Path-Q Solar

Should I size solar differently when exported electricity is worth less than imported electricity?

Answer

Usually, yes: when exports are worth less than imports, the economically optimal system may be smaller than one designed to offset all annual consumption, unless future load growth, storage, resilience, incentives, or other goals justify extra capacity. Size the system around the value of generation, not only annual energy usage.

Key points

  • Prioritize generation that offsets electricity used on site.
  • Use hourly load and production to estimate how much energy will be exported.
  • A battery or controllable load can raise self-consumption but adds cost, losses, maintenance, and replacement risk.
  • A larger system may still make sense for planned electrification or resilience.

What it depends on

  • Import and export rates by time period
  • Hourly load profile and expected future consumption
  • Roof or site constraints and system pricing
  • Battery cost, resilience value, incentives, and export limits

Risks and trade-offs

  • Undersizing can require later expansion or leave future load unmet.
  • Oversizing can produce low-value exports and lengthen payback.
  • Tariff changes may alter which size is optimal.

Information you may need

  • Recent bills and interval usage
  • Expected future loads such as electric vehicles or heat pumps
  • Current export arrangement and system quotes
  • Battery options and desired backup capability

Your next step

What to do next

Ask for several modeled system sizes using hourly production and load, with separate values for self-consumption and exports.

Path-Q

Find the right next step

Answer a few questions and we’ll narrow your options.

Loading…

SQ00753