Hawaiian Electric Co. has added a feature to its website that allows its residential and business customers on Oahu to type in their address and see how much electricity in their area is being generated by solar photovoltaic panels.

The information is expected to be used mostly by businesses with large-scale PV systems that may be required to pay for an interconnection study if the amount of solar power generation in their area is above a certain threshold. The cost of an interconnection study typically ranges from $30,000 to $50,000, not including any equipment upgrades that HECO might require.

The new Internet tool shows how much renewable energy capacity remains on a given circuit before reaching a 15 percent threshold that may indicate the need for further study to install a new PV system on the circuit.

HECO generally has not required homeowners or small businesses on Oahu to do interconnection studies on affected circuits if their PV systems have generating capacities of 10 kilowatts or less.

Some customers on Maui and Hawaii island on circuits exceeding the threshold have had to pay for interconnection studies ranging from $500 to several thousand dollars.

The interactive map is only available for HECO customers on Oahu, but the utility plans an expansion in the future for customers of its sister companies on Maui and the Big Isle. Ratepayers on those islands seeking to install solar panels can get a rough idea of the amount of PV penetration in their areas by viewing color-coded maps on the utility’s website.

The information is available at www.heco.com by clicking on “Clean Energy,” “Clean Energy Generation,” then “Locational Value Maps.” The information is updated daily Monday through Friday.

“Our goal is to provide our customers and solar providers with information that is timely, precise and clear,” said Scott Seu, HECO vice president of energy resources and operations.

HECO established thresholds for PV and other renewable energy generation because of the challenges it faces in balancing the intermittent nature of renewable energy sources with the need to maintain a steady power supply to customers. HECO, under the direction of the state Public Utilities Commission, over the past few years has eased its rules and allowed greater amounts of renewable energy penetration.

On Oahu, 170 of HECO’s 465 circuits have reached the 15 percent limit. That was up from 49 of 465 circuits in March 2012. The amount of PV generating capacity at HECO and its neighbor island subsidiaries has more than doubled every year since 2008.