Unlocking Europe’s clean future: How renewable energy storage can help the EU reach net zero

Global conflicts and unsustainability are making fossil fuels less reliable and less desirable. This is why the EU is working to make renewable sources like wind and solar a key part of its energy mix. But there's a catch: the wind doesn't always blow, and the sun doesn't always shine.

To fill those gaps, we urgently need more large-scale energy storage that can save excess energy for when it's needed most. Because if we focus too much on producing energy and not in storing it, we end up losing both energy and money - discouraging the same investments needed to meet our environmental goals.

Iacopo Savelli, a postdoctoral fellow at Bocconi University in Milan, is cracking the code on energy storage. His GREENERproject - funded under the Marie Skłodowska-Curie Actions - investigates the relationship between renewable energy production and storage. The main outcome: only by investing simultaneously in both can we keep the EU on track to reach net zero by 2050.

We spoke to Iacopo to learn more about the challenges of renewables, energy storage and how these technologies can affect the energy system and each other's revenues. He also tells us how his MSCA fellowship gave him the opportunity to contribute to one of the biggest puzzles in Europe's green transition.

Balancing sustainability and profitability in the renewable transition

Why is renewable energy storage such a big challenge for Europe right now?

Iacopo: It's relatively simple to reach 80% or maybe even 90% of renewable energy penetration, but the real problem is to reach 100%. To be able to cover that last mile, you need to spend a lot or build something very smart to store renewable energy long-term, and use it when the wind doesn't blow and the sun doesn't shine.

This can be done, for example, by using technologies such as long-duration energy storage, which works like a giant battery. Some of them, called compressed-air energy storage, use old mines and underground caverns to store high-pressure air for weeks to months. Then, when demand peaks, the air is released it to spin turbines and generate electricity. But we need to do more research on this technology to ensure we can efficiently and effectively supply energy when the system needs it.

What is the GREENER project all about?

Iacopo: The key idea of my research is to show that batteries and renewables are crucial to reach the EU's net zero goal by 2050. But to do that, we need a huge amount of them - and if we deploy so many, the per-unit profit will decrease over time simply because of competition and potentially reach zero, which would stop new investments. In the energy field, this is called revenue cannibalisation.

So, I built a huge model of the EU electricity market, and I ran thousands of simulations to see how the system would respond to changes in the capacity deployed of batteries and renewables. One of the most interesting results I found was that while cannibalisation indeed brings down the revenue from storage, this can be counteracted by increasing renewable energy deployment. That is, increasing renewables can increase storage profits.

This is because renewables push the price to near-to-zero during daylight, allowing the storage to charge at cheap prices, while discharging at peak times where the prices are higher.

"This implies that we should not think about storage and renewables as two different assets, but something that could create a lot of synergy if deployed together."

Accelerating the EU's race to net zero by 2050

How much of our environmental goals will really depend on better energy storage?

Iacopo: It depends on the overall energy mix that will unfold in the future, and on the availability of new technologies. But otherwise, storage will play a key role. I think that we really need to keep an agnostic approach - that means, not excluding any technology a priori, but really doing the math to see how we can efficiently and effectively cover that last mile to reach net zero. But overall, we also really need more incentive mechanisms, both from national governments and the EU, particularly to support energy storage.

Your project is heading towards completion later this year. How will you ensure GREENER's findings remain relevant to future EU energy policy?

Iacopo: I have already shared my findings with energy regulators, stakeholders and the wider academic community, and the topic definitely caught attention. Once I have completed my research findings, I am also planning on presenting them in a webinar to stimulate further discussions and new research opportunities.

The project's results could also open the door to new research questions and have concrete impact. I recently presented my work to colleagues from Spain, who want to use my code and data to supervise a new PhD student which will extend my research. For any researcher, it's a great result to see your idea picked up by another research group so that they can build upon what you've done.

How EU funding and a dynamic policy approach can help

The MSCA programme is turning 30 years old this year . How crucial was it for your project?

Iacopo: Very crucial - it allowed me to keep the same salary I had when I was carrying out research in Oxford and Edinburgh. But most importantly, I could use my budget to travel to conferences and other outreach events, and also take specialized training courses, which I would not have been able to do otherwise.

Moreover, the budget allowed me to plan the usage of High-Performance Computing facilities, which can cost thousands of euros. So, I would have not been able to do my research, or at least achieve the same level of quality.

If you could tell European energy policymakers one thing from your research, what would it be?

"Do not think in silos - we need to see the energy system as a dynamic system to really get the full picture. That is the key message."

More information

Follow Iacopo on LinkedIn

More information about the GREENER project

Project's page website

Read Iacopo's paper on self- and cross-cannibalization in Europe

The EU's 2050 long-term strategy

Renewable energy targets - European Commission