Energy efficiency (in energy transmission) – what is it and how to achieve it?

In view of the ever-increasing energy demand of the economy, one of the key issues to be addressed is energy efficiency. It refers not only to the commonly understood efficiency consisting in reducing energy consumption of end devices, but also to the energy generation and transmission process itself. What are the ways to achieve it?

One of the objectives of the “Energy Policy of Poland until 2040” – a document adopted by the Polish Council of Ministers – is energy efficiency. It is a term that is used in all possible combinations in many strategic documents – both at national and international level. The definition of this term can be found, among others, in the Energy Efficiency Act:

“The ratio between the achieved utility effect of a given facility, technical equipment or system under typical conditions of use or operation and the amount of energy consumed by that facility, technical equipment or system or as a result of the service necessary to achieve that effect.”

Electricity transmission efficiency

One of the areas affected by the issue of energy efficiency is the electrical power engineering. For the transmission grid, transformers and power line cables are crucial in this context. Generally, it can be assumed that the efficiency of energy generation and supply when using traditional transmission lines is not high. Part of the energy losses are permanent and are essentially impossible to eliminate. However, some arise in the process of energy distribution. The problem is particularly acute in the case of long-distance transmission of energy, which takes place within the power grid installed in Poland quite frequently. Technical losses can account for up to several per cent of the energy generated – especially in the case of lower voltage grids. The higher the voltage, the lower the losses.

The level of energy losses in power grids can be monitored and measured. For this purpose, an energy efficiency index is used. It is the quotient of the grid losses and balance differences at a given voltage level (expressed in GWh/a) and the electricity fed into the grid at a given voltage level (also expressed in GWh/a) multiplied by 100%. The result obtained indicates the efficiency ratio as a percentage.

Improving energy efficiency in relation to energy transmission is primarily about investing in grid development. This endeavour has multiple dimensions. One of them is the issue of infrastructure. The modernisation of substations, the use of high-efficiency transformers, new power poles and investment in new power cables on lines can result in greater efficiency in the transmission of electricity within a given grid or lower consumption of the fuel needed to produce energy with the required parameters. Renewable energy sources are another area where energy efficiency can be influenced.

Smart Grid technology and energy efficiency

The development of renewable energy sources and the associated decentralisation of energy generation and transmission creates new opportunities for improving the efficiency of energy supply. Photovoltaic panels or installations such as a wind farm can be located deep within the grid, thus shortening the path of energy transmission to consumers. As we already know, it is the transmission of energy over long distances that is characterised by a high risk of losses. Shortening this path makes it possible to reduce them. This is because, in practice, the dispersal of energy generation sources, through the use of numerous relatively small-scale RES installations, can significantly contribute to covering consumers’ energy needs.

Another important element that can affect energy efficiency is the issue of planning and managing power flows. This process is aided by Smart Grid technology. Its implementation is part of ensuring a secure, continuous supply of electricity and minimising energy losses. Through the use of appropriate metering and control systems, it is possible to optimally feed surplus energy produced from RES into the grid or optimise the use of energy storage facilities. In addition, the use of Smart Grid can also be an element that influences energy consumption, allows potential failures to be located and removed more quickly, so that users can count on an uninterrupted, high-quality energy supply.

Investment as the key to energy efficiency

Improving energy efficiency in the field of energy generation or supply requires investments in both the modernisation of the power grid itself and the infrastructure, as well as the development of RES. Considering the directions of the energy policies of Poland and the European Union, as well as contemporary challenges for the energy sector, striving for decarbonisation and a sustainable economy it is undoubtedly one of the basic directions for the development of the entire energy industry.