11. Commitments:

a. Operating leases

As of December 31, 2015, our estimated minimum rental commitments for our railcar leases for use at our coal-fired facilities over the next five years and thereafter are as follows:


		(dollars in thousands)

2016	$	5,318
2017		5,318
2018		5,318
2019		2,950
2020		588
Thereafter		–

The rental expenses for the railcar leases are added to the cost of the fossil inventories and are recognized in fuel expense. Rental expenses totaled $4,849,000, $5,139,000 and $5,213,000 in 2015, 2014 and 2013, respectively.

b. Fuel

To supply a portion of the fuel requirements to our generating units, Southern Nuclear on our behalf for nuclear fuel, and Georgia Power, on our behalf for coal, have entered into various long-term commitments for the procurement of coal and nuclear fuel. The contracts in most cases contain provision for price escalations, minimum and maximum purchase levels and other financial commitments. The value of the coal commitments is based on maximum coal prices and minimum volumes as provided in the contracts and does not include taxes, transportation, government impositions or railcar costs. For further discussion of total nuclear fuel expense, see Note 1h. As of December 31, 2015, our estimated minimum long-term commitments are as follows:


		(dollars in thousands)
		Coal		Nuclear Fuel

2016	$	29,658	$	55,400
2017		15,342		27,800
2018		8,117		29,200
2019		–		24,300
2020		–		21,700
Thereafter		–		60,800