The state Public Utilities Commission has approved an interim rate increase of 4.7 percent for Hawaiian Electric Co. that will result in annual net revenue of $61.1 million.

A typical residential customer on Oahu using 600 kilowatt-hours a month will see a monthly electric bill increase by $6.48 to $129.06.

HECO said yesterday the increase—its third since 2005—will help pay for major capital improvements and increased operating costs incurred over the last several years.

The PUC still must approve the details of the rate adjustment calculation before it is implemented. If approved as submitted, the impact of the increase will vary by type of customer and actual electricity usage.

Interim rulings allow HECO to adjust its rates to what is approved by the PUC, pending a final judgment that could be higher or lower. If a lower final increase is ultimately approved, the difference will be refunded to customers with interest.

HECO's original request, filed a year ago, was for a 7.5 percent increase, or $97 million in revenue.

The company subsequently revised its request to 6.7 percent, or $86.8 million. HECO said the PUC will consider the request before issuing its final decision.

“;We know how difficult a rate increase is in this economy, but it is our responsibility to meet the energy needs of our customers,”; HECO Vice President Robbie Alm said.

He said the money is needed to “;maintain our system in good operating condition, invest in our system to provide reliable service to our customers and invest in renewable energy resources.”;

The interim increase will be used to help cover more than $200 million in investments in capital projects completed in 2008 and 2009. It also will allow more frequent inspections of utility lines and poles, increased tree trimming around power lines, and increased servicing of power plants, the company said.

HECO is still awaiting a final decision on its 2007 rate case upon which the PUC granted an interim increase of 5.5 percent, or $77.9 million in revenue.

Fuel cost to push up July bill

The typical household electric bill on Oahu in July will rise 1.8 percent to an average of $122.58, or $2.22 higher than it was in June, according to rates released yesterday by Hawaiian Electric Co.

Oahu electric rates do not yet include the 4.7 percent interim rate increase that was just approved by the state Public Utilities Commission.

HECO's monthly rates fluctuate due to the cost of fuel.

On Maui, the typical July bill will be $147.19, up 30 cents, or 0.2 percent, from June. Those rates do not include Molokai and Lanai. On the Big Island, the typical bill will average $187.74 this month, which is $1.42 more, or 0.8 percent higher, than in June.

The effective rates, which include fuel and other charges, for July are 19 cents a kilowatt-hour on Oahu, 23.18 cents/kwh for Maui and 29.44 cents/kwh for the Big Island.

Rates vary on different isles due to different sources of fuel and storage capacities.

—Dave Segal