General Questions

[ysga]

Dear members of the WAsP team.


I am writing a thesis about wind turbines and I am using WAsP.


Till now, I am following 'step by step example' at the help menu of WAsP. I am just wondering that did I prepare the project properly?


It is easy to start a project and add a met. station. After that I am creating .tab file via OWC Wizard (using wind speed data which I have) and add to the project.
I can create a map via WAsP Map Editor (using SRTM ver.2 Database). I know the coordinates where I install turbines and I can write land roughness (I am using the value that for big cities, you know the value table in almost every book about wind turbines).
I think I did right till this step.


What about obstacle group? I am trying to model a city so obstacles are too many. What do you suggest when modelling cities? Should I model obstacles around the turbine for 1km diameter area or maybe just 100m is enough? Do you know any engineering approach about this situation?


Also, wind turbines! I am trying to create a turbine for my project via WAsP Turbine Editor (a small wind turbine). But I can not find Ct values from wind turbines' datasheets. Can I calculate somehow via WAsP? I could not find how to do it.


If you have any suggestion or warning or just something you want to say, please do not hesitate to say it. I need information desperately.


I will be glad if you can help me.


Best regards.

[Niels Gylling Mortensen]

Dear ysga,
Here are a some brief comments to your post:


Adding a met. station: we recommend you use the Climate Analyst instead. Remember the geographical coordinates of the anemometer, and export in the *.omwc format for best results.


Map for WAsP: once you have the SRTM elevation contour and land/sea roughness map, you can add more roughness areas using Google Earth or a scanned paper map. Procedures are described in these course notes: http://orbit.dtu.dk/en/publications/wind-resource-assessment-using-the-wasp-software-dtu-wind-energy-e0135(259e26f3-1828-4e3f-9c37-17de375cd057).html


Obstacle group: model most cities and towns as roughness areas. The obstacle model is only used for situations where the mast is closer than 50 obstacle heights and lower than 3 obstacle heights in relation to the obstacle. So this is a fairly local effect.


Wind turbine: you can have information on turbines from the manufacturer or the internet. Also, there are some turbine power and thrust curves in the WAsP library. WAsP cannot calculate these specifications, you must know them from somewhere else.


My best piece of advice for now is to study the course notes mentioned above carefully; they contain quite a bit of information and links to other sources.


Good luck with your thesis!


Best regards,
Niels
WAsP support

[ysga]

Dear Niels Gylling Mortensen.


I really appreciate for the answer. I have some questions too.

Dear ysga,
Here are a some brief comments to your post:


Adding a met. station: we recommend you use the Climate Analyst instead. Remember the geographical coordinates of the anemometer, and export in the *.omwc format for best results.

It is done. I used Climate Analyst.

Map for WAsP: once you have the SRTM elevation contour and land/sea roughness map, you can add more roughness areas using Google Earth or a scanned paper map. Procedures are described in these course notes:

Unfortunately it is not done. I simply could not do that. SRTM map is OK but I could not add more roughness areas using Google Earth. I am trying to do this for now.

Obstacle group: model most cities and towns as roughness areas. The obstacle model is only used for situations where the mast is closer than 50 obstacle heights and lower than 3 obstacle heights in relation to the obstacle. So this is a fairly local effect.

Well, the anemometer mast and wind turbine will be in the city (the turbine will be small wind turbine on the roof of a building). The exact location of the turbine is not decided yet but there are a lot of obstacles near the turbine and the mast. By the way, they are closer than 50 obstacle heights to turbine and mast obviously.


So, should I model all the obstacles? It will be so hard to do that as you can imagine. Instead of that, is it enough to set roughness length to 1 (it is coming from Table of roughness lengths at the WAsP help menu) when I am creating SRTM map file?

Wind turbine: you can have information on turbines from the manufacturer or the internet. Also, there are some turbine power and thrust curves in the WAsP library. WAsP cannot calculate these specifications, you must know them from somewhere else.

I tried to create wind turbine files without thrust curve and I could do that (with just power curve). However, I do not know the effect this situation on the software. What will happen if I use wind turbine files like this? Is it OK to use like that?

My best piece of advice for now is to study the course notes mentioned above carefully; they contain quite a bit of information and links to other sources.


Good luck with your thesis!


Best regards,
Niels
WAsP support

I am reading the document which you suggest.


Thanks for advance.


Best regards.
ysga