Solar Self-Consumption Calculator

See how much of your solar production is truly used on site by splitting direct daytime load, battery capture, and exported energy instead of treating every kilowatt-hour the same.

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Quick Facts

Fastest Lever
Daytime Load Matching
Using solar while it is produced usually creates the strongest value
Battery Role
Capture the Midday Excess
Storage lifts self-consumption only when there is surplus to store
Pricing Reality
Retail Beats Export
On-site use is usually worth more than exported energy
Decision Metric
Self-Consumption Rate
Best for judging whether the system is aligned to the load profile

Your Results

Calculated
Self-Consumption Rate
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Share of solar production used on site
Direct Solar Use
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Solar instantly consumed during the daytime
Battery-Captured Solar
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Extra solar shifted into later-use storage
Daily Energy Value
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Combined retail offset plus export credit

Healthy Solar Utilization Mix

These defaults show a strong share of solar being used on site, with storage catching part of the remaining midday excess.

What This Calculator Measures

Calculate solar self-consumption rate, directly used solar, exported energy, battery-captured energy, and daily bill value using daily solar production, daytime load, evening load, battery usable capacity, and export credit.

By combining practical inputs into a structured model, this calculator helps you move from vague estimation to clear planning actions you can execute consistently.

This calculator focuses on solar operating quality, not payback alone, by showing how much solar is used immediately, shifted through storage, or exported out of the site.

How to Use This Well

  1. Enter a realistic daily solar production figure for the season or average day you care about.
  2. Split your demand into daytime load and evening load.
  3. Set usable battery capacity and expected round-trip loss.
  4. Use retail and export pricing to compare value, not just energy volumes.
  5. Review whether direct use or battery capture is the bigger path to improvement.

Formula Breakdown

Self-consumption = direct daytime use + battery-shifted solar, divided by total solar production
Direct use: daytime load served instantly by solar.
Battery capture: surplus solar stored and later delivered after battery losses.
Daily value: retail offset for self-used solar plus export credit for leftovers.

Worked Example

  • A high-production system can still have weak self-consumption if the load profile is concentrated after sunset.
  • Battery capacity only helps if there is midday surplus available to charge it.
  • Retail-rate avoidance is usually the most valuable part of solar economics, which is why self-consumption matters.

Interpretation Guide

RangeMeaningAction
Under 40%Low self-consumption.Exports dominate and load matching needs work.
40% to 65%Moderate self-use.Time shifting or load shifting could add value.
65% to 85%Strong alignment.The system is using most solar productively on site.
Over 85%Very high self-use.Most solar is supporting on-site demand directly or through storage.

Optimization Playbook

  • Shift load into solar hours first: direct self-use usually beats stored or exported solar for value.
  • Size storage to actual surplus: oversizing a battery does little if midday excess is small.
  • Use pricing honestly: export credit and retail offset are rarely interchangeable.
  • Compare seasons: summer solar and winter solar can produce very different self-consumption patterns.

Scenario Planning

  • Daytime-load strategy: raise daytime consumption and compare whether direct self-use improves faster than battery value.
  • Battery sizing pass: adjust usable battery capacity to see when extra storage stops capturing more solar.
  • Low export credit market: reduce export value and compare how strongly self-consumption now matters.
  • Decision rule: if exported solar remains high after storage, load shifting may be a stronger next move than more panels.

Common Mistakes to Avoid

  • Looking only at total solar production and ignoring load timing.
  • Assuming a battery helps even when there is little midday surplus.
  • Using the same price for retail savings and exported energy.
  • Confusing self-consumption with self-sufficiency.

Implementation Checklist

  1. Estimate realistic daily solar production.
  2. Split demand into daytime and evening periods.
  3. Set usable battery capacity and losses.
  4. Compare self-consumption rate with daily value before making changes.

Measurement Notes

This calculator focuses on solar operating quality, not payback alone, by showing how much solar is used immediately, shifted through storage, or exported out of the site.

Run multiple scenarios, document what changed, and keep the decision tied to trends, not a single result snapshot.

FAQ

Why separate daytime and evening load?

Because solar value depends on when demand happens, not just how much total electricity the home uses in a day.

Does a bigger battery always improve value?

No. If there is not enough midday surplus to fill it, extra capacity sits idle and does not improve self-consumption much.

Why show daily value instead of annual payback?

This page is focused on operating profile and on-site solar usage, not full-system capital payback.

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