Innovative but very unusual power plant

“A Chinese energy company has successfully tested an experimental balloon-type wind turbine that can generate power over cities and land.

 

The S2000 airborne wind energy system (AWES) developed by Beijing-based Linyi Yunchuan Energy Technology is a large, helium-filled aircraft that is equipped with 12 wind turbines. The aircraft soars hundreds or even thousands of meters into the air to take advantage of stable wind speeds at higher altitudes, which spin turbines and generate electricity. It is then transmitted down a tether to the ground, where it can feed into the power grid.

 

During the test flight, the manufacturers lifted the S2000 to an altitude of 2,000 meters over Sichuan province and generated 385 kilowatt-hours of electricity. That’s enough to power the average U.S. household for about 13.3 days, according to usage data from the U.S. Energy Information Administration.

 

According to the Global Times, the S2000 is 60 meters long, 40 meters high and 40 meters wide. The total power of the system is 3 megawatts. The developers say the new technology has several potential applications. “One is in areas that are not connected to the power grid, such as border posts, where it can be used as a relatively stable traditional energy source,” explains Weng Hanke, technical director of Linyi Yunchuan Energy Technology. “Another is to supplement traditional ground-based wind power systems, creating a three-dimensional approach to energy supply.”

 

If implemented on a large scale, this approach could have transformative potential for countries with limited land area for onshore wind farms – such as many continental European countries, as well as those without the shallow seabeds required for offshore wind farms – such as Japan. However, further testing will be required to ensure that the tethered cable is reliable and delivers stable power to the grid.

 

In all but the most remote rural areas, a 2,000-metre cable could pose a dangerous obstacle to aircraft. In the UK, the Civil Aviation Authority requires those wishing to fly tethered balloons above 60m to apply for special permission – to avoid endangering aircraft sharing the airspace with the balloon.

 

In addition to safety concerns, the S2000 will also have to undergo rigorous testing to ensure the system is suitable for reliable commercial use. Standard wind turbines require regular maintenance, and this aircraft can be more complex and expensive to service, as it will have to return to the ground for each repair.

 

Wind turbines can generate more energy where the wind energy density – a measure of the amount of wind energy that can be used at a given altitude – is higher. For example, offshore wind turbines can capture higher and more consistent wind speeds over open water. These offshore turbines can also be significantly larger than their land-based counterparts – the mast of the DEW-26 MW-310 offshore turbine from Chinese manufacturer Dongfang Electric reaches a height of 185 m. Floating wind turbines can also be enormous – for example, the recently launched record-breaking floating wind turbine from China’s Huaneng Group has a tower that reaches 152 m. For example, the average offshore wind speed considered suitable for a wind turbine located 90 m above sea level in US waters is 7 meters per second.

 

However, it is difficult to give an exact wind speed at different altitudes, as it depends on location and weather conditions. Aerospace group Omnidea estimates that wind energy density increases by about a factor of six between 100 and 2,500 meters, and the average wind speed at 2,500 meters is 15 m/s (54 km/h). This shows the potential efficiency that can be achieved by better exploiting higher-altitude wind speeds with tethered flying wind turbines, such as the S2000, Live Science reports.”