Rehabilitate, repower, modernize: the new frontier for hydroelectric plants in Latin America.

By Arturo D. Alarcón.

The first hydroelectric project financed by the IDB was the Acaray hydroelectric plant in Paraguay. It started operating in 1968, almost 50 years ago. It is still operating, and it is expected that it can operate another 30, 40 or 50 years more.

I mention this example because the economic development of Latin America is strongly linked to hydroelectricity. The broad Latin American hydroelectric potential began to be exploited at the end of the 19th century (the first power plant was installed in Brazil in 1883), and, from that moment, this exploitation encouraged the establishment of electric companies, the extension of transmission systems and the creation of local technical capacity.

Currently they are about 180 gigawatts (GW) installed in Latin America and the Caribbean (LAC). Hydropower supplies more than half of the region’s electric power, making its electric matrix the greenest on the planet, and supplying a significant portion of electricity in several countries, such as Paraguay, Brazil, Uruguay, Colombia, Panama, Costa Rica, just to name a few.

The 1970s and 1980s were the most fruitful for Latin American hydroelectric development; In those two decades the installed capacity in LAC increased fivefold, from 19 GW (1970) to 93 GW (1990), particularly as a result of the 1973 oil crisis, and the regional situation, which allowed the installation of large projects, some even binational.

More than 30 years have passed since this peak, and it is necessary to take into account in the planning of our systems that the electromechanical equipment of the projects built in that period have already met, or are very close to meeting, their useful life (estimated between 25 to 40 years, depending on the operation and maintenance conditions). For example, a review of secondary sources estimated in 73 GW the power of plants larger than 10 MW that have been operating for more than 20 years in IDB member countries (as of 2016), and that in the coming years should be rehabilitated. Only in the case of Brazil, it is estimated that 50% of the plants are already more than 30 years old.

Resultado de imagen para pequeñas energia hidroelectrica

But, what does the rehabilitation of the power plants imply? What are its advantages? And what is the difference with repowering or modernization?

The rehabilitation of a hydroelectric plant consists of making investments to return it to its initial operating conditions. It is implemented when, due to the deterioration of the equipment, the operation and maintenance costs or the downtime have increased substantially, and the available capacity and / or the energy generated have been reduced. The rehabilitation can increase in some percentage points the efficiency or power of generation of a power plant (when using computerized designs, and electromechanical equipment and control systems more modern than those initially installed). However, the main and greatest benefit of the rehabilitation is to extend the useful life of the power plants for several additional decades, taking advantage of the existing civil works with new or rehabilitated electromechanical equipment.

Investments in plant rehabilitation have a high rate of return, normally higher than other alternatives for renewable generation (hydroelectric and other alternative sources), considering that the civil works already carried out are a sunken investment, both from a financial point of view and from the point of view of environmental and social impacts.

Given the current challenges for the construction of new large dams in our region, it is essential to evaluate the rehabilitation in the dam and reservoir plants. These reservoirs, in addition to providing backup generation for intermittent renewable sources (wind and solar), allow the seasonal storage of water and energy, for the dry seasons, helping to mitigate the impacts of climate change. In these cases, it is essential to include in the rehabilitation study the structural analysis of dams and complementary civil works, in order to confirm their status, investment needs, and reduce the risk of disasters. In the same way, it is necessary to carry out an analysis of the sedimentation of the reservoir, which in some cases could reduce the useful life of the plant.

The repowering (or “repowering”, in some countries), on the other hand, implies a redesign of the hydroelectric exploitation to increase the power of the plant, either by an update in the hydrological conditions (for example, new contributions of flow, information updated hydrology, or changes in basin conditions due to human use of water, or climate change), or by regulatory modifications (for example, implementation of peak prices in electricity systems, intermittent power increase in the systems, etc). The repowering aims to optimize the use of existing civil works, under new conditions, with the installation of additional generation equipment, or the replacement of old equipment with more powerful ones. Like the rehabilitation, having the costs of sunk civil works, these investments have high profitability; They must also incorporate an analysis of existing civil works and the risks of climate change. Repowering, however, can be implemented at any time during the life of a power plant (not necessarily at the end of the equipment’s useful life), when hydrological, financial, water use, or energy conditions require it .

The modernization, finally, points to the change of control equipment of the plant, without modifying the physical scheme of use, or increase additional power. These investments are usually minor, since they do not involve a change of the turbine or generator, or modifications in civil works, but allow a better hydroelectric use, improve safety, reduce downtime and the costs of operations and maintenance. This type of investment usually includes the replacement of old control systems (mechanical, or electromechanical), by electronic and tele-controlled control systems. Given the growing emphasis on the development of non-conventional renewable energies, the modernization of power plants can be attractive when planning to change the function of the plant, for example, to go from being a base generation, to operating as backup from intermittent sources.

Hydropower is a mature, reliable and low-cost technology. The possibility of storage and the rapid response capacity of this technology are particularly useful to cope with seasonal fluctuations in electricity demand, and to balance oscillations of intermittent generation sources. Therefore, it is essential that the region be able to maintain, rehabilitate and modernize its hydroelectric park to complement the development of other energy sources, such as wind and solar, in the coming years.

Since its founding, the IDB has been a key partner for hydroelectric development in the region, with historic funding of close to US $ 10 billion, which includes support for studies and investments, not only for new developments, but also for rehabilitation, repowering and modernization of hydroelectric power plants. For example, the Bank currently supports the rehabilitation and modernization of several hydroelectric plants, such as Guri, in Venezuela, Peligré, in Haiti, Central America and Carlos Fonseca, in Nicaragua, Furnas, Luiz Carlos Barreto, Passo Real, in Brazil. , as well as studies for the rehabilitation of the Salto Grande hydroelectric complex, between Uruguay and Argentina, and Acaray in Paraguay.

How many of the 180 GW of hydroelectric plants that operate today may be operating within 50 years? It will depend on the effort and investments made in the coming years. Let’s do it!

Rehabilitate, Repower, Modernize: The New Frontier For Hydroelectric Plants In Latin America
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