2023-05-09 00:01:04
The Spanish electrical puzzle, composed mostly of renewable pieces, has a great paradox: what happens when you are not available? Since the possibility of saving the box and continuing to assemble it when the sun rises or the wind blows is not contemplated, it is necessary to have backup technologies such as gas or the constant production of nuclear power. In addition, the National Integrated Energy and Climate Plan (PNIEC) foresees 6 GW of storage between pumping and batteries, but currently only the first technology exists -some 3.3 GW-, while the second is still in its infancy. At least in Spain, because countries like Australia or the United States have a growing park. And this, in any case, is the forecast before the revision of the plan, which will probably expand its objectives in a multitude of technologies. Spain knows that it needs ways to store electricity, because it is a key point in its energy plan, but, for now, it has a lot of work ahead of it.
The large electric companies already have projects underway or about to be in Spain, although it is about small capacity systems, especially when compared to the renewable parks they accompany. Almost all batteries are hybridized; In other words, they serve, in a way, to prolong the contribution of wind turbines or photovoltaic panels for a few hours at times when they are not available.
It should be noted that currently one of the problems -or, at least, one of the challenges- of the Spanish energy mix is dumps: There are times when renewable production is so high that the electricity generated must be discarded, because demand is less than supply. The idea is that the batteries solve this and allow energy to be stored to be released at another time.
Beyond hydrogen, which is still potential energy in a chemical format, the main ways to ‘save’ electricity are batteries and pumping. The pumping stations They are dams that allow the release of water to generate electricity, but which can then use sources of renewable origin to raise the liquid again and thus feed the pumping system. In hybrid plants, moreover, the wind turbines or plates from which their systems are fed can also give ‘light’ to the network when they are not being used.
Meanwhile, the batteries are almost the same ones used by electric vehicles and its operation and characteristics -also hits-, practically identical. What’s more, the automobile sector has been the great cause of the fact that today they are beginning to be used for the electrical sector. Although it varies depending on many factors, industry sources estimate the average price for a station that allows electricity to be stored for two hours in about 400,000 euros per MWh.
“The operation is the same and, in fact, it is the same technology used in electric vehicles,” illustrates Mara Prez, Head of Storage at Naturgy. “What happens is that they are a little more expensive and we are a little more careful when loading and unloading so that they last for us,” he jokes when introducing another of the keys: they cannot always come into operation, because they have a useful life of about 6,000 charging cycles. With a moderate forecast of about 500 cycles a year -we must also take into account that they take time to load and unload-, this means 12 years.
To alleviate this, there are various alternatives that allow electric companies to charge for what the batteries provide beyond the electricity that enters the system itself, stacking services. The first would be the most obvious, arbitration: it is loaded when there is excess production and the price is low and it is unloaded when the first falls and the second rises. Thus, the idea is that they can be used to flatten the duck curve that occurs in the electricity sector in a mix with a lot of renewable generation, where there is much more electricity supply in the central hours of the day, when the price of electricity also falls. ‘light’, and generation plummets at sunset, which also coincides with a rise in domestic demand.
It is also proposed, for example, that there be an inertia auction that can be accessed by the different storage technologies, or that it participates in frequency regulation markets. The latter is a somewhat more complex concept, which is based on the fact that the network, in order to function, needs a frequency –50 herzios– and this is achieved by keeping electricity production and demand balanced. When there is an imbalance, it means that more is produced, and it could be solved by feeding the ‘batteries’ or that there is a lack of electricity, in which case, they would discharge.
“Together with has a natural degradation: if you don’t use it, it also degrades“, explains Pérez. “You have to try to make it operate as much as possible, but not to operate for the sake of operating, because you have to make it profitable,” he details. In any case, its price has dropped thanks to the development of technology that has led to the electric vehicle “It has been that market that has promoted the research and development of production plants and so on,” he concedes. Alexander Ariasresponsible for special projects of Iberdrola Energa Sostenible.
“They really are similar in terms of operation and technology,” says Arias. The stationary batteries to connect the network and those that give life to electric cars are lithium ion batteries. The difference, explains Arias, is in some materials, especially the cathode: “In stationary batteries the cathode is made of a material called LFP (lithium iron phosphate) and in the vehicle, it is another, NMC (nickel, manganese, cobalt)”. This is because “in stationary the longevity of the batteries is valued more and, on the other hand, in the vehicle, what is valued more is the energy density: that is, that they weigh little for the storage capacity they have”.
The other side of this coin is precisely lithium, a material for which two sectors that are still one compete: storage. “Right now the price of lithium is very volatile“, illustrates Arias, who provides data that proves it: from 2020 to last year the price of lithium multiplied by five, but in the last year it was reduced and returned to 2020 levels again. “Production depends on the construction of large factories that also take years to manufacture and the demand is very unstable, depends on this factor of introduction of the electric vehicle”, he contextualizes. However, solutions appear on the horizon, such as switching to battery batteries sodium ionsa much more abundant material.
hydraulic batteries
Pumping, for its part, involves a greater investment and a much more complex engineering work, with times that can be around a decade, depending on the work required. In exchange, it grants much greater power -Iberdrola, for example, has a hydraulic gigabyter in Portugal with a combined capacity of 1,158 MW that cost more than 1,500 million euros- and it also allows energy to be stored for longer, even from season to season. station. For larger needs, it is much more efficient than ‘batteries’.
Both technologies are thus complementary. “We are in the transition and there is no technology that is going to solve the problem: what you have to achieve is a mix of all the solutions,” Prez details. “Batteries allow you to store fewer hours, but they are much faster, and then pumping contributes when you need to store more hours“, resume.
Despite the challenges that the batteries still have ahead of them, both experts agree that they will be key to the mix of countries such as Spain. “In a mix to which we are heading from 75% renewables by 2030 or 100% by 2050, batteries are necessary for the system due to the evidence that the sun and the wind are not there when they are needed”, sums up Arias “It is a complement and an aid to integrate renewables into the system”. The problem, he stresses, is that the services that they contribute “they are not paid yet” and “there is nothing to push the promoters and install batteries yet”.
Given this, Pérez, who also sees it as necessary to develop the markets, is optimistic: “The first step, which was to take advantage of European aid, has already been taken.” And it has happened, simply, because it needs to happen. “If you really want to make a transition you need to have storage,” he settles.
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