High Power Well Pumping for Irigation

lazzalazza Solar Expert Posts: 336 ✭✭✭
HI Forum

Does anyone have information on high power irrigation systems running on hybrid wind/solar?

We have someone very interested in replacing their current 70kW electric pumping system that pumps water 1 km to a reservoir for subsequent irrigation.

Ideally we'd like a wind generator and PV system (clearly of less power) that could reduce the size of this generator, pumping maybe over longer periods but constantly whenever the wind was blowing or sun shining. I.e. A direct pumping system to save on batteries.

Are there products/systems on this scale? I know that you can get direct well-pumping systems on a very small scale..

Any pointers, much appreciated

Larry

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: High Power Well Pumping for Irigation

    There's so many variables here ...

    Obviously if you were thinking of switching from a 70kW grid-powered system to solar/wind the first thing that would be necessary is to reevaluate the pumping needs. It's pretty much a given that solar/wind isn't going to replace grid power 1:1 for any reasonable amount of money. Not around these parts anyway.

    Elevation could be your friend here. Possibly the terrain would allow wind-power to pump water 24/7-ish to an elevated tank from which it could be released as-needed for irrigation. Basically replacing fast and furious pumping with slow and steady.

    There probably isn't much commercial equipment along these lines due to the high cost/low demand for such.

    Someone else may have a better take on it. I've only ever had one inquiry along these lines and it was quick to see it was a no-go.
  • BB.BB. Super Moderators, Administrators Posts: 31,684 admin
    Re: High Power Well Pumping for Irigation

    Here is one thread where we discussed 40-160 HP (30-120 kW) worth of pumping in the US using solar...

    The starting point for solar is the same one for every project: conservation (of resources and money)--Estimate your power needs to do the pumping. And compare the costs of "average" vs "the most energy efficient pumping system" you can find. Overlay the difference in pumping infrastructure costs and Solar costs (off grid, on grid, etc.) and even the costs of running a high voltage utility line+kWH billing to your pumping facility.

    Once you have sketched out the positives and negatives of the hand full of options (and their estimated costs)--Such a system should be large enough to attract multiple bidders to the project. With your knowledge from your paper review--you should quickly be able to see who is a worthwhile vendor and who is blowing smoke.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • lazzalazza Solar Expert Posts: 336 ✭✭✭
    Re: High Power Well Pumping for Irigation

    Thanks for your replies.

    The kind of system i am looking at would be say, for arguments sake, a 30kW turbine with 20kW of solar panels. This would power a pump to pump water from the well up to the reservoir. To avoid batteries, the system would be direct, and only pump up to the reservoir as and when wind and solar was available. A separate, electric pump (independent of the renewable system) would do the actual irrigation, which must be done at certain moments for a specified amount of time.

    In effect, I am looking at a direct pumping system, but on a very large scale. Problem- the products on the market... are they available?

    ps the reason i am not looking at grid-tie system is that net-metering is currently not available in Spain, and furthermore I am concerned regarding the Reactive energy that a pump consumes, which if i understand correctly, could not come from the renewable system.
  • BB.BB. Super Moderators, Administrators Posts: 31,684 admin
    Re: High Power Well Pumping for Irigation

    For induction motors, it is pretty "easy" to install a capacitor bank to bring the Power Factor back to ~0.95 (from ~0.67) for induction motors. Power companies do that all the time. In California, you can see capacitor banks on utility poles that are switched on during pumping/air conditioning season in the central valley. For (large?) commercial installations, our power company charges for poor power factor (more or less, the customer pays for kVA, not kWH).

    And why a 20kW array for a 30kW pump? Normally, I would have expected something along the lines of:

    30kW * 1/0.77 panel+controller deratings = 39 kW solar array (if you want to power the pump at 100% of rated power)

    For research, I would look for companies that build industrial VFD units (Variable Frequency Drives) for 3 phase motors and see if they have any suggestions/products.

    A few years ago, I stumbled over a larger (few kW?) VFD that was designed to connect directly with a solar array. I could not find it later--possibly the company was out of business or dropped the product. The VFD would vary the frequency (and pump RPM) based on the amount of available solar energy at any time (basically a MPPT controller with 3 phase AC output).

    You can use Aibaba for a list of Mfg (most are from China).

    Here is a guide (PDF) on Variable Speed Pumping from the US Dept of Energy... At the end they include some information from US and European Hydraulic/Pumping industrial organizations (they have a ~150 page guide available for ~95 Euro/$?).
    About Europump
    Europump, established in 1960, acts as spokesperson
    for 15 national pump manufacturing associations in
    Europe and represents more than 400 manufacturers.
    Europump serves and promotes the European
    pump industry. For information on Europump, visit
    www.europump.org.

    About the Hydraulic Institute
    The Hydraulic Institute (HI), established in 1917, is
    the largest association of pump producers and leading
    suppliers in North America. HI serves member
    companies and pump users by providing product
    standards and forums for the exchange of industry
    information. HI has been developing pump standards
    for over 80 years. For information on membership,
    organization structure, member and user
    services, and energy and life cycle cost issues, visit
    www.pumps.org.

    And here is a US based Sustainable Farming Organization--Perhaps they have some information on solar irrigation (a quick search of their site did not show much--probably just a Grundfos based pump--which seem to be in the ~1kW range):

    https://attra.ncat.org/

    Let us know what you find--I am sure others here will be interested.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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