Let me also remind you that CVR Partners completed a 1 for 10 reverse split of its common units on November 23, 2020.
Yesterday, we reported a first quarter consolidated net loss of $55 million and a loss per share of $0.39.
Unplanned downtime and increased operating costs associated with the winter storm negatively impacted our first quarter results by approximately $41 million.
Our earnings for the quarter were further impacted by a noncash mark-to-market on our 2020 RIN obligation of $98 million.
For our Petroleum segment, the combined throughput for the first quarter of 2021 was approximately 186,000 barrels per day as compared to 157,000 barrels per day for the first quarter of 2020, which was impacted by the planned turnaround at Coffeyville.
We experienced unplanned downtime at both facilities in February as a result of the winter storm, which reduced total throughput for the quarter by approximately 34,000 barrels per day.
The Group 3 2-1-1 crack averaged $16.33 per barrel in the first quarter as compared to $12.21 for the first quarter of 2020.
On a 2020 RVO basis, RIN prices averaged approximately $5.57 per barrel in the first quarter, a 250% increase from the first quarter of 2020.
The Brent-WTI differential averaged $3.18 in the first quarter compared to $5.04 per barrel in the prior year period.
The Midland Cushing differential was $0.87 per barrel over WTI in the quarter compared to $0.06 per barrel under WTI in the first quarter of 2020.
And the WCS to WTI differential was $11.82 per barrel compared to $17.77 for the same period last year.
Light product yield for the quarter was 100% on crude oil processed and current economics dictate maximizing gasoline.
In total, we gathered approximately 112,000 barrels per day of crude oil during the first quarter of 2021 compared to 136,000 barrels per day for the same period last year.
We currently forecast our gathering volumes for the second quarter to be in the 125,000 to 130,000 barrel a day range.
Ammonia utilization for the first quarter was 87% at Coffeyville and 89% at East Dubuque.
With the USDA estimating corn planning this year of 91 million acres, the 2020 inventory carryout could be at the lowest level since 2014.
Our consolidated net loss of $55 million and loss per diluted share of $0.39 includes a mark-to-market gain of $62 million related to our investment in Delek and favorable inventory valuation impact of $66 million.
The effective tax rate for the first quarter 2021 was a benefit of 43% compared to a benefit of 27% for the prior year period, primarily due to state income tax credits.
We continue to anticipate an income tax refund related to the CARES Act of $35 million or $40 million, which we expect to receive in the second half of 2021.
The Petroleum segment's EBITDA for the first quarter of 2021 was negative $61 million, which included an inventory valuation benefit of $66 million.
This compares to EBITDA of negative $77 million in the first quarter of 2020, which included unfavorable inventory valuation impact of $136 million.
Excluding inventory valuation impacts in both periods, our Petroleum segment EBITDA would have been negative $127 million for the first quarter of 2021 compared to positive $59 million in the prior year period.
In the first quarter of 2021, our Petroleum segment's refining margin, excluding inventory impacts, was negative $0.88 per total throughput barrel compared to $11.06 in the same quarter of 2020.
The increase in crude oil and refined product prices through the quarter generated an inventory valuation benefit of $3.93 per barrel, this compares to a $9.54 per barrel unfavorable impact in the same period last year.
Excluding inventory valuation impact, unrealized derivative gains and losses and the mark-to-market impact of our 2020 RIN obligation, the capture rate for the first quarter of 2021 was 46% compared to 86% in the first quarter of 2020.
In addition, RINs expense reduced our capture rate by 65% in the first quarter of 2021, which includes a 36% impact related to the mark-to-market of our 2020 RIN obligation.
Derivative losses for the first quarter of 2021 totaled $32 million, which includes unrealized losses of $43 million, primarily associated with frac spread derivatives, offset by gains on Canadian Crude Oil.
In the first quarter of 2020, we had total derivative gains of $46 million, which included unrealized gains of $12 million.
RINs expense in the first quarter of 2021 was $178 million or $10.62 per barrel of total throughput compared to $19 million or $1.32 per barrel for the same period last year.
Our first quarter RINs expense was inflated by $98 million from the mark-to-market impact related to our 2020 accrued RFS obligation, which was mark-to-market at an average RIN price of $1.39 at quarter end.
We believe Wynnewood's obligation for 2021 should be exempt under the RFS regulation; for the full year 2021, we forecast a net obligation of approximately of 230 million RINs without considering waivers yet inclusive of the RINs we expect to generate from the renewable diesel production in the second half of the year.
The Petroleum segment's direct operating expenses were $5.89 per barrel in the first quarter of 2021 as compared to $5.87 per barrel in the prior year period.
On an absolute basis, operating expenses increased approximately $15 million compared to the first quarter 2020, primarily due to higher natural gas costs that are currently in dispute and additional repair and maintenance expenditures related to winter storm Uri.
For the first quarter of 2021, the Fertilizer segment reported an operating loss of $14 million, a net loss of $25 million or $2.37 per common unit and EBITDA of $5 million.
This is compared to first quarter 2020 operating losses of $5 million, a net loss of $21 million or $1.83 per common unit and EBITDA of $11 million.
During the quarter, CVR Partners repurchased just over 24,000 of its common units for $0.5 million.
Total consolidated capital spending for the first quarter of 2021 was $68 million, which included $10 million from the Petroleum segment, $3 million from the Fertilizer segment and $55 million from the Renewables segment.
Environmental and maintenance capital spending comprised $12 million, including $10 million in the Petroleum segment and $2 million in the Fertilizer segment.
We estimate total consolidated capital spending for 2021 to be approximately $235 million to $250 million, of which approximately $106 million to $114 million is expected to be environmental and maintenance capital and $123 million to $128 million is related to the renewable diesel project at Wynnewood.
Our consolidated capital spending plan excludes planned turnaround spending, which we estimate to be approximately $9 million for the year in preparation for the planned turnaround at Wynnewood in 2022 and Coffeyville in 2023.
Cash provided by operations for the first quarter of 2021 was $96 million.
Despite elevated natural gas and utilities cost, increased capital spending and closing on the Oklahoma pipeline acquisition, we generated free cash flow in the quarter of $61 million.
Working capital was a source of approximately $218 million in the quarter due to an increase in our RINs obligation and an increase in lease pre payable.
At March 31, we ended the quarter with approximately $707 million in cash, an increase of $40 million from the end of 2020.
Our consolidated cash balance includes $53 million in the Fertilizer segment.
As of March 31, excluding CVR Partners, we had approximately $1 billion of liquidity, which was comprised of approximately $655 million of cash, securities available for sale of $235 million and availability under the ABL of approximately $364 million less cash included in the borrowing base of $208 million.
Looking ahead to the second quarter of 2021, for our Petroleum segment, we estimate total throughput to be approximately 200,000 to 220,000 barrels per day.
We expect total direct operating expenses to range between $75 million and $85 million and total capital spending to be between $6 million and $12 million.
For the Fertilizer segment, we estimate our ammonia utilization rate to be greater than 95%.
We expect direct operating expenses to be approximately $35 million to $40 million, excluding inventory impacts and total capital spending to be between $4 million and $7 million.
Capital spending in the Renewables segment is expected to range between $65 million and $70 million.
And with the increase in the Group 3 cracks, we have observed positive EBITDA trends in March, absent the 2020 mark-to-market impact for RINs.
Starting with crude oil, global inventories are at or near 5-year averages and worldwide demand is projected at 96 million barrels per day for 2021, according to OPEC, a year-over-year increase of 6 million barrels per day.
Passenger count and TSA checkpoint check-ins are higher, but still down over 40% compared to pre-pandemic levels and the imports of gasoline and diesel are higher while exports of both products are lower than a year ago.
US refining throughput is down over 1 million barrels per day versus the 5-year average, although EIA reported utilization stats are distorted due to permanent refinement closures and reduced operable capacity.
For the Fertilizer segment, the USDA is projecting 91 million acres of corn planted this year.
The spring run has been strong, and NOLA urea price is around 200 -- excuse me, $385 per ton with UAN at nearly $300 per ton.
Our net debt[Phonetic] prices have dramatically improved for nitrogen fertilizers by about 40% compared to the first quarter of 2021 levels.
We currently expect total cost of the project to be $135 million to $140 million.
As we work toward the completion of Phase 1, we are close to selecting technology for a potential Phase 2, which would involve adding pretreatment capabilities for lower cost and lower CI feedstocks.
We are also starting a feasibility study for Phase 3 of developing a similar renewable diesel conversion project at Coffeyville and we are exploring the opportunities to add biomasses of feedstock to one or both of our refineries to aid in our sustainability efforts.
Looking at the second quarter of 2021, quarter-to-date metrics are as follows: Group 3 2-1-1 cracks have averaged $19.48 per barrel with RINs averaging $6.92 on a 2020 RVO basis.
The Brent-TI spread has averaged $3.62, with the Midland Cushing differential at $0.36 over WTI and the WTL differential at $0.14 per barrel under WTI, Cushing WTI and a WCS differential of $11.29 per barrel under WTI.
Ammonia prices have increased to over $600 a ton, while UAN prices are over $325 per ton.
As of yesterday, Group 3 2-1-1 cracks were $20.26 per barrel; Brent-TI was $3.07 And WCS was $11.90 under WTI.
On a 2020 RVO basis, RINs were approximately $7.83 per barrel.

Summary:
Yesterday, we reported a first quarter consolidated net loss of $55 million and a loss per share of $0.39.
For our Petroleum segment, the combined throughput for the first quarter of 2021 was approximately 186,000 barrels per day as compared to 157,000 barrels per day for the first quarter of 2020, which was impacted by the planned turnaround at Coffeyville.
Our consolidated net loss of $55 million and loss per diluted share of $0.39 includes a mark-to-market gain of $62 million related to our investment in Delek and favorable inventory valuation impact of $66 million.
Derivative losses for the first quarter of 2021 totaled $32 million, which includes unrealized losses of $43 million, primarily associated with frac spread derivatives, offset by gains on Canadian Crude Oil.