Green electricity tariffs have become one of the most visible ways for households and companies to support the energy transition. Across Europe, millions of consumers deliberately choose electricity products marketed as “100% renewable”, often assuming that their electricity consumption is directly matched by renewable energy generation.
As renewable electricity claims play an increasingly important role in reporting frameworks and consumer decision-making, questions around their transparency and reliability are receiving growing attention. At the TUM Chair of Management Accounting, researchers have been investigating whether the way renewable electricity claims are accounted for aligns with how consumers understand them, exploring this question from both a system and a consumer perspective.
In a study published in Nature Communications, Hanna Scholta and Prof. Dr. Maximilian Blaschke analyzed data from the European certificate and electricity markets and found that current accounting practices can conceal substantial seasonal and day-night mismatches between renewable electricity generation and consumption.
Building on these findings, Johannes Bösch and Prof. Blaschke turned to the consumer perspective. Based on a randomized stated-choice experiment involving more than 1,000 participants in Germany, their study, published in The Energy Journal, found that a large majority of consumers are unaware that most “100% renewable” tariffs do not require electricity consumption and renewable generation to be matched in real time.
We spoke with Prof. Blaschke about what this research reveals about renewable electricity claims and why these findings matter for consumers, companies, and policymakers.
Prof. Blaschke, most green electricity products today are marketed as “100% renewable”. To what extent does this claim reflect how the system actually works?
Under current rules, “100% renewable” usually means that an equivalent amount of renewable electricity is certified over a year. If consumers understand it as renewable generation matching their consumption at every moment, the claim is misleading.
Together with Hanna Scholta, you investigated temporal mismatches in the European renewable electricity certificate market. What were the key findings?
These certificates are issued for electricity generated from renewable sources. However, annual matching can hide substantial seasonal and day-night mismatches between generation and consumption.
Together with Johannes Bösch, you also investigated the consumer perspective. How aware are households of these mismatches?
Most people, unfortunately, simply assume that the electricity they consume with their “100% renewable” tariff has actually been produced from renewables at any point in time. We found that around 85% of participants were either unaware of these temporal mismatches or unsure whether such matching exists.
What changes when consumers learn about them?
Our tests show that some consumers would no longer choose such a tariff if they knew. This suggests that current labeling can mislead a non-negligible share of consumers.
In your paper, you describe this as an information failure. Why is that problematic for consumers and for green electricity markets?
We suggest clearer labeling. This would allow consumers to choose according to their preferences. Some tariffs offer 24/7 renewable electricity, but consumers currently cannot distinguish them from tariffs based on annual matching.
What changes could make green electricity claims more transparent and reliable? And what role could future standards and reporting frameworks, such as the GHG Protocol, play?
A phased shift from annual to monthly and ultimately hourly matching would allow transparency while giving suppliers and consumers time to adapt. It could also strengthen incentives for storage and east- or west-facing solar PV. These changes are unlikely to come from the market itself. Standards and regulators should steer toward this, and the GHG Protocol's ongoing revision is a key opportunity to embed finer-grained, time-matched accounting into how renewable claims are verified.
Looking Ahead
The two studies point to a broader challenge: ensuring that renewable electricity claims are understood as clearly as they are accounted for in practice.
The accounting system behind today's renewable electricity claims can conceal important temporal differences between generation and consumption, while many consumers remain unaware of those differences. Bridging this gap through clearer labeling and progressively more granular accounting could improve transparency without requiring an immediate overhaul of existing systems.
As renewable electricity claims become increasingly important for household decisions and corporate sustainability reporting, ensuring that accounting practices and consumer understanding evolve together may help improve their transparency and credibility.
Publications
Bösch, J., Blaschke, M.J. (2026). Are “100% Renewable” Electricity Claims Misleading? Evidence on Consumer Awareness and Preferences for Temporal Matching.
Scholta, H.F., Blaschke, M.J. (2025). Temporal matching as an accounting principle for green electricity claims.
