Danish city is creating one of the world’s largest sustainable energy reserves

State of Green
By State of Green, September 16, 2020

The Danish utility Aalborg Forsyning plans to create one of the world’s largest sustainable energy reserves. The project will be located in the Danish city Aalborg and will be the first of its size and first to provide hot water at any time needed.

The engineering, architecture and consultancy company Rambøll will assist in the design of the new energy storage pits. Rambøll has previously advised in connection with the establishment of pit storages to store energy from solar heating systems, which have primarily functioned as seasonal heat storage.

“In Aalborg we wish to play an essential role in the green transition. We look forward to optimising our utilisation of the renewable energy sources with the new storage pits and giving the people from Aalborg an even greener product”, said Deputy Director of Aalborg Forsyning, Jesper Høstgaard-Jensen.

– Related solution: ABB delivers first urban battery storage solution in Denmark to support renewables 

Provides hot water to 2,500 households

The new installation will consist of two heat storage pits of 500,000 cubic metres of water each and will store surplus energy from i.a. wind turbines, industrial production and waste incineration, which would otherwise have been lost energy. But with the new sustainable energy reserve it will be sent back to consumers and businesses, in the form of hot water – when needed by the consumer. One million cubic metres of water corresponds to 2,500 households’ consumption of district heating in one year.

“Energy storage pits are the green technology of the future, which solves a significant societal challenge, namely storing the energy that is produced”
– Christian Teil Fyhn, Chief Project Manager, Rambøll

“Energy storage pits are the green technology of the future, which solves a significant societal challenge, namely storing the energy that is produced. Today, wind turbines often spin in vain if the washing machine or industrial machine is not running at the same time. And sometimes the wind turbines are stopped to avoid excess production of electricity. And in the same way, a lot of heat from industrial production is also wasted. We are changing this with the new giant stock, so that the energy can be stored and then used at a later date”, said Chief Project Manager Christian Teil Fyhn from Rambøll.

Collecting and storing energy from different renewable energy sources

Northern Jutland’s power plant named Nordjylland Power Station will close down the electricity and heat-producing coal facility in 2028 and in the period leading up to the closure, the storage pits will help optimise the operation of the plant. It will function as a peak and reserve load instead of the existing gas boilers. Following the closure of Nordjylland Power Station, the storage pit facilities will help to collect surplus production from wind turbines and other renewable energy sources such as seawater heat pumps and geothermal energy.

– Related solution: Innovative energy storage: 600-degree hot stones are used to store green electric power

Source: Rambøll (in Danish)

Photo: Rambøll

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