Harnessing the wind’s power isn’t a new concept. Wind has pushed boats up the Nile as early as 7,000 years ago, and 2,000 years ago simple windmills were pumping water in China. Fast forward to the present day, and the same basic principles are helping create renewable and sustainable energy, quickly and efficiently. Wind power is accelerating, delivering growing percentages of electricity generation year on year, for example in the UK in 2018 wind power surpassed nuclear power generation for the first time, creating an influx of engineering job opportunities. But what is the difference between offshore and onshore wind farms and ultimately, which one is best?
How do offshore and onshore wind farms work?
First of all, it’s useful to go back to basics and explain how a wind turbine works. As the wind turns the carbon-fibre blade on the unit, a motor turns, which turns kinetic energy into electricity. This energy is transferred to the gearbox, which converts the slow speed of the spinning blades into higher-speed rotary motion—turning the drive shaft quickly enough to power the electricity generator.
Wind farms can be based onshore (on land) or offshore (sea or freshwater), with key differences between the two. Below, we take a look at some of the advantages and disadvantages of each.
What is offshore wind?
Offshore wind power, sometimes referred to as offshore wind energy, is when wind over open water, usually in the ocean, is used to generate power. Wind farms are constructed in bodies of water where higher wind speeds are available.
Advantages of offshore wind:
- Windmills can be built that are larger and taller than their onshore counterparts, allowing for more energy collection.
- They tend to be far out at sea, meaning they are much less intrusive to neighbouring countries, allowing for larger farms to be created per square mile.
- Typically out at sea, there is a much higher wind speed/force allowing for more energy to be generated at a time.
- Wind farms have a relatively negative impact on the environment. They are not built in shipping lanes, fishing areas or in a delicate environment.
- There are no physical restrictions such as hills or buildings that could block the wind flow.
Disadvantages of offshore wind:
- The biggest disadvantage of an offshore wind farm is the cost. Onshore wind farms can be expensive to build and maintain and because of their hard to reach locations, they are susceptible to damage from very high-speed winds during storms or hurricanes which is expensive to repair.
- The effect of offshore wind farms on marine life and birds are not yet fully understood.
- Offshore wind farms that are built closer to coastlines (generally within 26 miles) can be unpopular with residents as it can affect property values and tourism.
What is onshore wind?
Onshore wind power refers to turbines that are located on land and use wind to generate electricity. They are generally located in areas where there is low conservation or habitat value.
Advantages of onshore wind:
- The cost of onshore wind farms is relatively cheap, allowing for mass farms of wind turbines.
- The shorter distance between the windmill and the consumer allows for less voltage drop off on the cabling.
- Wind turbines are very quick to install, unlike a nuclear power station, which can take over twenty years, a windmill can be built in a matter of months.
Disadvantages of onshore wind:
- One of the biggest issues of onshore wind farms is that many deem them to be an eyesore on the landscape.
- They don’t produce energy all year round due to often poor wind speed or physical blockages such as buildings or hills.
- The noise that wind turbines create can be compared to as the same as a lawnmower often causing noise pollution for nearby communities.
Which is best, onshore or offshore wind?
When deciding between onshore or offshore wind, there are many variables as to which type of wind farm is chosen by energy suppliers, including political, financial, and geographical factors. Generally, whether one or the other is used would be assessed on a case by case basis.
But, what is clear is that wind power is increasing in popularity around the world as the technology becomes more financially sustainable and global policies and targets on climate change are created. At the end of 2018, the installed wind capacity across the world reached 597 GW which was an increase of 18% compared with 2017. Once more, many countries outside of the traditional energy markets of Europe and North America are driving the trend. At the end of 2018, China accounted for roughly 34% of global installed wind power capacity, roughly the same as the whole of Europe.
NES and wind power
NES Global Talent is an experienced staffing provider to the renewable energy industry and we are currently solving staffing challenges for our clients all across the globe. If you have an onshore or offshore wind energy staffing requirement, get in touch with our experts today.
We are already working on some of the world’s most exciting renewables projects and we’re experts at finding the right placements for the right candidates. Wherever your expertise lies, we have plenty of renewable energy job opportunities for skilled engineers looking to enhance their career.