The majority of Rotorua electricity consumers will notice a bottom-line hike in their power accounts.
Some may have already.
The community relations manager for Trustpower, Graeme Purches, said the increases had resulted from a combination of transmission and local network charges.
"For Rotorua residential customers transmission charges [Transpower] have increased 15 per cent and local network charges [Unison] have increased 12.2 per cent," Mr Purches said.
"For Taupo transmission charges have increased 15 per cent and local network charges [Unison] have increased 11.1 per cent."
He said collectively, transmission and local network charges accounted for about 38 per cent of a residential customer's bill.
"There have also been increases in wholesale electricity costs, which make up about 35 per cent of a total bill, and our own costs have also increased."
Trustpower's 9692 Rotorua customers will notice the difference as increases have become effective from May 1. The increase will result in a $200 monthly account becoming $212.
Mr Purches said his company's customers were notified by letter at least one month before any price increases.
"People never like price increases but in an environment of increasing costs, most now accept they are inevitable."
Genesis Energy public affairs manager Richard Gordon also said increased power costs to the consumer took in a range of cost increases including a substantial increase in transmission charges
"These charges impact on all electricity consumers in New Zealand as Transpower, the national grid owner, is investing substantially in transmission upgrades," Mr Gordon said.
Genesis notified its customers of the increases by letter on April 4, as did Energy Online which is a subsidiary of Genesis Energy.
Mercury Energy's 5.8 per cent increase for Rotorua residential customers came into effect on April 1.
Mercury Energy general manager James Munro said the price change included an increase in the charges passed to customers from the local lines company.
"These charges support major investment in New Zealand's national electricity grid, improving grid security," Mr Munro said.
"Investment in electricity infrastructure is essential if New Zealand homes and businesses are to have a secure supply of energy as the economy and population grow, and this has been recognised by the Commerce Commission which approves maximum prices and revenues for transmission charges."
Contact Energy's Rotorua increase came into effect on April 1 while its Taupo customers would have noticed a rise after February 17. A spokesperson from Contact described the increases as primarily a "pass through" of costs from a rise in network prices.
Increases to Electricity Consumers:
Trustpower:
Rotorua (9692 customers) 6.1 per cent, Taupo (6172 customers) 5.7 per cent, Eastern Bay of Plenty (492 customers) 0 per cent
Genesis:
Rotorua and Taupo (7871 customers) 8.1 per cent, Eastern Bay of Plenty (680 customers) 0 per cent
Energy Online:
Rotorua and Taupo (2182 customers) 0 per cent, Eastern Bay of Plenty (198) 0 per cent
Mercury Energy:
Figures only available for Rotorua (just under 3000 customers) 5.8 per cent
Contact Energy:
Rotorua (2080 customers) 4.4 per cent, Taupo (1800 customers) 5.5 per cent, Eastern Bay of Plenty (customer figures not available) 0 per cent