Battery bank sizing for a grid connected wind system

[Adam1980]

Dear all,

i am designing a wind-generation grid connected system with battery system.

Are there any pointers about the size of the battery?
the load is stable and doesnt have a lot of change. The battery should cover a portion of the load and minimize export to the grid.

Any literature concerning these systems.

Thank you.

 

[dpc]

The battery system will have a certain capacity rating in Amp-hours. You have to determine how much storage capacity you want or need or can afford. This will depend on the size of the wind turbine, how much the wind blows (avg kW output over time), the profile of the load you are trying to serve, and how much power you are willing to purchase from the utility.

Nearly any battery capacity will help with the short-term variations in generator output - it will almost ever be a constant output, but to be able to handle long periods of calm without purchasing grid power is going to be an expensive proposition.

 

[Adam1980]

Thanks dpc.
are there any standards for that?
i think economics are the only boundary here.
load is mainly stable since it is a utility technical building, and only the variations of the wind should be flattened out specially the over generation.

 

[itsmoked]

If you are using lead acid batteries you need to keep in mind the life cycle to depth of charge relationship.


Discharging the full capacity of a LA battery each cycle will give you a battery life measured in tens of cycles. Whereas discharging the bank down to only about 50% of capacity may give you 500 cycles. Further, discharging the bank down to 60% may provide a 1000 cycles and 70% could provide 5,000 cycles. You see the trend here? You need to carefully design your bank to not be abused by the system's discharge/charge patterns.

Hunt down your battery's life/cycle-depth curves and see what the manufacturer recommends.

Keith Cress
kcress -

http://www.flaminsystems.com