Selling an RTB portfolio is no longer considered solely as a final exit. It increasingly constitutes a capital recycling operation.

The proceeds from the sale can be used for:

• to finance new projects;
• strengthen development teams;
• cover the guarantees and connection costs;
• reduce debt;
• retain a stake in certain priority assets;
• diversify the portfolio towards BESS or other technologies.

This approach allows the developer to maintain their business while limiting their exposure to the financing needs of the construction phase.

The value of a project no longer depends solely on obtaining permits. Investors now analyze the following with particular attention:

• the actual availability of the connection;
• the cost of connection;
• the risk of congestion;
• exposure to negative prices;
• the production profile;
• income security;
• the possibilities of hybridization with storage.

In 2025, negative wholesale prices accounted for approximately 6% of trading hours in several European markets, including France, Germany, the Netherlands, and Spain. This increasing frequency reinforces the uncertainties surrounding the future revenues of purely commercial projects.

Increased grid constraints and curtailment also contribute to greater investor selectivity. The IEA estimates that more than 10 TWh of renewable generation was curtailed in the European Union in 2024, illustrating the growing importance of flexibility and storage.

In this context, buyers are not only looking for megawatts under development. They favor assets with strong execution visibility:

• secure land;
• final permits or permits that are sufficiently advanced;
• Connection validated;
• realistic calendar;
• documented budget;
• electricity marketing strategy clearly identified.

A high-quality RTB project therefore remains attractive. However, the valuation gap between solid projects and those with technical or regulatory uncertainties tends to widen.

Selling an RTB portfolio in 2026 will therefore require more preparation. A competitive transaction relies on thorough documentation, a realistic risk analysis, and pricing consistent with market conditions.

For developers, selling RTB assets can be a relevant strategic decision: it allows them to realize some of the value created, preserve the company’s financial capacity and continue developing new projects.

The success of the operation nevertheless depends on the ability to present investors with a credible, documented and directly executable portfolio.

The value of a BESS can be expressed in different ways:

• price per MW;
• price per MWh of capacity;
• multiple of EBITDA;
• present value of cash flows;
• expected return on invested capital;
• premium compared to the remaining costs to be incurred.

These indicators are only comparable when the projects have similar characteristics.

A 100 MW BESS with a one-hour duration does not offer the same economic profile as a 100 MW, 400 MWh asset. Similarly, an operational project benefiting from a tolling contract cannot be directly compared to an RTB project fully exposed to market revenues.

The main factor driving valuation changes today is the security of income.

By 2025, the number of standalone tolling contracts identified in Europe increased from three to fifteen. Including financing based on such contracts, Modo Energy identifies nineteen transactions with a tolling structure.

These contracts allow the owner to receive predictable compensation in exchange for making the battery available to an operator, utility, or trader.

They reduce exposure to fluctuations in electricity markets and generally improve:

• bankability;
• cash flow visibility;
• debt capacity;
• the interest of institutional investors.

EY also notes that the European market is gradually evolving from a purely market-based model towards structures that allow for a more efficient distribution of risks between the asset owner and the counterparty taking on exposure to the electricity markets.

A merchant project may offer higher return potential, but its value depends heavily on the assumptions made regarding:

• day-to-day and intraday arbitration;
• system services;
• capacity markets;
• price volatility;
• the future saturation of ancillary revenues;
• the optimizer strategy;
• battery degradation;
• replacement costs.

Two investors can therefore arrive at very different valuations from the same asset.

Projects with a robust electrical connection, high operational flexibility, and access to multiple revenue streams are generally valued higher than assets dependent on a single service.

The decrease in equipment costs supports the economics of projects. According to market data reported in 2025, the construction cost of a two-hour UK BESS had decreased by approximately 30% in two years, to just over £500,000 per MW.

This decrease, however, does not automatically translate into a proportional increase in the value of projects under development. When technology costs fall, buyers may also reduce the premium they are willing to pay for an early-stage pipeline.

Value is therefore increasingly concentrated on elements that are difficult to reproduce:

• the connection;
• land;
• the authorizations;
• the income contract;
• market access;
• the quality of the execution.

Some public transactions do, however, provide some guidance. The acquisition of the UK portfolio Harmony Energy Income Trust was announced based on an enterprise value of approximately £340 million, or roughly £860,000 per MW. This figure, however, concerned an operational portfolio and is not a directly applicable benchmark for an RTB or development project.

In practice, BESS valuations are therefore evolving less towards a single “market multiple” than towards increasing segmentation between:

• early pipelines;
• authorized projects;
• RTB projects;
• assets under construction;
• merchant operating assets;
• Contracted operational assets.

The quality of the connection and the robustness of the revenue model become the true drivers of value.

For investors, a PPA remains an important tool for securing income. It can facilitate:

• bank financing;
• cash flow forecasting;
• reducing exposure to the spot market;
• the reduction in the cost of capital;
• visibility on the return on the asset.

However, the mere existence of a PPA is no longer sufficient to guarantee the attractiveness of a project.

Investors are now closely examining:

• the buyer’s creditworthiness;
• the duration of the contract;
• price indexation;
• termination clauses;
• the risk of volume;
• the risk profile;
• the treatment of negative prices;
• the guarantees provided by the parties.

The strength of the counterparty can thus directly influence the bankability and value of the project.

The increase in the number of hours at negative price weakens contracts that do not sufficiently take into account the actual production profile.

This situation fosters the emergence of new structures:

• PPA with floor and ceiling;
• PPA partially indexed;
• pay-as-produced contracts;
• baseload contracts;
• hybrid PPAs combining solar, wind and storage;
• contracts associated with flexibility mechanisms;
• shorter-term contracts with specific protections.

S&P Global anticipates, in particular, an increase in hybrid PPAs and storage-backed contracts to limit the risk associated with negative prices and the deterioration of captured prices.

The goal is no longer just to set a price, but to improve the match between the project’s output and the buyer’s consumption profile.

Combining a renewable energy park with a battery can enable:

• to shift part of the production to better-paid hours;
• to reduce exposure to negative prices;
• to improve the delivery profile;
• to provide energy that is closer to the consumer's needs;
• to participate in several markets.

This evolution is leading some investors to no longer analyze renewable energy production and storage separately. They are gradually assessing the value of an energy system that combines generation, flexibility, and contractual security.

Hybrid projects can therefore benefit from increasing interest, provided that the connection rules, authorizations and contracts actually allow for coordinated operation.

Large technology companies and data centers remain among the most active buyers. Their high consumption and continuous electricity needs lead them to seek long-term contracts, sometimes based on renewable energy supply that is more closely correlated to their hourly consumption.

At the same time, aggregated PPAs can facilitate access for several medium-sized companies to a joint contract.

This diversification expands the market, but also increases the legal and financial complexity of the operations.

The return of PPAs changes the investment criteria.

Buyers place greater value on projects that have:

• of a clearly defined marketing strategy;
• of a solvent counterparty;
• of a balanced contract;
• protection against periods of negative prices;
• technical flexibility;
• of a possibility of association with a BESS.

However, a poorly structured PPA can also reduce the value of an asset if it excessively limits its upside potential or transfers risks that are difficult to manage.

Therefore, by 2026, the PPA should no longer be considered solely as an electricity sales contract. It becomes a genuine instrument for allocating risks between the producer, the investor, the lender, and the consumer.

For investors, the best strategy is not necessarily to seek the longest contract duration, but to build a coherent balance between income security, flexibility and controlled exposure to the market.

Protection of sensitive information and securing of exchanges between parties.

Study of the main elements: Status of authorizations, Land, Connection, Environmental studies, Implementation schedule.

Targeted distribution to selected investors and industrialists matching the asset profile.

Collection and comparison of expressions of interest and non-binding offers.

Supporting buyers in technical, financial, legal and commercial audits.

Coordination of exchanges until the signing of final agreements and the completion of the transaction.

Finalization and official transfer of ownership of the energy asset.