Hydro

The term “hydropower” covers a wide variety of technologies, ranging from large to small and old to new. Most commonly associated with the term are dams, which store water behind a generating facility and harness its power through one of many different types of turbines. This type of conventional hydropower project represents the vast majority of U.S. hydropower generation. New technologies have entered the market or seen major advances in recent years, including ocean wave, tidal and hydrokinetic power (tapping the power of flowing water, much like wind power does with moving air).

Yes. Unlike power plants that burn fuels like coal, oil or gas, hydropower plants do not emit climate-altering gases that contribute to the greenhouse effect. If we take into account the complete life cycle of a hydropower plant, the quantity of CO2 produced per kilowatt-hour of energy generated is between 35 and 70 times lower than the amount produced in energy production using fossil.

According to the International Energy Agency (IEA), 4,333 terawatt-hours of hydroelectric energy were produced worldwide in 2019, saving more than 2 billion metric tons of CO2 a year – not to mention the benefit of reduced water consumption compared with fossil fuel-powered plants, which use enormous volumes of water for cooling purposes. 

For centuries, since its initial use to drive watermills, the power of water has been harnessed to benefit communities’ development. Both the International Renewable Energy Agency (IRENA) and the World Bank continue to recognize and reaffirm the role of hydropower in the development of local and rural economies. In the case of large plants, the benefits also include the creation of jobs, while all hydropower facilities provide an abundant source of power that is adaptable to local energy needs, enabling communities to move closer to energy self-sufficiency. Small plants, suitable for more remote areas or less industrialized contexts, are a fundamental opportunity to support local economic growth. 

In the case of hydropower plants, we rarely talk about the total dismantling of a facility, but rather about a modernization of structures such as dams and pipelines. The elements that need to be changed most often are the hydraulic turbines that operate as generators, transforming the power of water into electricity. The lifespans of these turbines range from 40 to 80 years, but sometimes they can be replaced earlier if new, more efficient technologies become available. Some large hydropower plants have already been running for more than 120 years and are still fully operational. In other cases, however, climate change – with the increasing frequency and severity of droughts or the reduction in available water it can bring – has led to the closure of plants.

The power of water is present everywhere on Earth and the transformation of this power into electric energy has already achieved extraordinary performance levels, with efficiency in excess of 80%. Thanks to technological innovations and digitalization, the quantity of energy wasted is being further reduced. While the initial investment to create a power plant can be quite high, overall, hydropower is the cheapest in the medium and long term. 

Hydropower plants pose questions concerning sustainability for the environment, the landscape, fish populations and the balance of ecosystems. Even before the focus shifted to improving efficiency, the emphasis was on reducing all types of impact on the environment and on finding strategies to harness the power of water without damaging the wildlife that live in or depend on it.

The management of reservoirs can actually mitigate the effects of adverse climate events, encourage the growth of vegetation and crops and, at opportune times, the water can be made to flow in such a way as to ensure the integrity of the natural biological context and the passage of fish, using so-called Minimal Vital Flow (MVF) technology, or fish ladders that enable fish to follow the current of a river both upstream and downstream.

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