“Net Billing or self-consumption?” compares concepts at different levels. Self-consumption means using generated energy on site. Net Billing concerns the arrangement combining that use with the financial treatment of permitted exports.
Two ratios that are often confused
Self-consumption ratio = generated energy used on site / total generation. Demand coverage = energy supplied by the system / total consumption. The denominators differ.
In a hypothetical year with 10,000 kWh generation, 15,000 kWh demand and 6,000 kWh direct use, self-consumption is 60% while demand coverage is 40%. Both are correct; they answer different questions.
Where Net Billing fits
Direct use reduces imports at that moment. Surplus and later purchases are assessed using the applicable contracts. Do not transfer the energy-offset logic of a historical Net Metering installation automatically to a new project.
Batteries and Zero Feed-In
| Option | Effect |
|---|---|
| Load shifting | Uses more energy during generation |
| Battery | Moves energy to another time with losses |
| Zero Feed-In | Limits exports and may curtail output |
Storage can increase use of generated energy, but the measurement boundary for losses must be stated. In a curtailed zero-export system, a high self-consumption percentage alone does not prove optimal use of the available solar resource.
What to request in a proposal
Ask for generation, direct use, import, export, battery losses and curtailment together. This makes the energy balance verifiable. A striking percentage without the underlying kWh makes comparisons difficult.
When comparing two options, keep the same weather assumptions and demand profile. A change in the reported ratio may otherwise come from different inputs rather than a better system. With storage, specify whether “used on site” is measured before or after battery losses.
Check HEDNO's official announcement for the application framework and explore Net Billing and storage. Our project records retain the historical description of each installation.
A short example of two percentages
In a purely hypothetical year, if a system generates 10,000 kWh and 6,000 kWh are used on site, the self-consumption ratio is 60%. If total building demand is 12,000 kWh, solar coverage is 50%. The two ratios have different denominators and must not be conflated in a proposal.
A battery can change these ratios by shifting surplus to later loads, but introduces losses. Net Billing addresses the financial treatment of flows, while self-consumption describes the physical use of generation. Ask to see absolute kWh alongside each percentage.
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