Does hydropower help to combat climate change?

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 fuels and avoids the release of more than 500 grams of carbon dioxide into the atmosphere. According to the International Energy Agency (IEA), 4,306 terawatt-hours of hydroelectric energy were produced worldwide in 2022, 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. The International Renewable Energy Agency (IRENA) estimates that the trend over the next few decades will be one of slow but persistent growth in installed capacity and generated power, with an overall increase of 50% in thirty years. Hydropower will therefore be able to reduce CO2 emissions by around one tenth of the quantity required to achieve the climate goal set out in the Paris Agreement: a key role that has also been recognized by the United Nations.

Are investments in hydropower technology increasing?

The installed capacity of hydropower continues to grow steadily, albeit at a slower pace than other green energies. In terms of investment, there are important differences between various regions: in North and South America and in Europe, significant growth is not expected during the 2020s and, actually, a stall or even a slight contraction is considered possible. Leading the way in driving the hydropower sector is China, but the Middle East, many African countries and other emerging economies are also playing a part. In terms of installed capacity, growth is expected to fluctuate between 20 and 30 gigawatt-hours a year until 2030, with an annual increase in actual energy produced of 700 terawatt-hours in the first half of the 2020s, and a further 700 in the second half. Even if the relative importance of hydropower declines slightly in the coming years – due to the dramatic increase in solar photovoltaic and, above all, wind power – its role will remain decisive: almost 60% of the world’s green energy is generated by hydropower plants (according to IEA data for 2020). Finally, in the next few years, major investments to modernize existing power plants are due to take place, offering substantial benefits in terms of efficiency, thanks in part to grid balancing services that are becoming increasingly necessary as the share of production from non-programmable renewable sources increases.

Does hydropower help rural economies?

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 decisive 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. As has been reported in various scientific publications, this will only help rural economies if the plants are planned and designed appropriately, not so much in a technical sense but in terms of involving all stakeholders. Moreover, hydropower plants can also provide piped water for drinking or for irrigation, adding further advantages in addition to supplying electricity.

Does hydropower create new jobs?

Yes, it creates many jobs all over the world. According to the International Renewable Energy Agency (IRENA), for example, at the beginning of the 2020s, more than 2 million people were employed in the hydropower sector: fewer than in solar photovoltaic but much more than in wind power and geothermal. According to the agency’s projections, the number of people employed in the hydropower sector worldwide is expected to reach 3.8 million in 2030 and then stabilize over the following twenty years. In 2050, in fact, the forecast is 3.6 million people employed in hydropower, compared to 2 million in wind power and 11.9 million in solar. Additional jobs are created indirectly: the US government, for example, predicts that from 2020 to 2025, between 140,000 and 400,000 new direct jobs will be created – that is, people working at the plants – but in addition to these will be a further 100,000 to 200,000 jobs generated from the rest of the supply chain and related activities.

What benefits does a hydropower plant create for the local area?

There are many different benefits that a local area can enjoy thanks to the presence of a hydropower plant. First of all, there are advantages for the local economy, both in terms of jobs across the length of the supply chain and through jobs created indirectly and ensured by the various phases of the project: from the initial development to the running and maintenance of the plants, including construction and modernization. In addition, as with other green energies, hydropower reduces reliance on imported energy, with the added advantage that the flow of water (and therefore electricity production) can be regulated based on actual energy needs. What’s more, thanks to the containment of watercourses within established reservoirs, hydropower plants are also a way to avoid flooding and to drain swampy areas. Storage reservoirs can also be used as water reserves during periods of drought, so they can help agriculture downstream and also lead to increased vegetation in the vicinity of the stored water, which in turn can attract animal life and encourage the repopulation of habitats in the area. Finally, power plants trap loose branches and trees, ensuring a clean and more navigable waterway.

Is there enough hydroelectric energy for everyone?

The giant masses of water that can be found at high altitudes offer a considerable amount of potential gravitational energy and harnessing just a fraction of it can provide an abundance of electrical energy. A single large hydropower plant can entirely satisfy the energy needs of millions of people. Almost everywhere in the world, there are watercourses that can be used for the production of hydroelectric energy, and in some locations the geography of the area and the availability of water means that there is enormous potential. In 2020, additional hydroelectric power installed worldwide exceeded 18 GW, thus reaching a total of more than 1200 GW – and the potential for growth is still vast, especially in countries where hydropower has not yet been widely exploited.

Hydropower depends on the availability of water: is that a problem?

Faced with a water supply that can vary over time, which naturally presents potential problems, hydropower plants are becoming increasingly flexible. Today, even a large plant can go from being at a total standstill to full power, and vice versa, in a matter of minutes. The variability of weather and climatic conditions can therefore be compensated by storage reservoirs held upstream, such as dams. What is potentially a drawback then becomes a strength: water flow can easily be regulated based on energy needs. And thanks to more specific innovations like flow optimization, water can be pumped back up to the higher level in order to have energy ready and available when needed. This is the case both in the short term, for example during different times of the day, and in a longer timeframes, with seasonal variations and periods of drought. The power grid already manages variability based on customer demand, which changes during the day and from one day to the next, and what’s more, it can use different sources of storage based on Demand Response (DR) programs and sophisticated electronic controls. Finally, advances in energy storage have made it possible to mitigate the intermittency of renewables without having to resort to burning fossil fuels.

Does hydropower receive energy incentives?

All forms of energy – including oil, gas, coal, nuclear and renewables –receive or are eligible to receive government incentives. On average, fossil fuels have received far more incentives than renewable energies. According to the Nuclear Energy Institute, between 1950 and 2016, 70% of all energy subsidies went to fossil fuels in the form of tax credits and other programs, while only 17% rewarded green energies like solar, wind power and geothermal. Hydropower received 10% of total funding; however, three quarters of these funds were not true incentives but simply government investments to build the plants.

How long does it take for a hydropower plant to offset the CO2 emitted during its construction?

The exact time depends on the characteristics of the plant and its installed capacity, but it is generally a matter of a few years. Unless it’s in a particularly arid area, building a hydropower plant is always worthwhile in terms of emissions. It is estimated that just 10 years after its construction, the difference when compared to fossil fuels is already so vast as to be incomparable, and that after 50 years of operations, the hydroelectric energy generated results in total emissions of just 13.6 grams of CO2 per kilowatt-hour, which falls to 8.1 grams after another 50 years. By way of comparison, at the beginning of the 2010s, the average was 469 grams per kilowatt-hour for natural gas combustion, 840 grams for oil and 1001 grams for coal.

What is the average lifespan of a hydropower plant?

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.

Can materials from hydropower plants be recycled?

Yes, almost all of what is used during the construction phase can be recovered or recycled when it reaches the end of its useful life. In addition, a concerted effort is underway to advance solutions that further increase the amount of materials that can be recovered, including those used on construction sites and those that are already almost entirely recycled. The most important challenge in the circularity of hydropower processes is in the dismantling phase. As recommended by the European Commission, it is important to completely remove inefficient or obsolete plants from the river system , restoring the river in question to a good ecological condition. Today, the dismantling phase is taken into consideration even during the design stage, including the effects of associated infrastructure such as access roads, pipelines or power lines. Finally, on the topic of recycling and reuse, it should be noted that there is no waste or consumption of water during the power generation phase, as the water flows without being contaminated or made unusable.

How long does it take to recoup the initial investment?

The exact quantification partly depends on available incentives and above all on the size of the plant in question, but in all cases the timescale is far shorter than the lifespan of the plant. For smaller plants, even less than 10 years may be sufficient, while for the larger ones, up to 15 to 20 years may be needed. In any case, the initial investment is more than recovered; once the dam has been built, the power plant constructed and the turbines installed, the necessary maintenance is minimal, as are the running costs for the plants.

Is hydropower cost-effective?

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. The total cost of energy per kilowatt-hour varies from a maximum of 21 euro cents for small plants and 7 cents for larger facilities, down to a minimum of just 3 cents or even 2 cents when the plant capacity is in excess of 20 megawatts. In the majority of cases, however, the cost ranges from between 4 and 10 euro cents per kilowatt-hour.

Do hydropower plants have an impact on the environment?

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 organisms 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. In the past, there were doubts as to whether hydropower could really be considered an entirely green energy because the organic residues that decompose in storage reservoirs can be a source of methane. This theory, however, has been challenged by a series of technical and scientific studies that claim that such emissions are negligible when compared to those from fossil fuels and are practically non-existent at the more modern plants.

Do hydropower plants have an impact on people’s health?

No peer-reviewed medical or scientific study has ever established a connection between hydropower plants and negative effects on human health. On the contrary, the transition to renewable energy that hydropower contributes to will avoid additional emissions of climate-altering gases and other atmospheric pollutants linked to public health problems, in addition to reducing the consumption of water often necessary to operate fossil fuel-powered energy plants.

Frequent questions about hydroelectric

Frequently asked questions about hydroelectric

For centuries, the power of water has been harnessed to support communities’ economic development. But hydropower plants are also a way to avoid flooding and to reclaim wetlands. Today, over 55% of the world’s green energy is generated by hydropower plants. Here are all the answers to your questions about this renewable energy source.

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Frequently asked questions about hydroelectric

Frequently asked questions about hydroelectric

Does hydropower help to combat climate change?

Are investments in hydropower technology increasing?

Does hydropower help rural economies?

Does hydropower create new jobs?

What benefits does a hydropower plant create for the local area?

Is there enough hydroelectric energy for everyone?

Hydropower depends on the availability of water: is that a problem?

Does hydropower receive energy incentives?

How long does it take for a hydropower plant to offset the CO2 emitted during its construction?

What is the average lifespan of a hydropower plant?

Can materials from hydropower plants be recycled?

How long does it take to recoup the initial investment?

Is hydropower cost-effective?

Do hydropower plants have an impact on the environment?

Do hydropower plants have an impact on people’s health?