Renewable energy share is the proportion of total electricity consumption (or total energy supply) that comes from renewable energy sources, usually expressed as a percentage. In EV charging, renewable energy share is used to describe how much of the electricity delivered to EVs is backed by renewables—either through measured on-site generation, contracted renewable supply, or defined certificate-based accounting.
What Is Renewable Energy Share?
Renewable energy share answers: “Out of all the electricity used for charging (or used by a site/network), what fraction is renewable?”
It is commonly calculated as:
– Renewable energy share (%) = (Renewable electricity (kWh) / Total electricity consumed (kWh)) × 100
The definition of “renewable electricity” depends on the chosen methodology, such as:
– On-site renewable share: renewable kWh generated on-site and used for charging (self-consumed)
– Contracted renewable share: renewable kWh supplied through a green tariff or PPA
– Certificate-backed share: renewable kWh claimed via RECs/GOs that are purchased and retired
– Time-matched share: renewable supply matched to charging by time interval (hourly or sub-hourly) under a defined method
Why Renewable Energy Share Matters in EV Charging
Renewable energy share is a key KPI for sustainability reporting and operational optimization. It helps:
– Quantify decarbonization progress for fleets and charging networks
– Support EV charging carbon reporting and ESG disclosures
– Meet tender requirements for renewable sourcing (public and corporate)
– Compare sites and identify opportunities for renewable energy integration
– Build credibility when communicating “green charging” claims
How Renewable Energy Share Is Measured in Practice
Depending on the setup, renewable share may be based on:
– Metered PV generation and charger consumption (to calculate self-consumed renewable kWh)
– Utility contracts and supplier reporting (green tariffs, PPA deliveries)
– Certificate retirement evidence (RECs/GOs) matched to consumption volumes
– EMS data that allocates renewable energy to charging sessions (where methodology is defined)
For accuracy and auditability, it’s important to define:
– System boundaries (which chargers/sites are included)
– Time period (daily, monthly, annual)
– Whether the share is location-based, market-based, or time-matched
– Treatment of storage (battery charging/discharging attribution rules)
Typical Use Cases
– Fleet reporting: % of fleet charging powered by renewables (home + depot + public)
– CPO reporting: network-level renewable share for public charging
– Real estate: tenant reporting for workplace and residential charging
– Municipal projects: renewable share targets tied to public funding and KPIs
– Optimization: increasing renewable share by shifting charging to solar or low-carbon grid hours
Key Benefits
– Simple KPI that stakeholders understand and can track over time
– Useful for comparing performance across sites and regions
– Encourages operational strategies like smart charging and solar-first charging
– Supports stronger sustainability claims when backed by evidence
– Helps prioritize investments (PV, storage, EMS, load control)
Limitations to Consider
– The metric can be misleading without a clear method (on-site vs certificates vs time-matched)
– Annual certificate matching does not reflect real-time grid conditions
– Renewable share does not automatically indicate low cost or low peak demand
– Data quality depends on metering, time alignment, and allocation rules
– “100% renewable” claims must be carefully scoped to avoid greenwashing
Related Glossary Terms
Renewable Energy
Renewable Energy Integration
On-site Solar PV
Energy Management System (EMS)
Green Energy Tariffs
Power Purchase Agreement (PPA)
Renewable Energy Certificates (RECs)
Guarantees of Origin (GO)
Real-time Carbon Tracking
Smart Charging