Drought plunges hydroelectric generation to its lowest level in three decades

The tentacles of drought are almost infinite.

Beyond the obvious impact on the fauna, flora and crops, the prolonged absence of rainfall and the low level of the reservoirs also have a very clear energy derivative: hydroelectric generation has sunk to a minimum of three decades in Spain and threatens to aggravate the European energy price crisis.

The reservoirs in Spain are currently at 37.9% of their capacity.

You have to go back to 1995 to find such a bad situation at this point.

But this situation —with reservoir filling levels well below normal— has been dragging on since long before summer, which has meant that some basins in the country, such as the Guadalquivir, have significant restrictions on irrigation now and, in some areas, problems in urban supply.

In addition, less water in reservoirs also means less capacity to use waterfalls: between January 1 and August 15, the electricity production of these plants was less than 11,400 gigawatt hours (GWh), the highest figure low since 1992 and half the average for that fraction of the year since then.

At this point in August,

The brutal drop in the contribution of hydro (-49.6% year-on-year, according to data from Red Eléctrica de España) and, to a much lesser extent, those of solar thermal (-8%) and wind (-0, 8%), they drag with them the whole of renewable generation, which fails to compensate for the notable boost from solar photovoltaic (+37%) and has fallen by more than 8% since the beginning of the year.

Everything, despite the substantial growth in installed capacity.

And in an electricity matrix like the Spanish one, in which combined cycles are almost always responsible for covering the gap between non-manageable generation -renewable- and demand, the decrease in hydroelectric production inevitably translates into an increase in generation with natural gas, with a higher economic cost and an increase in greenhouse gas emissions.

Hit on prices

The impact on prices will be especially substantial starting in the autumn, when the generation of electricity with water increases and marks the marginal price (the one that sets the cost of electricity for all the sources that enter the market).

“In the summer months no year is produced much with water and the technologies that mark the marginal price are others.

From October, on the other hand, it will affect ”, predicts the energy analyst Ignacio Gistau.

The cap on gas, the mechanism that the governments of Spain and Portugal have carried out with the approval of Brussels and that sets a maximum price ceiling on this fuel for the generation of electricity, allows this future impact to be substantially reduced.

But the damper is only partial: where it will be noticeable, and not a little, is in the compensation that the mechanism entails.

The more electricity is produced with gas, the greater is this adjustment, which is also paid by consumers.

“In the short term it is particularly bad for us because it forces us to generate more with gas, which is the cushion to cover demand.

The cap protects us to a certain extent, but we will not stop paying the extra cost of the thermal power plants used," says Luis Atienza, former president of REE.

August is a month of low consumption, due to the holidays, but as of September, "if it hasn't rained before, the compensation will grow and a large part of the benefit of the gas cap can be eaten," synthesizes Gistau.

"And the problem that may exist is that the combined cycles cannot cover the entire gap left by the hydroelectric plant, which would force the use of cogeneration, which is more expensive and which is now practically stopped."

The pumps, aside

Drought does not affect all hydroelectric generation in a symmetrical way.

Reversible or pumped plants, those that use a closed circuit to turbine water and obtain electricity, are practically left out: except for the losses derived from evaporation, in their case the resource is infinite once they have achieved fill your facility.

This reality is reflected in the figures: compared to the decrease in generation of the classic hydroelectric plant, turbine production grows by almost 15%.

“Pumping does not consume water resources and is going to be a fundamental piece in the electrical systems of the future.

It provides both flexibility and energy storage and, if it is strengthened, it could make it possible to replace what longer periods of drought are going to take away from large hydroelectric plants," Atienza points out.

“We should make a great plan to promote it, establishing the remuneration scheme that allows a recovery of the investment with certainty.

The more wind and solar there is in the system, the more we are going to need it.”

The former president of REE also introduces a second medium- and long-term reflection: “In a future environment of less water availability, it will be essential to take advantage of renewable generation peaks to desalinate.

Electricity will be very cheap during the hours of high sun and/or high wind, and we will be able to use those moments to store water for human consumption, irrigation or hydroelectric generation;

This will allow us both to solve the problems of water availability in the driest areas and to give additional flexibility to the electrical system”.

European phenomenon

The shaking of the drought on the electricity sector is not a uniquely Spanish element.

In countries less accustomed to prolonged phases of water scarcity, such as France or Germany, this phenomenon is wreaking havoc.

In the first case, the greatest impact is being suffered by nuclear power plants, which need water for their cooling processes.

“There is a precedent, in 2000 or 2001, when the drought affected the French nuclear company a lot.

But, unlike now, it was a much shorter period”, adds Gistau.

In Germany, the problem is another.

With the riverbed of the Rhine and Elbe rivers — its two main waterways — at a minimum, the barges that transport oil and, above all, coal, are having a much harder time reaching their destination.

In some cases, the shipowners are being forced to carry out the transfer in smaller vessels, which can navigate in these conditions.

This forced change makes freight more expensive and, therefore, also the price of both energy raw materials.

more complicated future

And what awaits us in the future?

The IPCC, the international panel of scientists that lays the foundations for scientific knowledge on climate change, warns that "the risks in the physical availability of water" will continue to increase in the medium and long term in all regions.

And, the greater the warming that is achieved (the planet's average temperature is now 1.1 degrees Celsius higher than pre-industrial levels), the greater those risks.

Due to the reduction of glaciers and snow on the planet, scientists predict a decrease in "the availability of water for agriculture, hydroelectric power and human settlements".

Those are the global trends, but when you go down to detail for the Mediterranean region, the situation is even more complicated.

"In southern Europe, more than a third of the population will be exposed to water scarcity if it reaches two degrees" of warming, exposes the IPCC.

If three degrees are reached, the risk will double and "significant economic losses are expected in sectors dependent on water and energy."

For each degree of increase, a 4% reduction in rainfall is expected in the Mediterranean.

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