Frequently asked questions

Voltary helps households and commercial sites make data-informed decisions about photovoltaics, battery storage, and electricity tariffs. You can upload measurements or a commercial W/kW load profile, generate a synthetic consumption profile for a household, and compare technical and economic scenarios.

The results provide a basis for decision-making, but they do not replace on-site planning, a grid-connection assessment, or individual professional advice.

Voltary offers three main workflows:

• Plan a new PV system: Compare PV capacity, battery storage, investment, and economics.
• Analyze an existing PV system: Assess a new or larger battery for an existing system.
• Compare electricity tariffs: Evaluate fixed and dynamic tariffs using the same load profile.

Households can upload measurements or generate a synthetic profile. For a commercial site, use a measured load profile.

If you are planning a new system, start with PV planning. If you already have PV and want to add or enlarge a battery, use the existing PV analysis. If your main concern is your electricity contract, begin with the electricity tariff comparison.

For a measured commercial site load profile, select CSV load profile – average power (W/kW) during upload. An individual review is particularly useful for complex metering setups, demand charges, or project-specific requirements.

An analysis typically consists of three steps:

1. Upload measurements or generate a household consumption profile.
2. Configure tariffs, PV size, battery, costs, and the optimization goal.
3. Review data quality, result charts, metrics, and possible next steps.

The self-service analyses currently provided are free for household and commercial users; paid standard features are not currently offered.

For optional individual advice on a complex project, the scope, data requirements, and potential costs can be agreed separately.

Time-resolved consumption or grid-import data covering as many representative months as possible is most informative, ideally in 15- or 60-minute intervals. For an existing PV system, PV generation, grid export, and any battery flows are also helpful.

Households without measurements can use a profile generator. Commercial analyses require a measured site load profile; a household profile is not a suitable substitute.

For cumulative energy meters, Voltary supports CSV files in long sensor format, for example with entity_id, state, and last_changed, as well as a wide format with a timestamp and multiple numeric energy columns. These values are mapped as Wh or kWh.

For average power in W or kW, use the separate data source CSV load profile – average power (W/kW). Excel files must first be exported as CSV.

With 15-minute resolution selected, existing quarter-hour values are retained. Where only hourly values are available for individual periods, their energy is distributed evenly across four quarter-hours under a constant-power assumption. With 60-minute resolution, quarter-hour energy values are summed by hour.

A 15-minute resolution captures short load and price fluctuations more accurately, but increases computation time and data volume. A 60-minute resolution is suitable for robust, faster comparisons.

Voltary checks the time structure, plausibility, and missing values. Suitable smaller gaps may be processed; the validation shows additions and data corrections. Large gaps, incorrect units, or invalid timestamps can significantly reduce the usefulness of the simulation.

In that case, review the data source first. For a commercial site, correct or re-export missing measurements instead of replacing them with a synthetic household profile.

For a household, you can generate a synthetic profile from annual consumption, number of occupants, base load, and major consumers such as an electric vehicle or heat pump. It is suitable for an initial assessment.

Measured data is better for concrete investment decisions. The profile generator is not intended as a synthetic substitute for a commercial load profile.

Yes. A single commercial site with a measured load profile can be analyzed through self-service, particularly when planning a new PV and battery solution. During upload, select CSV load profile – average power (W/kW).

Household thresholds are not applied when validating this profile. Peak load and load structure are analyzed descriptively instead.

The CSV file must contain exactly one timestamp column and one numeric column with the site's average power in W or kW. Recognized status or quality columns are ignored. If a source file contains multiple sites or companies, split it into separate files first.

During mapping, review the power unit, the 15- or 60-minute source interval, and whether each timestamp marks the start or end of its interval. Naive timestamps are interpreted as Europe/Berlin; for other time zones, the timestamp must include an explicit UTC offset or Z.

Voltary multiplies the average power in each interval by its duration to obtain energy in kWh. For example, 40 kW over 15 minutes equals 10 kWh.

The conversion is performed internally; your source file remains a W/kW load profile. Native quarter-hour values are not first smoothed into hourly values when 15-minute resolution is selected.

Voltary treats the complete uploaded site load as grid import. Existing PV generation, grid export, and the charge and discharge flows of an existing battery are assumed to be zero because they cannot be reconstructed from a single load column.

The simulation therefore shows how a newly planned PV system or battery would affect this unchanged grid-import profile. If the load profile already includes on-site supply, this assumption may not apply without further adjustments.

The standard analysis evaluates time-dependent energy flows, PV, batteries, and entered volumetric energy prices. Optional calendar-monthly demand-charge accounting can be enabled only for server-verified native 15-minute grid-import data. The contractual rate, its unit, net or gross price basis, billing timezone, and any annual escalation must be entered explicitly. The positive or negative A/B/C effect – project baseline (A), PV without a new battery (B), and total system (C) – is then included in the financial results and ROI.

Battery dispatch remains energy-oriented and is not optimized for load peaks. Demand-charge accounting is not a guarantee of contractual savings and does not fully represent complex contract clauses. Complex meter cascades, multiple connected sites, grid constraints, and project-specific taxes and subsidies are likewise not automatically modeled in full.

PV systems can be configured up to a total capacity of 10,000 kWp. This software limit does not indicate available roof area, permitting feasibility, or grid-connection capacity.

A battery can be economically worthwhile when enough PV surplus is available and stored electricity later replaces more expensive grid import. The key factors are the load profile, battery capacity, charge and discharge power, efficiencies, investment and maintenance costs, electricity price, and feed-in tariff.

For commercial sites, reducing load peaks may also be relevant; however, the financial value of demand charges can only be assessed correctly using the applicable contract logic.

The appropriate capacity and power depend on when consumption and PV surplus occur. An annual balance alone is not sufficient because a battery charges and discharges within specific daily and seasonal patterns.

The best economic option is often not the largest battery, but the one that fits the load profile, PV generation, costs, and your objective.

Voltary simulates consumption, PV generation, battery charging and discharging, grid import, and grid export in 15- or 60-minute intervals. The model includes capacity, charge and discharge power, efficiencies, state-of-charge limits, costs, and tariff assumptions, among other parameters.

For a new system, start with PV planning. The technical assumptions are documented in the Calculation basis.

The self-consumption rate is the share of PV generation used at the site, either directly or through the battery. The self-sufficiency rate is the share of total consumption covered by PV and battery storage.

A high value is not automatically the most economic solution. Assess both metrics together with investment, net profit, and payback.

Yes. You can change PV and battery limits, costs, tariffs, budget, and optimization objective, then run the simulation again. This shows whether a larger system provides more economic value or mainly increases self-sufficiency and self-consumption.

Depending on the workflow, freely defined battery assumptions and available real battery models can be compared.

The data validation describes annual and daily energy, peak, base, median, and high loads, load factor, the typical daily load curve, load duration curve, monthly seasonality, and time windows with high loads, among other metrics. This helps you assess data quality and load structure before the simulation.

Depending on the workflow, the results dashboard adds investment, savings, self-consumption, self-sufficiency, grid import, grid export, battery utilization, and time-dependent energy flows.

The payback period shows when the modeled net cash flows have mathematically recovered the investment. ROI relates the financial benefit to the capital invested. Net profit shows the absolute modeled surplus over the analysis period.

A larger system can generate more net profit but have a lower ROI or a longer payback period. You should therefore compare several metrics and the assumptions behind them.

The peak-shaving analysis compares the maximum modeled grid-import power with and without the new battery and shows the largest individual events. It describes the physical reduction in load peaks under the selected battery dispatch strategy.

When optional demand-charge accounting is enabled for server-verified native 15-minute grid-import data, the detailed analysis also shows the calendar-monthly A/B/C effect and includes it in the financial results and ROI. Battery dispatch nevertheless remains energy-oriented and is not optimized for load peaks. The result does not guarantee a contractual demand-charge reduction; complex contract clauses must be assessed separately.

Charts can be downloaded as PNG files. After completing an optimization, you can also export a PDF summary; generated household profiles are available as CSV files in the validation step.

Use exports to discuss assumptions and scenarios with installers, energy advisors, or internal decision-makers. Store sensitive measurement data appropriately.

Yes. The electricity tariff comparison evaluates the same time-dependent grid-import profile using a fixed energy price and a dynamic price series. Realistic energy prices, base charges, and other price components improve the comparison.

Commercial demand charges, their metering intervals, and complex contract clauses are not modeled in this separate tariff comparison. Optional calendar-monthly demand-charge accounting belongs to the PV and battery analysis and is not part of the tariff comparison.

A dynamic tariff can offer benefits when consumption or battery charging can be shifted to lower-price windows and expensive grid-import periods can be avoided. The interaction between load, PV generation, state of charge, efficiencies, and time-dependent market prices is what matters.

A low average price alone is not sufficient for making a decision; base charges, taxes, grid fees, and technical flexibility also need to be considered.

The entered feed-in tariff affects whether PV electricity is more economical to use directly, store, or export to the grid. Dynamic price series can also include very low or negative price periods and show their time-dependent effect.

The amount, duration, and regulatory treatment depend on the country, contract, system type, and commissioning date. Check your specific values; the simulation does not constitute legal advice.

A smart meter is not essential for a preliminary simulation. However, an intelligent metering system may be required or very helpful for precise measurement data, actual dynamic tariffs, automated control, or certain commercial metering arrangements.

Requirements depend on the country, grid operator, tariff, and system design. The guide Measuring electricity consumption and collecting data explains possible data sources.

Voltary calculates energy flows step by step over the analysis period. Depending on the scenario, consumption, PV generation, battery charging and discharging, state of charge, grid import, grid export, and costs are determined for each 15- or 60-minute interval.

The simulation combines measurement data or a household profile with technical limits, efficiencies, tariffs, investment costs, maintenance, degradation, and price development. Details are available in the Calculation basis.

For newly calculated PV scenarios, Voltary exclusively uses location-specific hourly yield profiles from the European Commission's PVGIS 5.3 with the 2025 crystalline-silicon model. If PVGIS does not provide a complete, validated profile, the calculation is stopped; no synthetic PV approximation is used.

For dynamic tariffs, daily updated day-ahead spot-market data is used, currently based on Bundesnetzagentur | SMARD.de. Your inputs and measurement data are also incorporated.

The usefulness of the results depends primarily on measurement data, the analysis period, and assumptions. Representative load data, correct units, realistic investment and maintenance costs, and appropriate tariff values improve the results.

The simulation is a scenario analysis, not a guaranteed forecast. Future electricity prices, weather, system availability, yields, and project costs may differ.

Voltary does not replace roof and structural assessments, grid-connection approval, electrical or fire-safety planning, permits, or tax or legal advice. Individual subsidies, financing, project-specific installation costs, availability, and special contracts must be assessed separately.

This is particularly important for commercial projects involving demand charges, complex metering structures, multiple sites, and operational constraints. Nevertheless, the online analysis provides a robust basis for clearly defined standard scenarios.

Voltary systematically compares the permitted configurations against your selected objective, such as maximum net profit, ROI, or self-sufficiency. For PV sizing, exactly eleven linearly spaced sizes from 0 kWp to the configured upper limit are evaluated and combined with the intended battery variants.

A recommendation is therefore the best result within this search space and the selected assumptions, not a blanket product recommendation or feasibility guarantee.

The calculation follows your inputs, selected objectives, and documented model assumptions. External offers or partner links do not change this simulation and are possible next steps, not mandatory recommendations.

Voltary may receive a commission for referred tariff switches, quote requests, or qualified leads. This does not create additional costs for you; the relevant partner pathways are transparently identified.

Privacy is part of Voltary's technical design. We minimize data, process it only for defined purposes, and provide online analyses without an account. Analysis data are linked to a random session identifier and are therefore pseudonymous, not anonymous.

We do not use web analytics, sell consumption, load-profile, or configuration data, or create personal advertising profiles.

Connections are protected with TLS. For direct uploads, the browser additionally encrypts the payload before transfer; short-lived uploads, cached data, and results are also stored with application-level encryption. Per-tab ownership checks isolate analysis data from other sessions.

Primary processing and storage take place in Voltary's EU backend at Hetzner, with Cloudflare as an upstream security and delivery provider. Operational access is restricted. This is not end-to-end encryption because the backend must decrypt data to run the analysis.

A session normally expires after 30 minutes and can be explicitly extended up to a maximum of two hours. Analysis data are then deleted automatically. For any remaining storage objects, a day-based lifecycle rule configured for one day provides an additional fallback; final execution by the storage provider may occur later.

Delete my data immediately triggers deletion of the current browser session's analysis data and local application data. Security records follow separate, limited retention periods and are not removed by this function. Details are available in the Privacy policy.

Voltary does not sell analysis data, create personal advertising profiles, use web analytics, or set marketing cookies. Necessary providers process only the data required to operate the service.

PVGIS receives coordinates and technical PV parameters, never your load profile. Data are sent to CHECK24 only after you explicitly activate the relevant option. Cloudflare and Hetzner provide essential infrastructure; details are available in the Privacy policy and Cookie policy.

Depending on the legal requirements, you may have rights to access, correction, deletion, restriction, data portability, and objection, as well as the right to lodge a complaint with a supervisory authority.

For a privacy request, email datenschutz@voltary.de and state which processing your request concerns. More information is available in the Privacy policy.

For questions about using Voltary or about a complex household or commercial project, contact us through the contact page. You can first analyze a standard commercial load profile yourself; individual advice is not a prerequisite.

Then compare several scenarios, check the assumptions against actual quotes, and clarify technical feasibility, the site, grid connection, and contract details with qualified professionals. Please do not send confidential measurement data by email unless this has been agreed in advance.