Hydroelectric Plants in Times of Drought






The president of Mexico has pointed out on multiple occasions that one of the pillars of his administration to achieve clean energy goals is the generation of electricity through hydroelectric plants. This plan is so important that on multiple occasions he has pointed out that with investment and repowering of current facilities we can generate the clean energy that the country needs without promoting renewable sources such as solar and wind, because he considers them intermittent.

According to the president and his trusted advisors, solar and wind generation are intermittent because they do not generate electricity when there is no sun and when there is no wind; as if the sunrise, the movement of clouds and air currents were unpredictable and spontaneous and there did not exist prediction algorithms with 90% probability that allow having an important degree of certainty of generation.

There are two reasons why this administration has promoted hydroelectric generation, the first because most hydroelectric plants belong to CFE and that implies that the State company is being strengthened while at the same time barriers to entry are established for private competitors.

To such a degree that one of the fundamental changes in the reform of the Electric Industry Law that is suspended with general effects is that hydroelectric plants will be the first to be dispatched. This favors CFE and displaces private generators, although other private ones benefit: Generadora Fenix.

Generadora Fenix is a consortium formed by a Portuguese company and a company created by a group from the extinct Luz y Fuerza del Centro union, to whom the State transferred ownership of some hydroelectric plants for their operation in the wholesale electricity market. Well, they would be favored.

The other reason that the present administration mentions is that hydroelectric plants have controllable electricity production, all else remaining constant, energy can be generated as a constant flow if there is a constant flow of electricity. But here lies the most important error of the strategy: water, although it is a renewable resource, is finite, exhaustible, and takes time to recover.

Not only that, water has other uses; it does not only serve to generate electricity. As obvious as this may seem, sometimes it seems that the leaders of the national electric company miss it. The water in dams serves so that farm workers can irrigate their lands, so that water systems provide water to our homes, so that companies produce food, clothing and other essential products, and so that ecosystems have the vital liquid.

Water management is an issue that requires long-term projection because unexpected climatological issues can occur, such as droughts; therefore, electricity generation from dams is a byproduct that is optimized considering all the other consumptive and non-consumptive uses of water and considering the projections and risks of adverse climatological events that could reduce the replacement rate of water.

If you only release the water because CFE generation must be favored, we all have a problem and a human right elevated to constitutional rank is affected: the right to water that we Mexicans have as a society. Having said this, the president’s strategy, increasing clean energy generation with hydroelectric plants, is tied from the beginning to the availability of enough water to meet the needs of citizens today and in the future.

Today we are suffering one of the most serious droughts in our country; water must be cared for and its other uses must be considered. As laudable as the task of rescuing CFE may be, this is not the priority. In such a way that this 2021 the entire clean electricity generation plan of the current administration is dead letter thanks to the drought.

This article was originally published by Business Insider México.
Date: May 11, 2021
Original Link: https://businessinsider.mx/hidroelectricas-mexico-sequia-opinion-paul-alejandro-sanchez/ [offline]
Archived Link: https://web.archive.org/web/20230324022817/https://businessinsider.mx/hidroelectricas-mexico-sequia-opinion-paul-alejandro-sanchez/ [Archived]

The Other Solar Energy






We anticipated last week that when we talk about solar energy, photovoltaic comes to mind, that is, electric energy generated with panels. But solar energy goes far beyond photovoltaic; there is also great thermal potential that is used to heat spaces, to heat hygienic water and in industrial processes.

It is also possible to generate electric energy with the sun using concentrated solar thermal technology. This operates in a similar way to the other primary sources of electricity; —in fact, it is photovoltaic solar that really uses a different principle—.

How does concentrated solar thermal energy work?

Almost all power plants produce electricity with one principle. This consists of the movement of a turbine connected to an electromagnetic generator that generates electricity. Or, said in another way, it generates electricity that can be used directly or transformed and conducted through transmission networks. This works the same for hydroelectric, wind and thermal plants.

Photovoltaic solar energy works differently. In a very reductionist way, solar panels generate electric current through photons that allow an electron to move between layers of silicon. The important thing, for today, is that in solar panels there is no steam nor turbine nor generator, only a direct current.

In contrast, concentrated solar thermal technology uses the same principle as thermal plants: converting water into steam to move a turbine connected to a generator to produce electricity. For this, thousands of mirrors are used to reflect and concentrate sunlight at the tip of a tower that functions as a heat exchanger using molten salt as a vehicle.

Concentrated solar energy increases the temperature of the molten salt, which is in turn used to generate the water steam that will move the turbine to produce electricity. In the process, the molten salt loses thermal energy and recirculates through the heat exchanger to repeat the process. In this process lies the great difference, strength and weakness, of concentrated solar thermal energy compared with photovoltaic solar energy.

Its strength, compared with photovoltaic energy, is that concentrated solar thermal energy can be stored; since molten salt with high temperature can retain heat between 10 and 16 hours. Consequently, it can be used when there is no solar irradiation, which allows generating continuous electricity without variability and at hours without sunlight.

However, its disadvantage is that it is still a technology with higher development, operation and maintenance costs than photovoltaic solar. Therefore, its progress has not followed the same logic as its photovoltaic sister. So, when you hear about solar energy, remember that there are other ways to use it and achieve decarbonization in the future.

This article was originally published by Business Insider México.
Date: April 27, 2021
Original Link: https://businessinsider.mx/energia-solar-opinion-energia-circular-paul-alejandro-sanchez/ [offline]
Archived Link: https://web.archive.org/web/20220810231024/https://businessinsider.mx/energia-solar-opinion-energia-circular-paul-alejandro-sanchez/ [Archived]

Solar Energy Beyond Photovoltaics






Sometimes we hear solar energy and quickly think of electric energy produced with photovoltaic panels. And it is that photovoltaic technology has become a boom in recent years.

The accelerated decrease in manufacturing prices of the panels, together with an increase in competition and adaptation of the technology, have driven an escalation in solar installations around the world.

In Mexico, in March alone, we broke the record for electric energy generated by photovoltaic solar panels. This reached 1.6 TWh of energy settled in the National Electric System operated by CENACE; which represented 6% of the electric energy generated in the country.

However, there are other forms of use of solar energy that we rarely talk about. On the one hand, thermal heat, that is, the use of solar irradiation to produce heat that can be used in industrial processes or for domestic or commercial consumption.

Heat consumption in homes can be divided into three large groups: space heating, cooking food and heating hygienic water. Together, cooking food and heating water represent 72% of heat in homes. For this purpose, electricity, LP gas and natural gas are used, but above all firewood. This represents 46% of the total primary energy used for heat in homes.

To address this part of the demand, various types of technology have been developed that collect solar irradiation to, for example, heat water or spaces both in homes and in businesses or offices, reaching temperatures from 30º to 90º Celsius.

Photovoltaic Solar Energy and Solar Thermal Heat

In a quieter revolution than the one photovoltaic solar energy has experienced, solar thermal heat has also had significant growth. In 2017, the total area covered by collectors was 675 million square meters and a total installed capacity of 472 GWth distributed in almost 120 million installations around the world.

According to data from the International Energy Agency, the mentioned installed capacity produced 1,404 PetaJoules in 2017. It represented a reduction of greenhouse gases of 135 million tons of CO2 equivalent worldwide, particularly in China.

In Mexico, according to data from the Ministry of Energy, CONUEE, IRENA and GIZ, there is an economically profitable potential in industry, businesses and homes that amounts to almost 33 Gigawatts. This could help reduce emissions not only from homes but also from industry.

Mexican industry represents close to 31% of heat demand at the country level and requires low heat cycles —less than 150ºC— for pasteurization, cleaning, cooking or bleaching; medium heat cycles —between 150 and 400ºC— for distillation, coloring and compression; and high heat cycles —more than 400ºC— for industrial transformation processes, which solar heat technology could provide with the correct incentives and with a policy oriented toward reducing greenhouse gas emissions.

This is not all, but space is running out, and next week we will address a very interesting technology: concentrated solar energy, which allows generating electric energy by conventional means but without using fuels, using a principle and a mechanism very different from that of photovoltaic panels. Until then.

This article was originally published by Business Insider México.
Date: April 20, 2021
Original Link: https://businessinsider.mx/energia-solar-opinion-paul-alejandro-sanchez/ [offline]
Archived Link: https://web.archive.org/web/20240723111757/https://businessinsider.mx/energia-solar-opinion-paul-alejandro-sanchez/ [Archived]