Sector coupling and the smart energy system

The green transition requires rethinking of our energy system, where we link the various elements of the energy system to create a smart system that is flexible while being robust and affordable.

The citizens’ use of energy varies during the day, throughout the week and from winter to summer. However, our energy consumption varies in familiar and somewhat predictable patterns, and as long as it is possible to plan the energy supply, the fluctuations are not an issue. However, many green energy sources do not allow for planned production. Wind turbines produce electricity as the wind blows, and heavy rain clouds cast their shadow over the solar energy production. As the share of green energy sources increases, there is a need to think smart, so we can continue to receive energy from our energy system with a high security of supply.

Therefore, the smart energy system of the future that can provide flexibility and security of supply at an acceptable cost needs to be one that is well thought out and utilises every element of the energy system in the best possible way.

At Ramboll, we see the energy system as consisting of four energy carriers:

1. the electrical system,
2. the gas network,
3. the district heating network and
4. the district cooling network.

Traditionally, the four energy carriers are considered separate and have not been thought together. However, they are connected as different technologies brings us from one energy carrier to the other. Combined heat and power production can for instance bring us from the gas network to the electrical and district heating network, and a synthetic gas plant (so-called Power-to-Gas) can convert electricality to gas (e.g. hydrogen). Therefore, one energy carrier can be used as storage for another, and the four energy carriers can provide flexibility to one another.

In the energy system of the future, each of the four energy carriers should therefore not be considered as four isolated silos. On the contrary, we need to connect the various elements and utilise the strengths of each of the four energy systems to establish the required flexibility of an energy system where the share of green energy is increasing. And we should not stop here. We can include other sectors to increase flexibility. The dynamic use of batteries in electric cars, for instance, is an obvious candidate.

In conclusion, a smart energy system requires a farewell to thinking in silos and a hello to a holistic view on how energy is produced, consumed and stored across the energy carriers.