100% exemption for 25 years.
In September 2009, the Honolulu City Council unanimously passed Bill 58 to create a real property tax exemption for alternative energy improvements. This bill became effective October 1, 2009. The alternative energy property installed on a building, property, or land is exempt from property taxes for 25 years. For the purposes of this property tax exemption, alternative energy sources include solar, wind, hydropower, tidal, wave, solid waste and increased efficiency in fossil-fuel burning facilities. Energy sources based on fossil fuels, nuclear fuels or geothermal energy are not eligible for this exemption.