Technological advances and falling costs have significantly improved the cost effectiveness of wind power in the recent years and spurred installations of wind turbines worldwide. Around 340,000 wind turbines were installed globally as of the end of 2016. Many of the wind turbines currently in operation are gigantic in scale, each capable supplying hundreds of homes. At the same time, wind power accounts for an increasing share of electricity generation in many countries. In 2016, for instance, wind power was responsible for nearly 40% of Denmark’s total electricity generation as well as about 10% of the electricity generation of the entire EU.
While wind turbines have been built on land and offshore, the offshore areas are currently considered as the most ideal locations for large-scale wind farms. The size of an offshore wind farm is not constrained by land availability and other geographical barriers that land-based or onshore wind farms have to consider. As installations of onshore wind farms are reaching saturation in many countries, wind power developers are now increasingly focused on offshore generation technologies.
Denmark has been making enormous contributions to the field of offshore wind. The Danish wind turbine maker MHI Vestas Offshore Wind A/S has developed offshore wind turbines that each can generate 9.5 megawatts of electricity for the consumption of around 8,000 homes.
Matthew Wright, UK managing director for Danish offshore wind farm operator Ørsted A/S, stated that there has been a steady increase in the generating capacity of individual wind turbines. The latest turbines can thus produce the same or greater amount of electricity in fewer numbers compared with turbines of the previous generations. Having fewer turbines required for generation also brings down installation and maintenance costs for wind farms.
Giles Dickson, CEO of WindEurope ASBL/VZW, predicted that the generating capacity of a single turbine may reach 15 megawatts by 2024. WindEurope is a Europe-based wind industry association representing hundreds of members worldwide.
Floating wind turbines are being built for deployment in deep waters
Europe has become the center of offshore wind development in the recent years because many European countries have long coast lines and shallow seabed. For other coastal countries with narrow continental shelf and face mainly deep waters, building offshore wind farms consisting of fixed turbines is much more challenging and less cost effective. Consequently, wind power developers are starting take interest in floating wind turbines that operate in deep seas and oceans.
Japan is one of the few countries that are developing floating wind turbines, and the country set up a trial project off the coast of Fukushima Prefecture in 2014. Norwegian energy company Statoil ASA also began building the world’s first floating wind farm off the coast of Scotland in October 2017. Once completed, this floating wind farm is expected have a generation capacity of 30 megawatts and will be supplying electricity to around 20,000 homes.
Floating wind turbines can be positioned in their respective designated areas using various mooring systems that are based on anchors and buoys. Since they are not fixed onto the seabed by foundations, they have less environmental impact. Currently, cost is the main concern that is constraining the development of floating wind farms. However, the installation and associated costs are expected to drop gradually as more floating wind turbines are deployed and tested.
Because wind power is an intermittent form of renewable energy, there are worries that blackouts may occur when wind turbines stop turning and not supplying electricity to the grid. Currently, wind power developers are integrating energy storage systems with their wind farms to minimize the risk of grid instability and to find uses for excess electricity produced during the extra windy periods. Wind power is not the ultimate source of renewable energy, but the application of energy storage solutions to wind farms can remedy its intermittency issue and ensure the continuing operation of the grid. In the future, this aspect of wind power generation will be a major focus of development.
(The above article is an English translation of a Chinese article written by Daisy Chuang. The credit of the photo at the top of the article goes to fernando butcher via Flickr and falls under the license of CC BY 2.0.