Kinetic hydropower has been used for thousands of years and is one of the cleanest, most sustainable, and most affordable sources. Today it represents one of the best alternatives to fossil fuels, with a key role to play in the energy transition process.

Hydropower is the world’s largest source of renewable energy, accounting, according to the IEA, for more than 70% of global renewable energy has been used for thousands of years, from water mills, through water wheels used in factories, to hydroelectric power plants used to produce electricity. The world’s first hydroelectric power station was born in Northumberland, UK, in 1878.

How is hydroelectric power produced?

In order to produce electricity using the kinetic energy of water, it is necessary to capture and store this resource. This is made possible by the construction of dams and hydroelectric plants.

When the dam releases the water, it goes through turbines, thereby generating electricity. This, in turn, is transported by transmission lines to its use by end consumers. The amount of water that each dam is capable of storing is measured in cubic hectometers (1 hm3 equals 1 billion liters).

What are its advantages?

• It is a clean, renewable energy source. It doesn’t emit greenhouse gases (GHG) or other air pollutants, unlike fossil fuels.
• It is more stable and predictable than other renewable sources, such as wind or solar power.
• It is one of the cheapest renewable energy sources, especially in countries with abundant hydroelectric resources.
• It helps reduce dependence on fossil fuels, such as oil, gas, and coal, for electricity production.
• In addition to generating electricity, power plants and dams help control flood risks and are sources of irrigation and clean drinking water.

And what disadvantages does it have?

• The construction of hydroelectric power plants can cause environmental impacts, such as the displacement of populations, the disappearance of some habitats, and the disappearance of river ecosystems.
• It entails high costs in the creation of all the necessary equipment for its collection.

The crucial role of hydropower in the energy transition

According to the International Energy Agency’s Hydropower Special Market Report Analysis and forecast to 2030, the construction of hydropower plants around the world is expected to slow down, thus putting at risk the goals of most countries that have set themselves net zero emissions.

Hydropower currently plays a crucial role in the energy transition to clean energy sources, not only because of the huge volume of low-carbon electricity it produces but also because of its flexibility and storage potential.

In 2020, hydropower supplied one-sixth of global electricity, making it the largest single source of low-carbon energy - larger than all other renewable energy sources combined. Although production has increased by 70% over the past two decades, its share of the global electricity supply has remained stable due to the increased use of wind or solar photovoltaic power, among others.

Global hydroelectric capacity is estimated to increase by 17% between 2021 and 2030 - in a process led by China, India, Turkey and Ethiopia. Despite this, the projected growth in the 2020s is almost 25% slower than the hydroelectric expansion in the previous decade.

Untapped potential and challenges

About half of the world’s economically viable hydropower potential remains untapped, and this potential is especially high in emerging and developing economies, where it is almost 60%.

While hydropower is economically attractive in many regions of the world, the report highlights some of the major challenges faced, such as long lead times for implementation projects, lengthy permitting processes, high costs and risks associated with environmental assessments, and resistance and opposition from local communities.

These issues pose higher investment risks and financing costs compared to other energy generation and storage technologies, thus discouraging investors.

EDP’s hydroelectric power plants

EDP has hydroelectric power plants in Portugal, Spain and Brazil. In Portugal alone, there are 59 hydroelectric power plants, and EDP Production is the largest hydroelectric energy producer in the country.

In managing reservoirs, priority is given to storing water for human consumption and irrigation and only then to energy production. In plants equipped with reversible machines, the surplus energy that is not used in the electricity grid by consumers is used to move the turbines in the opposite direction, thus allowing the reservoirs to be refilled with water.