Anyone who generates surplus electricity today will sooner or later face the same question: should this electricity be stored, fed in or utilised locally? In the past, the answer was often simple. Feeding in was the standard, because tariff schemes were attractive and alternatives were less often considered in economic terms. Today, the situation is far more nuanced.
The economically best strategy does not depend only on how much electricity is available. What matters above all are the load profile, storage behaviour, feed-in tariff, grid limits, heat potential and the question of what can be integrated at the site in a technically sensible way at all. There is therefore no blanket answer – only site-specific logic.
What you will learn in this article
- when battery storage plays to its strengths
- in which cases conventional feed-in can still make sense
- when local utilisation becomes more attractive economically
- why many sites benefit from a combination of storage, feed-in and utilisation
Key insight
The best strategy for surplus electricity is rarely a question of ideology, but almost always depends on the site. Storage, feed-in and utilisation solve different problems and can complement each other sensibly.
Who is this relevant for?
For operators of PV and energy systems who want to decide whether additional benefit is more likely to come from battery storage, conventional feed-in or a local utilisation path.
Three strategies, three different logics
At first glance, the three paths seem similar: in each case, the aim is to handle surplus electricity as sensibly as possible. Economically, however, they pursue different goals. Storing shifts energy in time and increases self-consumption. Feeding in sells surplus to the grid. Utilising directs surplus locally into an alternative value path.
Which option pays off depends on which problem actually needs to be solved at the site.
When storing makes sense
A battery storage system is particularly strong where electricity needs to be shifted in time. The classic case: PV surplus arises during the day, and electricity is needed again in the evening or at night. The storage system then helps to increase self-consumption and reduce grid imports.
In addition, storage can cushion load peaks. This is relevant above all where high short-term power demands cause costs or the grid connection needs to be relieved.
The strength of storage therefore lies above all in shifting electricity in time, higher self-consumption, reducing grid imports and possibly cushioning load peaks.
Where battery storage reaches its limits
Nevertheless, storage does not solve every surplus problem. Many systems are already fully charged in the morning or around midday. From that point on, the battery essentially waits to be discharged later in the evening. For the additional surplus that still arises after that, it is then often no longer an effective utilisation path.
This is exactly where combining it with HASHLYNK becomes interesting. A HASHLYNK system can not only put surplus energy to use directly, but in certain set-ups can also deliberately discharge an existing storage system again so that additional energy can be used economically. This increases the number of useful charging cycles, and the storage system is put to better economic use.
This is an important point: the battery storage system is not replaced, but integrated into a broader system logic.
Good to know
Storage is not automatically the final solution to every surplus problem. Especially if it is regularly full early in the day, an additional utilisation path can help to get more out of the same infrastructure.
When feeding in makes sense
Feed-in can still be a sensible path – especially when it is simple, reliable and sufficiently attractive economically. For some sites, this is exactly the most pragmatic route: surplus arises, is passed on to the grid and is properly remunerated.
Feed-in is the obvious choice above all when the tariff is still attractive, there is no technical limitation, the site has no better local way to benefit from the surplus and simplicity matters more than maximum optimisation.
This is also part of an honest assessment: not every site necessarily needs more complex logic if the existing feed-in solution works well economically.
Where feeding in reaches its limits
For many sites, however, this is no longer the case. Low feed-in tariffs, variable tariffs, grid restrictions or curtailment mean that conventional feed-in often falls short economically. Precisely when a particularly large amount of electricity is being produced, the value of the kilowatt-hour fed in is often at its lowest.
That is when it becomes interesting to ask whether a local utilisation path can create more benefit than feed-in alone.
At this point, a counter-question often comes up: why not simply design the PV system so small that as little surplus as possible arises? At first glance, that sounds logical, but in many cases it falls short. A larger system design can make economic sense precisely in spring, autumn and winter, because more energy then comes from the roof outside the summer months too. We explain why this makes sense in many cases nonetheless, or precisely for that reason, in the article Why PV oversizing makes sense.
When utilising makes sense
Utilisation becomes particularly interesting where surplus electricity is available but no longer achieves the best possible value through conventional feed-in. This is exactly where HASHLYNK systems come in. Surplus is directed locally into an alternative value path and – depending on the system and site – can also be combined with heat use.
This is particularly relevant with a low feed-in tariff, variable tariffs with a weak revenue profile, grid limitation or zero export, curtailment, recurring surplus despite existing storage, or additional heat demand at the site.
Utilisation therefore becomes economically compelling above all where feed-in is losing value and storage alone no longer covers the whole logic.
The most important insight: it is often not an either-or question
Many sites benefit not from a single strategy, but from a combination. A typical order might look like this: direct self-consumption at the site, then storage to shift energy in time, then local utilisation of the remaining surplus and finally feed-in of residual amounts where it remains economically sensible.
It is precisely in this system logic that the greatest economic lever often lies. Storage then no longer has to do everything alone, feed-in is no longer the automatic default, and utilisation is used where it creates the greatest additional benefit.
A simplified decision grid
| Strategy | What it is strong at | Where the limit lies |
|---|---|---|
| Storing | Shifting in time, higher self-consumption, cushioning load peaks. | Many storage systems are full early and can no longer handle additional surplus after that on their own. |
| Feeding in | A simple, established and often technically uncomplicated path for residual amounts. | Often weaker economically with low tariffs, grid limits or curtailment. |
| Utilising | Additional local benefit with recurring surplus, especially with weak feed-in or storage that is already full. | Needs clean technical and economic integration at the site. |
Conclusion: the best strategy depends on which problem you want to solve
Storing, feeding in and utilising are not interchangeable answers to the same question. They solve different problems and deliver their value in different situations. Storage is strong for self-consumption and load shifting, feed-in remains sensible where it still works well economically – and utilisation becomes particularly interesting when surplus can be used much better locally.
For many sites, therefore, it is not one single strategy that is right, but the right combination. Assessing this combination properly is part of a good site assessment. If you want to go deeper, you can also read the articles Which sites are particularly suitable for HASHLYNK systems and What should be clarified before a site assessment.
