Off-grid Solar-Wind hybrid system

khan08

Hi,

First of all, I have been going over some of the threads and I really appreciate the help and guidance provided by the people on this forum.
I am a mechanical engineer by profession and I am currently working with a client who wants an off-grid 40 kW solar(50%)-wind(50%) hybrid system at his facility. I have some experience with on-grid systems, but off-grid is something I have never been involved with.
I would appreciate if someone could help me understand how a hybrid off-grid system would work? What are some of the things that need to be kept in mind while designing such a system? And are there any constraints to how you can combine wind and solar to create such a system?

I would really appreciate any sort of guidance or support on this topic.

Thanks
khan08

NorthGuy

Re: Off-grid Solar-Wind hybrid system

In few words, that's quite simple.

The battery bank is the heart of the system.

An inverter is usually used to convert DC from the batteries to AC to the loads.

Charging sources - solar and wind - are connected to batteries and charge them. They can co-exist without knowing about each other.

niel

Re: Off-grid Solar-Wind hybrid system

welcome to the forum.
i think we could use some clarification on the system you are talking of. is that 40kwh needed or is it 40kwh in solar and 40kwh in wind turbines? or worse 40kw in pv and 40kw wind or 20kw solar and 20kw wind?

in general you will find the solar to be a bit more reliable than wind, but both will have their time periods of non production, meaning a good reliable generator should be had for the times when both other methods fall short. being off grid puts pressure on the production supply side to try and minimize the generator run time.

depending on your meaning for the kw of each system the battery bank size can vary quite a bit. any sizable wind setup is most likely to be of a gt setup making your inverters the closed grid system as most battery charging turbines are below 10kw. in any case the turbines need a load at all times be it feeding power to your mini grid (gt) or a diversion load charge batteries when not supplying grid. the problem there is that you may need an alternate diversion load for when the batteries are full so this is getting complicated.

depending on your location's pariculars as to what degree, you will find the solar aspect to be by far more reliable as i said so more emphases should be with solar and maybe have just a few kw in wind if any at all.

ggunn

Re: Off-grid Solar-Wind hybrid system

khan08 wrote: »

Hi,

First of all, I have been going over some of the threads and I really appreciate the help and guidance provided by the people on this forum.
I am a mechanical engineer by profession and I am currently working with a client who wants an off-grid 40 kW solar(50%)-wind(50%) hybrid system at his facility. I have some experience with on-grid systems, but off-grid is something I have never been involved with.
I would appreciate if someone could help me understand how a hybrid off-grid system would work? What are some of the things that need to be kept in mind while designing such a system? And are there any constraints to how you can combine wind and solar to create such a system?

I would really appreciate any sort of guidance or support on this topic.

Thanks
khan08

IMO the most important consideration on the wind side is to do a yearlong wind study at the location and altitude of the proposed turbine to determine if the wind resource is there. Many folks think they can just throw up a wind turbine wherever they want and it will produce its rated output. That is an excellent way to waste a big pile of money.