What was the growth rate of equipment orders in the offshore wind segment in the first half of 2021 
roductivity through lean and prior period restructuring. At the same time, we're accelerating our growth investment, particularly in digital and AI-enabled applications with increased spend planned for the second half.
And we'll continue to evaluate inorganic investments to complement this, such as Zionexa. Based on our first half, we now expect organic margins to expand more than 100 basis points for the year. This will be influenced by how quickly we can ramp certain growth investment. However, our medium-term expectations remain 25 to 75 basis points expansion.
Our investment ramp will support continued innovation and help us drive higher revenue growth over time. Turning to renewables. We're continuing to lead the energy transition, growing new generation, lowering the cost of electricity and modernizing the grid with a focus on new product platforms and technologies that enables profitable growth and cash generation over time. Looking at the market.
In onshore wind, we still expect the U.S. market to decline in the near term before stabilizing. We're watching the potential U.S. production tax credit extension closely.
A blanket long-term extension likely result in near-term uncertainty because it pushes out investment decisions for what could be years. This may impact our second half orders profile and positive free cash flow outlook for the year. In offshore wind, global momentum should continue through the decade. The recent U.S.
federal approval of the Vineyard Wind project supported by our Haliade-X represents meaningful progress for the U.S. market. And as the global energy transition accelerates and government stimulus increases, the grid will need to be upgraded and more actively managed. Orders grew mid-single digits, where onshore services more than doubled as repower orders increased, which will convert to second half deliveries.
This was partially offset by lower onshore equipment orders due to PTC dynamics. While both onshore and offshore equipment orders are lumpy, we expect them to increase significantly in the second half versus first half. Revenue was up 9%, driven by higher equipment revenue, offset by lower services. And reported equipment was up 12% on a two year view versus '19.
In onshore, equipment was up year over year on higher international unit deliveries while services were down on fewer repower upgrades, though up sequentially. And services ex repower grew double digits again. Segment margin, while still negative, improved more than 500 basis points as we drive toward segment profitability over time. Onshore was profitable in the quarter and year-to-date.
This was driven by continued cost out and volume leverage that more than offset mix and other headwinds, such as lower margin on new products, which typically improves our product life cycle. In grid, cost productivity was offset by elevated restructuring. Looking ahead, we're focused on our operational priorities, including cost reduction to help offset increased medium-term headwinds from the market inflation and new technology and platform transitions. Moving to power.
The team performed very well with operational improvements across the business, particularly at Gas Power. Looking at the market. Global gas generation grew low single digits while GE gas turbine utilization continued to be resilient, with megawatt hours growing high single digits. Encouragingly, outage starts were up 50% year over year and up mid-single digits versus 2Q '19.
For the year, we expect the gas market to remain stable with gas generation growing low single digits. The dispatch of our fleet is well positioned with upgraded missions and a growing HA backlog. Outside of gas, markets remain mixed. Power orders were up significantly, driven by gas power equipment.
This quarter, we booked 12 heavy-duty gas turbines and 35 aeroderivative orders, primarily LM, that will complement variable renewable power by providing distributed fast-response power to help deliver grid stability. Orders were also up in gas power services, steel, power conversion and nuclear. Power
roductivity through lean and prior period restructuring. At the same time, we're accelerating our growth investment, particularly in digital and AI-enabled applications with increased spend planned for the second half.
And we'll continue to evaluate inorganic investments to complement this, such as Zionexa. Based on our first half, we now expect organic margins to expand more than 100 basis points for the year. This will be influenced by how quickly we can ramp certain growth investment. However, our medium-term expectations remain 25 to 75 basis points expansion.
Our investment ramp will support continued innovation and help us drive higher revenue growth over time. Turning to renewables. We're continuing to lead the energy transition, growing new generation, lowering the cost of electricity and modernizing the grid with a focus on new product platforms and technologies that enables profitable growth and cash generation over time. Looking at the market.
In onshore wind, we still expect the U.S. market to decline in the near term before stabilizing. We're watching the potential U.S. production tax credit extension closely.
A blanket long-term extension likely result in near-term uncertainty because it pushes out investment decisions for what could be years. This may impact our second half orders profile and positive free cash flow outlook for the year. In offshore wind, global momentum should continue through the decade. The recent U.S.
federal approval of the Vineyard Wind project supported by our Haliade-X represents meaningful progress for the U.S. market. And as the global energy transition accelerates and government stimulus increases, the grid will need to be upgraded and more actively managed. Orders grew mid-single digits, where onshore services more than doubled as repower orders increased, which will convert to second half deliveries.
This was partially offset by lower onshore equipment orders due to PTC dynamics. While both onshore and offshore equipment orders are lumpy, we expect them to increase significantly in the second half versus first half. Revenue was up 9%, driven by higher equipment revenue, offset by lower services. And reported equipment was up 12% on a two year view versus '19.
In onshore, equipment was up year over year on higher international unit deliveries while services were down on fewer repower upgrades, though up sequentially. And services ex repower grew double digits again. Segment margin, while still negative, improved more than 500 basis points as we drive toward segment profitability over time. Onshore was profitable in the quarter and year-to-date.
 This was driven by continued cost out and volume leverage that more than offset mix and other headwinds, such as lower margin on new products, which typically improves our product life cycle. In grid, cost productivity was offset by elevated restructuring. Looking ahead, we're focused on our operational priorities, including cost reduction to help offset increased medium-term headwinds from the market inflation and new technology and platform transitions. Moving to power.
The team performed very well with operational improvements across the business, particularly at Gas Power. Looking at the market. Global gas generation grew low single digits while GE gas turbine utilization continued to be resilient, with megawatt hours growing high single digits. Encouragingly, outage starts were up 50% year over year and up mid-single digits versus 2Q '19.
For the year, we expect the gas market to remain stable with gas generation growing low single digits. The dispatch of our fleet is well positioned with upgraded missions and a growing HA backlog. Outside of gas, markets remain mixed. Power orders were up significantly, driven by gas power equipment.
This quarter, we booked 12 heavy-duty gas turbines and 35 aeroderivative orders, primarily LM, that will complement variable renewable power by providing distributed fast-response power to help deliver grid stability. Orders were also up in gas power services, steel, power conversion and nuclear. Power