Wind turbine tower loading

rdolinski

New Member
Joined
Feb 25, 2021
Messages
8
Hi all, I have a unique and interesting opportunity that I am pondering.

I have a rural property with an 80’ antenna tower used by a local wireless Internet service provider (WISP). With Fibre To the home coming to our area in 2023 the WISP asked what I would like for them to do with the old tower once they are finished with it.

One option is for them to abandon the tower in place as it will cost more to remove the tower than it’s worth (crane & crew). Tower was built in 2016 so it’s pretty new.

First thought in my mind is wind turbine! It is an 80’ lattice structure with a concrete foundation 8’x8’ square and 8’ deep. Ya, a lot of concrete! The tower loading capacity at 80’ is 20 square feet but for every 8’ section of tower you remove the wind loading capacity increases by about 6 square feet so 72’ is good for 26 sq ft and 64’ is good for 32 sq ft.

My question is, how would you determine the loading of the wind turbine on the structure?

My first thought is worst case. If the turbine blades formed a solid circular disc, so long as the area of that disc was less than the tower capacity I’m ok. A disc with 2.5’ radius would have an area of 19.63’. If my assessment is correct I could safety install a wind turbine with 2.5’ (30”) blades.

I have had a anemometer/weather station at my place for the past 5 years so I calculated the annual average wind speed which is ~5m/s.

Should I consider a smaller turbine higher or larger at a lower elevation?

Smaller turbines need higher wind velocity to generate but the higher/smoother air might be more efficient.

A larger turbine that can operate with lower velocity but I would have to install it at a lower elevation 60’.

Looking for input. Thanks!
 

Robin K4IDC

New Member
Joined
Oct 21, 2021
Messages
7
Hi all, I have a unique and interesting opportunity that I am pondering.

I have a rural property with an 80’ antenna tower used by a local wireless Internet service provider (WISP). With Fibre To the home coming to our area in 2023 the WISP asked what I would like for them to do with the old tower once they are finished with it.

One option is for them to abandon the tower in place as it will cost more to remove the tower than it’s worth (crane & crew). Tower was built in 2016 so it’s pretty new.

First thought in my mind is wind turbine! It is an 80’ lattice structure with a concrete foundation 8’x8’ square and 8’ deep. Ya, a lot of concrete! The tower loading capacity at 80’ is 20 square feet but for every 8’ section of tower you remove the wind loading capacity increases by about 6 square feet so 72’ is good for 26 sq ft and 64’ is good for 32 sq ft.

My question is, how would you determine the loading of the wind turbine on the structure?

My first thought is worst case. If the turbine blades formed a solid circular disc, so long as the area of that disc was less than the tower capacity I’m ok. A disc with 2.5’ radius would have an area of 19.63’. If my assessment is correct I could safety install a wind turbine with 2.5’ (30”) blades.

I have had a anemometer/weather station at my place for the past 5 years so I calculated the annual average wind speed which is ~5m/s.

Should I consider a smaller turbine higher or larger at a lower elevation?

Smaller turbines need higher wind velocity to generate but the higher/smoother air might be more efficient.

A larger turbine that can operate with lower velocity but I would have to install it at a lower elevation 60’.

Looking for input. Thanks!
All good notions and it's apparent you're willing to do the homework. I don't have direct answers but can recommend Paul Gipe's book "Wind Power for Home & Business". I believe it has a chapter on the very issues you're working with.
 
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