Key Takeaways
- Half the world’s population lives close to coasts that can support offshore wind power.
- Ever-larger offshore wind turbines offer greater energy efficiency than onshore wind farms.
- Offshore wind power is almost entirely emissions-free once up and running.
- Countries must invest up to $100 billion annually to reach offshore wind power targets.
The United States is the world’s largest oil and natural gas producer. Almost two-thirds of its electricity generation comes from these fossil fuels, spewing emissions into the atmosphere.
Yet the country could produce almost double its electricity using offshore wind power.
Over 2,000 gigawatts (GW) of clean, renewable energy could power homes, industries, and electric vehicles. Green energy can support transitioning to a net-zero emissions economy to battle climate change.
However, despite its vast offshore wind capacity, offshore wind power is a minor player in America, with just two offshore wind farms operating in 2023. Is that about to change?
What Is Offshore Wind Power?
Offshore wind power refers to wind turbines located out at sea or in vast lakes that spin their blades to create electricity. These wind farms may have one, several, dozens, or hundreds of turbines.
The wind turbines may be fixed to the sea bed or use a floating base attached to the sea floor with cables to stay upright. The United States has enormous stretches of coastline and great lakes suitable for offshore wind power.
What’s more, offshore wind energy is more powerful than onshore wind capabilities because wind at sea is generally stronger and more reliable.
How Do Offshore Wind Turbines Generate Electricity?
A breeze blowing between 9-13 mph is enough to turn a utility-scale wind turbine and generate electricity.
Wind turbines work by taking the wind’s kinetic energy, which passes over a wind turbine’s blades to create lift, much like how a wing helps planes take off. This is how the wind makes the blades spin.
That spinning motion, a type of mechanical energy, turns an electric generator to create electricity. Underwater cables, via substations, take this current onto land and into the electricity grid.
How Tall Are Offshore Wind Turbines?
Offshore wind turbines are giant. According to the U.S. Department of Energy (DOE), the average size of wind turbines has gone from 100 ft / 30m to 330 ft / 100m behemoths in the last 20 years, taller than the Statue of Liberty at 305 feet. And that’s just the start.
The Block Island Wind Farm, built by Denmark’s wind turbine specialists, Ørsted, has five turbines. They stand at 593 ft / 181m, generating 30 megawatts of electricity year-round for 1,000 permanent Rhode Island residents.
Next, Vineyard Wind, located off the coast of Massachusetts, has started delivering power via its Haliada X-series offshore turbines. These measure 853 ft / 260m and generate twice as much electricity as the Block Island turbines. The entire array will eventually power around 400,000 homes.
The world’s most powerful working offshore wind turbine is the Goldwind GWH252-16MW intelligent wind turbine. The turbine’s hub stands at 479 ft / 146 m, about the height of a 50-story building, with blades around 410ft / 125m. It can produce 16 megawatts (MW) of electricity in full flow. During a recent typhoon, in 24 hours, it generated enough electricity to power almost 170,000 homes.
How Is the Location for an Offshore Wind Farm Chosen?
Successfully gathering wind resources depends on many factors. These include:
- Geography
- Average wind speeds
- When and how often the wind blows
- Proximity to human populations
Around half the world’s population—and 80% of Americans—live within 125 miles / 600 km of the coast. Sea breezes often occur during the day and afternoon. Electricity demand in the U.S. is at its highest when folks get home from work, making offshore wind a perfect fit to meet many people’s energy demands.
What Are the Different Types of Floating Offshore Wind Turbines?
Where ocean depths are under 200 to 262 feet (60-80m), offshore wind turbines are usually fastened to the sea floor with foundations. At greater depths, floating offshore wind projects are more suitable.
Given that two-thirds of the country’s offshore wind resources are in deeper waters, harnessing this technology is vital to U.S. clean energy production. According to the National Renewable Energy Laboratory, doing so would give access to 4,200 gigawatts of offshore wind electricity generation capacity. By comparison, the average U.S. nuclear reactor produces 1 GW of power.
There are currently three principal types of floating offshore wind turbines:
- Spar foundations involve a heavy, cylindrical ballast added to the bottom of a wind turbine’s tower. This keeps the tower upright, and mooring lines and anchors keep it in place.
- Semi-submersibles are the most popular offshore wind turbines at present. They have a 3-, 4-, or 5-column base, half of which is submerged and the rest above water with gangways. This floating base is anchored to the sea bed with cables and uses the base’s buoyancy to stay upright.
- Tension Leg Platforms (TLC) are similar to the semi-submersibles. The difference is the base is almost entirely underwater, and the turbine is rooted primarily by sea bed anchors attached to the base.
- Barges use wide, shallow floating platforms to provide buoyancy.
There are also hybrid types that mix these designs, many of which have been inspired by the floating platforms used in oil and natural gas for floating platforms. Around 75% of planned U.S. offshore wind projects plan to use semi-submersible wind turbines.
How Much Offshore Wind Power Is Installed Globally?
Offshore and onshore wind farms currently meet some 6% of all global electricity demand. Wind has the potential to meet 35% of the world’s electricity generation requirements.
But most wind power, current and being installed, is from onshore wind projects. In 2022, just 7% of new wind power added was offshore.
China leads the way in wind power generation in operational and planned projects. It’s also planning to add the most offshore wind power. The United Kingdom installed more offshore wind power in 2022 (3 GW) than the rest of the world combined, excluding China.
There is currently around 64 GW of offshore wind capacity globally. To reach net-zero emissions targets, this needs to increase to 228 GW by 2030 and then 1,000 GW by 2050.
Offshore Wind Power’s Future in the United States
In 2023, the U.S. had 8.3 GW of offshore wind capacity installed.
President Biden’s Inflation Reduction Act (IRA) should help boost America’s offshore wind industry. The East Coast is particularly promising for wind energy development.
In 2022, the Bureau of Ocean Energy Management (BOEM) held the New York Bight offshore lease auction. It sold six seabed leases near New York and New Jersey for $1.1 billion. Offshore wind developers are now busy building 3 GW of offshore wind capacity there, enough to power around 1.1 million homes nearby. It is expected to come online in 2030.
More than 13 gigawatts of offshore wind energy projects are approved in the country, enough to power nearly 5 million homes with renewable energy.
The following U.S. targets are 30 GW by 2030 and 110 GW by 2050. The White House expects this to create 77,000 offshore wind jobs and 57,000 associated posts and save millions of tons of greenhouse gas emissions.
Offshore Wind Power vs. Onshore Wind Power: What’s the Difference?
Onshore and offshore wind farms both use turbines to create electricity. But there are differences:
- Most current wind farm capacity is onshore.
- Onshore wind turbines are smaller than the larger offshore turbines.
- Onshore is also quicker and cheaper to install than offshore wind turbines.
- Offshore wind farms can generate more power than onshore sites thanks to stronger and more dependable winds.
- Onshore sites tend to produce more electricity at night when onshore winds are more potent. In contrast, offshore wind is often stronger in afternoons and evenings.
- Offshore wind power is usually more efficient at electricity generation.
- Onshore wind farms can intrude on landscapes and views, whereas offshore wind farms are often far from sight.
- There is more sea available than land for wind turbines.
What Are the Advantages of Offshore Wind Power?
Offshore wind power offers many advantages in the battle against climate change. Large turbines are more energy-efficient than onshore sites and produce more energy.
Rotating turbine blades do not cause noise pollution for local communities. Pollution drops, improving the air quality for local people and their health prospects. Transporting the enormous components out to sea is relatively easy, with no tunnels, bridges, or buildings getting in the way.
The oceans are vast, meaning there are plenty of places to build. These construction sites create employment, with many jobs requiring skills used by workers in the fossil fuel industries, such as natural gas and oil extraction.
In the long term, wind turbines’ efficiency may help bring down electricity bills. Gone are volatile fossil fuel prices; in come reliable, predictable prices.
With this clean energy, greenhouse gas emissions will drop radically, and the green energy revolution will become circular. For example, the increased demand for charging electric vehicle batteries can be met with emissions-free wind energy.
Wind speeds in many offshore wind areas are highest in the afternoon and evening and can meet peak demand. Most Americans live near the coast or a Great Lake, meaning transmission distances from source to use are relatively small, so less power is lost over the power grid.
Ships can avoid and sail past wind farms, incurring only slight changes in travel direction.
What Are the Disadvantages of Offshore Wind Farms?
The Achilles’ Heel of offshore wind power is there is no electricity generation if the wind doesn’t blow. Windless days require a backup power supply. Furthermore, on days of recess production, that energy is lost unless there are utility-scale energy storage facilities nearby, like batteries or pumped hydro storage.
These enormous structures have an environmental impact on marine wildlife and birds. The ocean noise and electromagnetic fields created by wind turbines could hamper migratory species like whales and change the behavior of fish and other species. This includes spawning, breeding, and species numbers. The enormous, spinning blades may also kill birds on the wing.
Some wind turbines may become reefs for species, moving them away from traditional habits and forever changing local ecosystems. Maintenance ships also pose a risk of pollution.
All the greenhouse gas emissions related to the wind turbine’s construction should be considered, although most of these can be recycled. However, a wind turbine’s supply chain requires steel, fiberglass, iron, copper, zinc, and rare earth elements, all of which have associated emissions and polluting processes.
A massive challenge for the offshore wind industry is making wind turbines hurricane-, typhoon-, and storm-proof. The strongest winds ever recorded were 215 mph. A MingYang Smart Energy offshore wind turbine can survive 134 mph winds for 10 minutes. Wind turbines may also be stopped in storms to prevent damage if the worst weather strikes.
What Are the Advantages of Offshore Wind Farms Over Other Renewable Energy Sources?
Renewable energy sources reduce greenhouse gas emissions compared to burning fossil fuels like coal, oil, and natural gas.
Yet solar panels need many precious resources to build. Onshore wind power can upset neighbors with noise and disrupt views. Tidal energy and green hydrogen are in their infancy, and hydropower often disrupts the local environment.
Offshore wind turbines generally have fewer environmental impacts than these energy sources. With proper maintenance, they can last 30-40 years, and recyclable components reduce their initial carbon footprint.
A spinning turbine releases no air or water pollutants and doesn’t need water for cooling. Wind farms at sea have little visual impact on humans. For all these reasons, offshore wind power offers excellent potential compared to other renewable energy sources.
How Does Offshore Wind Power Contribute to Reducing Greenhouse Gas Emissions?
Once built, offshore wind power offers almost entirely emissions-free renewable energy over the turbine’s 30- to 40-year lifetime. That’s good news for the environment and air quality.
The DOE estimates wind power produces 11 g of carbon dioxide for every kilowatt-hour (kWh) of electricity it generates. Contrast that with 465 g of CO2 per kWh for natural gas-generated electricity and 980 g of CO2 per kWh for coal, which is almost 90 times more polluting.
Based on an average U.S. home, using 10,500 kWh annually, that gives these yearly carbon dioxide emissions:
- Wind: 255 lbs / 115.5 kg
- Natural gas: 4,882.5 kg / over 5.3 U.S. tons
- Coal: 10,290 kg / 11.3 U.S. tons
Remember, that’s emissions from just one average home for one year.
Which Country Currently Produces the Most Offshore Wind?
As of June 2024, China had the most offshore wind farms, followed by the United Kingdom (39) and Germany (30).
In terms of production, in 2023, China had over 31 GW of offshore wind power in operation, with the UK next with almost 15 GW and Germany with 8.3 GW.
China accounts for 71% of offshore wind power capacity globally. As its investment in offshore wind power surges, the country is expected to have 487 GW of wind power installed within the next 10 years.
What Is the Future Outlook for Offshore Wind Power?
Offshore wind power looks set for massive growth if countries want to hit their net-zero emissions targets.
The International Renewable Energy Agency, IRENA, is pushing for 35% of all electricity to be generated by wind power by 2050 on the road to net zero. More than half of this needs to happen in Asia, where China is already leading the way.
Europe must build nearly a quarter of this new capacity, and North America some 16%, so all regions are taking advantage of their enormous wind resources. This could mean an investment of $100 billion annually for the next 26 years.
The Offshore Wind Market Report is an excellent read for anyone wanting to learn more.
Offshore Wind Power Vital to Climate Change Battle
Onshore wind farms were once highly controversial. While still a sensitive subject to many, wind turbines have become a part of life in many regions. They have helped reduce pollution and greenhouse gas emissions, and small wind turbines even power off-grid homes and communities.
Offshore wind power is the upscaling of this model and is a potential game changer in the fight against global warming. Vast ocean areas can house ever-larger wind turbines that produce more electricity more efficiently, close to the point of use.
Efficiency is the watchword for these behemoths that harness reliable and robust sea breezes to power our homes and industries. China leads the way with this renewable energy source, seeking to wean itself off coal.
The challenge is for Europe, the United States, and Asia to build wind turbines quickly enough to meet a third of all electricity demand by 2050. According to the experts, hitting this target is crucial to offset the worst effects of energy production on climate change.
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