Replacing natural gas with renewable energy sources is a natural step in Denmark’s green energy transition where most district heating plants typically switch to solar or biomass. However, combining several energy technologies to produce both heat and power is certainly a proof of innovative thinking which recently led to the realization of an ambitious green energy project in the town of Brønderslev.
The system is the first combined heat and power (CHP) plant in Denmark, but also in the whole world to integrate concentrated solar power (CSP) and a biomass boiler while also using Organic Rankine Cycle (ORC) to turn the energy into district heating and electricity.
Utilizing benefits of these innovative technologies enables the district heating plant (Brønderslev Forsyning) to achieve record energy efficiency, lower energy prices and a future-proof solution that is no longer dependent on fluctuating fossil fuel prices. Clean energy also means the reduction of more than 25,000 CO2 annually.
This pioneering facility was inaugurated on the 19th of March by the Danish Minister of Energy, Utilities and Climate, Mr. Lars Christian Lilleholt, by the Danish Minister for Taxation, Mr. Karsten Lauritzen and by the Chairwoman of the Board at Energy Technology Development and Demonstration Programme (EUDP), Mrs. Ann-Dorthea Larsen.
“We have been honoured to participate in this revolutionary project which is yet another good example of how innovative Danish technologies have the potential to boost energy transition”, said Jes Donneborg, Executive Vice President.
“The era of gas and coal power plants is slowly coming to an end. We are positive that Brønderslev Forsyning’s example is a global trendsetter for markets such as China, where Danish solutions provide a proven answers to the country’s future heat and power demands” – added Mr. Donneborg.
Concentrated solar power (CSP) – a flexible energy technology
Part of the new, sustainable CHP facility is an advanced, 26,929m2 solar energy plant from Aalborg CSP. This solar-thermal system is based on the concentrated solar power (CSP) technology that has already been producing heat since the end of 2016. With the ORC and biomass units also going online, it is now ready to contribute to electricity production as well.
The CSP technology consists of 40 rows x 125m U-shaped mirrors that collect the sunrays throughout the day and reflect them onto a receiver pipe. This receiver pipe is surrounded by a special glass vacuum tube and inside this runs – only heated by the sun – thermal oil with temperatures up to 330 °C.
This high temperature is able to drive an electric turbine to produce electricity, but the flexibility of the system also allows production of lower temperatures for district heating purposes.
The solar heating system can thus alternate between providing combined heat and power at peak price periods, or exclusively deliver heat. On sunny days, the solar-thermal system in Brønderslev is set to reach 16.6 MWth capacity.
“The CSP technology is capable of supporting the production of pretty much any energy outputs, be it heat, electricity, cooling, process steam or even desalinated water. That is why our corporate strategy has been focusing on learning from our existing projects and optimizing this technology as a result. Soon, we will be able to deliver the next generation of this type, and reduce the gap between renewable and conventional fuel prices on a global scale”, added Mr. Donneborg.
The achievement of the world’s first CSP system combined with a biomass-ORC plant was supported by the Danish Government’s Energy Technology Development and Demonstration Programme (EUDP).