Many of us have already returned from our holidays. Others are still waiting to leave. But how many have stopped to think about the amount of energy our way of travelling and spending our holidays actually consumes?

The figures that most readily come to mind are those related to aviation. According to the European Commission, if it were a country, aviation would rank among the world’s ten largest greenhouse gas emitters. A single return flight from Lisbon to New York, for instance, generates roughly the same amount of emissions as the average EU citizen produces by heating their home for an entire year. Hidden behind these striking figures, however, are others that are less visible and far more difficult to quantify. Tourism is one of the European Union’s largest service sectors, generating enormous energy demand across hotels, airports, transport systems and leisure facilities. Several studies rank hotels among the five most energy-intensive categories of tertiary-sector buildings. And although no comprehensive EU-wide figures exist for their electricity consumption, the European Commission explicitly identifies them as a priority sector for improving energy efficiency. Not only that. “The tourism ecosystem also has an important role in contributing to the shared goals of a climate-neutral Europe,” the European Commission states in its Transition Pathway for Tourism.

So why should tourism remain merely a passive consumer of energy? Why couldn’t it instead become an active player in optimising electricity use, reducing demand peaks and easing pressure on the grid? If you’re reading this article from your electric vehicle, part of the answer might quite literally be beneath you.

That is precisely what is being tested at Porto’s Sá Carneiro Airport, in the P0 long-stay premium parking area. Airports are among the most energy-intensive transport infrastructures, but the growing number of electric vehicles parked for long, predictable periods also turns them into valuable energy assets. “Bookings are made online, so we know in advance, for example, that a traveller will arrive at 2 pm on Friday and leave the following Thursday at 4 pm. During that time window, we can charge the vehicle when electricity is cheaper and use part of the battery’s energy when prices are higher and demand peaks occur. When the traveller comes back, the car will be fully charged again, without them paying anything for the charging service,” explains Samuel Matias, R&D Project Manager at the Portuguese energy company EDP.

For Miguel Palma, from the Portuguese airport operator ANA, this approach combines several advantages at once: accommodating a growing number of electric vehicles, increasing the use of renewable energy and advancing real-world testing of EV battery technologies, all while contributing to decarbonisation. “Medium- to long-term vehicle stays make airport parking lots a perfect testbed for these technologies. They allow us to test different battery cycles and fine-tune smart charging and bidirectional charging algorithms to achieve the best possible outcomes,” he notes.

The “bidirectionality” he refers to lies at the heart of DriVe2X, a European project that aims to accelerate the uptake of electric mobility through a new generation of smart charging technologies (with Matias coordinating several of its demonstration sites). The concept is straightforward: instead of functioning solely as devices that consume electricity, electric vehicles become “batteries on wheels”, capable of both drawing energy from the grid and supplying it back to the grid or to buildings. In the project’s name, the “2X” stands for “to everything”, referring to the multiple ways in which electric vehicles can interact with the energy system, from Vehicle-to-Grid (V2G) and Vehicle-to-Building (V2B) to several other applications. “We can either receive energy or send it back, whether to the grid or to a building,” Palma explains. “Whatever receives that energy can then use it when demand is higher, when the grid is under greater stress, or simply when electricity prices are higher.” To make the most of this flexibility, Porto Airport’s bidirectional chargers are integrated with smart algorithms that forecast the airport’s electricity demand. This allows charging sessions to be scheduled when electricity prices are lowest or when renewable energy production is at its highest.

Like airports, tourist accommodation also offers ideal conditions for testing these technologies. Here too, the combination of a growing number of electric vehicles parked on site and predictable peaks in electricity demand creates an opportunity to take the best out of EV batteries. “In hotels, for instance, meals are prepared and guests typically take showers at fairly predictable times, while their electric vehicles are parked outside,” explains Matias. “That’s when we can use their batteries to provide energy precisely when demand is highest, and then recharge them overnight, when both electricity consumption and prices are lower. That’s how we make use of this flexibility.”

This is why his project has extended its demonstrations to several hotels on the Isle of Wight, a 100-square-mile island off England’s south coast, known for its sandy beaches, beautiful cliffs and a legendary music festival. “Thirty-eight percent of the Isle of Wight’s economy depends directly on tourism, but it’s a highly seasonal business,” says Steven Wells, Vice Chair of the island’s tourism organisation, Visit Isle of Wight. “In winter we have around 160,000 residents, but during the summer we welcome well over a million visitors.” Those seasonal peaks inevitably bring a sharp increase in electricity demand. Yet they also coincide with periods when the island can rely on abundant renewable energy production. “We have several large solar farms because the Isle of Wight enjoys more sunshine than anywhere else in the UK, particularly around Shanklin, where our hotels are located,” he points out. Indeed, Wells also manages Luccombe Manor and Luccombe Hall Hotel, two of the establishments where Drive2X is testing its solutions. “Guests can simply plug in their electric vehicles. Then, during the hotel’s peak demand periods — for example in the evening, when the kitchens are preparing dinner — part of the energy stored in those vehicles can support the hotel’s electricity demand. Overnight, when electricity is cheaper, the cars are charged back up, ready for guests to use the next day,” he explains.

If enough chargers were available and enough drivers used them, “you could probably avoid having to upgrade your electricity connection altogether,” Wells argues. The initiative has also attracted considerable interest from guests themselves. Once they hear about it, many ask whether they can use the bidirectional chargers. “We’ve had an extremely positive response,” Wells recalls. “Unfortunately, for the time being we’ve had to tell people ‘not yet’, because we’re still waiting for regulatory approval in the UK.”

In fact, the potential of bidirectional charging extends well beyond the demonstration sites in Porto and on the Isle of Wight. “These solutions can be replicated in hotels and airports across Europe, but also in many other settings: mobility hubs, tourist attractions, apartment buildings and even single-family homes. The main lesson we’ve learned is just how many different use cases this technology can support,” Matias emphasises. Yet unlocking the full potential of these solutions ultimately depends on something far more fundamental: allowing electric vehicles to communicate seamlessly with the grid and with the other components of the energy ecosystem.

“In theory, every electric vehicle is bidirectional. In practice, however, the number of vehicles that are actually compatible is still very limited. While there is already an open communication standard for bidirectional charging (ISO 15118-20), many manufacturers do not yet follow it strictly or implement it consistently, which creates interoperability challenges,” Matias recognises. What is needed, he argues, is what he calls “interoperability”: “Ensuring that vehicles, charging infrastructure and every actor involved in the energy ecosystem are all able to ‘speak the same language’. The relevant standards already exist, but in practice some OEM implementations include slight variations in message definitions and identifiers, making full interoperability across different systems more difficult than expected.” That urgency is becoming even more pressing as infrastructure struggles to keep pace with the rapid growth of electric mobility. “Electric vehicles already account for one of the largest sources of electricity consumption in our homes. Our electricity grids were simply not designed to cope with this level of demand growth. That’s why we need to accelerate the deployment of flexibility solutions,” Matias concludes.