Let me also remind you that CVR Partners completed a 1-for-10 reverse split of its common units on November 23, 2020.
For this reason, we've began exploring utilizing excess hydrogen capacity at our refineries for renewable diesel production nearly two years ago and have invested nearly $150 million since on those initiatives.
We have made progress on several fronts since our last call and are accelerating our efforts with the Board's recent approval of the feed pretreater at Wynnewood at an estimated cost of $60 million.
Yesterday, we reported third quarter consolidated net income of $106 million and earnings per share of $0.83.
EBITDA for the quarter was $243 million.
For our Petroleum segment, the combined total throughput for the third quarter of '21 was approximately 211,000 barrels per day as compared to 201,000 barrels per day in the third quarter of 2020, which was impacted by some weather-related power outages.
The Group 3 2-1-1 crack averaged $20.50 per barrel in the third quarter as compared to $8.34 in the third quarter of '20.
Based on the 2020 RVO levels, RIN prices averaged approximately $7.31 per barrel in the third quarter, an increase of 177% from the third quarter of 2020.
The Brent-TI differential averaged $2.71 per barrel in the third quarter compared to $2.42 in the prior year period.
Light product yield for the quarter was 100% on crude oil processed.
In total, we gathered approximately 112,000 barrels per day of crude oil during the third quarter of '21 compared to 124,000 barrels per day in the same period last year.
In the Fertilizer segment, both plants ran well during the quarter with a consolidated ammonia utilization of 94%.
For the third quarter of 2021, our consolidated net income was $106 million, earnings per share was $0.83 and EBITDA was $243 million.
Our third quarter results include a positive mark-to-market impact on our estimated outstanding RIN obligation of $115 million, unrealized derivative gains of $22 million and favorable inventory valuation impacts of $8 million.
Excluding the above mentioned items, adjusted EBITDA for the quarter was $99 million.
The Petroleum segment's adjusted EBITDA for the third quarter of 2021 was $43 million compared to breakeven adjusted EBITDA for the third quarter of 2020.
In the third quarter of 2021, our Petroleum segment's reported refining margin was $15.03 per barrel.
Excluding favorable inventory impacts of $0.41 per barrel, unrealized derivative gains of $1.17 per barrel, and the mark-to-market impact of our estimated outstanding RIN obligation of $5.94 per barrel, our refining margin would have been approximately $7.51 per barrel.
On this basis, capture rate for the third quarter of 2021 was 37% compared to 55% in the third quarter of 2020.
RINs expense excluding mark-to -market impacts reduced our third quarter capture rate by approximately 26% compared to a 22% reduction in the prior period.
In total, RINs expense in the third quarter of 2021 was a benefit of $16 million or $0.81 per barrel of total throughput, compared to $36 million, or $1.96 per barrel of expense for the same period last year.
Our third quarter RINs expense was reduced by $115 million from the mark-to-market impact on our estimated RFS obligation, which was mark-to-market at an average RIN price of $1.31 at quarter end compared to $1.67 at the end of the second quarter.
Third quarter RINs expense excluding mark-to-market impacts was $99 million compared to $35 million in the prior year period.
For the full year of 2021, we forecast an obligation based on 2020 RVO levels of approximately 270 million RINs, which does not include the impact of any waivers or exemptions.
Derivative losses for the third quarter of 2021 totaled $12 million, which includes unrealized gains of $22 million, primarily associated with crack spread derivatives.
In the third quarter of 2020, we had total derivative gains of $5 million, which included unrealized gains of $1 million.
The Petroleum segment's direct operating expenses were $4.52 per barrel in the third quarter of 2021 as compared to $4.17 per barrel in the prior year period.
For the third quarter of 2021, the Fertilizer segment reported operating income of $46 million, net income of $35 million or $3.28 per common unit and EBITDA of $64 million.
This is compared to third quarter of 2020 operating losses of $3 million and net loss of $19 million or $1.70 per common unit and EBITDA of $15 million.
The partnership declared a distribution of $2.93 per common unit for the third quarter of 2021.
As CVR Energy owns approximately 36% of CVR Partners' common units, we will receive a proportionate cash distribution of approximately $11 million.
Total capital spending for the third quarter of 2021 was $38 million, which included $12 million from the Petroleum segment, $7 million from the Fertilizer segment and $19 million on the renewable diesel unit.
Environmental and maintenance capital spending comprised $15 million, including $12 million in the Petroleum segment and $3 million in the Fertilizer segment.
We estimate total consolidated capital spending for 2021 to be approximately $208 million to $223 million, of which approximately $66 million to $73 million is expected to be environmental and maintenance capital.
Our consolidated capital spending plan excludes planned turnaround spending, which we estimate will be approximately $4 million for the year and preparation for the planned turnarounds at Wynnewood in 2022 and Coffeyville in 2023.
Cash provided by operations for the third quarter of 2021 was $139 million and free cash flow was $76 million.
During the quarter, we paid cash taxes of $67 million, which was partially offset by the receipt of a $32 million income tax refund related to the NOL carryback provisions of the CARES Act.
Other material cash uses in the quarter included $31 million for interest, $15 million for the partial redemption of CVR Partners' 2023 senior notes and $11 million for the non-controlling interest portion of the CVR Partners' second quarter distribution.
At September 30th, we ended the quarter with approximately $566 million of cash.
Our consolidated cash balance includes $101 million in the Fertilizer segment.
As a September 30th, excluding CVR Partners, we had approximately $680 million of look liquidity, which was primarily comprised of approximately $469 million of cash and availability under the ABL of approximately $370 million, less cash included in the borrowing base of $160 million.
Looking ahead to the fourth of 2021 for a Petroleum segment, we estimate total throughput to be approximately 210,000 to 230,000 barrels per day.
We expect total direct operating expenses to range between $90 million and $100 million and total capital spending to be between $26 million and $30 million.
For the Fertilizer segment, we estimate our fourth quarter 2021 ammonia utilization rate to be between 90% and 95%.
Direct operating expenses to be approximately $45 million to $50 million, excluding inventory in turn around impacts and total capital spending to be between $9 million and $12 million.
Starting with crude oil, OPEC is clearly in the driver seat from a crude price standpoint, inventories have dropped in the US and across the world and backwardation is firmly in place around $12 a barrel over the next year.
While we expect to see shale oil production improving at $80 crude, additional Canadian production has been slow to develop despite additional takeaway capacity.
The outlook for the nitrogen fertilizer market is very positive through the next year and we are happy to have our 36% ownership in CVR Partners common units.
The Board has approved the project and we are currently estimating completion late in the fourth quarter of 2022 at a capital investment of approximately $60 million.
Third, on the Coffeyville project, Schedule A engineering is in process for the renewable diesel conversion with an expected annual capacity of approximately 150 million gallons of renewable fuel per year with an option of up to 25 million gallons of that amount to be sustainable aviation fuels should regulations support it.
Looking at the fourth quarter of 2021, quarter-to-date metrics are as follows: Group 3 2-1-1 cracks have averaged $19.24 with RINs averaging $6.77 on a 2020 RVO basis.
The Brent-TI spread has averaged $2.52 with the Midland Cushing differential at $0.31 over WTI and the WTI differential at $0.19 per barrel over Cushing WTI, and the WCS differential of $13.56 per barrel under WTI.
Forward ammonia prices have increased to over a $1,000 per ton, while UAN prices are over $500 a ton.
As of yesterday, Group 3 2-1-1 cracks were $15.65 per barrel, the Brent-TI was $0.66 per barrel and the WCS was $15.10 under WTI.
On the 2020 RVO basis, RINs were approximately $6.26 per barrel.

Summary:
Yesterday, we reported third quarter consolidated net income of $106 million and earnings per share of $0.83.
For the third quarter of 2021, our consolidated net income was $106 million, earnings per share was $0.83 and EBITDA was $243 million.