Germany's Energy Efficiency Act, the Energieeffizienzgesetz (EnEfG), links three practical records that are often kept separately: the enterprise energy total, a register of economic energy-saving measures and a description of direct waste heat. Its consumption-led scope differs from Spain's current large-company energy-audit test. The legal duties use the company's average total final energy consumption over the previous three completed calendar years, rather than one site's electricity bill.
This matters to a multi-site industrial group. Electricity, gas, delivered heat and transport fuel can sit in different systems and under different managers. A threshold assessment that leaves one carrier or site out may put the enterprise in the wrong compliance band. The energy unit converter can put the carriers on one basis, but the organisation still needs a controlled boundary and traceable source records.
The two enterprise thresholds
| Three-year average annual total final energy use | Main EnEfG duties covered here |
|---|---|
| More than 7.5 GWh | Establish an energy or environmental management system under Section 8 |
| More than 2.5 GWh | Publish implementation plans for identified economic measures under Section 9; apply the waste-heat duties in Sections 16 and 17, subject to specific exceptions |
The wording is more than each threshold. Exactly 7.5 GWh does not cross the Section 8 threshold, and exactly 2.5 GWh does not cross the thresholds stated in Sections 9, 16 and 17. Preserve the unrounded calculation because a dashboard rounded to one decimal place could display 7.5 GWh for a value on either side.
Section 8 gave companies that already met its definition on 17 November 2023 until 18 July 2025 to establish their system. A company that reaches the status from 18 November 2023 onward has 20 months from the time it reaches it. The assessment therefore needs both the rolling three-year calculation and the date at which the status was first established.
The EnEfG threshold is different from the EU Energy Efficiency Directive. The EU Directive uses 85 TJ, about 23.6 GWh, for a certified energy management system and 10 TJ, about 2.8 GWh, for an energy audit. German national requirements can apply below those EU levels.
What the management system needs to retain
Section 8 allows an energy management system meeting DIN EN ISO 50001 or an environmental management system under EMAS. Its additional EnEfG work includes identifying energy-saving measures and examining waste-heat sources and recovery opportunities.
A useful measurement plan starts with these layers:
- Enterprise boundary. List each legal entity and site included in the calculation, each energy carrier, the data owner and the conversion basis.
- Source total. Retain supplier invoices, boundary-meter readings, fuel records and corrections. Mark estimated bills and later reconciliations.
- Significant energy use. Submeter major production lines, compressed air, refrigeration, ovens, boilers, pumps, HVAC and other material loads.
- Operating context. Record production, runtime, flow, temperature, pressure, weather or occupancy values needed to explain changes.
- Measure register. Link each proposed measure to its affected boundary, baseline, expected saving, cost, useful life, owner and decision.
- Waste-heat source. Record energy input and output, process temperatures, heat-bearing media, annual quantity, maximum output and availability.
The ISO 50001 guide explains the significant-energy-use register, indicators, baselines and data collection plan. EnEfG adds national thresholds and publication duties to that management process.
Section 9 implementation plans
A company above 2.5 GWh must create and publish concrete, feasible implementation plans for economic final-energy-saving measures identified in the relevant management system or energy audit. The deadline is three years from the recertification or renewal milestone for a management system, or from completion of an energy audit.
The company must have the completeness and correctness of the plans confirmed by a certifier, environmental verifier or energy auditor before publication. Protected business and trade secrets are excluded from publication. That exclusion does not remove the need for the underlying controlled record.
Section 9 defines when a measure is economic. The assessment follows DIN EN 17463. The measure needs a positive net present value within at most 50% of its useful life, and the statutory test is limited to measures with a useful life of no more than 15 years. Federal depreciation tables determine the useful life for the calculation.
Do not replace that calculation with a simple payback column. Keep the assumptions, energy price, discounting, investment, operating cost, useful life and saving estimate that support the net present value. Once a measure is implemented, keep the planned and measured effects separate. The baseline measurement guide shows how to account for production, weather and other independent variables.
Sections 16 and 17 waste-heat duties
Section 16 requires covered companies to avoid waste heat according to the state of the art and reduce it to the technically unavoidable share where possible and reasonable. Remaining waste heat must be reused through energy-saving measures and techniques where possible and reasonable. Technical, economic and operational concerns form part of that reasonableness assessment.
The duty looks beyond the originating machine. It calls for reuse opportunities on the wider site and by external third parties, with cascading use at decreasing temperature levels where appropriate. A high-temperature stream may serve a process first and lower-temperature heating afterward.
Section 17 defines a specific information set for direct waste heat:
- company name and the address of each site where the heat arises;
- annual heat quantity;
- maximum thermal output;
- annual availability as a load profile;
- available control of temperature, pressure and feed-in; and
- average temperature level in degrees Celsius.
Covered companies must provide this information to heat-network operators, district-heating suppliers and other potential heat users on request. They must also transmit it to the federal energy-efficiency body by 31 March each year and update changes without delay. Section 17 includes protections for business secrets and security-sensitive information, but those provisions need a legal and organisational decision rather than a monitoring-system default.
Measure heat, availability and control separately
One temperature sensor cannot establish a waste-heat offer. Annual quantity, maximum power, availability and controllability answer different questions.
| Required fact | Measurement approach | Common error |
|---|---|---|
| Annual heat quantity | Heat meter or calculated thermal power integrated over time, with known flow, supply and return temperatures | Multiplying one spot measurement by all annual operating hours |
| Maximum thermal output | Validated peak thermal power over a defined interval | Reporting boiler input rating or electrical load instead of recoverable heat |
| Annual availability | Timestamped output profile tied to production state and planned outages | Giving a yearly total with no indication of when heat is available |
| Temperature | Representative supply and return or source and sink temperatures | Reporting a nameplate maximum that is never sustained |
| Controllability | State, set point, valve or pump command, constraint and safe fallback | Assuming a controllable pump makes the production process dispatchable |
For a liquid stream, thermal power can be estimated as mass flow multiplied by specific heat capacity and temperature difference. The units, fluid properties and measurement location must match. Steam, exhaust gas, contaminated media and phase change need a suitable engineering method. A calculated series should retain the raw flow and temperature points so that the result can be reproduced.
Availability needs operating context. Mark planned shutdowns, product changes, maintenance, minimum run periods and any process condition that changes quantity or temperature. If a third party depends on the heat, define what happens when production stops. A historical profile is evidence of past availability, not a guarantee of future supply.
Where EpiSensor fits
EpiSensor can collect owner-side operational measurements around an existing industrial energy system. Electricity monitoring can separate production lines and utilities. Pulse, M-Bus, Modbus and analogue inputs can collect fuel, heat, flow, temperature, pressure and plant-state values where the source equipment provides a supported interface. Edge can retain interval history locally and pass approved data to an energy management platform.
That record can support the energy review, measure baseline and waste-heat profile. It does not certify an ISO 50001 or EMAS system, perform the statutory economic test, confirm legal scope or submit information to the federal platform. The company, its energy manager and its appointed auditor or certifier keep those responsibilities.
Start with the industrial process instrumentation application, then use the BMS and SCADA integration guide to connect existing heat meters, controllers and instruments without changing their commissioning or safety roles.
Common questions
What is the EnEfG energy-management threshold?
More than 7.5 GWh average annual total final energy consumption over the previous three completed calendar years. Section 8 requires an energy or environmental management system. A company that first crosses the threshold from 18 November 2023 onward has 20 months from that point to establish it.
What happens above 2.5 GWh under the EnEfG?
Section 9 requires concrete, feasible implementation plans for economic measures identified through the relevant management system or energy audit. Sections 16 and 17 also apply waste-heat avoidance, reuse and information duties above that three-year-average threshold, subject to the law's specific exceptions.
What must a German waste-heat record contain?
For direct waste heat, Section 17 names the site, annual heat quantity, maximum thermal output, annual availability as a load profile, available control of temperature, pressure and feed-in, and the average temperature level. The statutory record and submission process remain the company's responsibility.
Does EnEfG require every identified measure to be installed?
Section 9 requires a published implementation plan for every identified economic measure. It defines the economic test through DIN EN 17463 and a positive net present value within at most half the measure's useful life, with the calculation limited to measures whose useful life is no more than 15 years.
Is the EnEfG the same as the EU Energy Efficiency Directive?
No. The EU Directive sets EU-level enterprise thresholds and national transposition duties. Germany's EnEfG has its own 7.5 GWh and 2.5 GWh thresholds and additional waste-heat requirements. A company may be covered by both frameworks.