Solar generation
Value from producing electricity, using it on site and exporting surplus.
CUSTOM TARIFFS & USAGE
Detailed hourly energy model.
This separate model compares energy costs using an hourly simulation. It includes tariff-based battery export, but no additional wholesale trading or grid-service payments.
Preparing your calculator…
YOUR STARTING POINT
Build your system
kWp
Installed peak capacity. Drag the slider or type a value.
No solar20 kWp
kWh
Storage capacity. Drag the slider or type a value.
No battery25 kWh
Electricity use
Choose a representative level. No bills or personal details needed.
Optional: tailor the assumptions
Operating pattern
Choose when your site typically uses electricity.
Both site types use the same engine. Presets are starting assumptions, not promises. Enter tariff prices on a consistent tax basis. The reference tariff uses UK local time: off-peak 02:00-05:00, peak 16:00-19:00, and day rates otherwise.
Solar yield starts at 866.62 kWh/kWp/year: a PVGIS Haslingden, Lancashire, UK example (53.70, -2.33), south-facing, 35° tilt, 14% system-loss setting. This is not your roof assessment. Default prices use the published August 2026 Flux region E snapshot shown in the tariff assumptions. Battery efficiency and usable capacity start at 90%. You can use the starting assumptions for a representative example or enter your own rates. Additional market service revenue is excluded.
Sized to your site, not just the array
Inverter selection requires a site assessment.
INDEPENDENT ENERGY-ONLY ESTIMATE
Illustrative scenarioYour results
N/A/ year
Compared with the same electricity use with no solar or battery. After modelled battery wear, before equipment, finance and service costs.
Energy cost without assets
Net operating surplus
View detailed breakdown
Solar on its own
Extra benefit from adding the battery
Indicative only, not a guarantee of revenue. We’ll review your assets, tariff and live market data with you before confirming a proposal.
View tariff assumptions
Where the value comes from
per yearAvoided electricity purchases
Export receipts
Battery wear allowance
Solar + battery operation
Added through scheduling and export
Usable-capacity cycles
Solar used on siteDirectly or via storage
Annual demandkWh / year
Start with an energy asset.
Add solar or a battery to explore your results.
nodez. independent scenario · Editable assumptions
SIDE BY SIDE
A clearer choice.
UNDERSTAND THE RESULT
One system.
Four sources of value.
Explore solar savings, export income and battery scheduling. Battery exports use the entered export tariff.
Battery storage
The additional value of storing energy for use when you need it.
Tariff scheduling
Scheduling battery operation around demand, generation and tariff conditions.
Battery export
Battery export is valued at the entered tariff. Additional wholesale and flexibility contracts need a separate assessment.
Assumptions and sources
nodez. independent hourly dispatch model v3. The model runs through all 8,760 hours of a year. It compares no assets, solar alone, self-use battery storage, tariff scheduling, and scheduling with battery export. Each extra component is the change from the preceding scenario, so the same energy is not sold twice.
The solar shape comes from European Commission PVGIS SARAH3 hourly output for 2023 at Haslingden, Lancashire, UK (53.703, -2.325), south-facing at 35° with a 14% system-loss setting. Its hourly shape is normalised to the editable 866.62 kWh/kWp long-term example yield. Demand patterns are synthetic, scaled to your annual use. The model is not measured site data or a weather forecast.
Reference import/export prices are from the Octopus Energy API, Flux region E, August 2026. Off-peak is 02:00-05:00 and peak is 16:00-19:00 UK local time. Home reference import prices include the tax basis published for that snapshot. Commercial reference import prices exclude VAT and are illustrative inputs, not an available commercial tariff offer. Enter your actual contract rates and confirm export eligibility. A solar-free setup does not establish eligibility for Flux.
The optimiser uses perfect knowledge of the modelled year, which real forecasts cannot provide. It enforces battery capacity, charge/discharge power, losses and the site export limit. Stored-energy resolution is 0.1 kWh at home and coarser for large commercial systems. Battery wear starts at an illustrative 3p/kWh discharged. Battery exports are paid once at the entered export tariff. No additional wholesale trading, ancillary, capacity or flexibility payment is assumed. A larger battery can eventually stop adding value when power, export windows, demand or generation become the constraint.
Standing charges are held unchanged. Equipment, finance, service fees, replacement and multi-year degradation are not deducted from the headline. Enter capital and annual service costs to explore simple payback separately. Results are scenarios, not guaranteed savings or an investment return.
- Octopus Energy: import/export windows and eligibility
- Octopus API: published reference import rates
- Octopus API: published reference export rates
- European Commission JRC: PVGIS solar data and methodology
- Ofgem: export eligibility
Your system in context
Simple payback uses the costs you enter and assumes the annual energy benefit stays the same. Finance, replacement and future changes are outside this simple comparison.