The New York State Clean Heating Fuel Tax Credit has been extended through 2020.  The personal income tax credit, which was initially authorized in 2006, is provided to eligible taxpayers for biodiesel purchases used for residential space and water heating.  For each percent of biodiesel blended with conventional home heating oil, a tax credit of $0.01/gallon is available up to a maximum of $0.20/gallon.  A partial credit will be calculated for buildings with a shared oil storage tank for residential and non-residential space that is based on the percentage of residential square footage.  A refund will be provided to taxpayers whose allowable credit exceeds their liability for that year.