RTE launches ‘Cube Flex’ winter flexibility challenge

The Cube Flex challenge is aimed to accelerate the management of building energy consumption to support the grid at peak times during the winter months.

RTE, the French transmission system operator (TSO), is partnering with the French institute for building performance (IFPEB) and market engagement company A4MT on the initiative, which runs to the end of April.

The challenge is focussed on non-residential buildings, which can most readily smooth their consumption at critical periods either through load shedding or load shifting.

The tertiary building sector is a significant user of energy and with the residential sector together they account for up to almost three-quarters of the demand during the hours of concern, which run from 08h00 to 13h00 in the morning and 18h00 to 20h00 in the evening.

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The challenge is based on the delivery of orange or red alerts on the EcoWatt mobile app, which also gives the real time status of the system’s balance. ‘Orange’ indicates that flexibility is invited, while ‘red’ indicates the system state is critical and outages will be inevitable if demand is not reduced.

Seventy buildings nationally are participating in the challenge, including schools, offices, train stations, post office buildings, high-rise buildings, prefabricated modules and a shopping centre.

The launch of the challenge follows test days run in October, with one of these days demonstrating that four buildings reduced consumption by an average almost 35% during the peak hours, corresponding to a reduction in power demand of up to 5W/m2 for a day without heating.

Based on this result, RTE estimates that if the whole French tertiary building stock, amounting to about 1 billion m2, were to participate, then up to 5GW of demand could be removed from the grid.

“These figures clearly show that the flexibility of tertiary buildings can be an important lever to manage the balance of the electricity system this winter and eventually as part of the transition,” RTE states in its report.

In addition to delivering the flexibility, Cube Flex is intended to provide learnings on what levels can be achieved on a wider scale, how best to deliver it and how it can be valued.

RTE intends to make preliminary results from the initiative available at the end of February.