Raboresearch: Heat and cold storage becomes silent engine behind future-proof heat networks
The heat transition is accelerating, and with it the role of heat and cold networks in both the built environment and greenhouse horticulture is growing. New grids are being built, existing ones are being made more sustainable, and everywhere the same question sounds: how do we keep supply and demand in balance when fossil sources disappear? In an article, Raboresearch has therefore shown why storage is becoming the indispensable link in a system that increasingly runs on renewable sources.
Why storage is becoming indispensable
Heat demand fluctuates constantly. Demand is high in winter, but low in summer. Within a 24-hour period, we have peaks in the morning and evening, while tap water use varies throughout the day. As long as fossil sources feed the system, this is easy to absorb: more gas in, more heat out.
But as we move to renewable sources - such as geothermal, solar thermal, aquathermy and ground source energy - the balance becomes trickier. Production patterns simply do not match heat demand. Geothermal and ground source energy, for example, provide steady supply, while solar thermal has its peak just in the summer. This creates a mismatch that can only be solved with storage.
Heat and cold storage allows surpluses to be captured at times when sources are producing a lot, and used later when demand rises. Short-term storage helps especially with daily fluctuations. Seasonal storage helps when we want to store heat for months. Both together reduce dependence on peak fossil supplies and increase the share of renewable energy in the grid.
How storage strengthens heat systems
By using storage intelligently, heat systems can be made more reliable and efficient. Buffers prevent unwanted strain on infrastructure, ensure better use of renewable resources and reduce plant wear and tear. They make it possible to dimension systems more compactly, reducing investment costs and the need for less grid capacity. Especially in times of electricity grid congestion, this is an important added value.
The Netherlands now applies storage mainly in the form of buffer vessels and underground thermal storage (WKO). Other techniques such as large underground pit storage, high-temperature storage or thermal storage in stone or concrete are still at the beginning of large-scale application. International examples - including from Denmark and Germany - show that there is enormous potential here to store large amounts of sustainable heat for long periods of time.
Increasing this storage capacity is crucial to make optimal use of renewable resources. CE Delft estimates that total storage capacity in heat networks could triple by 2050. While this remains relatively modest relative to total heat demand, these buffers can be deployed several times a year or even a day - making the impact far greater than the figures might at first suggest.
Challenges on the road to wide adoption
The growth of thermal storage does not come naturally. Spatial integration remains difficult, especially in urban areas where space above and below ground is scarce. Permit procedures are also complex, especially when storage goes deeper than 500 meters and falls under the Mining Act. In addition, many technologies still require further cost reductions and technological development, especially for seasonal storage at medium and high temperatures.
Financing presents a second hurdle. Storage technologies are capital intensive and the revenue model depends on local conditions, the functioning of sources and developments in the energy market. At the same time, we see that projects are increasingly able to find financing, thanks in part to instruments such as the Heat Networks Investment Subsidy (WIS).
Public support also plays a role. Visible storage, drilling or construction projects can raise local concerns. Experiences from Denmark show that transparency, participation and sharing benefits with local residents are crucial to gain widespread support.
Accelerate: learn, standardize and develop further
Energy Storage NL shares Raboresearch's view that heat and cold storage will play an increasingly central role in a future without fossil fuels. It is the silent engine behind flexible, robust and sustainable heat networks. This picture was also confirmed in earlier research by ESNL together Invest-NL into the costs and benefits of heat storage in heat networks.
The Netherlands has a lot of knowledge and a strong position in soil energy, but lags behind in seasonal storage. To fully utilize the potential, Raboresearch says further development is needed at the technological, organizational and legal levels. Clear regulations, standardization of projects, further cost reductions and area management in the subsurface are important prerequisites. At the same time, we can learn a lot from surrounding countries that are already applying large-scale storage.
Read the entire article from Raboresearch here.
