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Note 3 - Rate and Regulatory Matters (Tables) | 12 Months Ended
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Dec. 31, 2019
Notes Tables |
Schedule of Information on Status of Updates for Previous Periods [Table Text Block] |
Rate Rider |  |  | R - Request Date A - Approval Date |  |  |  | Effective Date Requested or Approved |  |  | Annual Revenue ($000s) |  | Rate
Minnesota |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Conservation Improvement Program |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2018 Incentive and Cost Recovery |  |  | A – | December 27, 2019 |  |  |  | January 1, 2020 |  |  | $ | 11,926 |  | $0.00710 | /kwh
2017 Incentive and Cost Recovery |  |  | A – | October 4, 2018 |  |  |  | November 1, 2018 |  |  | $ | 10,283 |  | $0.00600 | /kwh
2016 Incentive and Cost Recovery |  |  | A – | September 15, 2017 |  |  |  | October 1, 2017 |  |  | $ | 9,868 |  | $0.00536 | /kwh
2015 Incentive and Cost Recovery |  |  | A – | July 19, 2016 |  |  |  | October 1, 2016 |  |  | $ | 8,590 |  | $0.00275 | /kwh
Transmission Cost Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2018 Annual Update–Scenario A |  |  | R – | November 30, 2018 |  |  |  | June 1, 2019 |  |  | $ | 6,475 |  | Various
–Scenario B |  |  |  |  |  |  |  |  |  |  | $ | 2,708 |  | Various
2017 Rate Reset |  |  | A – | October 30, 2017 |  |  |  | November 1, 2017 |  |  | $ | (3,311 | ) | Various
2016 Annual Update |  |  | A – | July 5, 2016 |  |  |  | September 1, 2016 |  |  | $ | 4,736 |  | Various
Environmental Cost Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2018 Annual Update |  |  | A – | November 29, 2018 |  |  |  | December 1, 2018 |  |  | $ | - |  | 0% | of base
2017 Rate Reset |  |  | A – | October 30, 2017 |  |  |  | November 1, 2017 |  |  | $ | (1,943 | ) | -0.935% | of base
2016 Annual Update |  |  | A – | July 5, 2016 |  |  |  | September 1, 2016 |  |  | $ | 11,884 |  | 6.927% | of base
Renewable Resource Adjustment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2019 Annual Update – Revised |  |  | A – | December 19, 2019 |  |  |  | January 1, 2020 |  |  | $ | 12,506 |  | $0.00467 | /kwh
2018 Annual Update |  |  | A – | August 29, 2018 |  |  |  | November 1, 2018 |  |  | $ | 5,886 |  | $0.00219 | /kwh
2017 Rate Reset |  |  | A – | October 30, 2017 |  |  |  | November 1, 2017 |  |  | $ | 1,279 |  | $0.00049 | /kwh
North Dakota |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Renewable Resource Adjustment |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2020 Annual Update |  |  | R – | December 31, 2019 |  |  |  | April 1, 2020 |  |  | $ | 3,828 |  | 3.744% | of base
2019 Annual Update |  |  | A – | May 1, 2019 |  |  |  | June 1, 2019 |  |  | $ | (235 | ) | -0.224% | of base
2018 Rate Reset for effect of TCJA |  |  | A – | February 27, 2018 |  |  |  | March 1, 2018 |  |  | $ | 9,650 |  | 7.493% | of base
2017 Rate Reset |  |  | A – | December 20, 2017 |  |  |  | January 1, 2018 |  |  | $ | 9,989 |  | 7.756% | of base
2016 Annual Update |  |  | A – | March 15, 2017 |  |  |  | April 1, 2017 |  |  | $ | 9,156 |  | 7.005% | of base
2015 Annual Update |  |  | A – | June 22, 2016 |  |  |  | July 1, 2016 |  |  | $ | 9,262 |  | 7.573% | of base
Transmission Cost Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2019 Annual Update |  |  | A – | December 18, 2019 |  |  |  | January 1, 2020 |  |  | $ | 5,739 |  | Various
2018 Supplemental Update |  |  | A – | December 6, 2018 |  |  |  | February 1, 2019 |  |  | $ | 4,801 |  | Various
2018 Rate Reset for effect of TCJA |  |  | A – | February 27, 2018 |  |  |  | March 1, 2018 |  |  | $ | 7,469 |  | Various
2017 Annual Update |  |  | A – | November 29, 2017 |  |  |  | January 1, 2018 |  |  | $ | 7,959 |  | Various
2016 Annual Update |  |  | A – | December 14, 2016 |  |  |  | January 1, 2017 |  |  | $ | 6,916 |  | Various
Environmental Cost Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2019 Update |  |  | A – | October 22, 2019 |  |  |  | November 1, 2019 |  |  | $ | - |  | 0% | of base
2018 Update |  |  | A – | December 19, 2018 |  |  |  | February 1, 2019 |  |  | $ | (378 | ) | -0.310% | of base
2018 Rate Reset for effect of TCJA |  |  | A – | February 27, 2018 |  |  |  | March 1, 2018 |  |  | $ | 7,718 |  | 5.593% | of base
2017 Rate Reset |  |  | A – | December 20, 2017 |  |  |  | January 1, 2018 |  |  | $ | 8,537 |  | 6.629% | of base
2017 Annual Update |  |  | A – | July 12, 2017 |  |  |  | August 1, 2017 |  |  | $ | 9,917 |  | 7.633% | of base
2016 Annual Update |  |  | A – | June 22, 2016 |  |  |  | July 1, 2016 |  |  | $ | 10,359 |  | 7.904% | of base
Generation Cost Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2019 Initial Request |  |  | A – | May 15, 2019 |  |  |  | July 1, 2019 |  |  | $ | 2,720 |  | 2.547% | of base
South Dakota |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Transmission Cost Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2020 Annual Update |  |  | R – | October 31, 2019 |  |  |  | March 1, 2020 |  |  | $ | 2,407 |  | Various
2019 Rate Reset |  |  | A – | September 17, 2019 |  |  |  | October 1, 2019 |  |  | $ | 2,046 |  | Various
2019 Annual Update |  |  | A – | February 20, 2019 |  |  |  | March 1, 2019 |  |  | $ | 1,638 |  | Various
2018 Interim Rate Reset |  |  | A – | October 18, 2018 |  |  |  | October 18, 2018 |  |  | $ | 1,171 |  | Various
2017 Annual Update |  |  | A – | February 28, 2018 |  |  |  | March 1, 2018 |  |  | $ | 1,779 |  | Various
2016 Annual Update |  |  | A – | February 17, 2017 |  |  |  | March 1, 2017 |  |  | $ | 2,053 |  | Various
2015 Annual Update |  |  | A – | February 12, 2016 |  |  |  | March 1, 2016 |  |  | $ | 1,895 |  | Various
Environmental Cost Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2018 Interim Rate Reset |  |  | A – | October 18, 2018 |  |  |  | October 18, 2018 |  |  | $ | (189 | ) | -$0.00075 | /kwh
2017 Annual Update |  |  | A – | October 13, 2017 |  |  |  | November 1, 2017 |  |  | $ | 2,082 |  | $0.00483 | /kwh
2016 Annual Update |  |  | A – | October 26, 2016 |  |  |  | November 1, 2016 |  |  | $ | 2,238 |  | $0.00536 | /kwh
Phase-In Rate Plan Recovery |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
2019 Initial Request |  |  | A – | August 21, 2019 |  |  |  | September 1, 2019 |  |  | $ | 864 |  | 3.345% | of base
Schedule of Revenues Recorded under Rate Riders [Table Text Block] |
Rate Rider (in thousands) |  | 2019 |  |  | 2018 |  |  | 2017 |
Minnesota |  |  |  |  |  |  |  |  |  |  |  |
Conservation Improvement Program Costs and Incentives |  | $ | 8,271 |  |  | $ | 8,127 |  |  | $ | 6,008 |
Renewable Resource Adjustment |  |  | 5,513 |  |  |  | 3,067 |  |  |  | (196 | )
Transmission Cost Recovery |  |  | 2,497 |  |  |  | (2,039 | ) |  |  | 2,973 |
Environmental Cost Recovery |  |  | (1 | ) |  |  | (24 | ) |  |  | 8,148 |
North Dakota |  |  |  |  |  |  |  |  |  |  |  |
Transmission Cost Recovery |  |  | 5,292 |  |  |  | 7,016 |  |  |  | 8,729 |
Generation Cost Recovery |  |  | 878 |  |  |  | - |  |  |  | - |
Environmental Cost Recovery |  |  | 550 |  |  |  | 7,318 |  |  |  | 9,782 |
Renewable Resource Adjustment |  |  | 230 |  |  |  | 8,529 |  |  |  | 7,620 |
South Dakota |  |  |  |  |  |  |  |  |  |  |  |
Transmission Cost Recovery |  |  | 2,165 |  |  |  | 1,664 |  |  |  | 1,843 |
Conservation Improvement Program Costs and Incentives |  |  | 851 |  |  |  | 628 |  |  |  | 598 |
Environmental Cost Recovery |  |  | (29 | ) |  |  | 1,676 |  |  |  | 2,345 |
Phase-In Rate Plan |  |  | (125 | ) |  |  | - |  |  |  | - |
Total |  | $ | 26,092 |  |  | $ | 35,962 |  |  | $ | 47,850 |

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