Wind Turbine That Stores Power

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The main problem with using renewable energy sources is that they are not as reliable or consistent as traditional sources. This is especially true of wind energy, since wind turbines work at generating power until the wind is blowing, but stop once the wind stops. Because of this, even areas that get a lot of wind can’t transfer solely to wind power. Furthermore, wind turbines have a cap as to the maximum speed at which they can rotate and generate power, which is in place to prevent the machine from getting damaged in high winds. However, this also leads to “spillage” of power.

An electrical engineering doctoral student at the University of Nebraska-Lincoln Jie Cheng recently came up with a new technology, which would solve both of these problems. The tech he proposes is able to harness the excess wind energy, which is wasted as spillage. The system he developed is also able to store this excess wind energy to be used in times of little or no wind.

Cheng’s device works by converting and directing the unused wind energy into an air compression tank. This is achieved via a rotary vane, placed between the turbine’s gearbox and generator, which works to divert the excess energy and stores it in the tank. Once the winds die down, the airflow is reversed back to the rotary vane and the machine is able to generate electricity again.

According to tests with a prototype, a 250-kW system built in this way would produce an additional 16,400 kWh per month compared to traditional wind turbines and using the wind data for Springview, Nebraska. To put in in perspective, this additional electricity is roughly 18 times the total monthly energy usage of a typical US household.

Cheng is currently working with the Lincoln Electric System, the American Public Power Association and UNL’s NUtech Ventures office in an effort to continue to research an develop this technology, as well as to market it to the industry.

Spanish Researchers Debunk Wind Energy Myth Showing Renewables Capable of Replacing Fossil Fuels

Photo credit: Shutterstock

Paul Brown

Photo credit: Shutterstock

Photo credit: Shutterstock

One of the most oft-repeated arguments of the anti-wind lobby is that turbines produce electricity only intermittently, when there is enough wind to turn them.

This, the wind critics argue, means that so much gas has to be burnt to provide a reliable back-up supply of electricity that wind power’s overall benefit to the environment is erased.

But extensive research in Spain means this claim can now definitively be declared a myth. Wind, the researchers found, is a very efficient way of reducing carbon dioxide emissions.

The anti-wind campaigners claim that fossil fuel plants have to be kept running at a slow speed, continuously producing CO2, just in case the wind fails. At slow speeds these plants are less efficient and so produce so much CO2, wind opponents say, that they wipe out any gains from having wind power.

Not true, according to a report published in the journal Energy by researchers at the Universidad Politécnica de Madrid. There are some small losses, the researchers say, but even if wind produced as much as 50 percent of Spain’s electricity the CO2 savings would still be 80 percent of the emissions that would have been produced by the displaced thermal power stations.

25 percent of electricity

Spain is second behind Germany in wind energy production in Europe, according to the U.S. Energy Information Agency. The country regularly obtains 25 percent of its electricity from wind, reports Renewables International, a trade magazine.

The study looked at 87 of the country’s coal and gas plants and how they were run alongside Spain’s wind industry. Adjustments made by the fossil fuel plants as they compensated for variable wind strengths had little impact on the plants’ C02 emissions.

This is the opposite of reports reproduced repeatedly by right-wing think tanks and campaigners opposed to renewables.

The Spanish report adds that even the small losses caused by running thermal power plants at less-than-maximum efficiency to safeguard the grid can be reduced by better renewables management. Spain for example has wind, solar and wave power among its portfolio of renewables, each of which can support the others.

CO2 credits

The findings are important for governments trying to calculate the amount of CO2 they have saved by the introduction of wind power. Countries like Spain, struggling to meet EU targets on reducing emissions, need to know how much CO2 saved can be credited to their wind industries. This research provides the answers.

The paper says: “The finding has generated the first comprehensive analysis on interaction between wind parks and thermal power plants in Spain and has concluded that the global balance of CO2 reduction is still significant. Besides, the study suggests how to enhance the effectiveness of potential sources that can be helpful for promoters of renewable technologies.

“Renewable energy is capable of replacing fossil fuels and of reducing emissions dramatically.”

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