I want to take a moment to highlight a number of partnerships and strategic milestones, and the evolution of our next generation technologies.
As part of our alliance, Cummins will be the electrolyzer supplier for a 230 megawatt project for a leading fertilizer producer that will serve as a benchmark for large PEM scale electrolysis globally.
As one of the largest hydrogen suppliers in China, Sinopec's annual hydrogen production reaches 3.5 million tons, accounting for 14% of total -- China's total hydrogen production.
Following successful demonstration, the project includes ramp-ups, which -- with a total of 2,000 trucks to be delivered by the middle of the decade.
We've now deployed more than 2,000 fuel cells and 600 electrolyzers around the world as we continue the development of our hydrogen business.
Site selection search within the Guadalajara area of Castilla-La Mancha in Spain is currently underway for Cummins new approximately $60 million PEM electrolyzer manufacturing plant that will house system assembly and testing for approximately 500 megawatts per year of electrolyzer production and will be scalable to more than one gigawatt per year.
The JV will initially invest $47 million to locate a manufacturing plant to produce PEM electrolyzers.
The plant will open with a manufacturing capacity of 500 megawatts of electrolyzers per year, but will also be scalable to more than one gigawatt per year.
We announced the signing of an LOI to acquire a 50% equity interest in Momentum Fuel Technologies.
Revenues for the second quarter of 2021 were $6.1 billion, an increase of 59% compared to the second quarter of 2020.
EBITDA was $974 million or 15.9% compared to $549 million or 14.3% a year ago.
Our second quarter revenues in North America grew 74% to $3.5 billion, driven by higher industry build rates across all on-highway markets.
Industry production of heavy-duty trucks in the second quarter was 67,000 units, an increase of 180% from 2020 levels.
While our heavy-duty unit sales were $23,000, an increase of 217% from 2020.
Industry production of medium-duty trucks was 29,000 units in the second quarter of 2021, an increase of 94% from 2020 levels, while our unit sales were 22,000 units, an increase of 85% from 2020.
We shipped 42,000 engines to Stellantis for use in the Ram pickups in the second quarter of 2021, an increase of 272% from 2020 levels.
Revenues for Power Generation grew by 48% due to higher demand in recreational vehicle, standby power and data center markets.
Our international revenues increased by 42% in the second quarter of 2021 compared to a year ago.
Second quarter revenues in China, including joint ventures, were $2.1 billion, an increase of 8% due to higher sales in power generation and mining markets.
Industry demand for medium and heavy-duty trucks in China was 566,000 units, a decrease of 4%, but still well above replacement, driven by continued pre-buy of NS V trucks, ahead of the broader implementation of the new NS VI standards in July of this year.
Our sales and units, including joint ventures, were 85,000 units, a decrease of 5% versus the second quarter of 2020.
The light-duty market in China decreased 8% from 2020 levels to 614,000 units, while our units sold, including joint ventures, were 38,000, a decrease of 28%, driven by supply chain constraints, particularly in these lighter displacement vehicles.
Industry demand for excavators in the second quarter was 97,000 units, a decrease of 5% from very high 2020 levels.
Our units sold were 16,800 units, a decrease of 7%.
The demand for power generation equipment in China increased 47% in the second quarter, driven by growth in data center markets and other standby power markets.
Second quarter revenues in India including joint ventures were $392 million, an increase of 219% from the second quarter of 2020, despite experiencing a terrible second wave of COVID-19 during this period.
Industry truck production increased by 468%, while our shipments increased 535%, as our joint venture partner continued to gain share.
In Brazil, our revenues increased 175%, driven by increased demand in most end markets.
Based on our current forecast, we are maintaining full year 2021 revenue guidance of up 20% to 24% versus last year.
EBITDA is still expected to be in the range of 15.5% to 16%.
And the company expects to return 75% of operating cash flow to shareholders in 2021, in the form of dividend and share repurchases.
The business generated revenues of approximately $1.2 billion in 2020, and remains well positioned for continued growth, sustained margin performance and strong free cash flow generation.
And any costs associated with the evaluation of these alternatives for the Filtration business has been excluded from our financial outlook.
And fourthly, we returned $860 million to shareholders in the quarter through cash dividends and share repurchases and $1.48 billion for the first half of the year, consistent with our plan to return 75% of operating cash flow to shareholders this year.
Second quarter revenues were $6.1 billion, an increase of 59% from a year ago when the impact of COVID-19 was at its most severe.
Sales in North America grew 74% and international revenues rose 42%.
Currency positively impacted revenues by 3%, driven primarily by a weaker US dollar.
EBITDA was $974 million or 15.9% of sales for the quarter compared to $549 million or 14.3% of sales a year ago.
Gross margin of $1.5 billion or 24.2% of sales increased by $588 million or 110 basis points, primarily driven by the higher volumes, global supply chain tightness continued in the second quarter and resulted in approximately $100 million of additional freight, labor and logistics costs.
Selling, general and administrative expenses increased by $130 million or 28% due to higher compensation expenses.
And research expenses increased by $87 million or 46% from a year ago.
Salary reductions resulted in approximately $75 million of pre-tax savings for the company in the second quarter of 2020 across gross margin, selling, admin and research expenses.
Joint venture income was $137 million in the second quarter, up from $115 million a year ago.
Other income increased by $30 million from a year ago due to a number of positive items, including a one-time $18 million gain on the sale of some land in India, which benefited our Distribution segment.
Net earnings for the quarter were $600 million or $4.10 per diluted share compared to $276 million or $1.86 from a year ago, primarily due to stronger after-tax earnings driven by stronger volumes.
The gain on the sale of land in India contributed $0.05 of earnings per share this quarter.
The effective tax rate in the quarter was 21.4%.
Operating cash flow in the quarter was an inflow of $616 million, compared to an outflow of $22 million a year ago.
For the Engine segment, second quarter revenues increased by 75%, driven by increased demand for trucks in the U.S. and construction equipment in U.S. and Europe.
EBITDA increased from 10.5% to 16.1% of sales, primarily driven by higher volumes and lower product coverage expense, which more than offset higher costs and inefficiencies associated with global supply chain challenges.
We expect full year revenues to be up 23% to 27%, and EBITDA margins to be in the range of 14.5% to 15% for the Engine segment.
In Distribution, revenues increased 20% from a year ago.
And EBITDA increased as a percent of sales from 10% to 10.5%, primarily due to stronger performance in North America.
We have maintained our outlook for segment revenue growth to be up 6% to 10%, and EBITDA margins to be 9% at the midpoint of our guidance.
In the Components business, revenues increased 73% in the second quarter, driven primarily by stronger demand for trucks in North America.
EBITDA increased from 12.3% of sales to 15.1%, due to the benefits of stronger volumes, partially offset by higher product coverage costs.
For the full year 2021, we expect Components revenue to increase 30% to 34% and EBITDA to be 17%, at the midpoint.
In the Power Systems segment, revenues increased 47% in the second quarter, driven by stronger global demand for power generation and mining equipment.
EBITDA increased from 11.7% to 12.2% of sales, primarily due to the benefits of higher volumes and lower product coverage expenses.
We are maintaining our Power Systems guidance of revenues up 16% to 20%, and EBITDA margin in the range of 11% to 11.5% of sales.
In the New Power segment, revenues increased to $24 million, up 140%, due to stronger sales of battery electric systems and fuel cells.
EBITDA losses for the quarter were $60 million, in line with our expectations, as we continue to invest in new products and scale up ahead of widespread adoption of the new technologies.
For Full year, we currently project New Power revenues of $110 million to $130 million and EBITDA losses to be in the range of $190 million to $210 million.
Total company guidance remains unchanged, with revenues to grow between 20% and 24%.
And EBITDA margin to be between 15.5% and 16%, for the full year.
EBITDA perfect for the first half of the year was 16%.
We now expect earnings from joint ventures to be up 10% in 2021, compared to our prior year guidance of down 5%.
Our effective tax rate is expected to be approximately 21.5%, excluding discrete items, down from our prior guidance of 22.5% due to the mix of geographic earnings, capex -- capital expenditures were $125 million in the quarter, up from $77 million a year ago.
And we expect our full year capital expenditures to be at the high end of our range of $725 million to $775 million for the full year.
We returned $869 million to shareholders through dividends and share repurchases in the second quarter, bringing our total cash returns to $1.48 billion for the first half -- excuse me for my dry throat.

Summary:
I want to take a moment to highlight a number of partnerships and strategic milestones, and the evolution of our next generation technologies.
Revenues for the second quarter of 2021 were $6.1 billion, an increase of 59% compared to the second quarter of 2020.
Based on our current forecast, we are maintaining full year 2021 revenue guidance of up 20% to 24% versus last year.
And any costs associated with the evaluation of these alternatives for the Filtration business has been excluded from our financial outlook.
Net earnings for the quarter were $600 million or $4.10 per diluted share compared to $276 million or $1.86 from a year ago, primarily due to stronger after-tax earnings driven by stronger volumes.
Total company guidance remains unchanged, with revenues to grow between 20% and 24%.