Electricity Mix

Electricity mix defines where the electricity used by a heat pump comes from and how clean that electricity is. It breaks grid power into source shares such as hydropower, wind, solar, biomass, gas, coal, and nuclear, then connects those sources to CO2 intensity, primary energy factor, supplier disclosure, and real-time grid conditions. In the heat pump environment context, electricity mix is the upstream data entity behind operational emissions, subsidy-relevant energy calculations, and credible green electricity claims. A heat pump’s efficiency matters, but its real climate impact depends on the electricity mix powering it.

What is Electricity Mix?

Electricity mix is the composition of energy sources used to generate the electricity available in a grid. It expresses how much of that electricity comes from renewable sources, fossil sources, and nuclear sources, at a given point in time or as an annual average.

The electricity mix has several measurable attributes: source shares (hydro, wind, solar, biomass, gas, coal, nuclear), CO2 intensity (grams of CO2 per kilowatt-hour), geographic scope (national, supplier, or grid level), and time resolution (annual average or real-time). Each attribute answers a different question about the electricity a heat pump consumes.

What is the Purpose of Electricity Mix?

The core purpose of electricity mix data is to make the climate impact of electricity use measurable and comparable. A heat pump converts electricity into heat. The climate impact of that process depends entirely on how the electricity was generated, not on the heat pump alone.

Electricity mix data serves three functions:

• Quantification — it turns “clean electricity” from a marketing claim into a measurable value (g CO2/kWh).
• Comparability — it allows heat pump operation to be compared across countries, suppliers, and time periods on a like-for-like basis.
• Regulatory compliance — it is the legal basis for supplier disclosure obligations and for calculating primary energy factors used in building energy certificates and subsidy programs.

Why Electricity Mix Is Needed

A heat pump’s own efficiency, expressed as COP or seasonal performance factor (SPF/JAZ), only tells half the story. The other half is the electricity mix that powers it. Two identical heat pumps, one running on Austrian electricity and one on a coal-heavy grid, produce very different lifecycle emissions despite identical hardware.

Without electricity mix data, three problems occur:

1. No verifiable CO2 baseline. Operational emissions of a heat pump cannot be calculated without a grid CO2 intensity figure. See the CO2 Emissions cluster for how this figure is applied.
2. No defensible primary energy comparison. Primary energy factors used in building codes and subsidy eligibility are themselves derived from national electricity mix data. See the Primary Energy Factor cluster.
3. No regulatory transparency. Electricity suppliers in Austria and Germany are legally required to disclose their electricity mix to end customers. Without this disclosure, customers cannot verify supplier claims about “green electricity.”

What are the Key Features of Electricity Mix

• Source shares — the percentage breakdown of generation by energy carrier.
• CO2 intensity — grams of CO2 emitted per kilowatt-hour generated or consumed.
• Time resolution — annual average mix versus real-time or seasonal grid mix.
• Geographic and contractual scope — national production mix, supplier product mix, or residual mix.
• Disclosure mechanism — Guarantees of Origin (GO) or national equivalents (Herkunftsnachweis) that document renewable claims.

Key Feature Explanations

Source Shares

Definition. Source shares state the percentage of total electricity generation coming from each energy carrier: hydro, wind, solar, biomass, natural gas, coal, and nuclear.

Purpose. Source shares show dependency on fossil and nuclear generation versus renewable generation. They are the raw input for every downstream climate calculation.

Benefits. Source shares give a transparent, auditable basis for climate claims. They allow a heat pump operator to see exactly what powers their system, rather than relying on generic “green” labeling.

Example. Austria generated roughly 85% of its electricity from renewable sources in 2025, with hydropower alone contributing close to half of total generation. Austria’s average grid emissions in 2025 were around 86 grams of CO2 equivalent per kilowatt-hour, with hydro as the leading source at just under half of total generation. Switzerland’s mix is dominated by hydropower and nuclear, together accounting for the large majority of generation, which keeps its grid among the lowest-carbon in Europe.

CO2 Intensity

Definition. CO2 intensity is the mass of CO2 emitted per unit of electricity, measured in grams of CO2 per kilowatt-hour (g CO2/kWh).

Purpose. CO2 intensity converts an abstract source mix into a single comparable climate metric. It is the figure directly multiplied by a heat pump’s electricity consumption to calculate its operational carbon footprint.

Benefits. A single, standardized number allows heat pumps, gas boilers, and oil heating systems to be compared on the same climate basis, using official national methodology rather than estimates.

Example. Germany’s electricity generation emitted an average of 344 grams of CO2 per kilowatt-hour consumed in 2025, continuing a downward trend from 353 grams in 2024 and 379 grams in 2023, according to the German Federal Environment Agency (Umweltbundesamt). Austria’s figure sits considerably lower, reflecting its hydro-dominant mix, though exact values vary between roughly 86 and 106 g CO2/kWh depending on the calculation methodology and reporting year used.

Time Resolution

Definition. Time resolution describes whether an electricity mix figure represents an annual average or a real-time, hourly value.

Purpose. Grid composition shifts constantly. Solar and wind output rises and falls with weather and season, which changes the real-time CO2 intensity of the grid far more than the annual average suggests.

Benefits. Time-resolved data enables smart, load-shifting heat pump operation: running the system when the grid is cleanest, rather than only when heat is needed.

Example. Austria’s grid carbon intensity drops to lows of around 56 grams of CO2 per kilowatt-hour at summer midday, roughly three-quarters lower than winter levels, while winter evening peaks climb to around 300 grams of CO2 per kilowatt-hour. A heat pump with smart grid connectivity can shift part of its load toward the cleaner, cheaper hours within that daily swing.

Geographic and Contractual Scope

Definition. Electricity mix can be reported at three levels: the national production mix, an individual supplier’s product mix, or the residual mix — the electricity left over once tracked renewable claims have been subtracted.

Purpose. These levels prevent double-counting. If every supplier claimed the same renewable generation, national totals would not add up. The residual mix exists specifically to hold the electricity that no one has claimed as renewable.

Benefits. Clear separation between these levels protects the credibility of green electricity claims and gives regulators an auditable trail from generation to end customer.

Example. Austria’s official Electricity and Gas Labelling Report (Strom- und Gaskennzeichnungsbericht), published annually by the regulator E-Control, discloses both supplier and product mix figures separately, alongside import shares. No residual mix is calculated for Austria itself, since its disclosure regime already accounts for all electricity through certificates.

Disclosure Mechanism (Guarantees of Origin)

Definition. A Guarantee of Origin (GO), called Herkunftsnachweis in Austria and Germany, is a certificate confirming that one megawatt-hour of electricity was generated from a specific source, typically renewable.

Purpose. GOs prevent the same unit of renewable electricity from being sold as “green” to more than one customer. They are the legal instrument underlying every supplier’s electricity mix disclosure.

Benefits. GOs give end customers, including heat pump operators comparing electricity tariffs, a verifiable paper trail rather than a marketing claim.

Example. The Association of Issuing Bodies calculates a European residual mix each year for countries where suppliers rely on Guarantees of Origin, using a standardized issuing-based methodology. Austria and Switzerland are exceptions: both operate full disclosure regimes and therefore do not require a separately calculated residual mix.

Types of Electricity Mix

Use Cases of Electricity Mix

• Calculating heat pump operational emissions. National CO2 intensity is multiplied by annual electricity consumption to produce a comparable emissions figure. See the CO2 Emissions cluster.
• Determining primary energy factors for subsidy eligibility. National electricity mix data feeds directly into the primary energy factor used in energy performance certificates. See the Primary Energy Factor cluster.
• Smart-grid-timed heat pump operation. Systems with grid connectivity, such as iDM’s Navigator, can shift heating and hot water production toward hours when the electricity mix is cleanest and cheapest.
• Comparing heat pump systems against fossil heating. Electricity mix data is what makes a fair, apples-to-apples comparison between a heat pump and a gas or oil boiler possible.
• Sizing PV-plus-heat-pump systems. Self-consumption mix data helps determine how much of a building’s own solar generation can directly power the heat pump.

Benefits of Electricity Mix

• Transparent climate accounting. Replaces vague “green electricity” claims with an auditable, regulator-published figure.
• Regulatory alignment. Supports compliance with EU Taxonomy criteria and national subsidy programs that require verified emissions or primary energy data.
• Realistic system comparison. Enables fair comparison between heat pumps and combustion-based heating systems.
• Operational optimization potential. Time-resolved mix data allows smart heat pump control to reduce real emissions beyond what device efficiency alone can achieve.
• Customer trust. Gives installers and homeowners a verifiable basis for climate claims made about a heat pump installation.

Electricity Mix Selection Criteria

When choosing which electricity mix figure to apply — for content, calculations, or customer communication — the following criteria determine data quality:

• Data currency. Use the most recent published year; electricity mix shifts annually and sometimes significantly.
• Source authority. Prioritize national regulators and statistical bodies (E-Control, Umweltbundesamt, Swiss Federal Office of Energy) over private aggregators.
• Calculation methodology. Distinguish between generation-based and consumption-based figures; import/export balances change the result.
• Regulatory recognition. Confirm the figure is accepted for the intended use — subsidy application, certification, or public claim.
• Granularity match. Match the resolution (annual vs. hourly) to the use case; annual averages are unsuitable for smart-grid load-shifting claims.

Electricity Mix Comparisons

The gap between Austria/Switzerland and Germany illustrates why a single European average figure is unsuitable for country-specific heat pump climate claims. A heat pump operating in Austria or Switzerland already benefits from a substantially lower-carbon electricity mix than the EU average, before any device efficiency gains are considered.

Electricity Mix Integration With Other Systems

Electricity mix is not a standalone data point. It functions as the shared upstream input for several other clusters and systems in this hub:

• CO2 Emissions — uses electricity mix CO2 intensity as the direct multiplier for calculating heat pump operational emissions.
• Carbon Footprint — incorporates electricity mix data as one component of a heat pump’s total lifecycle footprint.
• Primary Energy Factor — the national primary energy factor is itself derived from electricity mix composition; a cleaner mix produces a lower non-renewable PEF.
• Decarbonization of Heating— national decarbonization trajectories, such as Austria’s EAG target of a fully renewable balance by 2030, define how the electricity mix — and therefore heat pump climate performance — will improve over the system’s lifetime.
• Smart Grid Connection — real-time and seasonal electricity mix data is the input that makes smart-grid-timed operation meaningful; without it, load-shifting has no climate basis.
• iDM Navigator — iDM’s smart grid control system uses time-resolved electricity mix and price signals to shift heat pump operation toward the cleanest and most cost-effective hours available, turning electricity mix data from a passive reporting figure into an active operational advantage.

Electricity mix is the foundation for measuring, comparing, and improving the environmental performance of heat pumps. It determines CO2 emissions, influences primary energy factors, supports electricity supplier transparency, and enables smart-grid operation when cleaner electricity is available. For markets such as Austria, Germany, and Switzerland, using the correct national, supplier, residual, real-time, or self-consumption mix prevents misleading climate claims and improves decision quality. By linking electricity mix data with heat pump efficiency, PV integration, carbon footprint, and decarbonization goals, homeowners, installers, and manufacturers can turn abstract “green electricity” claims into verifiable low-carbon heating decisions.