Grid tie 3phase wind inverter

koutasekkoutasek Posts: 2Registered Users
Hello everyone,
I would like to ask you if someone of you have any experiences with my problem. First of all I would like to introduce myself, I'm Michal from Czech Republic, i'm working in company which building small photovoltaic solution for special applications, like telecom, oil&gas companies.
Now we have request from one customer which want solution like this:
They now have grid power + as backup diesel gens. They want to replace DGs and as main power use wind turbine and as backup use grid power. They have 5kw wind turbine and they want 3PHASE (400V 50Hz) grid tie inverter for 5kW wind turbine but i cant find 3 phase 5kw wind inverter. They dont want to sell overproduction (FiT) so solution will be easy to connect it into main junction box.

Please anyone know three phase wind inverter? i really never touch on wind power so its new area for me.

Thanks for your advice
Michal

Comments

  • ggunnggunn Posts: 1,973Solar Expert ✭✭✭
    Re: Grid tie 3phase wind inverter

    You'd probably have more luck with this question if it were posted in the wind forum a couple of forums down the list.
  • BB.BB. Posts: 27,347Super Moderators admin
    Re: Grid tie 3phase wind inverter

    SMA out of Germany would be one place to start (very good product and very good company).

    www.sma.de

    And here is your problem... A pure GT system (solar in this case) that can sell back to the grid will cost you around $0.10 to $0.20 per kWH in a reasonably sunny climate. If you want to run off grid, it will cost you around $1 to $2+ per kWH (US prices), or 10x the cost of Grid Tied.

    So--Your first question--What are people willing to pay for off grid AC power?

    Does the AC power need to be 400 VAC 50 Hz 3 phase power or can it be variable (only present when the wind blows/sun shines). I am going to guess the power needs to be 24x7 steady--So you either need batteries or grid power to make for a stable power source.

    And, that ends up leading you back to Grid Tied system (wind or solar) or battery based.

    You can probably find 3-5 kWH single phase inverters that can be wired to supply 3 phase power (9-15 kW worth of power).

    Another option is a VFD (variable frequency drive). These devices can take single phase power in (design a 6kW single phase inverter system) then use the VFD to supply 3 phase power out (VFD's can also provide soft start, variable frequency, etc.).

    In the end, can you work with the power company/regulators to see if a Grid Tied system can be supported? Almost any other solution I can think of is going to be horribly expensive (not that 30-50 kW of wind turbines is going to be cheap either).

    Sorry... I don't see any other cost effect solutions when you already have Grid Power available. And GT Billing is (for the most part) a regulatory/billing issue (I can see the power company's point of view, they do not make money with "net metered" solar/wind AC power systems. It has to be subsidized by other customers/governments).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • CariboocootCariboocoot Posts: 17,615Banned ✭✭
    Re: Grid tie 3phase wind inverter

    Okay I moved the thread to the Wind Power section.

    Have to agree with Bill on all counts. I don't see direct wind driven GT power as viable in a situation where there is no sell back to the grid. It is more likely it would have to have battery based inverters, otherwise any "extra" power generated at any given moment which could not be immediately used by loads would have to be dumped somewhere. That would become a major power management headache.
  • ggunnggunn Posts: 1,973Solar Expert ✭✭✭
    Re: Grid tie 3phase wind inverter
    Okay I moved the thread to the Wind Power section.

    Have to agree with Bill on all counts. I don't see direct wind driven GT power as viable in a situation where there is no sell back to the grid. It is more likely it would have to have battery based inverters, otherwise any "extra" power generated at any given moment which could not be immediately used by loads would have to be dumped somewhere. That would become a major power management headache.
    And that's leaving aside one very important issue, which is how certain you are (and how you are certain) that wind is even an exploitable resource at the location in question.
  • koutasekkoutasek Posts: 2Registered Users
    Re: Grid tie 3phase wind inverter

    Thanks for your reactions. But i cant explain them the wind is not realiable source for them. We design them solar solution with batteries + dg but they want some sites with wind turbine+grid power. They want to save bills for electric power. Its in middle east and they can't understand the wind is very variable source. They need to power up 2kW (and they have 5kw turbine) equipment but some of them is three phase, so they need 3phase wind inverter. I dont have any experiences with wind turbines but my boss still want to offer them solution :-)
    I cant understand to their PoV where they want to waste all overproduction, best solution is to use batteries but they dont want to understand it.
    Is possible to use for wind turbine solar inverter? Kostal and Fronius have 3phase inverters for 5kW or it must be exactly wind inverter like SMA Windy boy or Power One W series?

    Regards,
    Michal
  • BB.BB. Posts: 27,347Super Moderators admin
    Re: Grid tie 3phase wind inverter

    Here is a great chart from California (represents >~80% of the power generated/used in California):

    ems_renewables.gif
    RenewablesGraphKey.gif

    It is a near real time view of "renewable" power generation in California for today. Take a screen shot of this graph near the end of the day (California time) and you will see what utility scale wind/solar can produce.

    Even this morning, over the period of a few hours, wind has varied from 2,200 MW to 1,100 MW and probably will be fairly near zero (less than 500 MW) by mid-day.

    Do your customer have "opportunity" loads? Typical loads that can take variable power/voltage/frequency are pumping water from a well to a cistern/reservoir. Otherwise, most loads require a stable energy (or at least predictable) source.

    As far as I can see, your customers would need to use the Grid for energy storage/stable power (I explain that the utility grid is a sort of giant AC Battery Bank). If the local utility does not support/allow Net Metered power, then you are out of luck there (and from the utility's point of view, Net Metering costs them money--so why would they allow it).

    Which leaves local energy storage. Battery bank is going to be the "standard" option. Local water pumping (i.e., reduce power costs for installation by supporting only water pumping via wind turbines/solar arrays) would be one possibility... But I do not see a lot of options for you to "redesign" the customer's plant to use highly variable wind power directly (grinding grain is another variable energy load traditional to windmills).

    Another concern--Wind Turbines (horizontal axis wind turbines--HAWT) need loads/brakes/furling/feathering of blades/etc. to manage their RPM... An "unloaded/uncontrolled" HAWT will self destruct in even moderate winds. A large load/storage bank is needed to provide a "dump" destination to keep the turbine loaded and spinning at the correct/appropriate RPM.

    Remember, the above chart is the total for a an entire (geographically large) state--A single installation/location is going to have much more variability (over time and seasons).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ggunnggunn Posts: 1,973Solar Expert ✭✭✭
    Re: Grid tie 3phase wind inverter
    koutasek wrote: »
    Thanks for your reactions. But i cant explain them the wind is not realiable source for them. We design them solar solution with batteries + dg but they want some sites with wind turbine+grid power. They want to save bills for electric power. Its in middle east and they can't understand the wind is very variable source. They need to power up 2kW (and they have 5kw turbine) equipment but some of them is three phase, so they need 3phase wind inverter. I dont have any experiences with wind turbines but my boss still want to offer them solution :-)
    I cant understand to their PoV where they want to waste all overproduction, best solution is to use batteries but they dont want to understand it.
    Is possible to use for wind turbine solar inverter? Kostal and Fronius have 3phase inverters for 5kW or it must be exactly wind inverter like SMA Windy boy or Power One W series?

    Before investing in wind generation hardware, especially on a medium to large scale, a wind study of at least a year should be performed at the site and altitude of the proposed turbine. Anything less is just foolhardy. If the customer is insistent, then you might as well take his money (he will just give it to someone else if you don't), but DO NOT under any circumstances sign any sort of agreement that guarantees ANY amount of energy production from an installation done without extensive analysis of the wind resource, ESPECIALLY if (as you freely admit) you have no experience with wind energy production. You could get severely burned.
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