Currently, the German energy system is going through a transition process of historic dimensions. The long-term objective with regard to climate policy of reducing greenhouse gas emissions by 80 to 95 % (compared to 1990) by the middle of this century means a successive renunciation of using fossil carbon-based energy sources. This radical change regarding the energy base of electricity supply partly makes completely new demands on power grids so that currently this results in a substantial pressure to take action with regard to grid expansion and upgrading as well as to the development of new concepts of operation in order to continue ensuring a reliable and safe electricity supply.

Against this background, TAB has been commissioned by the Committee on Education, Research and Technology Assessment of the German Bundestag to point out the technological perspectives and options concerning the conversion and operation of the future power grid for a medium to long-term horizon (2030 and beyond). A broad analytical approach has been adopted to be able to give an overview of the current state of knowledge and the state of discussions regarding many relevant issues associated with the expansion and upgrading of both transmission and distribution grids. Because it would be short-sighted to focus only on technological aspects when it comes to investigate and to describe the future development of power grids, economic aspects have been discussed as well both regarding future expenditures required for power grids as well as costs and benefits of using certain technologies such as so-called »Smart Meters«. Moreover, several dimensions of consequences and impacts involved in grid expansion and in the use of modern technologies have been investigated as well. This particularly includes data privacy issues in modern power grids which are increasingly merging with information networks (»Smart Grid«), but also possible impacts on the environment and on human health.

Results

In the following, you will be given a brief overview of the major results stated in the TAB report concerning central thematic areas that have been examined:

Required expansion and upgrading of power grids

A comparison and analysis of current studies quantifying the need for expansion shows the magnitude of the expansion required. The investment requirements until 2020 for distribution grids will amount to approx. EUR 25 billion and another approx. EUR 20 billion have to be added for transmission grids until 2022.

The future development of the power system and particularly the expansion and upgrading of power grids will not take place autonomously, driven by technological developments and an irrefutable intrinsic logic, but there is a considerable scope for action and design. For this reason, the aim is to conduct an open debate in order to define preferences at a social level and then implement them in a political approach.

Modern technologies and operating modes for power grids

The project describes and discusses the functionality, the scope of application as well as the development status or need for research and development of essential technologies, which currently still have not been broadly introduced into practice in Germany, but which are considered to have a substantial potential in the foreseeable future. For transmission grids, this refers e. g. to the on-line temperature monitoring of overhead lines, high-temperature conductors, power-electronic components or high-voltage direct current (HVDC) transmission. For distribution grids, i. a. controllable local grid transformers, feed-in grids and technologies for a decentralized provision of system services (e.g. voltage and frequency control) will be investigated. Great importance is attached to the issue of so-called »Smart Meters«, i. e. intelligent digital measuring devices for determining power consumption.

Future scenarios regarding the power grid

As the future development of power grids is not only driven by technology, but finally will take place considering preferences to be defined at a social level, several future scenarios have been developed here regarding the two terms »centralized/decentralized« with the intention of exploring the space of possibilities of future development.

A closer look has been taken on a specific technological vision: operating the grid in so-called »regional cells« which are able to maintain power supply in case of a failure at the interconnected level even independently via stand-alone (»island«) operation. This would mean a radical renunciation of conventional operating strategies applied so far, but could represent a strategy aiming at improving system resilience with regard to major supply disruptions. It has been investigated whether this operating mode is appropriate to support the integration of renewable energy sources, to reduce the need for grid expansion and to contribute to an improved resilience of the power supply system.

Reliability and safety

Substantial micro- and macroeconomic damage might result not only in case of total blackouts, but also in case of short-term deviations of operating parameters (voltage, current intensity etc.) from standard values. Moreover, novel challenges have been discussed which might be provoked by an increased use of information and communication technologies within the power supply system mainly with regard to unwanted or criminal manipulations which might affect reliable functioning of the infrastructure.

Environmental and health impacts

Possible impacts of the construction and operation of power lines on flora and fauna, soil or hydrological balance as well as on the countryside have been investigated. The respective properties of overhead lines and underground cables have been compared to each other.

As there is a clearly noticeable public concern assuming that electromagnetic fields caused by power lines might affect human health, the state of scientific knowledge and its evidence was presented and characterized here.

Public acceptance regarding the expansion of power grids

It is not a matter of course that the construction of a power line route is accepted by the population affected, even if the decision has been made democratically and in full accordance with the law. In this context, the consultation and participation procedures currently applied in the course of the creation of a grid development plan or Federal Requirements Plan have been examined and several factors of success regarding public participation procedures have been identified.