. Invest in a recording anemometer and mount it at the height a wind gennie would be mounted, and collect a years worth of data before considering wind. Seriously. You can get a years worth of data on a plug in chip and import it into excel and KNOW what your site will have as a resource. Much cheaper than a turbine install. And you can always sell the anemometer when you’re done.
 

Boonies

New Member
We have 12 full time people here and more people in and out all the time. There are 2 houses, a few out buildings, a laundry room, and combo wood/metal workshop. This is why the load can be pretty high at times. I did the hydro plant myself 25 years ago. I have done the same calculations you did for solar and it is a really large system. What I think would be the best solution here is what you have, hybrid solar/hydro. If it were just me I would be more comfortable experimenting and developing something over time that would work. Unfortunately there are other people here that need and use the power. Since hydro is 24/7 we have been spoiled. I am interested in hiring a consultant. I need someone with more experience than I have to help filter through the options and configure the system for optimum output and reliability. Do you know anyone who might be interested?
 

DCPower

New Member
Boonies,

I do occasional consulting work on these types of projects, though generally locally - I’m involved in a similar ground-up development now, in fact. I’d be happy to discuss your situation with you, but let’s take it offline here - my email is - bill at dcpowerandlight dot com - drop me a note there if you’d like.

Bill
 
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