If Europe wants to have more green energy by 2050 it must also think about how to accumulate it. Producing it is already a big step forward, but having it available when needed is equally essential. The issue is open and the EU's indications are not yet entirely clear. So one wonders what they are the best roads in order not to invest billions of euros in renewables without being able to store them.
Lo studio "Accumulation systems and long-term scenarios" elaborated by the Laboratory Ref examines the storage capacity of wind and photovoltaic energy. Starting from this need "is essential to realign temporal production and consumption of electricity" write the researchers.
With their research, the Ref scholars have accustomed us to seeing things in a more articulated way than emergencies give us. Now, the energy transition, fortunately, is a gradual path, but planning at scale is very cost-effective. The energy requirement to 2050 is estimated at 670 terawatt hours with 95% coverage from renewable sources and only 5% from gas.
Given that sun and wind are not always available during the day, considering the areas more or less exposed to one or the other source, it is balance entries of electricity and withdrawals. One of the «limits of wind and photovoltaic generation is precisely linked to non-schedulability of production, which can determine hours of overgeneration, where energy production exceeds demand and hours of undergeneration, in which the demand is greater than the total hourly electricity production». Currently to conserve clean energy there are hydroelectric systems, those of battery storage and the production of hydrogen through electrolysis. The latter exploits excess electricity and water for later use. It is a system on which European industry wants to focus, with the advantage of being able to transport the non-polluting source.
What's going on in Italy?
For Italy, a greater production of is expected in the next few years renewables in the South but a major consumption in the North. If you choose hydrogen storage transport costs must also be considered. Thus we will once again have two Italys on opposing fronts for natural and historical reasons.
In other words, the system must be able to overcome these problems in order to make optimal use of the production from non-programmable renewable sources. There challenge is technological, also taking into account the reduction in the costs of the storage systems. For batteries, a good solution is represented by a lithium ions, today the most used at decreasing market costs.
For 2050 at the Ref Laboratory they have made an estimate for a complete decarbonisation which has included among the good sources for our country, the biomethane. It is constant, it is not subject to climatic variations, it interests many projects and can support the system. By 2050 Italy can produce 13 billion cubic meters corresponding to approx 70 terawatt hours. Another 40 Terawatt hours could be generated by imports. Everything that is still missing to reach the finish line «must necessarily be covered by the use of storage systems, which will have to accumulate energy during the hours of surplus and release it in the remaining hours of deficit».
Establish rules and premi for new energy
We are late. What to do? "It must be certain that in the short term a certain number of storage systems will be needed to compensate for the discrepancies between production from intermittent renewable energies and peaks in demand" answer the researchers. It takes a public intervention, somehow already underway, for a country among the most exposed in Europe.
The Arera he asked Terna to organize an auction system based on direct subsidies. In this case there would be two advantages: a market for the forward supply of storage capacity with an annual premium, and a subsequent market for time-shifting products perhaps on a geographical basis. But if it will be done it must be “valid for plants accumulation of new construction, who receive the annual bonus from Terna as their only remuneration".
- existing storage facilities, on the other hand, can request to participate in the "second half" mechanism of energy injection, without receiving prizes. The indications are clear and outline one positive scenario, it remains to be seen who, how and when will decide.
