Water and energy: how to contain the “thirst” of the energy transition

Flow of Italian rivers, such as the Po, reduced by 4 or 5 times, drought, rationing of water in urban areas, problems with agricultural crops.

Even in our country there water crisis and access to water it is becoming another factor in a systemic crisis whose evolution we do not yet know in the short term. But let’s imagine what it could cause in the medium and long term on a global scale in terms of conflicts and humanitarian crises.

Water availability along withpower i ai climate change these are issues closely related. These will be the challenges of the coming decades and we will all have to work in this direction, even if we waste time. If we do not do it immediately, we run the risk of having economic losses that are difficult to quantify.

The problem of water stress it is bound to get worse in the coming years, due to various factors, including rising energy demand, climate change, urban overpopulation.

The relationship between energy and water it is much stronger than we think and refers to all sources, both fossil and renewable. Already in 2018 an analysis of the World Resources Institute (WRI) left no doubt from the title “No water, no energy“.

Thus, low rainfall will create problems adequacy for the electricity marketboth for hydroelectric power plants and for thermoelectric power plants: nuclear reactors, gas, coal and biomass units are plants that require a lot of water for multiple needs, for example for cooling systems and to generate steam; water that in many cases is extracted directly from nearby rivers and lakes.

The study estimated that a Europe thermoelectric generation could down 19-20% from 2030 to 2060 due to climate impacts, with the consequent water supply crisis.

These days in Italy state of water emergency imposed the Stop almost 2000 MW of thermal power plants: 1,154 MW of Sermide (A2A), a group of 400 MW of Ostiglia (EP Produzione) and a group of 400 MW of Moncalieri (Iren). But there are another 4,600 MW at risk.

Invest morewind power is in the photovoltaicsin addition to building an energy mix a low CO2 content, It also reduces water consumption and minimizes competition between the different uses of the precious liquid: energy production, agriculture, industrial and domestic uses. There solar generation only requires the 2-15% of the water used by coal and nuclear power plants for every megawatt hour produced.

For thermoelectric power plants it will be necessary to focus on technologies of air cooling o sea ​​water salad and water recovery-recycling systems.

A few years ago even the IEA had indicated the need to reduce production on a large scale of biofuelsthe development of new nuclear reactors and the construction of large thermodynamic solar power plants, systems that require a significant supply of water.

The WRI has always assessed for which such data would be critical to plan properly installing new energy sources, but it is not easy to get this information from many countries.

For this he has developed a method based on the comparison of satellite imagesidentify thermal power plants and the respective characteristics of refrigeration systems, and then combine empirical estimates of the intensity of water extraction from individual plants with electricity generation data, finally calculating approximately the amount of water extracted – consumed in a certain period.

In the document A methodology for estimating water demand for thermal power plants in regions with scarce data using satellite imagery“The method was tested on 200 implants in the United States with an accuracy of 90% in terms of identifying the type of fuel / cooling system, and an accuracy of around 69% on water demand estimates, depending on the greater or lesser availability of production data of electricity.

Guarantee fresh water at affordable prices for everyone and use renewable sources in the processes of desalination they will be among the priority actions on the agenda of national and local governments.

In 2030, according to the Stockholm International Water Institute, approximately 47% of the world’s population could have water shortage problems.

Seawater desalination is a valid alternative, as evidenced by the case of Israel, which is already recovering 20% ​​of its drinking water from the sea.

However, these plants and processes must be built respecting natural ecosystems. In fact, one of their environmental problems is this dumping of brine into the searesidue from the desalination process: a solution with a high salt concentration that can be very harmful.

In addition, the cost global average level ofdrinking water (LCOW) from plants desalination is still very high although with the use of photovoltaicsstorage systems and other renewable energy could be halved in a couple of decades.

It is one of the results of a study “Strengthening global water supply through a decarbonised global desalination sector and improved irrigation systems “carried out a couple of years ago by the Lappeenranta University of Technology (LUT) in Finland.

According to the study, led by solar economics professor Christian Breyer and his team, the cost of desalinated water in most regions could range from 0.32 euros per cubic meter a 1.66 euro per 2050including shipping costs.

In addition to photovoltaic and storage systems, wind, gas and thermal energy will also feed desalination operations, according to the LUT study, which also considers the demand for energy to transport water desalinated from the coast inland.

However, Breyer had described it as a global energy-based energy system renewable would be reduced by more than 95% water consumption linked to conventional energy production.

Meanwhile, in Italy we should fix our water system, with leaking networks, in certain areas, even half of the water they carry. However, filters and membrane systems could be used wastewater treatmentrecovering large volumes of fresh water today thrown into the sea.

But as average rainfall and snow cover will continue to decline over the next two decades, investing in Italy in the desalination industry will also be a necessary strategy to not depend on other countries for this technology as well.

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