The $15 payment - known as a loss rental rebate - is what Transpower pays out from any surplus each year once the costs in the electricity wholesale market have been worked out.
Loss rental rebates may vary each year depending on the dynamics of the electricity market and last year were $30. In addition, last year's payment covered a period of 15 months, whereas this year's payment was for a 12-month period.
Entrust owns 75.1 per cent of Vector, and says the $375 in dividend and Transpower rebate will be paid to eligible customers later this month.
The trust's chairman, William Cairns, says the dividend will contribute more than $120 million to Auckland's economy.
"Entrust is determined to deliver for our beneficiaries. We know that some in our community really rely on the dividend, and that it makes a difference. A good portion of it will be spent in local neighbourhoods, with local businesses, which further benefits local communities.''
During the past 26 years, Entrust has paid out more than $1.7 billion to those in the old AEPB area - Auckland, Manukau, northern Papakura and eastern Franklin.
Last year, the trust paid a $350 dividend.
Under an agreement with Vector, $10.4m a year is spent on undergrounding power lines, a commitment that has been criticised as too small. So far, 108km of power lines have been buried.
Last month, Vector declared a net profit after tax of $84m in the year to June 30, 2019 after the $46.6m impairment on impairment from its E-co Products Group, which trades as HRV.
That was down from the previous year's profit of $149.8m which included a one-off tax gain of $16.7m.
Excluding the impairment, the company said its net profit of $130.6m was down slightly on the previous year.