Hydro with grid tied inverter and power outage

Hello,

I plan to use a hydro generator with a grid tied inverter to lower my electricity bill and get a more green power.
I have read a lot on this topic, and it seems that if a power outage occurs, the grid tied inverter will shut down totally.

I currently never found a way to get the house powered from the hydro generator during a power outage. Do you have any idea ?
All the system I found use batteries, but in my case this is a bad idea, because the hydro generator gives me 2000W all the time.

Thank you for you help

Comments

  • AguarancherAguarancher Solar Expert Posts: 313 ✭✭✭
    Some grid tie inverters do have a grid down auxiliary 15amp 120V receptacle. SMA being one of them.

  • BB.BB. Super Moderators, Administrators Posts: 32,233 admin
    Welcome to the forum Poxito,

    I guess you are in France, so you will need to see what is available in your region of the world and meets your local Grid Tied system laws.

    With Hydro (and most wind turbine), they have an issue with how they work. They need constant load or destination for their energy (such as a battery bank, Utility Grid, or "dump load" resistor bank) to keep them running at the correct RPM. 

    If you have a loaded turbine (water or wind) and cut the load (such as a utility failure), the turbine needs to have its water flow turned off/down, or an alternative load needs to be supplied to keep the turbine from overspeeding (wind turbines can actually self destruct, throw blades, knock towers down, etc. and will usually have multiple extra safety features such as a mechanical brake, short the turbine, turn away from the wind, feather the blades, etc.).

    The SMA system (that I am aware of--I am not an expert here)--Basically uses the power from the solar array and its internal AC inverter to generate power to a second circuit (in the USA, 120 VAC @ something like 10-15 amps) that manually needs to be turned on for backup power (during the day) (a large 3,000 Watt+ array to supply enough power for a single AC load circuit during daylight hours).

    This system is "relatively" easy to do (from an engineering point of view) because solar panels can supply loads or not--And they will not damage themselves if the loads are removed (there is one class of solar panel that can damage itself--But that is not an issue for 99.99% of the population).

    What you really need is a Wind Turbine style of electronics package. One that accepts the variable output of a water turbine, and has the controls to shutdown the turbine in the event of a load failure. To do that, and supply stable AC power without a battery bank is difficult--Turbines can take seconds to respond, and your refrigerator turning on may take >600 Watts starting, and after a second fall back to 120 Watts running.

    The typical method to "solve" this problem is to add cost... A large battery bank to buffer your loads, and a Hybrid AC inverter, with charge controllers (charge controller for the turbine, charge controller for solar, backup genset controller, etc.).

    Hybrid AC inverters are very common these days (and many Off Grid inverters include  "GT mode" for almost free)... The can generate AC power from the battery bank (like and off grid AC inverter), and they can also, when the battery is full and you have Utility Power, feed the excess power from your charging sources (turbine, solar, etc.) back to the AC grid (using the grid as "dump load" to avoid overcharging the battery bank).

    All of that is relatively well known and the hardwave and experience is out there. Not cheap, and the battery bank certainly adds costs and maintenance issues (cheap batteries may last 3-5 years, better batteries may last 8 years, or even 15+ years).

    This is not a trivial system design. And hydro is a bit of twist. Most people do not live in a location blessed with lots of water flow and elevation drop to run hydro power. So finding hardware that can do what you need for hydro may also need some work on your part (or an engineer) to do the control system interface for your turbine/water flow.

    You will have to look at the reliability of your utilty power (down for 1 week a year, highly unreliable, or what). And what it is worth to you. Generally a hybrid off grid system--The power is "not cheap" when you roll in the costs of all the equipment, battery bank, and replacement battery bank every X years (the electronics generally need replacing every 10+ years too when/if they fail).

    This company seems to offer a fair amount of Hydro Power support:

    https://www.backwoodssolar.com/products/microhydro-power
    https://www.offgridbootcamp.com/off-grid-hydro-power-101/ (more hydro links)

    You might also try contacting member "clockmanfran" (@clockmanfran)

    Leslie has posted about his AC inverter projects and book here... He is in Normandy, France and may be able to better help you with your project, or at least give you some ideas/links that would support your hydro project:

    https://forum.solar-electric.com/discussion/354711/2nd-edition-6kw-ozinverter-build-book-manual-pcbs

    You can message him here through our forum software:

    https://forum.solar-electric.com/messages/add/clockmanfran

    Good luck and let us know about your progress.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • poxitopoxito Registered Users Posts: 3

    Thank you for your very detailed answer Bill.
    Yes, I am from France, and I wonder how you figured it.
    I must say that this project is also for fun, really like to build stuff.

    Currently, I think that the easiest way to have something working is to forget about the off-grid stuff.
    My plan is to get a quite cheap 2000W grid tied inverter for wind generator, they have a dump load and a limiter.
    Like this one: https://www.aliexpress.com/item/2029922759.html
    And then I will need a 3 phase electric generator and a pelton wheel, I need to do calculation to be sure that the voltage/rpm is suitable.

    Another problem is the power loss in the electric wire from the generator to my home, the wire will be about 80m long. Maybe it's better to have a higher voltage to lower the losses. I could build a transformer to step up the voltage just after the turbine, and then another one to step down the voltage just before the inverter.

    Any advices?

  • mike95490mike95490 Solar Expert Posts: 9,466 ✭✭✭✭✭
    I would use slightly oversize wire - there are losses ( and expensive ) in transformers.

    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • poxitopoxito Registered Users Posts: 3
    I also hope to be able to get all the data from the inverter on my home linux server. I already use Grafana for several things, it would be a great add.
  • BB.BB. Super Moderators, Administrators Posts: 32,233 admin
    Poxito,

    As a moderator here, I can "see" your IP address... I use an IP locator website (usually this one):

    https://www.iplocation.net/

    Works well for general IP addresses... But for mobile phone/satellite not good... And obviously Proxy servers and server farms hide the end address (or are reused over wide regions).

    Here is a guy that documented his (successful--I think) hydroelectric adventures:

    http://ludens.cl/paradise/turbine/turbine.html

    Good luck and have fun!

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