The development of renewable sources of electricity means that Poland increasingly has surpluses of electricity during periods of high production. However, it proves much more difficult to ensure a reliable power supply when there is no sunshine or wind for extended periods. It is precisely the long-term storage of electricity that remains one of the greatest challenges of the energy transition.
Energy storage facilities are increasingly emerging as an essential component of a modern electricity system. They enable the surplus energy produced by renewable sources to be harnessed and used at a later date, thereby improving the system’s operational flexibility and facilitating the integration of an ever-increasing number of renewable energy installations. Their role will grow as the share of renewable energy sources in the national energy mix increases.
However, the solutions currently in use primarily address the need for short-term system balancing. The power generated during the day by photovoltaic installations can be used in the evening or at night, when generation from solar panels drops. Such storage facilities effectively address the issue of shifting consumption by a few hours and enable renewable energy to be utilised more efficiently. However, they do not eliminate the problem of ensuring a power supply during multi-day periods of adverse weather conditions.
The biggest problem is not the construction of energy storage facilities itself, but the lack of solutions that would allow energy to be stored for long periods in an economically viable manner and on the scale required by the electricity system. The solutions available today work very well for balancing the system over a period of a few hours, but they still do not answer the question of how to safeguard the system for many days or weeks – says Leszek Goli, CEO of SPIE Energy Poland.
The most challenging scenario is several days without sun or wind
The greatest challenge for the electricity system is not isolated hours of lower renewable energy generation, but much longer periods of adverse weather conditions. In Poland, there are winter periods lasting up to a dozen or so days when electricity generation from photovoltaics is very limited, whilst at the same time conditions are not favourable for wind farms to operate. In such situations, energy demand must be met from other sources. It is precisely these scenarios that highlight the limitations of current storage technologies.
We must view the electricity system not through the lens of a single sunny day, but over the course of the whole year. The greatest test comes during the winter months, when photovoltaic systems are out of action for many days in a row and there is practically no wind. It is precisely then that it becomes clear how important it is to have stable energy sources that guarantee security of supply regardless of the weather – emphasises the CEO of SPIE Energy Poland.
This is one of the reasons why the issue of retaining some conventional generation sources so often arises in discussions about the energy transition. They are valued not only for the volume of energy they produce, but above all for their ability to ensure a stable supply at the most demanding moments of the system’s operation. From an operator’s perspective, energy security means being ready to act even when renewable energy sources are unable to meet consumer demand for extended periods. Until effective solutions enabling long-term energy storage on a sufficiently large scale become widespread, conventional power generation will continue to play an important role in ensuring the stability of the electricity system.
Energy storage facilities are a key element of system security
The importance of energy storage facilities extends far beyond the ability to utilise surplus generation from renewable sources. Their development is closely linked to changes in the way the entire electricity system operates, in which sources that function differently from conventional power stations are playing an increasingly significant role. The greater the share of such installations, the greater the importance of solutions that support grid stability and enable flexible system balancing.
In public debate, we often assume that the development of renewable energy sources will automatically solve the problem of energy security. In my view, this is an oversimplification. Until we have economically viable methods of long-term energy storage, the transition will have to be based on several complementary technologies, rather than solely on renewable energy sources – says Leszek Goli.
The development of renewable energy sources will continue, as will investment in energy storage and the modernisation of electricity grids. However, the success of the transition will not be determined solely by the pace of construction of new installations. Equally important will be the development of solutions enabling the effective storage of energy over the long term and the maintenance of stable operation of the entire system regardless of weather conditions. It is precisely in this area that the most significant challenges facing the modern electricity sector are concentrated today.
