"Nuclear doesn't take kindly to load variations..."
Those of us who served on nuclear powered ships will disagree, strongly,
with that statement, Ken.
On Mon, Mar 24, 2014 at 7:10 AM, Ken Norton <ken@xxxxxxxxxxx> wrote:
> >> I've also heard that over a certain windspeed that it is unsafe for the
> >> turbines to operate which seems rather ironic
> >
> > I was watching some wind farms, and wondered why the older, smaller ones
> go slower than the huge new ones. I could think
> > of some engineering reasons that might apply.
>
> The manufacturers have different designs. Most of the large wind
> turbines have transmissions between the hub and and generator. This
> allows them to change rotational speeds. Also, the blades feather in
> higher winds to prevent overspeed. They've got a lot of control over
> them. There is also a braking system and shaft locking. Finally, they
> can always adjust angle to the wind. Lots of ways to control
> rotational speeds under most conditions. However, there is one time
> the operators will idle their turbines. That's when a supercell is
> rolling through with a strong wind-shift. Due to the gyroscopic
> effect, you can only change direction on these things so quickly and
> if the wind sheer is to violent, it can't redirect fast enough.
> Speaking of wind sheer, this is one reason why they idle the turbines
> because the boundary layer is deep enough that you have too much of a
> differential in wind speed or direction from top of disk to bottom of
> disk. That's really hard on some of them.
>
> Base line generating plants, such as nuclear or coal, need to be run
> near maximum capacity 24/7. Nuclear doesn't take kindly to load
> variations and coal plants are only running at maximum efficiency
> after everything is stabilized at precise settings which can take many
> hours to achieve. Predictions of wind capacity are done days in
> advance and the power plant generating capacity is determined
> accordingly. If the wind is stronger than expected, they will idle
> wind turbines. If it's less than expected, they have to supplement
> with natural gas boost plants or fire up another coal boiler which is
> a nightmare. So, operators with large windfarms will project to
> something like 75% maximum capacity for projected winds and idle some
> of the turbines as necessary.
>
> Cost per MW or BTU and determining payback is a joke. The fact is that
> a well designed wind energy facility capacity is a win-win. The
> natering nabobs of negativism (driven by the coal/oil industry and
> east-coast media idiots) say that wind and ethanol are negative
> energy. It takes more energy to build/maintain/operating them than the
> energy you get out of them in return. Ethanol is frequently the brunt
> of this unfounded criticism. The reality is that if you applied the
> same exact rules of calculation to coal or oil you would find that it
> would take about 1.5 barrels of oil to get 1 barrel of oil out of the
> ground. Some of the things are laughable.
>
> My favorite point of entertainment has to do with the theoretical
> calculations for maximum wind turbine density. The aerodynamicists
> recognize that you can't stack them too closely together because of
> the turbulance coming off of the blades (which is being addressed with
> new blade designs). The axe-grinding folks say that each turbine sucks
> up 30% of the energy out of the wind and that's why you can't put them
> too closely together because the downwind turbines won't get enough
> wind to turn. Their calculations assume closed tube air movment.
> That's not how it works in the real world. In fact, my own experience
> being around high-density wind farms is that the wind is still blowing
> at the same speeds as measured by the airport weather systems.
>
> Wind energy works extremely well when the entire energy production
> ecosystem is built around it. You need base-line production of
> coal/nuclear/hydro which provides gross minus renewable production.
> Then you have natural gas powered boost plants which share the
> responsibility with the wind. When the wind turbines are at 100%, the
> gas plants are idle. When the wind ain't blowing, they're at 100%.
>
>
> --
> Ken Norton
> ken@xxxxxxxxxxx
> http://www.zone-10.com
> --
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