Why do we need flexible demand?

In order to achieve carbon neutrality, we need to shift our energy systems away from fossil fuels, such as coal, oil and gas, and towards renewable energy, using for example wind, the sun or hydropower. That shift forces us to change the way energy systems are modelled and operated.

In energy systems, demand needs to equal supply at all time. Let’s say that we want to transform the electricity supply of an island that currently runs entirely on a diesel-fired power plant. With the status quo, system operation would mean running the diesel plant such that it constantly matches electricity demand, the latter varying continuously. If we replace the diesel plant with wind turbines, system operation is different. We cannot control the wind, so instead, electricity demand needs to be flexible, so that we can ensure that demand always equals supply. In summary, the control problem moves from the supply side to the demand side – energy system operation is flipped by 180 degrees.

So what’s the problem?

The challenge is that demand cannot be controlled as easily as supply, since it depends on when consumers choose to use devices and appliances – for example when they switch on radiators or charge electric cars, but also when factories run machines or cooling systems in data centers are turned on. We believe that future energy systems will incentivize flexibility using prices, that vary across time depending on the current state of the system. For example, if at a certain point in time, wind power generation is lower than expected, electricity prices go up, incentivizing consumers to shift their demand to another point in time, when prices are lower. And if more energy is being produced than expected, prices would drop. We do not expect that everyone will constantly have to check power prices before turning on the lights, but that consumers will have smart and fully automated control systems in their homes, which will do the job for them. 

And what does Frigg do?

To model energy systems that way, we need to incorporate dynamic price formation and the reaction from the demand side into energy system models. In Frigg, demand flexibility and consumer behaviour are modelled through a set of differential equations –  flexibility functions. And a smart dynamic price-making algorithm is run for every hour to minimise system costs. The physical side of the energy system can be modelled through well-established frameworks, such as TIMES, Balmorel or Calliope. Frigg uses data from these models, generates hourly prices and simulates the demand side. Passing an altered demand level back to the energy system model allows computing energy system equilibria that take demand side flexibility into account in a realistic way.

Frigg is currently in early-stage development at the Technical University of Denmark (DTU). The development is financed by the projects CITIESopenENTRANCE  and Cool-Data. Stay tuned for the development status here!

About Us

Amos Schledorn

Amos is a PhD student at DTU Compute. His research focuses on mathematical methods for energy system modelling, in particular optimisation under uncertainty and behavioural modelling, with a focus on flexible energy systems.

Dominik Franjo Dominkovic

Dominik is a Postdoc at DTU Compute. He holds a PhD on Modelling Energy Supply of Future Smart Cities. Dominik is an expert on smart and flexible energy systems with a focus on demand response.

Daniela Guericke

Daniela is an Assistant Professor at DTU Compute. In her research she focuses on the development of optimisation methods for planning problems in different application areas with a focus on energy systems.

Rune Grønborg Junker

Rune is an Assistant Professor at DTU Compute. He is a leading expert in the field of energy flexibility modelling. Rune has developed the concept of flexibility functions which has become the defacto standard for characterising energy flexibility.

Henrik Madsen

Henrik is a professor at DTU Compute and professor II at NTNU. He is a leading expert in the field of modelling, forecasting and control.
According to Google Scholar, he is the number one researcher in the entire world on “demand response”.

Publications

Short presentation of Frigg at the EMP-E 2020

Short presentation of Frigg at the EMP-E 2020

Schledorn, Dominkovic, Junker, Guericke, Madsen 2020
Implementing flexibility into energy planning models: Soft-linking of a high-level energy planning model and a short-term operational model

Implementing flexibility into energy planning models: Soft-linking of a high-level energy planning model and a short-term operational model

Dominkovic, Junker, Lindberg, Madsen 2020
Characterizing the energy flexibility of buildings and districts

Characterizing the energy flexibility of buildings and districts

Junker, Azar, Lopes, Lindberg, Reynders, Relan, Madsen 2019