Robert J. Durian
Executive Vice President and Chief Financial Officer at Alliant Energy
Thanks, John. Good morning, everyone. Yesterday, we announced third quarter 2021 GAAP earnings of $1.02 per share compared to $0.98 per share in the third quarter last year. Our higher earnings year over year were driven by higher revenue requirements due to increasing rate base as well as higher temperature normalized sales compared to the third quarter of 2020. These higher earnings were partially offset by higher depreciation expense and timing of income tax expense. Additionally, in the third quarter of 2020, we recorded a non-GAAP adjustment of $0.04 per share related to a legacy guarantee in our nonutility operations.
Through the first nine months of this year, temperatures in our service territory have increased retail electric and gas margins by approximately $0.08 per share. By comparison in 2020, the year-to-date temperature impacts through the first three quarters increased retail electric and gas margins by approximately $0.01 per share. Turning to temperature normalized sales. Our retail electric sales in the third quarter of 2021 were up 4.1% versus last year.
The two key drivers for this increase are continued pandemic recovery in year-over-year sales, particularly in the commercial and industrial classes and minimal storm activity this year compared to the third quarter of 2020 when our Iowa territory experienced a derecho windstorm. Through the first nine months of 2021, temperature-normalized electric sales have been better than forecasted, largely due to higher-than-expected demand from residential and industrial customer classes. As John mentioned, last night, we issued our consolidated 2022 earnings guidance range of $2.65 to $2.79 per share.
The key driver of the 6% growth in temperature normalized EPS is higher earnings on increasing capital investments, primarily driven by our solar program. The details of our refreshed capital expenditure plans are shown on slides 5 and 6. Our capital expenditures, net of expected tax equity contributions over the five year period from 2021 through 2025, will total approximately $7 billion or an average of $1.4 billion per year. Our capital expenditure plans continue to be focused on the transition to cleaner energy and strengthening the reliability and resiliency of our electric grid.
We continue to make progress on our plans to add 1,500 megawatts of solar energy for both our Wisconsin and Iowa customers and have adjusted our flexible capital expenditure plans to address the current market conditions for solar panels and related project materials. Our plan includes expectations for increasing costs for these solar projects as supply constraints and commodity inflation continue to be prevalent in the solar market. Despite increasing costs, these solar projects remain key elements of our clean energy blueprints and will bring long-term environmental and cost benefits to our customers.
In addition to the 1.1 gigawatts of solar previously announced for our Wisconsin customers, our plan includes additional renewables and energy storage in Wisconsin, in part to replace the capacity from a portion of the West Riverside Energy Center that we anticipate will be purchased by our neighboring utilities over the next few years. In Iowa, we recently completed an advanced rate making filing for our announced 400 megawatts of solar and 75 megawatts of battery storage. We plan for 200 megawatts of that solar, plus the battery storage, to be located at the site of the recently retired Duane Arnold Energy Center, leveraging the existing transmission interconnection from the former nuclear plant.
This will be our first utility-scale battery storage installation and will be an important complement to our solar generation. Finally, we've also included capital expenditures in the latter part of our five year plan for additional energy storage and renewables, including wind repowering opportunities, to increase our portfolio of cost-effective clean energy sources for our utility customers. Slide 9 has been provided to assist you in modeling the effective tax rates for our two utilities and our consolidated group. We estimate a consolidated effective tax rate of negative 13% for 2021 and positive 6% for 2022.
At our Wisconsin utility, we will have returned essentially all of the available excess deferred income tax benefits to our customers by the end of 2021, leading to a higher effective tax rate going forward. At our Iowa utility, our large wind portfolio and the resulting production tax credits will maintain our lower effective tax rate for several more years. The production tax credits and excess deferred tax benefits flow back to customers, resulting in lower electric margins. Thus, the changes in the effective tax rate related to the PTCs and excess deferred tax benefits are largely earnings neutral.
Next, I'd highlight our continued focus on controlling costs for our customers. We have met virtually with many of you throughout this year and shared our strategy to reduce O&M over the next few years. This strategy is important as we head into the upcoming winter heating season, with much higher anticipated fuel prices, reminding us that our customers need our continued focus on controlling costs to keep rates affordable. Additionally, while we are not immune to rising commodity prices, we are able to leverage our risk management programs to mitigate the impact of rising natural gas and coal costs on customer bills.
Let's move next to our financing plans. In September, we issued a $300 million green bond at WPL to finance renewal projects in Wisconsin. The coupon rate of 1.95% represents the lowest interest rate for a 10-year debenture issued by WPL, helping to support our customer affordability objectives. Our financing plan over the next 14 months includes issuing up to $1.4 billion of long-term debt at our utilities and Alliant Energy Finance. The proceeds from the new debt issuances will be used to refinance existing debt and the redemption of preferred stock and to finance the utilities capital expenditure plans.
Our 2022 financing plans also include $25 million of new common equity through our DRIP plan. Lastly, we have included our regulatory initiatives of note on slide 7. As mentioned earlier, this week, we filed the advanced ratemaking principles for 400 megawatts of solar and 75 megawatts of storage for our Iowa utility. The key details of this filing are outlined on slide 8. We plan to receive a decision on this filing in the second half of 2022.
Looking ahead, this quarter, we expect to receive the written decision regarding our WPL rate review, including the decision on the innovative cost recovery mechanism for the Edgewater Unit 5 coal plant expected to retire by the end of 2022. And in the first half of next year, we plan to receive a decision on our second solar CA filing in Wisconsin. We very much appreciate your continued support of our company and look forward to meeting with many of you during the EEI finance conference next week. Later today, we expect to post on our website the EEI investor presentation and the November 2021 fact book, which details the separate IPL and WPL updated capital expenditures, rate base and construction work and progress forecast through 2025.
At this time, I'll turn the call back over to the operator to facilitate the question-and-answer session.
