Need help on some Off-Shore Wind calcs

Natural-gas-fired power plant planned on 30 acres in Oregon - Toledo Blade
800 mw plant on 30 acres.... a bit larger than a 2 story home

Greater Gabbard wind farm - Wikipedia, the free encyclopedia

504 MW windfarm in the UK The project site is located approximately 25 kilometers offshore within the Thames Estuary Strategic Environmental Assessment Area and adjacent to two sand banks known as the Inner Gabbard and The Galloper. The 147-square kilometer project site will encompass the wind turbines and associated infrastructure, including the met masts and offshore substation platforms. Connection to the high-voltage national grid will be made at a new onshore substation located at Sizewell, Suffolk. 104 wind turbines

 

I don't think VA is really the key demographic for solar power...
Annual Days of Sunshine in Virginia - Current Results barely a 30% of the days are "sunny" and then you have the whole angle of the sun/intensity. much better to have a solar plant where it will be productive.

Same thing with wind... Id say having wind turbines high up on hills would be better than out in the ocean...
based on the this map not much planned for VA. remmebr the key with a wind farm is to plant the turbines were you get the most wind.

 

Hills and trees can slow wind down. Ocean and plains will tend to have more steady wind. Out at sea is less likely to have Nimby than hill top installations also.

 

I agree on the nimby. but you are wrong on the hills...

Hills, plateaus and bluffs provide for the ability to get the generators higher in the atmosphere where there are generally higher windspeeds. pluss as air is blown towards a hill the lower layers get compressed and actually accelerate. much like when you put your thumb over the ends of the hose. the water pressure increases at the expense of volume...

Geography and Wind - Iowa Energy Center
Hills, plateaus and bluffs provide high ground on which to raise a wind turbine into a region of higher wind speeds. Valleys, which are lower and sheltered, generally have lower wind speeds. - See more at: Geography and Wind - Iowa Energy Center
Hills, plateaus and bluffs provide high ground on which to raise a wind turbine into a region of higher wind speeds. Valleys, which are lower and sheltered, generally have lower wind speeds. - See more at: Geography and Wind - Iowa Energy Center
Hills, plateaus and bluffs provide high ground on which to raise a wind turbine into a region of higher wind speeds. Valleys, which are lower and sheltered, generally have lower wind speeds. - See more at: Geography and Wind - Iowa Energy Center

 

I agree, sticking the turbines on a hill or ridge is best when the region has elevation changes. The average wind speed over the ocean and open plains is higher though. They might also be more consistent.
WINDExchange: Utility-Scale Land-Based 80-Meter Wind Maps

WINDExchange: Offshore 90-Meter Wind Maps and Wind Resource Potential


You can click on the images at the links to get details to get region details.

 

nice maps... not sure how my "triple post" got in there...

The Op was talking about Virginia, and not a whole lot of "plains" which is why I'd consider the western part of VA, and the area of high wind off shore is south or north of VA. And I think the ROI for a solar plant would be a long long time.

nice thing about putting wind farms on land, means it usually easier to build, closer to the grid, a lot less infrastructure to deal with. but then you have NIMBY problem..

no matter where you put them you'll have the tree huggers and fish lovers screaming bloody murder... especially when some hairless 2 toed bird on the endangered list flies into a spinning blade or the the sonic vibrations of a spinning turbine causes a dolphin to beach itself...

 

Yeah, offshore costs more, but it can be placed closer to where it's needed. I'm sure you know how built up that region is. Finding a location and space for a wind farm on land might mean placing it farther away, or the land costs could take up some of the savings of land based installation. Those savings could also disappear if more turbines are needed due to lesser wind conditions.

There are pros and cons for each. Offshore might be easier to get started on the crowded eastern seaboard.

 

Fishermen would love it...

I woudl think that getting some leased land from farmers for crops or cattle since the turbines could be planted there with not as much impact... as you'd have closer to residential areas...

Hell I live 18 miles outside of DC and I can't even get a good cell signal since none of the well-to-do in Fairfax County want any Cell towers in their backyards.

On the plus side... on weekends, work can't call me...

The NIMBY power in Northern VA is a strong force..

 

Offshore windmills tend to be larger than those placed on land. 5 MW I think is typical nowadays.
Much more expensive to place, but better yield. If a typical well-sited large windmill is 30% capacity factor* on land, IIRC 50% is expected off-shore.

So a 5MW capacity windmill would generate ~ 2.5 MW*year per year, or about
2.5 * 365*24*1000 KWh/year.

For comparison, here is yield data from off-shore windfarms in Denmark
Capacity factors at Danish offshore wind farms


*capacity factor is the fraction of nameplate that is collected.

 

someone did a study that the farther apart you place them also the better. as if you end up with one windmill down wind from another the dirty air causes reduced efficiency of the downwind units...

 

Looking at the map western part of virginia or parts of west virginia would be suitable for on shore wind to serve virginia. This should be less expensive than off shore. In texas we have put up areas for about $0.06/kwh (after the federal subsidy) not including grid improvements. Offshore should cost more than tripple that much unless prices have gone down. That assumes cheap borrowing at today's low interest rates for the wind farm.

A 500 MW fast cycling ccgt plant will cost about $500 M to build then about $0.02/kwh to fuel and operate. The natural gas plant will likely have twice the utilization as a wind farm, but that depends on demand and location.

Yes but grid still must run to the wind farm(s)

Those wind farms that have gone up in texas and iowa seem to be liked by those at the location. Most of the screaming comes from the coasts. I don't know why. I think it would be fairly easy to build the wind farm in west virgina to serve virginia, but.... that means virgina would need proper utility regulation to build out the grid and a way to sell the power so that it the extra cost is absored. Th federal government helped build out the texas grid for wind, and all electrical customers pay a little extra for the grid upgrades. Offshore they only need to regulate in state, but costs are much higher.

 

At least in the case of VA, Dominion claims it is too expensive still. They bought the lease area (maybe they just don't want competition) but then basically told people not to expect anything out there.

Dominion Virginia Power won’t build offshore wind farm on tract it leased unless cost drops - The Washington Post

Keep in mind all the users in offshore area near Norfolk too. To my knowledge they can only go so deep too, so you are looking for a sweet spot for wind and bathymetry, no conflict with other users, and close enough to shore to easily service and connect to the grid. Oh and don't choose a spot where a pricey resort can see your turbines spinning.

 

Not forgetting about the southern VA folks....

The OP , just wanted some info... no sure if we have helped him or not....

 

Offshore wind is becomming ever popular here. No Nimbys to worry about. We have a high population density so wind turbines always affect someone.

Just reading the following link and was surprised to note we have the largest offshore wind farms in the world. I think also because the North Sea is quite shallow too.

Offshore wind power - Wikipedia, the free encyclopedia

List of offshore wind farms in the United Kingdom - Wikipedia, the free encyclopedia

Oh, and the wind is pretty much always blowing at sea.

 

England, Denmark, and Germany are quite different from Virginia. Those european countries are willing to pay much more for the power than virgina and have quite different politics.

Virginia has cheap natural gas, and mainly is nuclear then coal. On bang for buck for reducing ghg, they likely are better off building more natural gas and shutting down coal. This can result in 60% less ghg/kwh replaced. Next cheapest is to expand wind farms in west virginia. Dominion already has some, but can build more. Environmental groups though seem to want the most expensive offshore wind. I doubt offshore can do much without raising costs to consumer. Wind in virginia, especially offshore, looks like it would mainly displace natural gas, not coal, limiting its ghg impact. In the future the state may have enough to shut some coal down, but it is not going to be soon at these prices.

In Texas wind is better and cheaper, but also regulators are set up so people that want the wind can buy it, without raising the cost much for other electricity users. I don't think virginia allows this yet.

 

That is a modern plant of 760 MW, You can definitely get 500 MW smaller. The difference between that 20 year old unit and a new fast cycling one, is slightly higher efficiency and the ability to better handle changes in demand.

Yep. I really think people need to look at wind regionally. Chicago can tap into the good wind in Iowa given grid upgrades. West virginia equally can supply more wind to northern virginia. The problem is many groups want it within the state. That is great if you have good wind in the state like texas and Iowa, or good sun like california and the southwest, but not if you are virginia.