Exhibit 21.01 NORTHERN STATES POWER COMPANY, MINNESOTA AND SUBSIDIARIES Subsidiaries of Registrant Name State of Incorporation Purpose Northern States Power Company (Wisconsin) Wisconsin Electric and gas utility First Midwest Auto Park, Inc. Minnesota Own and manage a parking ramp United Power and Land Company Minnesota Real estate holding company Cormorant Corporation Montana Holds interest in coal and lignite properties NRG Energy, Inc. Delaware Own and manage non- regulated energy subsidiaries of the Company Cenergy, Inc. Minnesota Natural gas marketing and energy services Viking Gas Transmission Delaware Natural gas Company transmission Eloigne Company Minnesota Own and operate affordable housing units NEO Corporation Minnesota Development of small scale waste to energy opportunities utilizing landfill gas