Fight against CO₂ emissions: global and Italian hydropower contribution

If hydropower were replaced by coal or gas combustion, the additional annual carbon emissions would be enormous, amounting to approximately 2.6 billion tonnes (roughly equivalent to India’s current total annual emissions) and 1.3 billion tonnes (more than Japan’s annual emissions, for example). Such emissions would clearly be incompatible with halting climate change.

In parallel with the desired decarbonization process, the overall level of electricity generation is expected to more than double as economies grow and electricity replaces other fuels in a wide range of sectors, including the transportation sector. The International Energy Agency (IEA) and the International Renewable Energy Agency (IRENA) estimate that global annual electricity demand is expected to increase to around 75,000 TWh by 2050, nearly three times the current demand (28,000 TWh in 2021, 28,700 TWh in 2022).

Hydropower currently represents the largest source of renewable electricity, with over 1,300 GW of installed capacity providing more than 15% of global electricity. For the more ambitious goal of achieving net-zero emissions (limiting the temperature increase to below 1.5°C), the numbers are even higher, with at least 2,500 GW of capacity needed (approximately double the current installed capacity). Therefore, hydropower will play a key role in future energy systems, taking into account the importance of economic, environmental, and social factors in assessing the potential of future projects.

Source: IHA  “2023 World Hydropower Outlook – Opportunities to advance net zero

The global growth of hydropower in recent years has been steady (an improvement of 37 GW in installed capacity over the previous year from 2021 to 2022), demonstrating admirable commitment, although it is still not sufficient to realistically achieve the ambitious goal of net-zero emissions by 2050. In the overall framework of renewable energies, contributions from wind and solar energy are expected to grow to around 70%, while coal, oil, and gas capacity must decrease at a rate of 100 GW per year. All renewable-based technologies will need to step in to assume the role of “grid guardians” and support hydropower during this complex transition period.

Projections published by the International Energy Agency (IEA) show that in a decarbonized economy, hydropower is expected to become the primary source of electricity, contributing to over 40% of annual production (approximately 22,700 TWh) by this group by 2050. An ambitious roadmap: hydropower production will need to double in the next 25 years, reaching an overall installed capacity of over 2,500 GW (as mentioned earlier), with nearly 420 GW generated by pumped storage plants.

Total installed capacity per country – Source: IHA  “2023 World Hydropower Outlook – Opportunities to advance net zero

Italy is also facing this urgent challenge: the need to reduce CO₂ emissions and address climate change. In this context, renewable energies emerge as a fundamental tool to effectively tackle the problem. Here are some insights and data on the contribution of Italian hydropower in the ‘battle’ against CO₂ emissions. In terms of installed capacity for 2022, Italy ranks eleventh globally with approximately 23 GW in total.

Now, let’s analyze the total amount of CO₂ (in tons) saved in the last three years thanks to renewable production (recorded by the Terna systems), reporting the savings for each source: Hydropower, Wind, Photovoltaic, and Geothermal (geological sources of heat). We also provide the (partially available) data for this year (as of the publication date of this article).

The Italian hydropower sector saved over 15,020,516 tons of CO₂ in 2022, although it will be remembered as a challenging year for renewables, especially for hydropower. Renewable energies met 31.1% of the national electricity demand, compared to 35.4% in 2021. The country’s electricity demand decreased by 1% compared to 2021, amounting to 316.8 TWh (approximately 3 TWh less).

This data aligns with the trends of the last decade, with the exception of 2020, an anomalous year characterized by the COVID-19 lockdown. For the first time since 2014, production from renewable sources has fallen below the 100 TWh threshold, reaching 98.4 TWh, a decrease of approximately 14.8 TWh compared to 2021 (-13%). Considering the partial trend in the current year, the expected scenario seems to indicate a modest resurgence of hydropower, which could reverse the negative trend observed in 2022 and start growing again, while other renewables remain stable.

It is significant to report also the tons of CO₂ emitted into the atmosphere in 2022 due to thermoelectric production, divided into the main fuel categories: Solid Fuels (coal, lignite, and coke), Gas (natural gas and synthetic gas/residues), Fuel Oil (oil, gasoline, kerosene, diesel, and fuel oil), and Others (biomass, biogas, other heat sources), along with the respective trend over the last three years.