(d) The commission may adopt new, or expand existing, fixed charges for the purpose of collecting a reasonable portion of the fixed costs of providing electrical service to residential customers. The commission shall ensure that any approved charges do all of the following:

1. (1) Reasonably reflect an appropriate portion of the different costs of serving small and large customers.
2. (2) Not unreasonably impair incentives for conservation, energy efficiency, and beneficial electrification and greenhouse gas emissions reduction.
3. (3) Are set at levels that do not overburden low-income customers.

(e)

1. (1) For the purposes of this section and Section 739.1, the commission may authorize fixed charges for any rate schedule applicable to a residential customer account. The fixed charge shall be established on an income-graduated basis with no fewer than three income thresholds so that a low-income ratepayer in each baseline territory would realize a lower average monthly bill without making any changes in usage. The commission shall, no later than July 1, 2024, authorize a fixed charge for default residential rates.
2. (2) For purposes of this subdivision, “income-graduated” means that low-income customers pay a smaller fixed charge than high-income customers.