Thank you and thank you for inviting
me here and I'm glad to be able to

make the trip up here to Atlanta and speak
with you about the work the Myself and

some colleagues been doing on the suspect
title streams as an energy source.

So basically what we have done here for
about four years.

We started working on looking at
titles and energy for Georgia and it's

now spun up to a project we're doing this
assessment for the full United States.

So this is a department energy project
that we have been working on for

about two years now.

So first I want to talk about different
forms of energy from the ocean.

There's a variety of ways you can
extract energy from the ocean.

You have Wave Energy Tollner G.
current in.

Thermal energy wave energy the is
the when you go to beats you see waves.

You can they have a lot of energy and

they actually have a significant
amount of energy in them.

The problem is how do you
extract energy from them.

There are literally hundreds
of ideas out there.

None of been proven because
it turns out to wave energy.

You can build device you can
put out there in the ocean.

You can extract energy the biggest
the most difficult part is

what happens when a storm comes there and
you get so large.

There's not been any devices that So
Dr Long term a big storm comes in.

Absolutely.

Wipes them out.

Some basic numbers you get into
up into some coast up in Ireland

in that area up in the North Sea They have
so much wave energy up there under storm.

I mean intense storm conditions but

this happens at least yearly they
can have waves that are delivering.

Two to three megawatts of power per meter.

Those are and Norma's numbers.

They're not trying to extract energy that
point time they're in survival mode at

that point trying to get whatever device
they have to survive beyond the storm.

For Georgia in the southeast
wave energy are waves are tiny

because we have this broad continental
shelf down here on the coast.

So the waves are coming
from the deep ocean.

They're propagating across the sparely
shallow water a lot of bottom

friction by the time
the waves reach our coast.

They're pretty small them in order
to extract energy from the waves on

the southeast had to go
pretty far offshore and

it's just not practical for
total energy that's when I

talk about today current energy
this is ocean currents occur.

There's one primary ocean
current that's of interest.

That's the gulf stream the show a lot
of energy involvement off stream.

It's persistent but it's not always you
think it's just flow in the same place.

Well this thing actually meanders
around as different strains

as pulsates are being shed so it's not
a completely straightforward issue for

Georgia the Gulf Stream pretty far off
shore it's not terribly practical the big

hot spot for
the Boston coming down in Miami.

Because it's only a few miles
offshore down in Miami area

jobs have large population
centers there's plenty of demand.

So there's a lot of work going on and
if I were in a cost free MS energy source.

One of the issues that they're working
on is if you start struct energy from

the Gulf Stream.

What's the impact going to be because
if you extract too much energy from it.

You're going to cause a winner to occur up
in Europe because a Gulfstream brings heat

up to Europe.

So the climate in Europe
could be completely changed.

And if you extract and

wipe out the cost that would require
extracting a tremendous amount of energy.

The last categories thermal this
is ocean thermal extraction

that idea there is you use
the warm water in cold water so

you use warm water it's on the surface you
go down deep and get the cold water and

they're able to generate
electricity that way.

That requires access the warm and
cold water in the general vicinity.

That usually means large debts where
you get the warm on the surface and

then you go down deep from the cold water.

There's not many places where
that's practical hotspots

the United States there's Hawaii because
there you can go very close to shore and

have the necessary depths.

So I'm going to focus here
on the top of energy.

So first I'm going to be a little bit
physics of ties some based on how many of

you all are familiar with it's most
people know the tides the rising and

falling of the water level.

But what's less known is
what actually causes that.

Well the concept is it's
the gravitational forces from the moon.

So you have the moon.

It's pulling the earth towards it.

Pulling the water particles
towards you get a bulge of water

going towards the moon.

Well of course the gravitational forces
pulling the moon earth towards each other

they don't actually collide.

I mean obviously they haven't collided.

It's what they do is they
rotate around each other so

they're just spinning around and
around each other.

Generating centrifugal force.

So what happens then is you get a bulge on
the other side of the planet as well so

do the centrifugal forces.

But look at the breakdown of the forces.

Yeah the gravitational forces the blue
vectors going towards the moon and

they happen on both sides but
because it's a function of the distance

the gravitational vector on this
side is larger than on this side.

Then because they're spinning around
each other we have the centrifugal

force pushing away from the moon and

those tend to be the same size
on either side of the planet.

So on the side of the planet
towards the moon.

You have a net force that's
the blue line here the blue arrow

you have a net force pushing towards
the moon's that's generating this bulge or

water on this side on this side
the centrifugal force is larger.

So that means we now have a net
force pushing away from them that

gives us the second bulge of water.

So then as the moon rotates
around the planet you and

up with these two boulders of water
one that's fallen the moon once

on opposite sides and
that's what's going to lead to the.

High tide that occurs the base that pulls
water at least the high tide occurs

twice a day but it follows
the lunar day not the solar day.

Well there's multiple
constituents mall but

ways you can add up the tides
there's not just the lunar tide.

There's a solar tide the sun
has the same effect.

There's gravity pulling a lot
of particles towards the sun.

So you're also going to get a tide
that occurs on the solar day as well.

And then there's the different
distances the moon is not

always the same distance from the earth.

So there's all these different
constituents that can be then add together

and overall there's literally hundreds
of these possible constituents and

there's nonlinear facts that you have
the constituents acting together.

You end up with additional constituents.

So what we usually do then
as we sum them all together.

Well when you have a high tide from
one and into a high tide of another.

You can get what's called a spring tide.

So what happens if you think about just
the two main constituents the moon and

the sun so when they coincide you get
high tide both the current exact same

time you can get a much higher tides so
this is going to be when we're.

I have a new moon.

So when the sun is here the moons there
are in line with each other or it happens

on the full moon because remember this
is where the bulge on the opposite side.

So you've got the moon here
pulling its boulders but

the sun has its bulge on both sides So
again they're coinciding so

on either or New Moon or a full moon we
get what's referred to as a spring tide

as just the case where the tides
are larger than average.

So you get the larger
tides on that scale but

when the moon is in
the one the two quarters.

You're going to get a much smaller
tides because they're your lunar

tide high tide is going to match
that up with the solar low tide.

So that reduces the overall amplitude So
when you add these together you get this

modulation this is an actual
time series of some time.

Near Savannah.

So we see we get the spring tide here
where the high tides higher low tides

lower than the neat tide here where
you have much smaller variation.

Then this that varies on a time
period this is about a two week from

one spring tide to the next spring tide
and then it varies throughout the years.

Well the overall time scale if you want
to take all the constituents together and

figure out when it's going to repeat
is approximately eighteen years.

So if you want to fully resolve everything
you have to go out somewhere and

measure the tides for eighteen years in
order to fully resolved the most accurate

result we generally don't have that type
of time scale in a project to go out and

wait eighteen years for results are a lot
of places they have been measuring

that long but we can do a fairly good
job with much shorter measurements.

So here's a look at more about how
the constituents work equation is

quite simple.

You're simply for the water level you're
adding cosigns you have an amplitude which

is unknown for a particular location
that's going to vary depending where

you are you're going to have a frequency.

That's known that comes from astronomy we
know the frequency of the sun rotating

around the Earth we know
the frequency of the moon.

We know all the different constituents
frequencies that's a given and

in the face.

So the different.

Of all the different components that's
going to vary in space as well.

So the two unknowns
that we try to find for

each constituent is its
amplitude in its face.

So there's just a list of a couple
different lunar semi Darnall into that

just means that a lunar tide
that varies twice a day and

it's two same thing before the sun then
you have ones that just very daily.

And then you have a bunch of different
These are just some of the major ones we

have there's also thing called over
tides these are the non-linear So

the interactions between
the different tides can compute.

The end up of higher harmonics so the M
four is the type that happens four times

a day and six happen six times a day and
there's higher constituents as well.

So the end result is you take all these
different time series all these different

cosigned waves.

Yeah them together and
this is what you get is you just

do simple superposition of them right.

So how do we get energy out of tides
how do we base the bottom lines how

do we generate electricity.

Well there's two basic methods.

One is you go out and you build a dam and

this is what's referred to as a total
barrage you take unnecessary turn flood

tide when the water is flowing in you open
the dam up and let all the water come in.

So if you reach high
tide you close the gates.

Once you close the gates you let
the water outside of it drop.

And you get a sufficient head
differential between the inside and

outside then you let the water
run through a turbine and

it's basically acting just like
a traditional hydroelectric dam.

The drawback is you need pretty
significant head differential for

this to operate.

So you need very large Totteridge is there
are some places that that is possible.

One place up in the Bay of Fundy where
they have a more than thirty foot

tide range.

There are some places in France that they
are doing this they have a couple of these

facilities in operation right now
drawback is the environmental impact

is actually quite significant because
you've completely changed the dynamics of

us sure you're going to wipe out your
eco system when you first build this so

it can recover but what's going to
cover is going to be different.

So the pet care.

This is going to be a very difficult
thing to implement in the United States.

So the alternative is to do what's
called a tidal turbine farm.

This is based on a concept
very similar to wind energy

you base can think it is underwater
windmill you put some device under

the water that's going to strike
energy directly from the current so

you get the flow and you're trying to
extract from the kinetic energy directly.

So there's a examples of
a number of different devices.

I like throwing this one.

They're even doing this down in Brazil
providing some power from the Amazon.

This is what's referred to as marine hard
to connect energy where you're just trying

to extract energy from to generate
power from the kinetic energy.

There's just a variety of
different options that always.

As you see most of these are conceptual
drawings because this is a very new

industry in its infancy there's
nobody doing this commercially yet.

And of course they always like
drawing the fish around them so

and that's a Vironment some really nice
lot of them had this open design that so

they allowed the fish to swim
through them saying they're not

going to be fish choppers we're not
going to make sushi out of this and for

the most part these things do spend quite
slowly the R.P.M.'s are fairly low.

There are relatively benign devices but we
don't know for sure yet there is a lot of

studies that are going on now to
assess the environments and packs.

So how do we do assessment of power
one simple thing is to calculate

what is the power density kinetic power
density that's available question for

this is quite simple.

It's just one half of a cube you take your
velocity so this is TELL you how much

power per unit area so this is looking at
a vertical section of how much power you

have won't flowing through a unit vertical
section of course a real turbine.

I mean this blue curve shows it
increases with the cube of lost the so

it increases rapidly.

One nice thing is the density of
water much more dense than air.

So we get a lot more power out of water
than we would out of the quiver of

lost the in.

Air.
So we don't.

Need as much for
anywhere close to the same velocities and

water as we need in air.

But of course for

real turbine There's losses you are going
to have a maximum efficiency that you can

extract a certain amount of power there is
also what's referred to as a cut in speed

to get the blades turning you need
a certain amount of force before you can

even overcome the friction on
the turbine to get the blade spinning.

So that's what's referred
to the cut in speed so for

example you know right in this example we
have about a half meter per second cut

in speed anything below
half meter per second.

No power whatsoever
things not even spending.

Then you get the swing it starts spinning
and then you start dinner electricity and

you have then efficiency so you're only
going to extract a certain proportion and

a forty percent maybe fifty percent.

There's sort of an upper bound of
around fifty seven percent is what's

considered the theoretical limit.

So we see here.

We're not extracting everything.

Then generally there's going to be
a flatlining you're going to hit the rated

limit of your turbine you have some limit
where that's the fastest This thing can

spin and after that point doesn't matter
how fast your flow gets You're not going

to increase your power output you're
going to totally flat line your turbine.

So this may be the curve in theory this
is in practice what we can extract.

So how do we go about doing an assessment.

When we first were faced with
this we said well let's find

any information about the Tata
currents that's available.

Well I know which is
the National Oceanographic and

Atmospheric Administration they put out
lots of information about tides a lot

of total predictions they put
wallowed predictions that but

current predictions and these two maps
show for Georgia some of the total

current predictions for
this is the Savannah River.

And a couple things to say what
I'm plotting here is actually

the power density.

But it's based on the cube
of the velocity so

it gives an idea of how large of
lost it can be when the points here.

Look how much it varies.

This is just along the Savannah River
the flow rate you could think it's almost.

Constant as it goes up here so

the flow through here is equal
to flow through there yet.

The power in the main currents are so
different.

That's because the flow is the river.

It's a natural river it could
it converges it expands.

Well conservation mass tells us when
something converges for alright

stays the same but the glossies have to
go up because the area's gotten smaller.

So what you see is if you know
the currents in one location.

And you go hundred meters away you get
a totally different current field.

So just because you know what's
available in one location and

it doesn't help you for
knowing much about the neighboring areas.

The other problem with this map and
the quality of these predictions from Noah

turns out most of these predictions in the
Savannah area and much of the southeast.

They came from some measurements Noah did
back in the one nine hundred thirty S.

quality of those measurements is
quite suspect to say the least.

Knowing that they did the measurements for
one to two days.

You can't do totals it's very
difficult to do any predictions

based on only one to two
days worth of measurements.

So the quality of these measurements
they're off by a factor of

two three four and they the errors
associated these is quite significant.

So using this as a detailed
assessment is just not going to work.

We can have twice the current get
half the current We just don't know.

So here's an overall objective for
our national project

that we did on just briefly Save Our idea
is instead of using these measurements or

using those type of predictions which
are so suspect what we'll do is

we'll use a numerical model good thing
about tides they are very predictable.

They are deterministic we can run in
America model we can force the tides on

the offshore boundary and with that
we can run the numerical model and

come up with very accurate predictions for

what the water levels and
what the currents are going to be.

So this is a case where we can
actually run the model and

predict in the future what
the tides are going to be.

So our objectives here first use
the model simulate the tides.

Once we have the prediction so
in the model that is this time series

we can then calculate those
constituents as harmonic constituents.

We pull straight out of the model.

This is on high resolution we have
resolution on the order of two hundred to

five hundred meters.

So every two to five hundred meters
on the entire coast the United States

we come up with these predictions for

the tides will have to validate it we do
more running the model for some period in

the past we take measurements to actually
validate and calibrate the models we're

going to have a lot of quality control
that's a big part of this project.

We then take this data
we put it into a G.I.S.

database and I'll demonstrate
that here in a little bit and

we have a quite a few different tools
that we can use with this database.

There's things ventures there's someone
who's developing this technology

they have a certain depth
you put some in the water.

What's going to be well below
the water surface because a boat

is going to come overhead you want
your boat running into your device

see a certain minimum depth that you have
to maintain there's other issues there sea

space conflicts if it's a fishing ground
doesn't matter how deep you are those nets

are going to drag down on their There's
protected areas that you can't.

So having these tools and put them
into just Web site is the developers

that's what they're asking for and so what
we're providing for them and then our last

objective here is that actually
the web page itself in the American

model this is been an incredibly
ambitious numerical modeling project.

We have basically divided
the entire coast and

United States up into multiple
domains we can't just run them.

But we can try to run the model for
the entire coast at one time.

It's not very practical.

So we do is we're just breaking it up so

you can say we've done the whole
Gulf Coast coming down to Florida.

We've done the whole East Coast.

And so each one of these squares
represent a different domain.

They are fit in there so that we have
overlap but so that we're resolving

individual estuaries with then we don't
cut a single asteroid off on a border.

So everything.

It's self-contained so in some spots
where we go for a large area and

said hey this area needs
a little more detail.

This is actually
St John's River in Jacksonville.

It's pretty significant currents in there
so we put a second grid in there to

resolve that area a little bit
better than we have the West Coast

which we've completed so we started down
St Diego we've done the whole coast here.

Then up here this is actually Puget Sound
This is one the hot spots is one the best

places in the United States one the top
place in the world actually fertile

occurrence with a number
of different domains we

have here we can spend approximately
two weeks per grid and

there's a lot of overlap
between the grids.

For A ESTAR as complex and
dynamic as Puget Sound.

We can't do that in a two
three week period so

what we've done is there's another
group at University of Washington

who've been simulating this for
about the past five years.

They're actually using
the exact same model said

they're doing everything exactly the same
that we're doing so what we've done

is obtain their model results and we're
putting it through our quality control but

they simulate this whole box and
they have that whole area in their domain.

They're also doing Alaska Alaska
is another hot spot for

energy into a Christian here
there are some very significant

currents are occurring in there and
they believe or

not they have they do have energy
issues they want to be able to provide

energy with these alternative sources and
they were even do that.

Lucian islands.

There's just a hole here
that we're currently and

grids being set up right
now to finish that spot.

So we're running America model there
are some basic information needed.

Order one most important but they
mature we need to know the water depths

everywhere without the thin
material we can't run anything.

So we have a variety of sources
support but that materie wetlands for

the southeast and some of the north
western areas we have a lot of wedding and

drawing you have these type of mud flats
you have marshes where you have to account

for that when you have the water
coming in for high tide.

If you don't account for

the water going on to the areas
that are dried during low tide.

You don't get the volume right.

You don't get enough volume coming in.

And you can't get the currents right.

So it turned out to be very important for
us to include the wedding and

drawing in the model into account for
the wetlands so we use that we can get to

park a fifth of the wetlands from U.S.G.S.
and we feed that into the model as well.

Constituents there's two different
databases that we use we first started it

were to Susan what's called the ad search
data base where this was is that used

a numerical model to simulate the entire
North Atlantic Ocean and then compare

the constituents on a fairly course
grid running up close to the coastline.

So our procedure then is to take
their constituents which come up to

pretty much towards the shoreline.

But then we use our model to basically
to think about propagating those

type of constituents into
the areas in the end limits and

islands in the islands and
into the creeks and rivers and so on.

What turns on the West Coast.

There's a second database that the babble
it turns out to be a lot more accurate

does a better job on the West Coast for
us.

So we've switched to
what's called the T P X O.

Database this is been put together
by Oregon State University.

So procedure as we run thirty
two days with throughout

the first two days of the simulation
that's the model spokes we start with no

currents not still water everywhere.

Turn on the forcing them all
ramps up over the first two days.

So for all that what we're left
with is thirty days sniffin So

that number is it covers
a full lunar month.

The following month only twenty nine days.

So we have at least that fall under a
month in order to resolve the constituents

of fish and so we run the model for the
thirty two days then we do a calibration

procedure we compare our results from that
thirty two day simulation to whatever

measurements we can obtain and then we
use to shore up its a look too small so

let's see if we can decrease our roughness
we can do a little about the metric filter

in a number different knobs you
can kind of twist on the model.

And so we do a couple short
day runs just right back and

forth to we're happy with the results then
we redo that thirty two day simulation.

Once we do that then we're able.

Compute the harmonic constituents and
full time on the constituents.

Gives us our results to
go into the database.

Model verification how do we know
the mall is doing a good job.

Well one thing we can do is
compared to those know it.

Predictions.

We have to care for that it's like I said
the quality of those can be quite poor

those predictions so we don't want to
put a whole lot of credence into them.

But fortunately for a lot of locations.

That's the best we can do.

There is not data available.

So a couple of statistics we can look
at we can look at things like the mean

current magnitude ratio Maxim occurrence.

That says a lot but what that means
is what the no predictions provide is

the time and
the magnitude of the peak current So

says you peak flood current is
going to be at two fifty five and

it's going to have a current of
one point two meters per second.

That's all the information that provides
what we do as we look at our model results

we figure out what time
does our current happen and

what is its peak magnitude and
then we can pick that out for

every peak during the thirty two day or
whatever time period we're looking at.

And calculate the mean of that and
what we come up with in this case.

Nine point nine zero or
five once that's ninety four

percent of the peak predicts
occurrence will our models come out so

that shows that one is doing a pretty good
job that we can look at things like R.M.S.

differences so that gives us more into
the magnitude so we're for example eight

Simmias per second difference which
again is a pretty good result.

Then come down here we're looking
at base differences this is

the timing of the ties when
duels peak currents happen.

So here we're coming off of only thirteen
point eight minutes difference so

we're predicting the peak
current happens so

it's a thirteen point
eight minutes earlier.

It can.

That's a pretty small time you're
talking about the tides occurring over

twenty four hour period then thirteen
minutes is a pretty reasonable result.

Nothing we can do is compare
constituents directly that's what we're

putting in our database so

actually it's a good idea to compare
what's in our database so if there's

placement measurements of sufficient
length that calculate those constituents.

We can compare them dry.

So that's what's here the light is
the model the red is from the measurements

into this our Dhamma constituent This
is from a place Kingsbury Georgia.

You can see most energy is in that
one constituent from the moon

where the solar one is about
a quarter of the size but

overall you can see we're
doing a very nice job.

Comparing.

And then we have the phase
difference in terms of minutes.

So the ones that have the larger
differences the overall amp it's

a pretty small.

So we're not as concerned
about the phase difference for

those are into phase differences on
the order of just a few minutes.

So we're doing a good job
on the major constituents.

Some of the data we can obtain
it's too short to do and

it could such an calculations For example
here's one that just hits a tide cycles.

You can't calculate that from
that's what we can do is we ran

our model we got our constituents
once you have constituents.

You can calculate time series
from that any time you want.

So we then calculate our
time our model results for

the same time period and just do
a direct comparison between the model.

Currents and the measured currents.

But if you do have current
conditions that are large enough or

long enough to calculate
those constituents.

Then we can do here is into
a comparison for the current so

the same thing as with the water levels.

Right.

So now I want to get it actually
let me show you real quick.

One thing we're doing with
this is putting in a website.

And so just to show you our
results I was going to pull out.

This is a nice little website and
actually I'm back here went into.

I'm at the J.S.
center development website itself but

we can do is look at in the database
any user can log in here.

See if it's wakes up and

look at and download our raw results our
constituent database is fully accessible.

So for
example here we have the power density so

this is the interest
the Long Island Sound.

This is another potential hotspot for
type.

Energy you can see we get large
currents here in the entrance.

So you can zoom in and

see the hot spot there then you've got
a variety of hot spots along here.

Then we can identify you
can say OK I'm interested

in what the actual values are so
this tells us that we had a water depth

there twenty six meters main currents
one point two seven meters per second.

So pretty small at that point.

So let me move it a little bit.

Zoom in on the hot spot.

Pick a point here.

And now we're talking much larger
main current of one point one

nine meters per second.

Max current all at the two point
two six minutes per second.

This is now getting into the regime where
you get viable energy generation another

cool feature so you can actually get
the data directly and part of that

is you can filter so you can say hey I
want to get at least fifteen meters depth.

I don't have fifteen meters.

I can't put my device in there so
I'm going to eliminate every under fifty

meters but I want to mean current
of at least one meter percent.

If I don't have at least that mean current
I'm not going to generate enough power.

So let me filter in find all
the points that qualify so

everything and
if you hear all those green points.

Satisfies that criteria.

Then you can download it and
get this in a spreadsheet and

then you'll have our entire database all
its constituent so you'll get all the data

you need to for your assessment of where
you want to put your toilet turbines.

So that sort of our general
assessment project.

We also have done some
site specific assessments.

The data we're providing it's not
sufficient to do the testing and

know where exactly you know you're
going to put your turbine but

UNION know the flow characteristics
to a whole lot more detail.

So it done some work for the Marine Corps.

They have their training
facility on Parris Island So

this is personnel and
where all the recruits on the East Coast.

That's where they come in
to their basic training.

They're ideally located in here.

Right along here you've
got the Buford river.

It's got a lot of tidal flow coming in
here see a very strong currents and

it turns out they have energy plan
the diesel power energy plant right on

the bank there.

They have some cooling water intakes
they have a transformer station right

on the bank fifty feet
from the water they say

they've got all the infrastructure
necessary right there to tie into.

So our methodology for
helping them with their Susman

first step is to go out with a boat and
put a instrument on the boat and

measure the current So we just roll around
and try to figure out get an idea of

the spatial variability of the currents
once right then a five where the current

seen the largest we go out we deploy
an instrument in the water for

at least that lunar month in
order to get a better measure and

a kind of way to constituents for it then
what we did is we took our model system.

We used our measurements
calibrated the model.

Then we used the model and
put in some additional terms account for

energy extraction and I did.

There is what we want to see what the
impact of extracting energy from the tides

is on the top floor itself.

We know we don't want to go in there and
completely change the top of

flow because then you're going to have
those significant environmental impacts.

So here's our method for

doing the boat measure we have
a nice little pontoon boat.

Which we're able to mount a bomb in or
so in this hole in the middle where

we measure depths and then we have this
mount where this what's called an A.D.C.

piece an acoustic Doppler current
profile or it sends down for

accused the beans and different angles and
it measures the currents for.

You and
occurrence as a function of depth so

that goes over the bow of the boat and so
the idea is we're going to drive back and

forth across the channel
during the flood tide and

do the same thing again at the ebb tide to
get the spatial structure of the currents.

So here's the bath metric results you can
see kind of a path line now this is over

both title cycles but you can see we set
up kind of a grid but we went back and

forth and because this is where
the Marine Corps has their infrastructure.

We're more focused on here.

So we did a whole bunch of lines zig
zagging back in there to get them a tree.

So the cooler colors of blue
colors are deeper water so

there's a couple of really
nice features tardiness here.

The deeper water is right on the bank
close to where the infrastructure

is that's good.

The other side gets really shallow so

that this area on the opposite side
is not going to be a very viable.

There's also there's two channels you
get the deeper channel which is here

we've got a second channel here.

This channel is actually
the Intercoastal Waterway.

We can't do anything in there is no way we
can put any sort of devices in there but

this channels outside of that.

So this is open area this is viable for
putting in some sort of devices.

So that in the boat based
current results this is shown

on the measurements during the flood
tide and this is the measurements for.

At tide the broader called the red color.

I mean stronger currents so
you can see along this area.

We had a pretty strong hotspot same thing.

It's the same area.

So the peak currents were
occurring in that area and

I corresponded today of the depth about
six metres so it's a moderate depth but

for some smaller scale devices
that would be sufficient.

As you get further away
announce that shallow

where you can see it's really true here.

Currents really drop off so
the largest currents are very fortunately

located on this side of the bank on
the side of the Marine Corps facility.

So then what we did is we have the A.C.P.
measure So

this is where we deployed the instrument
in the water and kept it there for a.

Months so it was deployed on
the twelfth of November and

we pulled it out on about the fifteenth or
sixteenth of December and

what we have here is we extract
all these different constituents.

Once we took the Duck time series
we downloaded their constituents.

We calculate the constituents and
then recalculate the time series with

just those constituents difference
between what we actually measured and

then what's with those constituents
that stuff we're not accounting for

that's pressure water flow that could be
wind driven floods other processes that

we're not catching what a good thing is we
actually account for ninety nine percent

of variance with just those constituents
that means we're totally dominated and

there's just about everything is
in those ties that we extracted.

There's only about one
percent of other flow.

So that's a good helpful result that
allows it to be much more predictable and

then this so that's water level
this is current same thing here

you can see we're picking up the peak
current So we're picking it a little over

a meter perception is our largest currents
very clear you get your spring tide.

You need to fall by another spring time.

The green line here is the residual but
it's the part we're not picking up.

So probably not picking up is about ten
fifteen centimeters per second only so

we're capturing the dominant
mode of them flow here.

Right.
So look at some of the numbers here.

These are the different Instead
she wants their frequencies and

then here is the water level amplitude so
this MTU absolutely dominates point eight

six meters is the amplitude
of the water level variation.

That's THEY HAVE TO THE ACTUAL of
variation you would double that.

And everything else the smaller
ten to fifteen centimeters.

Then the phase which I mean that's
from not really important but

now here's the main current amp to this
of the amp to the current as it's also

in back and forth.

So the MTU again dominates at eighty
seven centimeters per second and again.

No that's just amp who's going plus and
minus.

And here the other ones are smaller but

you can't neglect them
because they add up.

So there are many times
all these comments.

Side you add all those numbers up.

That's where you get those peak currents
of one one and a half meters per second.

So it could do some histograms but
it shows you how many hours per year.

The current is in a certain man to so or
so of our peak current here is occurring

but eighty centimeters per second is our
most frequent current so you can also

think that everything down here that's
way below your typical cut in speeds.

So this shows the power
density histogram so

it takes these numbers calculates what
is the power associated with that.

So everything that falls down here kind of
falls into this first bend you don't have

power on those lower of last days but
you do have power and all weapon you get

is peak ones where you can get an up close
to a thousand watts per meter squared.

So this is just the surface current
same thing for the depth average so

we could take the current sets
measured close to the surface.

That's really going to largest or

you can calculate it sort of take
the average current of the entire depth.

But the overall different
there's not much.

So it was kind of just slightly about
ten percent larger than the depth

average current.

So our arms modeling so
we want to now model

in get more detail because this is just
measurements at a single point for

a month we want to get
a little bit more information.

So this is the grid that we used we zoomed
in and this is the river coming in.

That's parasol in there.

So our field site is right there.

So what we do is we have a two hundred
meter grid resolution that's the distance

between different nodes in the grid and
that's just some basic information three

D. models we are resolving the vertical
variation is in eight different layers.

And it's in a little bit closer here so
this is the actual grid in that the city

so that's where the P. was you can see
it's right on the edge of our grid and

we have about eight points going
across that entire channel.

So here's how well the model works.

This is the water level where.

Blue is from the eighty's the measurement
red is what the models actually predicting

and we're doing a reasonable job a little
offset especially the first part and

then the second part of the month.

It does a much better job.

But one of the things that we like
to capture figure out how much

of the variance that's most poor how much
of the variance do we actually capture

in the signal and

turns out we're still capturing with the
Model ninety eight percent of variance.

So we're doing a fairly
nice job same thing.

The currency to see we're
picking up the speed currents

getting pretty close dropping
down with the need to.

Pick him back up.

So overall the model does a fairly
good job reproducing the flows here.

And some statistics some
basic statistics here.

This is that similar table before so we're
getting ninety five percent of the peak

current magnitude and with the face
the frontier of only again about thirteen

point eight minutes so we're doing a very
nice job of simulating this location.

Right.

So one things we want to do that is
modeled the impact of the devices

on the flow fields we want to extract
energy from the flow field and

see what the impact is on the surrounding
area what are the large scale impacts so

that we're not looking the detail
flow in the media saying the device.

We have a two hundred meter grid these
devices on the scale of several meters.

We can't resolve that level of flow
detail that takes a much higher much more

advanced than we're doing.

But we can figure out the large scale
tidal effects what is going to happen to

the stranding marshes what's going to
happen is the prism going to change.

So what we do that is we just implement
a fairly simple retarding force OK but

these devices are going to do their
act like a force that is exerting

actual meant them onto the float that's
kind of actually just a patient and

in particular grid cells we put these
in a couple of different grid cells.

So in those group cells we have multiple
devices that are inserting this force.

So what we end up with
then is a additional

stress term that just shows up in here and
we're going to come.

For dissipation So
we're not doesn't a thing.

Some of that dissipate
would go into electricity.

Some of it's just turbines
that's been generating we're not

resolving the difference between now
all we're doing is saying we're losing

a certain amount of momentum
from the flow field.

So we did is we put these devices on
the side of the channel we're trying to

simulate a realistic situation for
the Marine Corps if they put a couple

devices on the channel close to their
facility a star extracting energy.

What's going to happen the flow field.

What we have here this is a map
showing a change in main currents.

So we see is in the vicinity of
the device we have this extra friction.

We have a reduction in currents which
makes sense where extracting energy from

there you're putting is added roughness
those currents actually decrease slightly.

What's interesting is on the other
side the channel currents increase.

Well the reason is the overall flow
is going to stay very similar.

It's not going to change months but you
put extra friction on one spot will flow

is going to tend to go around that and so

you can increase your flown
opposite side a little bit and

that's what is observed to occur here is
you get a slight increase in currents here

fairly substantial decrease occurrence
where our devices dissipating energy.

And then we look at time series to see
how the how do the currents then change.

And so it's looking at a point upstream
and downstream of this location and

we see the currents they
are decreased a little bit.

We are extract energy so
the currents are going down but not a very

substantial about a five percent reduction
in the overall current strength.

That we can look at water level so

here we're looking at the water level
variations This is of great interest.

If you have a sensitive salt marsh.

It relies on it becoming wet and dry
during the different parts of the tidal

cycle you change that you're going to wipe
out your plants you know wipe out your

animals we have to make sure we don't have
a large fluctuations on the water level.

So we're showing here is variations in
the water level the scale here is of

millimeters we have variations
on the order of one to two

millimeters of the impact.

On the water level we can even
measure that if we want to go out and

measure that's beyond the accuracy of
what we could measure in the field so

that is an absolute
minimal impact right now.

So all we're doing here.

This was a simple case is what were
extracting ten percent of the vailable

kinetic energy.

It's a fairly small amount
the significance of that particular number

though is a couple years ago
Epperly put out a report and

they just kind of made up a number
they said we think you can safely

extract fifteen percent
of the kinetic energy.

Beyond that it gets to be too risky.

Well here we're extracting
almost that limit.

And there is no impact whatsoever.

And here's some more effect so here we're
looking at the change of the main power so

of course main power drops there goes up
there because velocity decrease velocity

increased and here we're shown the time
series of the power of the flow

feel at that location so red was
the rod no extraction case that's what

the power was prior to any extraction
Black is the actual dissipated.

That's how much power.

Despite only displaying ten percent so
very low dissipation there and

blue is the residual That's what's left
over after we extract our flow field.

So not much change with very little
reduction of the overall flow feel.

Let's crank things up.

Let's extract sixty percent so
way above that limit that every put out.

If you notice the differences
between these time series not

much different from that ten percent case.

Things haven't changed works
tracting six times the amount of

power dissipating six
times the amount of power.

We were before.

Yet there's minimal impact change on
the wall of yes a little more water

level impact levels drop here
on the order of four millimeters

that's still beyond our detection limit so
absolute minimal impact.

We look at the power gain the main power
distribution it looks very similar

reduction one side growth the other side.

Now here's where some
interesting comes out.

No extraction case again is
red a power dissipated We're

now at sixty percent of that.

So we're tracking a lot of power.

The overall powers in blue something
jumps out the page right here you

think OK you have your raw power.

If you extract the power and
have a residual power.

We'll show you extract it in residual
add up and you call your raw power.

Turns out.

No it doesn't work substantially
over that the black.

Plus the blue is way above the red.

The reason is the kinetic
power is not all that's there.

There's a lot more power than that
there's a lot more power than just

kinetic energy you have the potential
energy of the flow field.

So with tides you have the pressure due
to the water level there's a slope in

the water level this pressure force
is actually transmitting a lot more

power than the kinetic power
transport what's going on

is the flows ever recover you're
able to extract this kinetic energy.

There's a lot of flow
recovery that goes on.

So using kinetic power as your estimate
of the resource is a very bad idea

it underestimates your resources
by order of magnitude or more.

So how do we do this final resource
assessment how do we come up with and

this is back on to what part of Energy
wants us to do they want to know

how many gigawatts a power is available
United States from the tides.

That's what they are one US The provide
a final estimate for them.

So there's a couple of assumptions were
made and this is something we're still

discussing with different
experts first assumption for

general turf for
you put in a single turbine the water.

It's limit is what is the kinetic energy
at that point for that single turbine.

So there's a limit you can only
extract up to fifty seven percent

of that kinetic energy for
one particular turbine but

the total available power for
the full estuary.

It's not a function of
that kinetic energy flux.

It's going to include because there's
what's called a kill it affects you.

Struct energy at one point you're going
to affect what goes on downstream of that

you're changing
the dynamics by doing that.

Well the total power in extra a lie.

I said it's not just
the can connect energy flux

also includes that work done by pressure
that turns out for pretty much every

asteroid that worked on by the pressure
forces at least more magnitude larger So

there is a tremendous
amount of power available.

So to come up with our final assessment.

It's going to be some fraction
of this total power but

cannot energy flux will still come into
play but we also have to look at the.

The portion of done by the work
from the pressure that has to

be including the calculation it's going to
be a some fraction of that total power but

there is going to limit if you don't
have the kinetic energy in your estuary.

You can extract power if you don't hit
those mean currents you those currents

aren't large enough to
not extract anything.

So there is no Me upper bound that's could
be put in place from the kinetic energy

distribution but there's that the majority
calculation has to account for

the transmission of
the power by the pressure.

So some of the ways we can estimate
we're following a method by incomings

what they do is they calculate
the power and this is accounting for

if you take a turbine you put in the water
you extract certain amount of power but

a second turbine and
you extract more power but

you're changing the flow fields
are trying to account for that changes

as you put more turbines extract more more
power into you get a point at some point.

You're going to affect the flow field so
much you're going to start reducing

the overall power so there's an optimal
amount and that's what this get incomings

met that does in a very simplistic Methot
but it does a pretty good estimate of

what the available the for
the maximum power is and it's a function

that has this premier gamma which is
on the order of one point two two but

shown it can range point one nine point
two seven it's the exact value is.

The pen's on the what set of assumptions
you make but it gives us a good estimate

but then it's a function of
the total water level amplitude So

these are simple things we know that total
water empty that's somewhere tackling in

our model and then the maximum total for.

So you take those two things
more plumb together and

it gives you than this estimate
of how much power is available.

Well and the other limit is how much
kinetic power is actually a valuable

estuary.

We can't just sum that up.

What we have to do is realize
that's the power density

the kinetic part of density which
is the one half row the cube here.

That gives us the power
per vertical section area.

So when more plant pot of swept there
you have a device with a certain area.

So that's the swept area but
that now converts it to a power.

But then within each of our grid points.

We only have a certain number
of devices you can put in so

we take the surface area of our cell.

So that's our two hundred meter
by two hundred meter surface area

then we multiply it by the number
of devices per surface area so

we put in some realistic numbers.

This will give us an idea of well
how much power we could extract.

We also throw in there is sufficiency.

This accounts for
that cut in speed this accounts for

the maximum rated speed as well
as how much power we can actually

extract the you know the rated
efficiency of the devices.

So some examples.

The first example is Chesapeake Bay
these in the let's call this P.

Max method this is that their income.

It's estimate it tells us there should
be one hundred fifty one megawatts

of power available.

So it's a moderate
number not terribly big.

But the problem is this is actually
a map that we filter so we put in these

different threshold hit that at least five
meters depth which is pretty shallow.

Minimum current minimum current
at least a half meter percent.

Chesapeake Bay currents are tiny.

This is showing the power
with those filters applied.

It's a little tiny blue spot down
here that's the only area that

meets those criteria the rest of
the Bay does not meet those criteria so

that means even though we estimate there's
one hundred fifty one megawatts possible

with these of values in here.

There's only twenty four
megawatts which could be possible

right down here in the tip.

And these numbers are really at
the threshold for feasibility for us.

So in general going to pose a new type of
energy in Chesapeake Bay Don't vest money

in that there's just
there's no power there.

It's just not going to feasible location.

Right now we go down the St John's River
this is a fairly small river but

it's got a pretty large tide range is
that River into Jacksonville R.P.M.'s

about that says fifteen megawatts so
it says there's no whole lot of power but

that's a realistic number in this case
because when we put in our numbers here

currents are fairly large and so you can
see along the whole stretch of the river

here and there are some key hotspots where
you can get pretty large currents where

there are some places in the river
where you get the converging currents.

So this one.

There is enough matter of fact our little
P.K. method here says there should be

twenty three megawatts so this just
tells us there's a lot of uncertainty

between these two methods but
it gives us an order of magnitude.

There's perhaps twenty megawatts of power
available from this small asteroid.

This puts it on par with the entire
Chesapeake Bay test base with a large

astroids in the world.

This is a tiny river.

Yet there is probably more power
realistically available for this location.

Let's get a little bit.

Let's go.
St Cisco bay.

And sent Cisco but
we have a lot more flow coming in and

it's it is one large
estrange in the world.

It has three hundred sixty
nine megawatts available.

That's coming from the flow coming
the Golden Gate Golden Gate

is going to be a potential location
it's got some great characteristics

it's really deep you can put stuffed
animal water surface doesn't matter if

a full size freight ship comes through.

They're going to be below it's draft.

So there is some feasible locations
there but the currents are so

large coming through the Golden Gate
in the bottom of the Golden Gate.

There's actually large sand waste
there's sand waves with a wavelength and

they are about one hundred two hundred
meters wave height about six meters these

things are moving in the flow.

So you.

Some bought a mountain and
it's going to get buried.

So you're going to have to put something
that's more up above that bottom.

But there is quite a bit of interest as
you come through the Golden Gate there

are large currents and R.P.

came out that says yeah there should be
at least two hundred thirty megawatts.

And these are low conserved numbers for

that you can use much larger devices
because you have enough depth

there in the Golden Gate So
that number could be potentially larger.

Right.
Here's the biggest the biggest hot spot

and the United States Puget Sound is
actually devices that are going to go in

the water here for
some test grounds primary hotspots one

is the Admiralty in the inlet coming
down to the U.S. side of Puget Sound.

There are some very substantial
currents that are occurring in here.

And then a really large hotspot this is
what's called Tacoma Narrows there's just

this pinching of the flow through there
currents really get cranked up in here.

It currently lower a four five six meters
per second which is absolutely enormous

flow velocities.

So here are people Max met that says
there's almost twelve hundred megawatts so

now we're finally into or gigawatts and
this is where some utilities out here in

the West Coast that starts getting their
interest because that's all the power

plants right there of able power so
that's now commercially viable and

our P.K. method again these numbers
are very concerned for you can put a lot

more devices a lot bigger devices in here
because you're talking forty fifty meter

depths to Admiralty inlet so it's deep and
it's fast flowing through there.

So the overall magnitude therefore
Piquet method also shows.

Eleven hundred megawatts so
a very realistic result.

To summarize some advances why should
we be interested in ocean energy.

First of all it's completely
renewable extract whatever you want.

Today it's coming back there tomorrow.

So it's fully renewable we're
never going to deplete it.

It's also extremely predictable we
can predict the tides two hundred

years from now.

Once you have your constituents.

You know what the Assuming
that the sun in the moon.

Don't change.

We're going to be able to have
fairly accurate predictions

environmental impacts they tend to
be less they are soon to be last.

We're still trying to prove that what
are the issues Well first of all

large capital investment building
to these devices put them

in the water that's going to take
a fairly large amount of money.

It's also in mature technology at
this point in time we're still in

the design phase.

There is no commercial
application out there yet.

Also these devices they can be
reliable because this is a very

difficult environment to work
on you mix salt in with devices.

You've got major issues there you have
an environment with very large currents

you have very small windows opportunities
where you can get in there actually

service the device.

So some final remarks.

This is it's a distributed power source.

It's not like we're going to be able to
put I mean there's maybe some spots in

Puget Sound you could put something in
there and be a commercial application but

for the most part.

You can put in a number of
devices different locations and

provide some power for a small community
perhaps you're not going to end

up with these hundreds of megawatt power
plants from most parts of the country.

It's not continuous The tide is not
continuous You have your flood tide.

Then you have your slack
time where you get no power.

So it's predictable but
not continuous It's also

a new technology we don't know for sure
what the impacts are the thought is for

the most part they're fairly benign but
we don't know the impacts

on fish will impact on mammals migrating
birds these are all issues when I was

first like well how does
an underwater device affect a bird.

A lot of birds go for
fish they dive down the water.

What happens if they don't water and hit
a device that could be a negative impact.

They're also very highly
sensitive to the detail the flow.

Field.

We were providing If not mean currents.

But the very specific you get these eddies
being formed when the first advice is that

when the water up in long are in
the East River up near New York.

They put their device in the water with a.

Days the plates start breaking
you know what happened.

The main currents were any larger than
they thought but the problem is they have

these large scale eddies that are coming
and that means on one part of the blade

the flows going one way has one strength
the other part of blade has a much

different velocity you get a lot of shear
in the plate that they were not accounting

for that level of detail they had not
been able to measure before so that means

when you're going to decide assessment you
have to get out there and do extraordinary

detailed measurement to figure out
these turbulent characteristics.

We also need a lot of Mahler's a lot
of research that needs to go into

understanding the processes
that are present there.

So that's the final thing is just
the variety of sources that has

funded out work here over the past
four to five years on ocean energy.

Thank you.

Right.

That is definitely an issue if you do
bottom ounce and you're to have smaller

current stand there absolutely on the
boundary layer it can be on the order of

meters but it depends on you know
could be ten percent twenty percent of

your overall depth to get where there is
significant reduction in the currents so

ideally you want to get up towards
the middle of the water column but

see space conflicts is the biggest
issue in that regards.

You've got to be far enough below
that any of the expected boats.

You've got to be a main shipping channels
unless you have something as deep

as St Cisco for let's say Savannah.

We know we can't go in
our shipping channel and

we're spending ten year battle over trying
to deepen the channel by six feet of snow

where they're going to give up any
space for any device in their.

Right right.

Yeah I think we'll know
in the next year or

two little bit more because due to what do
we has done was for the about three years

ago there was zero money in the part of
energy for any of the water related energy

resources then they started putting in
some money into the hydro power and

what they're interested in doing
is these resource assessments and

they want to know what is the number of
what is the potential resource how many

gigawatts is available so they funded
are working on the title streams.

They've also find we have second project
now look at those offshore ocean currents.

There's a project running in parallel.

That's looking at waves and

figure out of the wave energy is
going to be looking at rivers.

Rivers the same thing as a tunnel current
the fresh water flows they're looking at

assessing that they're also sensing the
thermal So what they're trying to do is

put together what the final number
of what is the babble resource.

If those numbers are too low.

You're right they're just they're
not going to put the money into

They're not going to invest millions of
dollars if the return is not to be viable.

So they're invested in the financial part
right now isn't just resource assessment.

They're also investing meth money into and
permitting is she said we don't know

how to permit these things yet
because the agencies that the regulatory

agencies they never had to deal with
this before they're trying to use some.

From the mess which apparently is
not very good experience right now.

And in a mess.

They tend to go their doors jurisdiction
is three miles and further offshore So for

example the total stuff is all in shore so
I'm a mess has nothing to do with us.

But a lot of what's been what they're
using is the methodology that was outlined

by offshore petroleum industry.

They have much deeper pockets they have
much larger financial abilities they can

fund multimillion dollar studies for these
alternative energies you have people who

their budgets are hundred thousand
dollars that's all they can afford and

they're being asked to do these
multimillion studies they can't do it.

So that's why do we spend trying to help
fund some of the sea projects to help

start getting a handle on all
of these environments and packs.

This company that has
deployed in the East River.

They spent a factor of ten.

Of their budgets gone towards
environmental studies primarily

fish study they have monitored
more fish in the East River

that anybody's ever monitored before.

And this is the first thing people
know they tell them that they

said there's fish in the East River and
they simply then they're all dead.

But it turns out there's actually a lot of
fish very abundant in the East River and

the results so

far they've shown absolutely no
impact on the fish with their devices

this is.

Yeah absolutely.

It's a very dynamic area the ocean is
constantly Bollman and so are the general

But then which is probably fairly
reasonable if you're trying to get into

the details a particular site you want to
rely on our model of results there because

Filipinos change so for example this
person Island site we're going back there.

We're doing our own back budget survey and
we're going to remodel that area and

you have the current but

them for you because you've got
the detail specially made into law.

Total areas for
the currents very strong and

constant scour things
are changing very rapidly.

So that's very important is to try to get
updated but them a tree when you try to do

your specific site assessment on
a large scale resource estimate.

Yeah it may change things
by ten fifteen percent.

Let's say for those overall currents.

But for the focus this pick
a project that's a reasonable there

that's

an interesting question that people
generally don't know exactly is a lot

of work going in that area and a lot of
thought is actually an overall increase

in the currents because as
the tide level goes up.

You're going to get more in the day.

Sure to get more flooding of various
That means a larger volume of water

is coming in.

Course property owners aren't so happy
about that either either because they're

having high risk of flooding but
that's something that on

the fifty hundred year time
scale it's unknown question

right now is exactly how much of an impact
that's going to have I think in terms of

tidal energy that's not going to increase
the our overall potential substantially so

you know we're not really accounting for
that right now but

if there is plenty of implications for
other issues

sort of the other hat where coast
engineering we're going to be to Raj.

That's a huge issue you increase
the water level by ten centimeters.

You can totally change
the dynamics of a beach.

Thank you.