When we talk about energy transition, we first think of power produced from renewable energy sources. However, there is even more to a successful energy revolution. The “green” power has to be used – and ideally in the most meaningful way possible. This is where integrated energy plays a role. This integration combines:

  • Heat
  • Mobility
  • Electricity

What exactly is Integrated Energy?

To put it briefly: The integration of previously separate sectors of the energy industry. Here, electricity, heat and mobility are combined. Integrated energy includes the energy needs for both private households and the industrial consumers. In the industrial sector, this involves combining electricity, heat and mobility with industrial processes. The aim of all of this is to reduce the CO₂ emissions.

How does integrated energy work?

An important component of integrated energy is producing electricity from renewable energy sources. This is achieved in particular with decentralized solar and wind plants, but also with biomass plants and hydropower.
Almost two-thirds of the annual CO₂ emissions in Germany are caused by heat generation and traffic. Using electricity from one’s own PV plant for heating and powering electric cars is one way effectively reduce the amount of CO₂ produced. When this happens, three sectors of heat generation, power production and mobility have been combined.

Power-to-Heat – Using electricity for heating

As far as electricity is concerned, Germany is quite far long with the transition to clean energy. Over 30% of the total power consumption is already covered by “green” electricity. However, the transition to clean energy in regard to heating is still at the beginning. Most private homes and companies continue to use gas and oil for heating.
Integrated energy – combining heating and PV power – is a climate-neutral alternative. Of course, this is only when “green” electricity is used for heating (generally with a heat pump). There is a clear trend towards the installation of heat pumps, especially in new buildings, that run mostly on PV power.

Power-to-Wheel – Using electricity for mobility

The equivalent for electromobility is power-to-wheel. Admittedly, this term is not commonly used, but it makes its significance for integrated energy clear. Power is used for electromobility, ideally from renewable energy resources, to operate bikes, scooters, motorcycles and cars. This power can come directly from one’s roof or from a “green” electricity supplier.


Innovative storage methods are required

The availability of “green” electricity is currently the drawback of power-to-heat and power-to-wheel. Alternative energy sources such as from PV and wind do not produced the same level of electricity through out the day and night. Consequently, electricity has to be stored. There are very different systems when it comes to storage. We will present an overview of a few here:

  • Battery Storage: Energy storage systems are making inroads. The principle is simple: When there is a surplus, the electricity is stored in a battery. This electricity can then be used at any time when it is needed.
  • Ice Storage: Storing heat is usually done on a larger scale. One example is ice storage. Simple explanation: Liquids are frozen in winter, giving off heat. When the ice melts in summer, the coldness is transfered.
  • Gas storage: Another option is to save energy in a gaseous form. There is an extensive gas grid and large gas storage options.
  • Power-to-Gas: With electrolysis, power is used to produce hydrogen and with biological methanization, it becomes a synthetic natural gas. This is used for heating and industrial processes. Fuel cells or combined heat and power generators can be used to convert the gas back to electricity as it is needed. This conversion process is called gas-to-power.
  • Power-to-Liquid: Liquid fuels are produced from electricity in other processes, referred to as power-to-liquid.


What are the benefits of integrated energy for consumers?

The good news: Consumers can already use integrated energy today. This is rather useful when power is produced with one’s own photovoltaic plant. It is beneficial for PV plant owners to consume as much solar power themselves as possible. The electricity is used for heating water, heating, e-bikes and electric cars. The more PV power one uses directly, the cheaper it is.

There are energy management systems for the optimization of self-consumption that independently distribute solar power. For example:

  •  to heating systems
  • warm water or buffer tanks
  • heat pumps
  • electric cars

The management system factors in the power consumption needs of the household and the weather forecast. This allows the power production and consumption needs to be planned in advance.


What is the future like? What is next?

The most “profitable” applications of integrated energy are those current in households. When the energy from one’s roof is used directly, there is no grid usage charge. One can calculate directly with the production costs.

The implementation of integrated energy on a larger scale, e.g. in industry or in municipalities, is still difficult. The underlying conditions (e.g. taxes and grid usage fees) are the primary problems that makes it more difficult to use power from renewable energy sources. In addition, there is an incomplete legal framework for operators. That is why integrated energy on a large-scale is still the exception rather than the rule in Germany.

Integrated energy plays an important role in the energy supply with respect to the expansion of renewable energies, falling costs and appropriate regulations. Almost as a side thought, it also ensures that we optimally consume our energy.