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.

15-minute values capture short load and price changes in more detail; 60-minute values allow faster, coarser comparisons. Hourly energy is split evenly into four intervals at 15-minute resolution, while quarter-hour energy is summed at 60-minute resolution. Splitting hourly values does not create additional measured information. See the residential methodology for timing conventions.

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. It does not optimize demand charges and does not calculate guaranteed savings from them. 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 pay off when PV surplus replaces more expensive grid electricity later and the savings cover purchase costs, losses and maintenance. The main factors are your consumption pattern, PV generation, battery capacity and power, electricity price and feed-in payment. Commercial sites may also benefit from peak shaving, but potential demand-charge savings require a separate contract assessment.

The right size depends on how much PV surplus you can use later and the power needed to supply it. Compare several sizes using your consumption pattern and complete costs. The largest battery does not automatically offer the greatest financial benefit.

Automatic sizing compares PV sizes and battery capacities within your technical settings and budget. Manual configuration lets you specify and simulate a particular combination. The residential methodology explains how evaluated options are ranked under optimization objectives and metrics.

Self-consumption is the share of PV generation supplying your household; self-sufficiency is the share of household consumption covered by PV. Both include direct use and PV electricity delivered through storage, excluding storage losses and grid-charged electricity. High values alone do not establish financial viability. See the residential methodology for metrics and calculation boundaries.

Yes. Change sizes, costs, tariffs, budget or objectives and run the calculation again. You can assess a specific battery offer by manually entering its technical specifications and complete price; Voltary does not offer a selection of named battery models.

Validation shows data quality and consumption patterns, such as base and peak loads, typical daily profiles and seasonal differences. Depending on the analysis, the results compare energy flows, grid imports, exports, battery use and financial performance.

Net present value values the modeled payments, including investment and maintenance, at project start using your discount rate. Net profit adds those payments without discounting; at a 0% discount rate the two agree. Payback time indicates when nominal payments first cover the investment; a later shortfall remains possible. See the residential investment calculation for formulas and assumptions.

The results show how much a new battery reduces modeled peak grid import power and which peaks remain. A lower peak does not guarantee a lower bill: demand charges depend on metering windows and contract rules, among other factors. The standard analysis does not optimize those charges.

You can download charts as PNG files and, after optimization completes, a PDF summary. Generated household profiles are available as CSV files during validation. You can use these exports to discuss assumptions and results with an installer, for example.

Yes. The tariff comparison prices the same grid import profile using fixed and time-varying prices, including the standing charges and price components you enter. Commercial demand charges, metering windows and complex contract clauses are outside the standard comparison. The residential methodology explains the tariff and cost model.

What matters is when you still import electricity and the total tariff cost. PV and storage change that import profile. In the household model, the battery does not deliberately charge at low grid prices; grid charging only restores the minimum reserve.

Voltary values exported PV electricity using the assumed feed-in payment. Negative wholesale prices affect import costs through the selected dynamic tariff. The Solarspitzengesetz section explains which German feed-in rules the household analysis applies based on your system data.

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.

For each 15- or 60-minute interval, Voltary calculates how generation, consumption, storage and the grid interact. The model accounts for technical limits, losses and aging; tariffs and costs determine the financial results. The residential methodology describes the simulation process.

PV generation profiles come from the European Commission’s PVGIS, and dynamic market prices currently come from the Bundesnetzagentur’s SMARD service. Your inputs and measurements complete the data. New PV calculations require a complete, validated PVGIS profile; the residential methodology documents the data sources.

The usefulness of the results depends on representative measurements and realistic system, cost and tariff assumptions. Results describe scenarios: actual weather, electricity prices, consumption and system operation may differ. The residential methodology sets out the model limitations.

Voltary does not replace roof, structural, grid-connection, electrical, fire-safety or permit assessments, or tax and legal advice. Subsidies, financing, complete installation costs, availability and special contracts need separate assessment. For commercial projects this also covers demand charges, complex metering, connected sites and operational constraints.

For households, Voltary ranks evaluated options by your objective: highest net present value for financial performance or highest self-sufficiency. The recommendation applies within the evaluated search space, your constraints and assumptions; it is not a product endorsement or a feasibility guarantee. See optimization objectives and metrics.

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.

Analyses require an account. Pseudonymous session IDs link temporary analyses to your login; the data are not anonymous. Accounts, grants and credits are stored separately.

We do not sell analysis data or create personal advertising profiles. Google Analytics runs only after your consent; withdraw anytime in the footer. See the Privacy policy.

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.

Analysis processing and temporary analysis 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.

Sessions last 30 minutes, explicitly extendable to a maximum of two hours. Analysis data are then deleted. Remaining objects have a one-day lifecycle rule; final deletion may occur later.

Delete my data in the footer clears current-session analysis and local app data. Accounts, grants and credits require separate account deletion. Security records and provider backups have separate lifetimes. Previously sent Google Analytics data requires a separate erasure request: datenschutz@voltary.de. See the Privacy policy.

Hetzner runs the analysis backend and storage; Cloudflare provides hosting, delivery, protection and the beta form. Supabase manages accounts, grants and credits; Resend sends account/beta emails; Zoho Mail hosts our mailboxes.

PVGIS receives coordinates and PV parameters, never your load profile. CHECK24 receives data only when the external affiliate link is explicitly opened. No CHECK24 content is embedded in Voltary. Google Analytics receives pageviews and technical metadata only after your consent, excluding account details, forms and simulation results. No marketing cookies. Details: 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.