Lawmakers at the end of last year let the 21 year-old incentive expire. It reduces the federal income taxes of qualified owners of wind or other renewable energy assets based on their electrical output - $23 per MWh, inflation adjusted, for the first decade of operation.

Most projects that will qualify for the 2013 PTC will get built this year and in 2015, benefitting from the provision that allows work of a “significant nature,” and 5% of the project’s cost to have been incurred by 31 December last year.