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Property, Plant and Equipment Property, Plant and Equipment | 12 Months Ended
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Dec. 31, 2013
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment Disclosure | PROPERTY, PLANT AND EQUIPMENT (a) Utility - Electric Plant - At December 31, details of electric plant were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2013 |  | 2012 |  | 2013 |  | 2012 |  | 2013 |  | 2012
Plant in service: |  |  |  |  |  |  |  |  |  |  |
Generation (a) |  | $4,792.0 |  |  |  | $4,798.9 |  |  |  | $2,513.2 |  |  |  | $2,393.0 |  |  |  | $2,278.8 |  |  |  | $2,405.9 |
Distribution | 4,179.6 |  |  | 3,981.5 |  |  | 2,311.2 |  |  | 2,205.9 |  |  | 1,868.4 |  |  | 1,775.6 |
Other | 286.3 |  |  | 290.3 |  |  | 210.5 |  |  | 216.3 |  |  | 75.8 |  |  | 74.0 |
Plant anticipated to be retired early (b) | 157.8 |  |  | — |  |  | — |  |  | — |  |  | 157.8 |  |  | — |
|  | $9,415.7 |  |  |  | $9,070.7 |  |  |  | $5,034.9 |  |  |  | $4,815.2 |  |  |  | $4,380.8 |  |  |  | $4,255.5 |
(a) | The decrease in Alliant Energy’s and WPL’s generation portion of electric plant in service was primarily due to classifying Edgewater Unit 3 and Nelson Dewey Units 1 and 2 as “Plant anticipated to be retired early” as of December 31, 2013, which is discussed below. Partially offsetting this decrease at Alliant Energy, and contributing to the increase in IPL’s generation portion of electric plant in service, was an increase at IPL due to a scrubber and baghouse at George Neal Unit 4 being placed in service in the fourth quarter of 2013. As of December 31, 2013, the capitalized project costs for the George Neal Unit 4 scrubber and baghouse were $61 million.
(b) | In 2013, WPL received approval from MISO to retire Edgewater Unit 3, and Nelson Dewey Units 1 and 2. WPL currently anticipates retiring these EGUs by December 31, 2015, contingent on completion of transmission network upgrades needed for system reliability. WPL is recovering the remaining net book value of these EGUs over a 10-year period beginning January 1, 2013 pursuant to a May 2012 PSCW order.
Wind Generation Projects - Wind Site in Franklin County, Iowa - In 2007, IPL acquired approximately 500 MW of wind site capacity in Franklin County, Iowa. The initial 200 MW of the wind site was utilized for IPL’s Whispering Willow - East wind project, which began generating electricity in 2009. In 2011, IPL sold approximately 100 MW of wind site capacity to Resources for construction of a non-regulated wind project referred to as the Franklin County wind project. Future development of the balance of the wind site by IPL will depend on numerous factors such as RPS, environmental legislation, fossil fuel prices, technology advancements and transmission capabilities. As of December 31, 2013, Alliant Energy’s and IPL’s capitalized costs related to the remaining approximately 200 MW of wind site capacity in Franklin County, Iowa were $13 million and were recorded in “Other property, plant and equipment” on their Consolidated Balance Sheets. IPL’s Whispering Willow - East Wind Project - In 2011, IPL received an order from the MPUC approving a temporary recovery rate for the Minnesota retail portion of its Whispering Willow - East wind project construction costs. In its order, the MPUC did not reach a conclusion as to the prudence of these project costs. The prudence of these project costs and the final recovery rate was addressed in a separate proceeding in 2013. The initial recovery rate approved by the MPUC was below the amount required by IPL to recover the Minnesota retail portion of its total project costs. Based on its interpretation of the order, IPL believed that it was probable it would not be allowed to recover the entire Minnesota retail portion of its project costs. IPL estimated the most likely outcome of the final rate proceeding would result in the MPUC effectively disallowing recovery of approximately $8 million of project costs out of a total of approximately $30 million of project costs allocated to the Minnesota retail jurisdiction. As a result, Alliant Energy and IPL recognized an $8 million impairment related to this probable disallowance, which was recorded as a reduction to electric plant and a charge to “Utility - Other operation and maintenance” in their Consolidated Statements of Income in 2011. In December 2013, IPL received an order from the MPUC approving full cost recovery of the Minnesota retail portion of IPL’s Whispering Willow - East wind project construction costs effective January 1, 2013. As a result, Alliant Energy and IPL recognized a $7 million regulatory-related credit, which was recorded as an an increase to “Electric plant” on their Consolidated Balance Sheets and a decrease to “Utility - Other operation and maintenance” in their Consolidated Statements of Income in 2013. Franklin County Wind Project - In 2008, Alliant Energy entered into a master supply agreement with Vestas to purchase 500 MW of wind turbine generator sets and related equipment. Alliant Energy utilized 401 MW of these wind turbine generator sets and related equipment to construct IPL’s Whispering Willow - East and WPL’s Bent Tree - Phase I wind projects. In 2011, IPL sold the remaining 99 MW of wind turbine generator sets and related equipment to Resources for $115.3 million, which represented IPL’s book value for progress payments to date for the wind turbine generator sets and related equipment and land rights in Franklin County, Iowa. In addition, Resources assumed the remaining progress payments to Vestas for the 99 MW of wind turbine generator sets and related equipment. The proceeds received by IPL are presented in investing activities in IPL’s Consolidated Statement of Cash Flows in 2011. Refer to Note 3(b) for further discussion of the Franklin County wind project. Wind Site in Green Lake and Fond du Lac Counties in Wisconsin - In 2009, WPL purchased development rights to an approximate 100 MW wind site in Green Lake and Fond du Lac Counties in Wisconsin. Due to events in 2011 resulting in uncertainty regarding wind siting requirements in Wisconsin and increased risks with permitting this wind site, WPL determined it would be difficult to sell or effectively use the site for wind development. As a result, WPL recognized a $5 million impairment in 2011 for the amount of capitalized costs incurred for this site. Alliant Energy and WPL recorded the impairment as a reduction in other utility property, plant and equipment, and a charge to “Utility - Other operation and maintenance” in their Consolidated Statements of Income in 2011. Environmental Compliance Plans Emission Controls Projects - IPL’s George Neal Units 3 and 4 - In 2011, MidAmerican began installing scrubbers and baghouses at George Neal Units 3 and 4 to reduce SO2 and mercury emissions at the EGUs. The scrubbers and baghouses are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. IPL owns a 28.0% and 25.695% interest in George Neal Units 3 and 4, respectively. Construction of the scrubber and baghouse at George Neal Unit 4 was completed in the fourth quarter of 2013, which resulted in a transfer of the capitalized project costs from “Construction work in progress - Other” to “Electric plant” on Alliant Energy’s and IPL’s Consolidated Balance Sheets in 2013. As of December 31, 2013, the capitalized project costs consisted of capital expenditures of $57 million and AFUDC of $4 million for IPL’s allocated portion of the George Neal Unit 4 scrubber and baghouse. Construction of the scrubber and baghouse at George Neal Unit 3 is expected to be completed in 2014. As of December 31, 2013, Alliant Energy and IPL recorded capitalized expenditures of $53 million and AFUDC of $2 million for IPL’s allocated portion of the George Neal Unit 3 scrubber and baghouse in “Construction work in progress - George Neal Generating Station Unit 3 emission controls” on their Consolidated Balance Sheets. IPL’s Ottumwa Unit 1 - IPL is currently installing a scrubber and baghouse at Ottumwa Unit 1 to reduce SO2 and mercury emissions at the EGU. IPL owns a 48% interest in Ottumwa Unit 1. Construction began in the second quarter of 2012 and is expected to be completed in 2014. The scrubber and baghouse are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. As of December 31, 2013, Alliant Energy and IPL recorded capitalized expenditures of $125 million and AFUDC of $10 million for IPL’s allocated portion of the scrubber and baghouse in “Construction work in progress - Ottumwa Generating Station Unit 1 emission controls” on their Consolidated Balance Sheets. WPL’s Columbia Units 1 and 2 - WPL is currently installing scrubbers and baghouses at Columbia Units 1 and 2 to reduce SO2 and mercury emissions at the EGU. WPL owns a 46.2% interest in Columbia Units 1 and 2. Construction began in the first quarter of 2012 and is expected to be completed in 2014. The scrubbers and baghouses are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. As of December 31, 2013, Alliant Energy and WPL recorded capitalized expenditures of $254 million and AFUDC of $11 million for WPL’s allocated portion of the scrubbers and baghouses in “Construction work in progress - Columbia Energy Center Units 1 and 2 emission controls” on their Consolidated Balance Sheets. WPL’s Edgewater Unit 5 - In June 2013, WPL received an order from the PSCW approving WPL’s CA application to install a scrubber and baghouse at Edgewater Unit 5 to reduce SO2 and mercury emissions at the EGU. WPL currently expects to begin construction of the project in 2014 and place it in service in 2016. The scrubber and baghouse are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. Proposed Sales of IPL’s Minnesota Electric and Natural Gas Distribution Assets - In September 2013, IPL signed a definitive agreement to sell its Minnesota electric distribution assets to Southern Minnesota Energy Cooperative, a combined group of various neighboring electric cooperatives. Also in September 2013, IPL signed a definitive agreement to sell its Minnesota natural gas distribution assets to Minnesota Energy Resources Corporation, a subsidiary of Integrys Energy Group, Inc. Proceeds from the sales are expected to be approximately $128 million in aggregate, subject to customary closing adjustments. The proceeds are expected to reduce Alliant Energy’s and IPL’s future financing requirements. Pending all necessary federal and state regulatory approvals, including the MPUC, FERC and the IUB, the transactions are expected to be concluded in the second half of 2014. The sales price of the assets expected to be sold, which primarily consist of property, plant and equipment, and working capital items, is expected to result in a modest gain. Any after-tax gain realized from the transaction may be subject to refund to IPL’s customers. As of December 31, 2013, IPL’s assets and liabilities included in the sale agreements did not meet the criteria to be classified as held for sale due to uncertainties in the regulatory approval process. The operating results of IPL’s Minnesota electric and natural gas distribution businesses also did not qualify as discontinued operations as of December 31, 2013. The electric distribution asset sales agreement includes a wholesale power supply agreement between IPL and Southern Minnesota Energy Cooperative, which is subject to FERC approval. The agreement contains a five-year termination notice, which may not be given until the fifth anniversary of the effective date of the agreement, resulting in a minimum term of 10 years. The agreement remains in effect indefinitely, unless notice to terminate is provided by either party. This wholesale power supply agreement includes standardized pricing mechanisms that are detailed in IPL’s current tariffs accepted by FERC through wholesale rate case proceedings. IPL’s current return on common equity authorized by FERC related to its wholesale electric rates is 10.97%. As a result of IPL’s requirement to supply electricity to Southern Minnesota Energy Cooperative under the wholesale power supply agreement, the sale of the electric distribution assets is not expected to have a significant impact on IPL’s current generation plans or operating results. AFUDC - AFUDC represents costs to finance construction additions including a return on equity component and cost of debt component as required by regulatory accounting. The concurrent credit for the amount of AFUDC capitalized is recorded as “Allowance for funds used during construction” in the Consolidated Statements of Income. The amount of AFUDC generated by equity and debt components was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2013 |  | 2012 |  | 2011 |  | 2013 |  | 2012 |  | 2011 |  | 2013 |  | 2012 |  | 2011
Equity |  | $20.3 |  |  |  | $14.1 |  |  |  | $7.6 |  |  |  | $13.8 |  |  |  | $5.2 |  |  |  | $3.5 |  |  |  | $6.5 |  |  |  | $8.9 |  |  |  | $4.1 |
Debt | 10.5 |  |  | 7.8 |  |  | 4.4 |  |  | 7.2 |  |  | 3.2 |  |  | 2.3 |  |  | 3.3 |  |  | 4.6 |  |  | 2.1 |
|  | $30.8 |  |  |  | $21.9 |  |  |  | $12.0 |  |  |  | $21.0 |  |  |  | $8.4 |  |  |  | $5.8 |  |  |  | $9.8 |  |  |  | $13.5 |  |  |  | $6.2 |
AFUDC related to various construction projects was recognized in Alliant Energy’s, IPL’s and WPL’s Consolidated Statements of Income as follows (in millions):
| 2013 |  | 2012 |  | 2011
IPL: |  |  |  |  |
Emission controls - Ottumwa Unit 1 |  | $8.0 |  |  |  | $2.0 |  |  |  | $— |
Emission controls - George Neal Units 3 and 4 | 5.1 |  |  | 0.9 |  |  | — |
Other | 7.9 |  |  | 5.5 |  |  | 5.8 |
| 21.0 |  |  | 8.4 |  |  | 5.8 |
WPL: |  |  |  |  |
Emission controls - Columbia Units 1 and 2 | 7.2 |  |  | 3.9 |  |  | 0.2 |
Emission controls - Edgewater Unit 5 | — |  |  | 7.2 |  |  | 2.9 |
Other | 2.6 |  |  | 2.4 |  |  | 3.1 |
| 9.8 |  |  | 13.5 |  |  | 6.2 |
Alliant Energy |  | $30.8 |  |  |  | $21.9 |  |  |  | $12.0 |
(b) Non-regulated and Other - The non-regulated and other property, plant and equipment on Alliant Energy’s Consolidated Balance Sheets includes the following: Franklin County Wind Project - The Franklin County wind project was placed into service in 2012 and is depreciated using the straight-line method over a 30-year period. As of December 31, 2013, Alliant Energy recorded $142 million in “Non-regulated Generation property, plant and equipment” on its Consolidated Balance Sheet related to the wind project. Refer to Note 3(a) for further discussion of the wind project, Note 5(d) for discussion of a cash grant received in 2013 related to the wind project and Note 13 for discussion of the wind project AROs. Sheboygan Falls - Sheboygan Falls was placed into service in 2005 and is depreciated using the straight-line method over a 35-year period. As of December 31, 2013, Alliant Energy recorded $107 million in “Non-regulated Generation property, plant and equipment” on its Consolidated Balance Sheet related to Sheboygan Falls. Other - The property, plant and equipment related to Corporate Services, Transportation and other non-regulated investments is recorded in “Alliant Energy Corporate Services, Inc. and other property, plant and equipment” on Alliant Energy’s Consolidated Balance Sheets and is depreciated using the straight-line method over periods ranging from 5 to 30 years.
IPL [Member] |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment Disclosure | PROPERTY, PLANT AND EQUIPMENT (a) Utility - Electric Plant - At December 31, details of electric plant were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2013 |  | 2012 |  | 2013 |  | 2012 |  | 2013 |  | 2012
Plant in service: |  |  |  |  |  |  |  |  |  |  |
Generation (a) |  | $4,792.0 |  |  |  | $4,798.9 |  |  |  | $2,513.2 |  |  |  | $2,393.0 |  |  |  | $2,278.8 |  |  |  | $2,405.9 |
Distribution | 4,179.6 |  |  | 3,981.5 |  |  | 2,311.2 |  |  | 2,205.9 |  |  | 1,868.4 |  |  | 1,775.6 |
Other | 286.3 |  |  | 290.3 |  |  | 210.5 |  |  | 216.3 |  |  | 75.8 |  |  | 74.0 |
Plant anticipated to be retired early (b) | 157.8 |  |  | — |  |  | — |  |  | — |  |  | 157.8 |  |  | — |
|  | $9,415.7 |  |  |  | $9,070.7 |  |  |  | $5,034.9 |  |  |  | $4,815.2 |  |  |  | $4,380.8 |  |  |  | $4,255.5 |
(a) | The decrease in Alliant Energy’s and WPL’s generation portion of electric plant in service was primarily due to classifying Edgewater Unit 3 and Nelson Dewey Units 1 and 2 as “Plant anticipated to be retired early” as of December 31, 2013, which is discussed below. Partially offsetting this decrease at Alliant Energy, and contributing to the increase in IPL’s generation portion of electric plant in service, was an increase at IPL due to a scrubber and baghouse at George Neal Unit 4 being placed in service in the fourth quarter of 2013. As of December 31, 2013, the capitalized project costs for the George Neal Unit 4 scrubber and baghouse were $61 million.
(b) | In 2013, WPL received approval from MISO to retire Edgewater Unit 3, and Nelson Dewey Units 1 and 2. WPL currently anticipates retiring these EGUs by December 31, 2015, contingent on completion of transmission network upgrades needed for system reliability. WPL is recovering the remaining net book value of these EGUs over a 10-year period beginning January 1, 2013 pursuant to a May 2012 PSCW order.
Wind Generation Projects - Wind Site in Franklin County, Iowa - In 2007, IPL acquired approximately 500 MW of wind site capacity in Franklin County, Iowa. The initial 200 MW of the wind site was utilized for IPL’s Whispering Willow - East wind project, which began generating electricity in 2009. In 2011, IPL sold approximately 100 MW of wind site capacity to Resources for construction of a non-regulated wind project referred to as the Franklin County wind project. Future development of the balance of the wind site by IPL will depend on numerous factors such as RPS, environmental legislation, fossil fuel prices, technology advancements and transmission capabilities. As of December 31, 2013, Alliant Energy’s and IPL’s capitalized costs related to the remaining approximately 200 MW of wind site capacity in Franklin County, Iowa were $13 million and were recorded in “Other property, plant and equipment” on their Consolidated Balance Sheets. IPL’s Whispering Willow - East Wind Project - In 2011, IPL received an order from the MPUC approving a temporary recovery rate for the Minnesota retail portion of its Whispering Willow - East wind project construction costs. In its order, the MPUC did not reach a conclusion as to the prudence of these project costs. The prudence of these project costs and the final recovery rate was addressed in a separate proceeding in 2013. The initial recovery rate approved by the MPUC was below the amount required by IPL to recover the Minnesota retail portion of its total project costs. Based on its interpretation of the order, IPL believed that it was probable it would not be allowed to recover the entire Minnesota retail portion of its project costs. IPL estimated the most likely outcome of the final rate proceeding would result in the MPUC effectively disallowing recovery of approximately $8 million of project costs out of a total of approximately $30 million of project costs allocated to the Minnesota retail jurisdiction. As a result, Alliant Energy and IPL recognized an $8 million impairment related to this probable disallowance, which was recorded as a reduction to electric plant and a charge to “Utility - Other operation and maintenance” in their Consolidated Statements of Income in 2011. In December 2013, IPL received an order from the MPUC approving full cost recovery of the Minnesota retail portion of IPL’s Whispering Willow - East wind project construction costs effective January 1, 2013. As a result, Alliant Energy and IPL recognized a $7 million regulatory-related credit, which was recorded as an an increase to “Electric plant” on their Consolidated Balance Sheets and a decrease to “Utility - Other operation and maintenance” in their Consolidated Statements of Income in 2013. Franklin County Wind Project - In 2008, Alliant Energy entered into a master supply agreement with Vestas to purchase 500 MW of wind turbine generator sets and related equipment. Alliant Energy utilized 401 MW of these wind turbine generator sets and related equipment to construct IPL’s Whispering Willow - East and WPL’s Bent Tree - Phase I wind projects. In 2011, IPL sold the remaining 99 MW of wind turbine generator sets and related equipment to Resources for $115.3 million, which represented IPL’s book value for progress payments to date for the wind turbine generator sets and related equipment and land rights in Franklin County, Iowa. In addition, Resources assumed the remaining progress payments to Vestas for the 99 MW of wind turbine generator sets and related equipment. The proceeds received by IPL are presented in investing activities in IPL’s Consolidated Statement of Cash Flows in 2011. Refer to Note 3(b) for further discussion of the Franklin County wind project. Wind Site in Green Lake and Fond du Lac Counties in Wisconsin - In 2009, WPL purchased development rights to an approximate 100 MW wind site in Green Lake and Fond du Lac Counties in Wisconsin. Due to events in 2011 resulting in uncertainty regarding wind siting requirements in Wisconsin and increased risks with permitting this wind site, WPL determined it would be difficult to sell or effectively use the site for wind development. As a result, WPL recognized a $5 million impairment in 2011 for the amount of capitalized costs incurred for this site. Alliant Energy and WPL recorded the impairment as a reduction in other utility property, plant and equipment, and a charge to “Utility - Other operation and maintenance” in their Consolidated Statements of Income in 2011. Environmental Compliance Plans Emission Controls Projects - IPL’s George Neal Units 3 and 4 - In 2011, MidAmerican began installing scrubbers and baghouses at George Neal Units 3 and 4 to reduce SO2 and mercury emissions at the EGUs. The scrubbers and baghouses are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. IPL owns a 28.0% and 25.695% interest in George Neal Units 3 and 4, respectively. Construction of the scrubber and baghouse at George Neal Unit 4 was completed in the fourth quarter of 2013, which resulted in a transfer of the capitalized project costs from “Construction work in progress - Other” to “Electric plant” on Alliant Energy’s and IPL’s Consolidated Balance Sheets in 2013. As of December 31, 2013, the capitalized project costs consisted of capital expenditures of $57 million and AFUDC of $4 million for IPL’s allocated portion of the George Neal Unit 4 scrubber and baghouse. Construction of the scrubber and baghouse at George Neal Unit 3 is expected to be completed in 2014. As of December 31, 2013, Alliant Energy and IPL recorded capitalized expenditures of $53 million and AFUDC of $2 million for IPL’s allocated portion of the George Neal Unit 3 scrubber and baghouse in “Construction work in progress - George Neal Generating Station Unit 3 emission controls” on their Consolidated Balance Sheets. IPL’s Ottumwa Unit 1 - IPL is currently installing a scrubber and baghouse at Ottumwa Unit 1 to reduce SO2 and mercury emissions at the EGU. IPL owns a 48% interest in Ottumwa Unit 1. Construction began in the second quarter of 2012 and is expected to be completed in 2014. The scrubber and baghouse are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. As of December 31, 2013, Alliant Energy and IPL recorded capitalized expenditures of $125 million and AFUDC of $10 million for IPL’s allocated portion of the scrubber and baghouse in “Construction work in progress - Ottumwa Generating Station Unit 1 emission controls” on their Consolidated Balance Sheets. WPL’s Columbia Units 1 and 2 - WPL is currently installing scrubbers and baghouses at Columbia Units 1 and 2 to reduce SO2 and mercury emissions at the EGU. WPL owns a 46.2% interest in Columbia Units 1 and 2. Construction began in the first quarter of 2012 and is expected to be completed in 2014. The scrubbers and baghouses are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. As of December 31, 2013, Alliant Energy and WPL recorded capitalized expenditures of $254 million and AFUDC of $11 million for WPL’s allocated portion of the scrubbers and baghouses in “Construction work in progress - Columbia Energy Center Units 1 and 2 emission controls” on their Consolidated Balance Sheets. WPL’s Edgewater Unit 5 - In June 2013, WPL received an order from the PSCW approving WPL’s CA application to install a scrubber and baghouse at Edgewater Unit 5 to reduce SO2 and mercury emissions at the EGU. WPL currently expects to begin construction of the project in 2014 and place it in service in 2016. The scrubber and baghouse are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. Proposed Sales of IPL’s Minnesota Electric and Natural Gas Distribution Assets - In September 2013, IPL signed a definitive agreement to sell its Minnesota electric distribution assets to Southern Minnesota Energy Cooperative, a combined group of various neighboring electric cooperatives. Also in September 2013, IPL signed a definitive agreement to sell its Minnesota natural gas distribution assets to Minnesota Energy Resources Corporation, a subsidiary of Integrys Energy Group, Inc. Proceeds from the sales are expected to be approximately $128 million in aggregate, subject to customary closing adjustments. The proceeds are expected to reduce Alliant Energy’s and IPL’s future financing requirements. Pending all necessary federal and state regulatory approvals, including the MPUC, FERC and the IUB, the transactions are expected to be concluded in the second half of 2014. The sales price of the assets expected to be sold, which primarily consist of property, plant and equipment, and working capital items, is expected to result in a modest gain. Any after-tax gain realized from the transaction may be subject to refund to IPL’s customers. As of December 31, 2013, IPL’s assets and liabilities included in the sale agreements did not meet the criteria to be classified as held for sale due to uncertainties in the regulatory approval process. The operating results of IPL’s Minnesota electric and natural gas distribution businesses also did not qualify as discontinued operations as of December 31, 2013. The electric distribution asset sales agreement includes a wholesale power supply agreement between IPL and Southern Minnesota Energy Cooperative, which is subject to FERC approval. The agreement contains a five-year termination notice, which may not be given until the fifth anniversary of the effective date of the agreement, resulting in a minimum term of 10 years. The agreement remains in effect indefinitely, unless notice to terminate is provided by either party. This wholesale power supply agreement includes standardized pricing mechanisms that are detailed in IPL’s current tariffs accepted by FERC through wholesale rate case proceedings. IPL’s current return on common equity authorized by FERC related to its wholesale electric rates is 10.97%. As a result of IPL’s requirement to supply electricity to Southern Minnesota Energy Cooperative under the wholesale power supply agreement, the sale of the electric distribution assets is not expected to have a significant impact on IPL’s current generation plans or operating results. AFUDC - AFUDC represents costs to finance construction additions including a return on equity component and cost of debt component as required by regulatory accounting. The concurrent credit for the amount of AFUDC capitalized is recorded as “Allowance for funds used during construction” in the Consolidated Statements of Income. The amount of AFUDC generated by equity and debt components was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2013 |  | 2012 |  | 2011 |  | 2013 |  | 2012 |  | 2011 |  | 2013 |  | 2012 |  | 2011
Equity |  | $20.3 |  |  |  | $14.1 |  |  |  | $7.6 |  |  |  | $13.8 |  |  |  | $5.2 |  |  |  | $3.5 |  |  |  | $6.5 |  |  |  | $8.9 |  |  |  | $4.1 |
Debt | 10.5 |  |  | 7.8 |  |  | 4.4 |  |  | 7.2 |  |  | 3.2 |  |  | 2.3 |  |  | 3.3 |  |  | 4.6 |  |  | 2.1 |
|  | $30.8 |  |  |  | $21.9 |  |  |  | $12.0 |  |  |  | $21.0 |  |  |  | $8.4 |  |  |  | $5.8 |  |  |  | $9.8 |  |  |  | $13.5 |  |  |  | $6.2 |
AFUDC related to various construction projects was recognized in Alliant Energy’s, IPL’s and WPL’s Consolidated Statements of Income as follows (in millions):
| 2013 |  | 2012 |  | 2011
IPL: |  |  |  |  |
Emission controls - Ottumwa Unit 1 |  | $8.0 |  |  |  | $2.0 |  |  |  | $— |
Emission controls - George Neal Units 3 and 4 | 5.1 |  |  | 0.9 |  |  | — |
Other | 7.9 |  |  | 5.5 |  |  | 5.8 |
| 21.0 |  |  | 8.4 |  |  | 5.8 |
WPL: |  |  |  |  |
Emission controls - Columbia Units 1 and 2 | 7.2 |  |  | 3.9 |  |  | 0.2 |
Emission controls - Edgewater Unit 5 | — |  |  | 7.2 |  |  | 2.9 |
Other | 2.6 |  |  | 2.4 |  |  | 3.1 |
| 9.8 |  |  | 13.5 |  |  | 6.2 |
Alliant Energy |  | $30.8 |  |  |  | $21.9 |  |  |  | $12.0 |
WPL [Member] |
Property, Plant and Equipment [Line Items] |
Property, Plant and Equipment Disclosure | PROPERTY, PLANT AND EQUIPMENT (a) Utility - Electric Plant - At December 31, details of electric plant were as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2013 |  | 2012 |  | 2013 |  | 2012 |  | 2013 |  | 2012
Plant in service: |  |  |  |  |  |  |  |  |  |  |
Generation (a) |  | $4,792.0 |  |  |  | $4,798.9 |  |  |  | $2,513.2 |  |  |  | $2,393.0 |  |  |  | $2,278.8 |  |  |  | $2,405.9 |
Distribution | 4,179.6 |  |  | 3,981.5 |  |  | 2,311.2 |  |  | 2,205.9 |  |  | 1,868.4 |  |  | 1,775.6 |
Other | 286.3 |  |  | 290.3 |  |  | 210.5 |  |  | 216.3 |  |  | 75.8 |  |  | 74.0 |
Plant anticipated to be retired early (b) | 157.8 |  |  | — |  |  | — |  |  | — |  |  | 157.8 |  |  | — |
|  | $9,415.7 |  |  |  | $9,070.7 |  |  |  | $5,034.9 |  |  |  | $4,815.2 |  |  |  | $4,380.8 |  |  |  | $4,255.5 |
(a) | The decrease in Alliant Energy’s and WPL’s generation portion of electric plant in service was primarily due to classifying Edgewater Unit 3 and Nelson Dewey Units 1 and 2 as “Plant anticipated to be retired early” as of December 31, 2013, which is discussed below. Partially offsetting this decrease at Alliant Energy, and contributing to the increase in IPL’s generation portion of electric plant in service, was an increase at IPL due to a scrubber and baghouse at George Neal Unit 4 being placed in service in the fourth quarter of 2013. As of December 31, 2013, the capitalized project costs for the George Neal Unit 4 scrubber and baghouse were $61 million.
(b) | In 2013, WPL received approval from MISO to retire Edgewater Unit 3, and Nelson Dewey Units 1 and 2. WPL currently anticipates retiring these EGUs by December 31, 2015, contingent on completion of transmission network upgrades needed for system reliability. WPL is recovering the remaining net book value of these EGUs over a 10-year period beginning January 1, 2013 pursuant to a May 2012 PSCW order.
Wind Generation Projects - Wind Site in Franklin County, Iowa - In 2007, IPL acquired approximately 500 MW of wind site capacity in Franklin County, Iowa. The initial 200 MW of the wind site was utilized for IPL’s Whispering Willow - East wind project, which began generating electricity in 2009. In 2011, IPL sold approximately 100 MW of wind site capacity to Resources for construction of a non-regulated wind project referred to as the Franklin County wind project. Future development of the balance of the wind site by IPL will depend on numerous factors such as RPS, environmental legislation, fossil fuel prices, technology advancements and transmission capabilities. As of December 31, 2013, Alliant Energy’s and IPL’s capitalized costs related to the remaining approximately 200 MW of wind site capacity in Franklin County, Iowa were $13 million and were recorded in “Other property, plant and equipment” on their Consolidated Balance Sheets. IPL’s Whispering Willow - East Wind Project - In 2011, IPL received an order from the MPUC approving a temporary recovery rate for the Minnesota retail portion of its Whispering Willow - East wind project construction costs. In its order, the MPUC did not reach a conclusion as to the prudence of these project costs. The prudence of these project costs and the final recovery rate was addressed in a separate proceeding in 2013. The initial recovery rate approved by the MPUC was below the amount required by IPL to recover the Minnesota retail portion of its total project costs. Based on its interpretation of the order, IPL believed that it was probable it would not be allowed to recover the entire Minnesota retail portion of its project costs. IPL estimated the most likely outcome of the final rate proceeding would result in the MPUC effectively disallowing recovery of approximately $8 million of project costs out of a total of approximately $30 million of project costs allocated to the Minnesota retail jurisdiction. As a result, Alliant Energy and IPL recognized an $8 million impairment related to this probable disallowance, which was recorded as a reduction to electric plant and a charge to “Utility - Other operation and maintenance” in their Consolidated Statements of Income in 2011. In December 2013, IPL received an order from the MPUC approving full cost recovery of the Minnesota retail portion of IPL’s Whispering Willow - East wind project construction costs effective January 1, 2013. As a result, Alliant Energy and IPL recognized a $7 million regulatory-related credit, which was recorded as an an increase to “Electric plant” on their Consolidated Balance Sheets and a decrease to “Utility - Other operation and maintenance” in their Consolidated Statements of Income in 2013. Franklin County Wind Project - In 2008, Alliant Energy entered into a master supply agreement with Vestas to purchase 500 MW of wind turbine generator sets and related equipment. Alliant Energy utilized 401 MW of these wind turbine generator sets and related equipment to construct IPL’s Whispering Willow - East and WPL’s Bent Tree - Phase I wind projects. In 2011, IPL sold the remaining 99 MW of wind turbine generator sets and related equipment to Resources for $115.3 million, which represented IPL’s book value for progress payments to date for the wind turbine generator sets and related equipment and land rights in Franklin County, Iowa. In addition, Resources assumed the remaining progress payments to Vestas for the 99 MW of wind turbine generator sets and related equipment. The proceeds received by IPL are presented in investing activities in IPL’s Consolidated Statement of Cash Flows in 2011. Refer to Note 3(b) for further discussion of the Franklin County wind project. Wind Site in Green Lake and Fond du Lac Counties in Wisconsin - In 2009, WPL purchased development rights to an approximate 100 MW wind site in Green Lake and Fond du Lac Counties in Wisconsin. Due to events in 2011 resulting in uncertainty regarding wind siting requirements in Wisconsin and increased risks with permitting this wind site, WPL determined it would be difficult to sell or effectively use the site for wind development. As a result, WPL recognized a $5 million impairment in 2011 for the amount of capitalized costs incurred for this site. Alliant Energy and WPL recorded the impairment as a reduction in other utility property, plant and equipment, and a charge to “Utility - Other operation and maintenance” in their Consolidated Statements of Income in 2011. Environmental Compliance Plans Emission Controls Projects - IPL’s George Neal Units 3 and 4 - In 2011, MidAmerican began installing scrubbers and baghouses at George Neal Units 3 and 4 to reduce SO2 and mercury emissions at the EGUs. The scrubbers and baghouses are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. IPL owns a 28.0% and 25.695% interest in George Neal Units 3 and 4, respectively. Construction of the scrubber and baghouse at George Neal Unit 4 was completed in the fourth quarter of 2013, which resulted in a transfer of the capitalized project costs from “Construction work in progress - Other” to “Electric plant” on Alliant Energy’s and IPL’s Consolidated Balance Sheets in 2013. As of December 31, 2013, the capitalized project costs consisted of capital expenditures of $57 million and AFUDC of $4 million for IPL’s allocated portion of the George Neal Unit 4 scrubber and baghouse. Construction of the scrubber and baghouse at George Neal Unit 3 is expected to be completed in 2014. As of December 31, 2013, Alliant Energy and IPL recorded capitalized expenditures of $53 million and AFUDC of $2 million for IPL’s allocated portion of the George Neal Unit 3 scrubber and baghouse in “Construction work in progress - George Neal Generating Station Unit 3 emission controls” on their Consolidated Balance Sheets. IPL’s Ottumwa Unit 1 - IPL is currently installing a scrubber and baghouse at Ottumwa Unit 1 to reduce SO2 and mercury emissions at the EGU. IPL owns a 48% interest in Ottumwa Unit 1. Construction began in the second quarter of 2012 and is expected to be completed in 2014. The scrubber and baghouse are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. As of December 31, 2013, Alliant Energy and IPL recorded capitalized expenditures of $125 million and AFUDC of $10 million for IPL’s allocated portion of the scrubber and baghouse in “Construction work in progress - Ottumwa Generating Station Unit 1 emission controls” on their Consolidated Balance Sheets. WPL’s Columbia Units 1 and 2 - WPL is currently installing scrubbers and baghouses at Columbia Units 1 and 2 to reduce SO2 and mercury emissions at the EGU. WPL owns a 46.2% interest in Columbia Units 1 and 2. Construction began in the first quarter of 2012 and is expected to be completed in 2014. The scrubbers and baghouses are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. As of December 31, 2013, Alliant Energy and WPL recorded capitalized expenditures of $254 million and AFUDC of $11 million for WPL’s allocated portion of the scrubbers and baghouses in “Construction work in progress - Columbia Energy Center Units 1 and 2 emission controls” on their Consolidated Balance Sheets. WPL’s Edgewater Unit 5 - In June 2013, WPL received an order from the PSCW approving WPL’s CA application to install a scrubber and baghouse at Edgewater Unit 5 to reduce SO2 and mercury emissions at the EGU. WPL currently expects to begin construction of the project in 2014 and place it in service in 2016. The scrubber and baghouse are expected to help meet requirements under the MATS Rule and CAIR or some alternative to CAIR that may be implemented. Proposed Sales of IPL’s Minnesota Electric and Natural Gas Distribution Assets - In September 2013, IPL signed a definitive agreement to sell its Minnesota electric distribution assets to Southern Minnesota Energy Cooperative, a combined group of various neighboring electric cooperatives. Also in September 2013, IPL signed a definitive agreement to sell its Minnesota natural gas distribution assets to Minnesota Energy Resources Corporation, a subsidiary of Integrys Energy Group, Inc. Proceeds from the sales are expected to be approximately $128 million in aggregate, subject to customary closing adjustments. The proceeds are expected to reduce Alliant Energy’s and IPL’s future financing requirements. Pending all necessary federal and state regulatory approvals, including the MPUC, FERC and the IUB, the transactions are expected to be concluded in the second half of 2014. The sales price of the assets expected to be sold, which primarily consist of property, plant and equipment, and working capital items, is expected to result in a modest gain. Any after-tax gain realized from the transaction may be subject to refund to IPL’s customers. As of December 31, 2013, IPL’s assets and liabilities included in the sale agreements did not meet the criteria to be classified as held for sale due to uncertainties in the regulatory approval process. The operating results of IPL’s Minnesota electric and natural gas distribution businesses also did not qualify as discontinued operations as of December 31, 2013. The electric distribution asset sales agreement includes a wholesale power supply agreement between IPL and Southern Minnesota Energy Cooperative, which is subject to FERC approval. The agreement contains a five-year termination notice, which may not be given until the fifth anniversary of the effective date of the agreement, resulting in a minimum term of 10 years. The agreement remains in effect indefinitely, unless notice to terminate is provided by either party. This wholesale power supply agreement includes standardized pricing mechanisms that are detailed in IPL’s current tariffs accepted by FERC through wholesale rate case proceedings. IPL’s current return on common equity authorized by FERC related to its wholesale electric rates is 10.97%. As a result of IPL’s requirement to supply electricity to Southern Minnesota Energy Cooperative under the wholesale power supply agreement, the sale of the electric distribution assets is not expected to have a significant impact on IPL’s current generation plans or operating results. AFUDC - AFUDC represents costs to finance construction additions including a return on equity component and cost of debt component as required by regulatory accounting. The concurrent credit for the amount of AFUDC capitalized is recorded as “Allowance for funds used during construction” in the Consolidated Statements of Income. The amount of AFUDC generated by equity and debt components was as follows (in millions):
| Alliant Energy |  | IPL |  | WPL
| 2013 |  | 2012 |  | 2011 |  | 2013 |  | 2012 |  | 2011 |  | 2013 |  | 2012 |  | 2011
Equity |  | $20.3 |  |  |  | $14.1 |  |  |  | $7.6 |  |  |  | $13.8 |  |  |  | $5.2 |  |  |  | $3.5 |  |  |  | $6.5 |  |  |  | $8.9 |  |  |  | $4.1 |
Debt | 10.5 |  |  | 7.8 |  |  | 4.4 |  |  | 7.2 |  |  | 3.2 |  |  | 2.3 |  |  | 3.3 |  |  | 4.6 |  |  | 2.1 |
|  | $30.8 |  |  |  | $21.9 |  |  |  | $12.0 |  |  |  | $21.0 |  |  |  | $8.4 |  |  |  | $5.8 |  |  |  | $9.8 |  |  |  | $13.5 |  |  |  | $6.2 |
AFUDC related to various construction projects was recognized in Alliant Energy’s, IPL’s and WPL’s Consolidated Statements of Income as follows (in millions):
| 2013 |  | 2012 |  | 2011
IPL: |  |  |  |  |
Emission controls - Ottumwa Unit 1 |  | $8.0 |  |  |  | $2.0 |  |  |  | $— |
Emission controls - George Neal Units 3 and 4 | 5.1 |  |  | 0.9 |  |  | — |
Other | 7.9 |  |  | 5.5 |  |  | 5.8 |
| 21.0 |  |  | 8.4 |  |  | 5.8 |
WPL: |  |  |  |  |
Emission controls - Columbia Units 1 and 2 | 7.2 |  |  | 3.9 |  |  | 0.2 |
Emission controls - Edgewater Unit 5 | — |  |  | 7.2 |  |  | 2.9 |
Other | 2.6 |  |  | 2.4 |  |  | 3.1 |
| 9.8 |  |  | 13.5 |  |  | 6.2 |
Alliant Energy |  | $30.8 |  |  |  | $21.9 |  |  |  | $12.0 |

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