Differences Between Onshore & Offshore Wind Energy

Using the wind for energy isn’t a new idea by any means. People have been utilizing the incredible power of the wind for centuries. Today, wind power is accelerating, delivering growing percentages of electricity generation year over year.In fact, the overall capacity of all wind turbines installed worldwide by the end of 2018 reached 597 Gigawatt, according to recent statistics published by World Wind Energy Association (WWEA), which is enough to cover close to 6% of the global electricity demand.

Wind farms can be based onshore (on land) or offshore (sea or freshwater), with key differences between the two. Traditionally, onshore wind turbines solely dominated the market, until the firstoffshore wind turbine was installed in 1991 off of the coast of Denmark. Onshore wind power refers to turbines that are located on land and use wind to generate electricity. Offshore wind power is when wind over open water (typically the ocean) is used to generate electricity.

In this post, we’ll dive into the characteristics of both offshore wind energy and onshore wind energy so that you can understand the differences between the two, as well as the pros and cons of each.

Characteristics of Onshore Wind

  • Onshore wind farms are typically located in areas where there is low conservation or habitat value
  • The infrastructure necessary to transmit electricity from onshore turbines is considerably less than of offshore since there is less voltage drop between the wind turbine and the consumer
  • Onshore wind turbines are very quick to install. Because of the ease in installation, transportation, and other factors affecting capital cost, onshore wind farms are less expensive than offshore wind farms
  • Additionally, thanks to its proven technology and reduced wear and tear (the moisture available in the area of the installation onshore wind turbines have very low erosion), maintenance costs are also lower than offshore wind farms
  • People complain that wind turbines are an eyesore and also noisy
  • Onshore wind speeds are not as predictable as offshore wind speeds. Similarly, onshore wind direction changes more frequently. Since turbines are optimized at a specific speed, this can limit their efficiency

Characteristics of Offshore Wind

  • Offshore wind farms are constructed in bodies of water where higher wind speeds are available
  • Offshore wind speeds tend to be faster meaning more energy can be generated. There are no physical restrictions such as hills or buildings that could block the wind flow
  • Offshore wind speeds and direction are also steadier and therefore provide a more reliable and efficient source of energy
  • Offshore wind turbines can be built are much larger and taller than their onshore counterparts, allowing for more energy collection
  • However, due to the larger structures and complex logistics of installing the towers, offshore wind farms are capital-intensive and are considerably more expensive to build than onshore wind farms
    • Usually, offshore turbines cost 20% more, and towers and foundations cost more than 2.5 times the price for a project of similar size onshore
    • The costs of offshore foundations, construction, installations, and grid connection are also significantly higher than for onshore
  • Once the facility is built, operations and maintenance costs are also much higher for offshore facilities. This is attributed to the fact that:
    • Despite the efforts taken to minimize the impacts of corrosion, seawater causes additional maintenance needs that aren’t required for onshore turbines. Offshore wind turbines also endure more wear and tear from waves and higher wind speeds than onshore turbines
    • Any turbine maintenance at an offshore facility is a major undertaking that involves a helicopter full of highly trained technicians, and any major maintenance requires the rental of a highly expensive jack-up rig
  • Because they tend to be far out at sea, offshore wind farms tend to have little to no visual (or noise) impact to humans, so the “not in my backyard” argument cannot be used
  • Offshore wind farms do not interfere with land use
  • Offshore wind could even benefit marine ecosystems. In fact, studies indicate that offshore wind farms protect sea life by restricting access to certain waters and increasing artificial habitats

Overall, wind turbines, regardless of their location (onshore vs offshore), are quick to install, especially when compared to other energy sources. Having proven itself as a key player in providing energy to the public, wind energy will continue to be an integral part of the energy conversation for as long as the wind blows. As wind power becomes an increasingly popular renewable energy source, researchers anticipate significant improvements in both onshore and offshore wind technology.

If you’re curious about how you can support the wind industry, then you may want to speak to one of our representatives about our Kiwi Clean + Wind REC electricity plan, which matches 100% of your energy usage with Green-e Certified Renewable Energy Certificates sourced from national wind. Give us a call today at 1.888.812.2284.

2019-08-13T13:48:31-05:00August 21st, 2019|