Everything as a Grid – A successful energy transition requires a new infrastructure

Will the scenario no wind and no sun, no electricity soon become reality? Large-scale blackouts could indeed pose a permanent threat in the future if we are unable to transform our power grids. In order for them to be able to support the energy transition and guarantee an energy supply, a cellular structure including flexible local storage and markets will be needed.

 Even today, when we are still a long way from a 100 percent green energy supply, breakdowns in the grids occur time and again: In January of this year, France faced serious problems with its power supply – yet again. The combination of aging nuclear reactors and cold temperatures regularly causes electricity supply bottlenecks there. That very same month, an incident in southeastern Europe also caused widespread disruptions throughout the European interconnected grid. First, an automatic overcurrent protection system in a Croatian substation failed and disrupted an important connection line. Within only a short time, the alternative transmission lines were also overloaded and caused further disconnections. In fact, this disconnection even resulted in an oversupply of electricity in the southeast and a simultaneous deficit in the northwest. This had to be responded to with the targeted shutdown of large industrial power consumers in order to avoid further outages.

Structural problems in the interconnected grid

 The first electricity grids were designed to be only local and supplied a town or a single factory with power. As early as the 1920s, however, the basis for a larger-scale interconnection was laid with the North-South line in Germany. The idea at the time was to use hydropower resources from the Alps to satisfy the Ruhr region’s insatiable hunger for energy. This was already a fundamental principle of the interconnection: to produce electricity where the resources are located and then redistribute it to consumers. However, when the main burden of energy production was taken over by large thermal power plants, the aspect of balancing was added. The large nuclear or coal-fired power plants can only be run at a relatively constant output and cannot be ramped up or down spontaneously, even though the demand for electricity fluctuates over the course of the day. This means solutions on how to deal with surplus electricity had to be found. These include pumped storage power plants, load control in energy-intensive industries, but also dual-tariff meters and night storage heaters in private households.

This basic design of the interconnected grid is geared towards long-term, plannable, constant generation in a few main power plants, from where energy is then to be distributed as efficiently as possible and local differences are to be balanced out. Due to climate change, however, we have been experiencing nothing less than a radical shift in energy production in recent years, which is of course positive in itself. But wind and solar power are decentralised resources. Thanks to increasingly better weather forecasts and the possibilities that digitalization offers, they can now be planned relatively well. Ramp-up and down phases still follow each other very quickly, however. A grid that dates back to the nuclear and coal era is not made for this. Since it is already struggling with problems time and again, it can be assumed that the European interconnected grid in its current form would be unable to cope with fully renewable generation. But what is the alternative?

The grid of the future: flexible and cellular

Wind and solar power plants are far less tied to specific location factors than the old large-scale power plants. Nuclear reactors need large rivers for their cooling water supply, large hydroelectric power plants likewise or they are located at reservoirs in the mountains and lignite-fired power plants were ideally built directly adjacent to the opencast mines. Photovoltaic systems, on the other hand, can be mounted on any roof, and wind turbines can likewise be erected in a wide variety of locations. A certain uncertainty and lack of predictability in generation, as well as the much more decentralised generation, make it necessary to do a bit of rethinking at the grid level, nevertheless. Electricity generated locally should also be used locally and, in the case of surpluses, be able to be stored locally. Coming up with a cellular energy system should ultimately be the goal of the entire project.

 In the article entitled “Zellulares Energiesystem – Ein Beitrag zur Konkretisierung des zellularen Ansatzes mit Handlungsempfehlungen” (Cellular Energy System – A Contribution to the Concretisation of the Cellular Approach including Recommendations for Action) by the Association for Electrical, Electronic & Information Technologies, such an energy cell is defined as follows:

 “An energy cell consists of the infrastructure for different types of energy, in which the balancing of generation and consumption across all available forms of energy is organised through energy cell management in possible coordination with adjacent cells.”

 In this holistic approach, transport, heating and industry are also taken into consideration. Electromobility is particularly interesting here. In a traditional approach, the large-scale spread of e-cars is often seen as an additional burden on the grid; one fear, for example, is that simultaneous charging of many vehicles could lead to grid overload. This may also be true for the “old” grids. In the cellular view, however, the e-car is no longer merely seen as a consumer, but rather as part of the integrated energy grid. In practice, this can mean that the vehicles take load from the grid through time-controlled, intelligent charging during generation peaks. The vehicle-to-grid approach goes even one step further: vehicles that are not being used can feed energy back into the grid and thus support short-term frequency control.

In addition, stationary storage facilities can be considered an elementary pillar for a flexible electricity grid of the future. Power-to-gas could be an interesting approach for the long-term storage of green energy. The term describes the electrolytic production of hydrogen using green electricity. The hydrogen produced this way could then be either converted back into electricity later on or be used as clean fuel gas. Hydrogen production by way of electrolysis is a process that has been known for quite some time, although it has not yet been economically viable. This will change though as prices for renewables fall and green hydrogen also becomes more attractive as a business case. We are already much further along with battery storage for short-term storage of energy. In fact, these types of solutions are already commercially available.

Local energy management

At Eaton, we take the approach of viewing individual buildings as the smallest local energy unit. Such a unit optionally includes generation, but in any case storage, distribution and delivery of energy (also in the form of charging stations). This Buildings-as-a-Grid approach is aimed at transforming buildings into local energy centres. The Amsterdam Arena is one example of an energy centre that has already been realised. A battery storage system with a capacity of 3 megawatts was installed in the stadium’s multi-storey car park that not only guarantees the emergency power supply, but can also perform local balancing functions for the grid. The first bidirectional charging stations have also already been installed in the arena. What is also worth mentioning about this project is that so-called second-life batteries are also installed in the energy storage system. These are batteries that are no longer powerful enough to be used in cars.

Such comprehensive energy considerations that also include storage units should become the rule rather than the exception with new buildings. This will lay an important foundation for localisation and flexibilisation of the electricity grids that are key to a modern grid and the urgently needed energy transition. For building owners, now is definitely the time to act: Help create solutions for a clean future and save energy costs at the same time! Not sure where to start? Well, in that case we are here to help you with advice and support.