OTEC instalation posibilities in Mexico

Abstract

This summarizes the preliminary result of the analysis of different places in the Mexican coast where OTEC or deep cold water extraction plants could be installed. The fundamental requirements for an OTEC are: water gradient temperature above 20 degrees year round; ease of close access (10km or less) to deeps (around 1000m) to gain access to the required cold water to ensure the gradient. Unfavorable conditions: probability of hurricanes in the area and restrictions on constructions in protected areas near the coasts (i.e. tourist areas). With respect to the required gradient year round, the south Pacific coast of Mexico, the Gulf of Mexico and the Caribbean sea meet the required conditions. The access to deeps is present in the Caribbean and the Pacific coast. Restricted areas are found in the Baja California peninsula, the center of the Pacific coast and in the Caribbean. All shores are exposed to hurricanes, but with different probabilities. Even though none of the analyzed places meet all requirements, a detailed analysis of various places where OTEC or cold water extraction plants could be installed.

Full text

PROCEEDINGS OF THE 5TH OTEC SYMPOSIUM
NOVEMBER 7-NOVEMBER 9, 2017, SAINT PIERRE, REUNION ISLAND, FRANCE
OTEC instalation posibilities in Mexico
Alatorre Miguela*, Garcia Alejandrob, Estela Cerezoc, Francisco Barcenasc & Angel Jimenezd & Silva
Rodolfoe
aInstituto de Ciencias del Mar y Limnologia Universidad Nacional Autonoma de Mexico
Av. Universidad 3000 Mexico ity, Mexico CP 04510
energiaoceano@gmail.com
bFacultad de Ingeniería, Universidad Nacional Autonoma de Mexico
Av. Universidad 3000 Mexico city, Mexico CP 04510
cUniversidad del Caribe
Lt. 1 Mz. 1 Esq. Fracc. Tabachines SM 78
CP 77528 Cancún, Quintana Roo, México
ecerezo@ucaribe.edu.mx
cUniversidad del Caribe
Lt. 1 Mz. 1 Esq. Fracc. Tabachines SM 78
CP 77528 Cancún, Quintana Roo, México
jbarcenas@ucaribe.edu.mx
dCentro Interdisciplinario de Ciencias Marinas
Av. Instituto Politécnico Nacional s/n. Col. Playa Palo de Santa Rita. Apdo. Postal. 592. CP.
23096. La Paz, B.C.S., México.
angeljimenezillescas@gmail.com
eInstituto de Ingenieria Universidad Nacional Autonoma de Mexico
Av.Universidad 3000, Mexico City, Mexico CP 04510
RSilvaC@iingen.unam.mx
* energiaoceano@gmail.com
ABSTRACT
This summarizes the preliminary result of the analysis of different places in the Mexican coast where OTEC or deep
cold water extraction plants could be installed. The fundamental requirements for an OTEC are: water gradient tempe-
rature above 20 degrees year round; ease of close access (10km or less) to deeps (around 1000m) to gain access to the
required cold water to ensure the gradient. Unfavorable conditions: probability of hurricanes in the area and restrictions
on constructions in protected areas near the coasts (i.e. tourist areas).
With respect to the required gradient year round, the south Pacific coast of Mexico, the Gulf of Mexico and the Carib-
bean sea meet the required conditions. The access to deeps is present in the Caribbean and the Pacific coast. Restricted
areas are found in the Baja California peninsula, the center of the Pacific coast and in the Caribbean. All shores are
exposed to hurricanes, but with different probabilities. Even though none of the analyzed places meet all requirements,
a detailed analysis of various places where OTEC or cold water extraction plants could be installed.
Keywords: OTEC, Mexico
1) INTRODUCCION
In the XXth century the main source of energy in Mexico had been hydrocarbons. However from XXIth
century without a doubt this resource is limited therefore the use of alternative resources will be necessary.
Nevertheless the current technology estimates that those alternative energies will be insufficient and only a
small amount of the energy requirements will be obtained so it is worth exploring.
One of the possibilities is ocean energy specifically thermal gradient. There are already small OTEC plants
with room to upgrade to large scale production. This article presents an investigation to possible sites in
Mexico to install this type of plants. Within OTEC plants, other application exists such as desalinization and
air conditioning.
Mexico has coasts on both the Pacific and Atlantic( The caribbean and Gulf of Mexico). The aim is to study
the potential sites for OTEC plants installation.

PROCEEDINGS OF THE 5TH OTEC SYMPOSIUM
NOVEMBER 7-NOVEMBER 9, 2017, SAINT PIERRE, REUNION ISLAND, FRANCE
The main source of energy in 20th century Mexico was hydrocarbons. In the 21st century, however,
without a doubt this resource is limited, and as a result the use of alternative resources will be nec-
essary.
Although current technology estimates that alternative energies will be insufficient and that only a
small amount of the energy requirements will be obtained, they are still worth exploring.
One option is ocean energy – specifically the thermal gradient. There are already small OTEC
plants with room to upgrade to large scale production. This article presents research on possible
installation sites in Mexico. OTEC plants can also be employed for applications such as desaliniza-
tion or air conditioning.
Mexico has coasts on both the Pacific Ocean and the Atlantic (the Caribbean and Gulf of Mexico).
The aim is to study potential sites for OTEC plant installation.
Alternative energy sources are possible. To place this into context, such sources will only be capa-
ble of supplying a small percentage of the energy required in the 21st century, but their contribution
is potentially quite useful. In the case of the OTEC, it can be connected to the electricity grid or in
isolated places on coasts or islands. As OTEC technology progresses, it will become more efficient;
furthermore, new ideas for the utilization of the thermal energy of the sea will surely be developed.
The following requisites, vital to the installation of an OTEC plant, are analyzed in this study:
1) The existence of a thermal gradient pronounced enough with which to operate a plant. Vega
[3]suggests a 20 °C minimum.
2) The distance to deep zones (access to cold water). Vega [3] suggests a distance of no more than 10
km.
3) The distance to the electrical grid and consumption centers.
4) Natural hazards.
5) Protected areas.
There are other key factors that are considered for future inclusion, such as legislation and social and
environmental impact.
2. METHOD
A specific analysis was conducted for each of the factors.
2.1 Existence of a thermal gradient.
Figure 1 shows the summer thermal gradient in August 2014, and figure 2 that of the winter in January 2012.
Gradients were calculated from NASA databases [1] for surface temperatures and Copernicus [2] for tem-
peratures at 1000 m.

PROCEEDINGS OF THE 5TH OTEC SYMPOSIUM
NOVEMBER 7-NOVEMBER 9, 2017, SAINT PIERRE, REUNION ISLAND, FRANCE
Figure 1. Temperature gradient greater than 20° along the coasts of Mexico in the summer of August 2014.
Figure 1. Temperature gradient greater than 20° along the coasts of Mexico in the winter of January2012.
2.2 Sites near the coast
Figure 3 illustrates the location of 1000 meter isobaths along the coasts of Mexico, obtained from
NASA databases [2]. Current bathymetric maps are inexact. They may be used as a first approxima-
tion, but when undertaking a real project — whether it be a prototype or a large inshore or offshore
OTEC plant — high resolution bathymetry is required, such as that obtained through the use of a
multibeam echosounder.

PROCEEDINGS OF THE 5TH OTEC SYMPOSIUM
NOVEMBER 7-NOVEMBER 9, 2017, SAINT PIERRE, REUNION ISLAND, FRANCE
Figure 3. 1000m isobaths and selected zones and possible sites of OTEC installation.
2.3 Distance from the electrical grid and consumption centers.
Here it will initially be necessary to define how the OTEC will be applied: whether for the pro-
curement of energy or also for the utilization of cold water, and whether it will be connected to the
electrical grid (Figure 4) or if it will work independently.
Figure 4. Mexico’s electric grid [4].

PROCEEDINGS OF THE 5TH OTEC SYMPOSIUM
NOVEMBER 7-NOVEMBER 9, 2017, SAINT PIERRE, REUNION ISLAND, FRANCE
2.4 Natural hazards
Hurricanes pose the main threat to OTEC plants. As hurricane trajectories are not predictable, his-
torical data are employed to determine probabilities. Figures 5 and 6 show the category 2 and 5 hur-
ricanes that have struck Mexico over the past 20 years, CONABIO[5].
Figure 5 Probability of occurrence Category 2 hurricanes in Mexico [5].
Figure 6 Probability of occurrence Category 5 hurricanes in Mexico [5].
Other hazards such as earthquakes or tsunamis have not yet been taken into account.

PROCEEDINGS OF THE 5TH OTEC SYMPOSIUM
NOVEMBER 7-NOVEMBER 9, 2017, SAINT PIERRE, REUNION ISLAND, FRANCE
2.5 Protected areas
This is an important point that includes the existence of legislation covering the installation of sea
energy extraction plants. In reference to Mexico, there is still no such legislation and it may be a
considerably long time before it comes into existence. There are several statuses of protected areas,
and Figure 7 exhibits the protected areas in Mexico that are currently under protection, such as:
Biosphere reserves
Sanctuaries
Areas for the protection of natural resources
Areas for the protection of flora and fauna
Areas under ambiguous management
Figure 7 Protected areas in México [5].
There are different statuses for each area, and we do not necessarily consider them to exclude
OTEC plant installation. For the time being, regions considered to be protected areas are presented.
3. DISCUSSION
Of all the points that have been mentioned, there is not one site that truly complies with each and
every requisite. The advantages and disadvantages of each place must be analyzed. Figure 8 shows
distinct zones and the conclusions to which we have come:
3.1 Exclusion
The zones that are not currently considered able to offer adequate conditions (but that may possibly
be included in the future) are as follows:
Along the western coast of the Baja California peninsula (Zone 1), as surface waters are cold due to
the presence of the California current, there is no adequate gradient during any season of the year.
In the Gulf of Mexico (Zone 2), the continental shelf is quite large. Despite the presence of islands,
these are in shallow waters, which means that for the moment this coast has been ruled out.

PROCEEDINGS OF THE 5TH OTEC SYMPOSIUM
NOVEMBER 7-NOVEMBER 9, 2017, SAINT PIERRE, REUNION ISLAND, FRANCE
In the interior of the Gulf of California (Zone 3) there are several drawbacks, such as an exception-
ally wide continental shelf on the east coast, very small towns with no access to the electrical grid
dotting an otherwise uninhabited west coast, waters in the northern portion of the gulf that do not
reach the required depths, and a thermal gradient that is only present during the summer. Due to the
above, this region has been excluded.
Although in the Southern Mexican Pacific (Zone 6) there are favorable conditions such as the gra-
dient, a location external to any protected areas, and few hurricanes, the continental platform is ex-
tensive. Because of this zone 6 has been excluded.
3.2 Possible but tremendously difficult installation:
In the Mexican Caribbean (Zone 4), it would be quite challenging to obtain the acceptance neces-
sary to install a plant of this kind within the touristic area known as the Mayan Riviera. Point A,
east of Cozumel Island, is close to a deep site and presents the required thermal gradient year-
round. Another immense inconvenience of this zone is that it lies in the path of all categories of
hurricanes.
3.3 Zones that seem promising
The disadvantage of Zone 3, the southern Baja California peninsula, is that the gradient is lost dur-
ing the winter. Certain noticeable advantages include the proximity of large cities with a high de-
mand for electricity, air conditioning and desalinized water, as well as sites remarkably close to the
coast that boast depths greater than 1000 meters (point B in particular, called Los Frailes).
Zone 5, the Central Mexican Pacific, is quite extensive and contains several advantageous places.
The thermal gradient is favorable throughout the year, there are various sites of great depth proxi-
mal to the coast, there is access to the electrical grid, and there are important consumption centers.
Among the unfavorable aspects, there is the possible presence of intense hurricanes and the fact that
it contains protected areas. Concerning hurricanes on this side of the Pacific Ocean, it is important
to note that they evolve from south to north in such a way that, while in the south the category is
normally 1 or 2, category 5 hurricanes strike the north and even travel as far as the Baja California
peninsula (Zones 2 and 3). Two sites are currently under more detailed study: point C in Bahía de
Banderas, Nayarit and point D in Puerto Ángel, Oaxaca.
In relation to islands, there are several in Zone 4 (included in Figure 3). These have not been stud-
ied, but may be adequate for OTEC plant installation.
4. CONCLUSIONS
There are, in fact, several sites along the coasts of Mexico at which OTEC plants can be installed.
The most adequate points are those labeled C (Bahía de Banderas) and D (Puerto Ángel), and other
such points are likely to exist within the Central Mexican Pacific zone.
Point A (Los Frailes) suffers a gradient that is absent for a portion of the year; nevertheless, other
applications such as the utilization of cold water can be of great interest.
Point B (Cozumel) gives several advantages, although there are two major drawbacks: it is situated
within a tourist area, and there are intense hurricanes.

PROCEEDINGS OF THE 5TH OTEC SYMPOSIUM
NOVEMBER 7-NOVEMBER 9, 2017, SAINT PIERRE, REUNION ISLAND, FRANCE
ACKNOWLEDGMENTS
This research named CEMIE-O is supported by SENER-CONACYT México.
Thanks to Ricardo E. Hernández Contreras for data process.
Thanks to León R. Álvarez of UNINMAR, ICMYL for data process.
REFERENCES
[1] <http://marine.copernicus.eu/services-portfolio/access-to-products/?option=c> (accessed,25.9.2017)
[2] gradientes http://neo.sci.gsf.nasa.gob/> (Accesed 28.11.2016).
[3] Vega, L. A. 2010. Economics of Ocean Thermal Energy Conversion (OTEC): An
Update. Offshore Infrastructure Associates, Inc. University of Hawaii . 78 p.
[4]<http://base.energia.gob.mx/prodesen/PRODESEN2016/PRODESEN-2016-2030.pdf(acceded
26.10.2017).
[5]:<http://www.conabio.gob.mx/informacion/gis/> (accessed 5.5.2017).