Related Party Transactions

12 Months Ended

Dec. 31, 2018

Xcel Energy Services Inc. provides management, administrative and other services for the subsidiaries of Xcel Energy Inc., including NSP-Wisconsin. The services are provided and billed to each subsidiary in accordance with service agreements executed by each subsidiary. NSP-Wisconsin uses services provided by Xcel Energy Services Inc. whenever possible. Costs are charged directly to the subsidiary and are allocated if they cannot be directly assigned.

The electric production and transmission costs of the entire NSP System are shared by NSP-Minnesota and NSP-Wisconsin. The Interchange Agreement provides for the sharing of all costs of generation and transmission facilities of the system, including capital costs.

Significant affiliate transactions among the companies and related parties including billings under the Interchange Agreement for the years ended Dec. 31:



(Millions of Dollars)	2018		2017		2016
Operating revenues:
Electric	$	157.9	$	177.2	$	170.4
Operating expenses:
Purchased power	410.9		421.6		413.6
Transmission expense	62.8		68.6		61.9
Other operating expenses — paid to Xcel Energy Services Inc.	86.9		92.7		106.5

Accounts receivable and payable with affiliates at Dec. 31 were:



	2018				2017
(Millions of Dollars)	Accounts Receivable		Accounts Payable		Accounts Receivable		Accounts Payable
NSP-Minnesota	$	—	$	11.0	$	—	$	17.8
PSCo	0.2		—		—		—
Other subsidiaries of Xcel Energy Inc.	14.9		9.0		3.4		11.8
	$	15.1	$	20.0	$	3.4	$	29.6