Weekend reading: It’s time to get Sirius



Wallbox, a Spanish supplier of electric vehicle (EV) chargers, has designed a multi-layered energy intelligence solution to avoid expensive grid expansion, proving that necessity is the mother of invention.

It was almost a perfect match. The eight-story building in the center of Barcelona was exactly what Wallbox wanted. In February 2020, the company’s head office, located 30 km away, was congested. “We managed to find a building where all the boxes were checked except for one – the availability of electricity,” says Daniel Utges, Wallbox’s energy manager.

The building only had 173 kW of grid electricity, but the Wallbox needed 300 kW to 400 kW. Testing electric cars and chargers is energy intensive. “The company told us we could solve this problem by investing 500,000 euros ($536,000) in a new transformer, but we thought there were better ways to spend the money,” says Utges.

Big data

A year before Wallbox became the first Spanish unicorn (over a billion euro company) to be listed on the New York Stock Exchange, Wallbox decided to develop a networked building as a microgrid. It is investing about $400,000 in 400kWp solar panels, 560kWh of fixed battery capacity, 23 of its Quasar bi-directional EV chargers and 23 Nissan Leaf vehicles, each with a 62kWh battery. “We needed something on top of that that understands when each asset should consume or generate energy in real time, and that’s how Sirius was born,” says Utges.

The first Sirius, announced in 2021, is expected to enter the market in the first quarter of next year. By choosing the greenest and cheapest energy source available, Sirius optimizes the building’s energy consumption and saves money. “Thanks to Sirius, we had no power outages in the building and saved more than 50% of our Barcelona HQ energy bills, which were estimated to be over €200,000 per year,” says Utges.

On March 27, about 54% of the building’s 2.4 MWh daily energy consumption was covered by solar energy and only 16.5% came from the grid, which saves about 420 euros. Sirius relies on big data analytics to integrate inputs including real-time pricing, weather forecasts and installation constraints such as wiring capacity. It does not control loads such as heating, ventilation and air conditioning; lighting; or water heating. “We treat the building as a black box, but there is a lot of variation in energy consumption depending on the days of the week or whether the laboratory is open or closed,” says Utges. “Integrating an AI layer would help us learn about building behavior and improve Sirius by 10%.”

Capturing opportunities

Most EV charging systems are much simpler. The power is evenly distributed among the charging stations without taking into account user requirements or real-time availability. Business information company BloombergNEF predicts that there will be 77 million electric cars by 2025 and 229 million by 2030, and managing their network effects will be a challenge. Add in on-site solar and storage and the algorithms balance even more.

Wallbox is not alone in researching smart charging of electric cars in the microgrid. Dublin-headquartered power management company Eaton has commercialized and tested its ‘buildings as a network’ approach at its office in Le Mont-sur-Lausanne, Switzerland.

The project harnessed 100 kWp of rooftop solar energy, a 20 kW/21 kWh battery, 16 AC electric chargers and a public DC fast charger. “We made our office building a real test bed to collect statistics on how our buildings-as-a-network approach works and achieved excellent results, including 60% energy cost savings, averaging CHF 1,685 ($1,877) per month,” said Fabrice Roudet, Eaton’s General Manager of Energy Transition, which referred to the July-December period.

In the United States, Powerflex has put into use about 10,000 chargers with more than 330 MW of solar energy and about 44 MWh of battery storage for business premises. Powerflex, a California technology institute acquired by EDF Renewables in 2019, claims its proprietary software can reduce power system upgrade costs and peak demand charges by up to 60% and allow customers to install up to four times more stations. than the standard configuration.

Construction load

“We always consider the building’s load,” says Powerflex CEO Raphael Declercq. “We use formulas (e.g. predictable demand for office buildings) and real-time information (e.g. the increase in air conditioning consumption, which is balanced by reducing the load on electric cars). It is important to get a comprehensive view when the building and the electric cars are on the same meter.

Most EV charging companies are in the early stages of integrating the devices into broader on-site power management needs, and the addition of two-way charging has been mostly limited to research.

At Wallbox’s headquarters, cars are charged with mains power at night and electricity is discharged to the building during the day. “We use the power of our batteries early in the morning, when electricity tariffs in Spain are high, and charge them with solar electricity during the day to reduce our electricity consumption from the grid in the late afternoon,” says Utges.

“Our fleet is intended for internal mobility from the headquarters to the factory (5 km) and some for commercial visits, but not for a long trip to, for example, Madrid,” he explains. “You can book this and we can prepare the car for a long journey as well, but it’s probably easier to go to a fast charger here on the premises and fill your car in half an hour than to use the Quasar, which only gives you 7.4kW.”

David is a passionate writer and researcher who specializes in solar energy. He has a strong background in engineering and environmental science, which gives him a deep understanding of the science behind solar power and its benefits. David writes about the latest developments in solar technology and provides practical advice for homeowners and businesses who are interested in switching to solar.

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