2. Revenue from contracts

Disaggregation of revenue

We have four reportable segments: Solid Fuel, Natural Gas, Hydroelectric and Corporate. We revised our reportable business segments in the fourth quarter of 2019 as the result of recent asset acquisitions, PPA expirations and project decommissioning, and in order to align with changes to management’s structure, resource allocation and performance assessment in making decisions regarding our operations. Segment information for the comparative 2019 period has been revised to conform to the new segment presentation. Each segment contains various power generation projects and performance obligations as described above. For more detailed information about reportable segments, see Note 12, Segment and geographical information. Revenue by segment consists of the following:


	Three Months Ended March 31, 2020
										Consolidated
	Solid Fuel		Natural Gas		Hydroelectric			Corporate		Total
Project revenue:
Energy sales	$	16.8	$	6.2	$	17.7	$		—	$	40.7
Energy capacity revenue		6.3		21.7		—			—		28.0
Steam energy and capacity revenue		—		2.7		—			—		2.7
Waste heat revenue		0.3		—		—			—		0.3
Ancillary and transmission services		—		0.7		0.7			—		1.4
Asset management and operation		—		—		—			0.2		0.2
Miscellaneous revenue		—		(0.5)		—			—		(0.5)
		23.4		30.8		18.4			0.2		72.8


	Three Months Ended March 31, 2019
										Consolidated
		Solid Fuel		Natural Gas		Hydroelectric		Corporate		Total
Project revenue:
Energy sales	$	10.4	$	9.0	$	17.6	$	—	$	37.0
Energy capacity revenue		9.3		20.9		—		—		30.2
Steam energy and capacity revenue		—		0.6		—		—		0.6
Ancillary and transmission services		—		4.3		0.8		—		5.1
Asset management and operation		0.1		(0.1)		—		0.2		0.2
Miscellaneous revenue		—		(0.1)		—		—		(0.1)
		19.8		34.6		18.4		0.2		73.0

Contract balances

Contract liabilities as of March 31, 2020 include a $0.1 million fuel reserve fund at Dorchester (Solid Fuel segment) and a $0.1 million steam sale credit at the San Diego plants (Natural Gas segment). Contract liabilities as of December 31, 2019 include a $0.2 million fuel reserve fund at Dorchester and a $0.1 million steam sale credit at the San Diego plants. We had no contract assets at March 31, 2020 and December 31, 2019.