Is Europe Ready? An Interview With an Energy Management Expert Vlastimil Mazal
Given rising temperatures and the resulting droughts, do you see a potential threat to renewable energy sources in Europe? If so, which sources are most vulnerable and why?
All electrical equipment is sensitive to temperature changes to some extent. In fossil fuel-fired plants, the internal temperature of the turbine, engine or reactor is much more important, but that does not mean that the outside temperature plays no role. Solar panels also have an optimal operating temperature at which electricity production from solar energy is most efficient, and to a certain extent this also applies to wind turbines.
Electricity production from the sun in areas of extreme drought exists in the world today and can be relatively efficient. Drought typically means a cloudless sky, and a cloudless sky provides sufficient direct sunlight, which creates favorable conditions for photovoltaic power generation.
Of course, when drought is combined with extreme heat, individual panels reach the limits of their operating capacity, which reduces their efficiency, which is highest at temperatures around 20-23 degrees Celsius. Wind power plants, if located in an area with sufficient wind flow, can operate even at relatively high and low temperatures without significant fluctuations in production efficiency.
Hydroelectric power plants are a separate issue, however, as there are a number of factors that are just as important as air temperature and humidity when it comes to setting production efficiency and stability. Under certain circumstances, higher temperatures can lead to increased electricity production from water – higher water temperatures can slightly increase the speed of river flow and thus also the flow rate, melting of snow and glaciers in the mountains where rivers originate can increase the volume of water flowing through the riverbed, etc.
It is important to note here that hydroelectric power plants are often built on a single watercourse in successive sections in a so-called cascade, which manages not only electricity production but also the flow of the river itself, and the production of its individual units (separate power plants) depends on how the other units in the cascade are currently operating.
If the electricity system consists not only of renewable sources but also of stabilizing elements, which can be rotating sources (gas power plants, diesel generators, etc.), nuclear power plants, and storage systems, and if the system is properly managed, any climate change is manageable. Extreme weather events (storms, typhoons, etc.) currently have the greatest impact on systems in our latitudes, damaging components of the transmission and distribution system and causing power outages for end users.
Can you explain whether we can expect more outages similar to those in Spain in Slovakia, for example? What factors play a role in such threats and do they differ from country to country?
Slovakia and Spain have diametrically different energy mixes and approaches to frequency control of the system. The stabilizing elements of the Slovak system, which include nuclear power plants in Jaslovské Bohunice and Mochovce, as well as a steam-gas cycle in Malženice with a capacity of more than 450 MW, make it possible to prevent phenomena such as those that occurred in Spain. As the share of renewable sources grows, it will be necessary to adapt grid management strategies to the new circumstances, but in this case I am optimistic and believe that Slovakia will be able to manage a more fragmented and unstable grid without catastrophic outages.
What are the differences between energy production from sustainable sources in summer and winter? Will we see the impact of climate change on energy in winter too?
Winter in Europe is still a paradise for fossil fuels, whether we like it or not. We burn them for heating, use them to generate electricity, and use them in industrial production. Electricity production from wind increases significantly in the winter months, but electricity production from solar energy decreases even more significantly.
However, neither of these sources is suitable (without support systems such as storage or rotating sources) for providing a stable supply of energy to the grid. Therefore, even the transition from gas to electric heating is not a clear step towards greening energy production – fossil fuels will still be a stabilizing element of the grid in Europe in 2025, especially in winter.
Only nuclear energy could fully replace them from today’s commercially available technologies for electricity production. There are various hybrid plans that envisage a predominance of renewable sources and large battery energy storage facilities as part of a green future for Europe, but with ever-increasing consumption, it will not be possible to remove nuclear power from this mix.
Can you give me an idea of how energy production from sustainable sources is planned, especially given the current irregular weather fluctuations?
If you want to plan production for a period of, say, one year, this is quite possible based on historical weather data for a given location and some prediction models. Successful producers achieve a difference of less than 5% in their predictions over a 12-month period. However, when we talk about short time intervals – a week, a day, or an hour – planning is, paradoxically, often much less accurate.
That is why there is a short-term market where deviations (i.e., the difference between expected and actual production) are often traded as a priority, and why there is a set of so-called ancillary services (or regulatory services), which are primarily rotating sources that supplement the voltage in the system in situations when the production of connected commercial sources is insufficient.
That is why we have SEPS and OKTE in Slovakia and ČEPS and OTE in the Czech Republic, for example, to always ensure that differences between the plan and reality (whether on the production or consumption side) do not lead to a catastrophic situation such as in Spain.
SEPS is a transmission system operator in Slovakia ensuring the transmission of electricity across the territory of Slovakia and the connection of the country’s electricity system with the systems of continental European countries.
OKTE coordinates the trade of energy on the daily and hour markets, where there are differences between production and consumption of energy, taking into account the differences within Slovakia. For Czech Republic, these institutions are ČEPS and OTE, respectively.
