This article, originally prepared as a presentation for e-SMART training material, by Electro Ljubljana RES Ltd, is going to present electricity distribution network in the conditions of so called green transition. This ambitious plan is a big challenge for distribution network to support, since all needs proposed in green transition are huge.

In the future, electricity consumption will increase a lot. The reasons for that is our ambition to generate power for our society in a sustainable and environmentally friendly way. Another reason is that technologies we are using now for carbon free energy generation are mostly connected with the electric energy or at the end any kind of generation is turned into electricity. In Slovenian National Energy and Climate Plan (NECP) estimates are given that 70% of electricity consumption increase will happen till 2050. However, today's primary energy supply in Slovenia is at the level of 70 terawatt hours what is much more than 20 terawatt hours estimated in NECP. Increase in electricity demand will be much higher than expected if we, by chance, don't implement completely new energy sources, not known yet or at least not commercially available yet. Estimation to be really carbon neutral society goes up to 40 terawatt hours of electric energy from renewable sources.

CO2 neutrality of our society will have major impact on distribution network. If we use at the moment mostly popular renewable resource – the photovoltaic, we will have to connect about 40 giga watts mostly distributed generation capacity, while today's capacity is at the level of 3 gigawatts. Renewable Energy Sources are mostly connected to the distribution network where today only about 0.4 gigawatts are connected. Distribution of 40 terawatt hours of energy instead of today's 12.5 is a huge challenge for existing network which needs to be totally refurbished, land rebuild. In ideal case minimum needed network capacity increase is between 250 and 300% but probably even close to 400%. With today's investment pace, as we increase network capacity by 1.5 to 3% each year, to reach required national plans we would need 100 years. Estimation is that increase of investment in distribution network needs to be 300% and the question here is can users of the network afford it and still being competitive.

If we compare our Slovenian national plans with estimations at the EU level we can find a lot of similarities. Eurelectric estimates investment needed for distribution network to double, from 33.5 billion EUR per year, to 60 during 2021 to 2030, that means in the next 10 years. European Commission estimates this needs to be even higher, between 60 and 110 billion EUR per year, which means between 200 and almost 400% of increase. Our own estimates are at about 350%. Imagine influence on network tariffs and costs for electric energy and consequentially competitiveness of EU economy when these figures are really implemented. Question is also, where to find founds and human resources because, founds are not the only problem. There is a lack of engineers in this field in Europe and distribution network needs all possible support to follow these trends of green transition and overcome bottlenecks on that way. Otherwise it will not be possible to connect all these renewable clean energy sources and deliver all needed electricity to the society, economy, households, traffic heating and everything else what it's supposed to be driven by electricity in the near future.

Why we are so sure that electricity demand will increase in the future? One of the reasons is that most of the strategies of sustainable development rely on electrification of heating. The reason for that is that heat pumps are really very efficient means of heating and that they use electric energy. At the EU level already by 2030 four times more heat pumps is estimated then in operation today. In Slovenia the number of heat pumps rises very quickly already. Their total electric capacity is already over 270 megawatts what is 13% of peak load of the whole country. Estimated number of heat pumps by 2030 is 200,000 heat pumps with total loading of additional 950 megawatts. Only in 2019 the number of heat pumps increased for 53% and installed capacity raised for 67 megawatts.

To be continued...