What governs storage projects in 2026.

For co-location projects with existing solar this is the central rule. Until now mixed operation — subsidised green power and grid power in the same battery — could barely be accounted for cleanly, which is why many projects artificially separated storage from the existing plant.

MiSpeL introduces a demarcation option: quantities are apportioned by defined formulas. In practice, storage can trade on the market without endangering the support of the existing plant.

For planning, the decisive point is that legal force and applicability diverge: metering concepts, market communication and grid operator systems have to follow. We therefore design projects so that they hold before and after the effective date.

This is the most effective lever against the queue. Whoever accepts being curtailed in a few hours of the year gets a connection that would otherwise not exist.

The price is availability. For storage running Arbitrage this is often bearable, because curtailment usually falls in hours when it would not be discharging anyway. For storage selling balancing services and guaranteeing availability, the same limitation can destroy the business model.

Before agreeing to a flexible arrangement, a simulation is required: how often, for how long and in which hours would curtailment bite? Without that answer the agreement is a blind trade.

This rule decides the revenue side of every grid-connected storage plant. Without it, each stored kilowatt hour would bear grid fees twice — which would make most arbitrage models uneconomic.

The August 2029 cut-off is therefore a hard schedule anchor: plants commissioned later fall under the coming AgNes regime. For projects starting today that is not a distant future but the real question of whether the schedule holds.

In our models we therefore treat the exemption not as given but as a scenario with an end date.

A long-open question is thus settled — against the storage industry. Battery storage is treated like any other final consumer for the contribution, although it does not consume the electricity drawn but returns it later.

In practice the contribution strongly steers site selection: it follows the local capacity price and can differ by a multiple between two grid areas. A site with a short cable in an expensive area can cost more than one with a longer cable in a cheap area.

For us that means the contribution is estimated before land is secured, not after. It is not an incidental cost item but a selection criterion.

This is the most important open regulatory question for projects commissioned after 2029. Capacity charges are proposed for new storage whose final investment decision falls after the determination takes effect.⁹

For project planning this creates a window that is not a guess but a date: projects with an investment decision before the effective date are treated differently from later ones.

We therefore model projects in two variants — with and without a future capacity charge. A model with only one variant is too short-sighted for a twenty-year horizon.

Under section 35(1) no. 11 BauGB storage is privileged where it stands in a spatial and functional connection with an existing renewable energy plant. That is the co-location case.

Under no. 12 storage is privileged without that connection if it has at least 4 MW of rated power and lies no more than 200 metres from the boundary of a substation or of a power plant of 50 MW or more. An upper limit applies as well: no more than 0.5 percent of the municipal area and in no case more than 50,000 square metres per municipality.¹⁰

The per-municipality cap is the point many overlook. It turns the privilege into a scarce good: whoever brings a project to permitting first consumes an allowance the next applicant will lack. That changes the order of work — the preliminary building enquiry moves forward.

Overriding public interest under section 11c EnWG is more than a formula. It shifts the weight in balancing against other interests — in nature conservation law, for instance — and therefore bears directly on permitting.

The change to section 118(6) EnWG ends the disadvantage of mixed-use storage: electricity fed back is treated as stored electricity and no longer carries grid fees twice.

Together with the planning privilege under section 35 BauGB this is the most tangible relief for outer-area storage projects in years.

First come, first served created the connection backlog: requests cost little but block capacity. With 574 GW requested and 54 GW offered in 2025 this is no longer a marginal problem.¹

The draft provides for prioritisation by statutory criteria (draft section 17b EnWG); storage co-located with renewable plants is to be connectable with priority.¹¹ The four transmission operators had already proposed in December 2025 a staged procedure with an application fee, a cluster study and instalments of the construction cost contribution as proof of seriousness.¹²

For developers the logic inverts: what counts is no longer the early request but demonstrable maturity. That is precisely why we work along the development stages — they are the currency such a procedure counts in.

Without a plant certificate there is no commissioning. The route starts with the components (unit certificate), runs through plant design (plant certificate) and ends with the declaration of conformity after construction.

The most common mistake is one of timing: certification is treated as closing work although it drives the design. Requirements for reactive power, protection settings and grid behaviour belong in the design, not in a retrospective proof.

We therefore involve the certifier before detailed design. That costs money early and saves months later.