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Comment by tda | Hacker News Reader

By far the most wind turbines have been built on land and for good reason: it's much cheaper. As long as there is space/not too many people complaining it makes more sense to build on land. Not sure exactly but on land installed wind is probably ~10x the installed capacity offshore. However on land turbines are pretty much maxed out at about 7,5MW, due to logistical difficulties of getting larger blades, towers and nacelles transported over the road. These limitations don't apply to offshore sites, so the up-scaling continues. In the last few years typical offshore turbines have grown to about 9MW, but that is not the limit. Within a few years we should see 12-15MW turbines being installed, which should bring the cost down. Combined with the better wind conditions offshore (at least around the North Sea) offshore wind may become cheaper than expanding on land.

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It was my impression that the main reason for building offshore is because the winds are much more steady there. The definition of trade wind is a "permanent prevailing wind"; building someplace with "permanent" winds sounds like a good idea to me.

Yes. Land based ones are often on plains or ridges. Steady and unimpeded wind is why aerial and offshore have better EROI.

Do land-based ones compete with agricultural usage?

No. In fact, they make marginal agricultural operations economically viable by providing a second source of income to the farmer/land owner.

We have huge wind farms here in Minnesota and Iowa. They're in the middle of crop fields. No problem at all.

The better wind conditions help, but offshore wind is really expensive. Transport and install alone for a big offshore turbine can easily cost EUR 1-2M. Add to that undersea cables, higher maintenance costs (salt water, difficult access) and it is clear why onshore wind (if possible) is still the preferred choice. Nonetheless, mainly due to the up-scaling and abundance of available ocean space offshore wind has taken off in the last few years.

There are other advantages. Urban centers are often a lot closer to the sea than they are to the large open spaces suitable for wind.

Offshore siting also allows for much larger wind turbines, which are needed to economically exploit the higher quality winds given the extra expense of offshore construction and maintenance.

Onshore turbines are size constrained by transportation limits. Waters-edge construction and transport by sea allows for larger elements.

Transmission!!! A huge appeal of offshore for densely populated areas is you can put the huge turbines far off the coast of a dense area and then have very effective transmission, something which onshore is vastly limited by due to NIMBYism and lobbying and regulation.

And offshore winds are steady, reliable, and really conveniently timed: early evening is the peak, right after solar is done.

In that case they will compliment each other well.

Unfortunately, offshore gets hit by NIMBYism a lot more than it should. Senator Ted Kennedy axed wind off the Massachussetts coast because it would interfere with his view.

Ted Kennedy has been dead for a decade. More recently, the president said that the noise from wind turbines gives people cancer. In the end they are just two people that are wrong.

"NIMBYism" is a word that turns off critical thought in some people and ruins discussions.

There is a large inventory of coastlines with wind energy potential. There will be many distractions as they are developed by coal companies trying to derail those projects. That may be through astroturfing which will present itself as "NIMBYism" and divides people to weaken them.

Anyone who complains wind-turbines being unsightly should be forced to live next to an oil-refinery :-(

Not so much NIMBY/regulation as lack of good sites onshore. Low efficiency sites effectively increase the cost.

Additionally, a lot of densely populate coastal areas are populated quite a ways inland. You need open space around the big wind turbines for safety reasons - farmland is best.

AIUI the next round of UK offshore auctions are expected to do better than onshore, along with being cheaper than already existing gas plants. That's based on the current state of the art 300m high 15MW turbines - and there's no sign scaling up is stopping yet.

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