Nav: Home

Re-thinking renewable energy predictions

March 03, 2016

Unlike conventional energy sources, like coal or oil, the supply and demand of renewable energy are, to a large extent, unpredictable because they are affected by the natural fluctuations in the power source itself. This poses a number of difficulties in calculating how much renewable energy will be available for consumer needs at any given time.

A team of researchers, led by Prof. Mahesh M. Bandi of the Okinawa Institute of Science and Technology Graduate University (OIST) wanted to explore some of these scientific problems involved in the fluctuations of renewable energy and how to better predict energy outputs. The team recently published their results in the New Journal of Physics.

"A fluctuating power source threatens the even distribution of power in the electrical grid," Bandi said. "That makes it difficult to balance the fluctuating power output with the fluctuating consumer demand."

Bandi and two of his co-authors, Golan Bel and Colm Connaughton, were post-docs at the Los Alamos National Laboratory at the same time and learned that they liked to "cook up scientific problems while hiking," said Bandi. So they decided to take their questions about renewable energy fluctuations with them on a hike in Okinawa, Japan.

The team, including Märt Toots, a graduate student working with Bandi at OIST during his first year rotation, analysed data from the Irish grid wind farms and saw that power outputs from the farms on the grid fluctuate in similar ways. This is different than previously thought.

"It's generally assumed that geographically distributed wind farms are independent. In other words, the fluctuations in power output from one wind farm are different from that of another wind farm, say 50 km away," Bandi said.

Instead, the data that Bandi and his team analysed showed that the wind farms on a grid no longer function independently of one another in response to local wind speed conditions, but instead become part of a larger geographic weather system that forces all the wind farms to have similar or correlated outputs for a time span of up to one day.

"If there is a medium that connects them, then one will observe that the two wind farms will fluctuate in a similar fashion. This does not mean their outputs are exactly synchronized at every instant, but on average their outputs fluctuate very similar to each other. The average is important. That is what we mean by correlated," said Bandi.

The unpredictability of wind power supply, as well as working with a larger geographic weather system can then create errors in forecasting power output. Therefore, Bandi and his team quantified two types of errors found in forecasting through statistical analysis to identify trends and analyse fluctuations around those trends in the wind power grid data. The two types of errors are: time-scale and scaling.

Time-scale error is the interval of time which the statistical models are not making any predictions, which creates uncertainty for select periods of time. Scaling error is the degree to which current forecast models fail to predict correlations in the fluctuations between different wind farms for generated power, which Bandi says is not often taken into consideration because "when people estimate error, they don't think about correlations."

The statistical analysis performed by the researchers could be important in more accurately predicting the supply and demand necessary in wind power and this method could be applied in other renewable energy research.

"This technique or tool is not limited to wind power," Bandi said. This means it can also be used across other renewable energy sources to predict error, so long as they possess time-related corresponding changes that have a statistical structure.

Okinawa Institute of Science and Technology (OIST) Graduate University

Related Renewable Energy Articles:

Croissant making inspires renewable energy solution
The art of croissant making has inspired researchers from Queen Mary University of London to find a solution to a sustainable energy problem.
Are we underestimating the benefits of investing in renewable energy?
Scientists have estimated the emissions intensity of carbon dioxide and other air pollutants from a major electricity distributor and highlighted key consequences - essential information for policymakers shaping decisions to reduce electricity system emissions.
Lighting the path to renewable energy
Professor Mahesh Bandi of Okinawa Institute of Science and Technology Graduate University (OIST) has co-developed a novel, standardized way of quantifying and comparing these variations in solar power.
How much energy storage costs must fall to reach renewable energy's full potential
The cost of energy storage will be critical in determining how much renewable energy can contribute to the decarbonization of electricity.
Renewable and nonrenewable energy in Myanmar's economic growth
An international group of scientists including a researcher from Ural Federal University developed a mathematical model that describes the influence of regenerative and non-regenerative energy sources on the economic growth of Myanmar.
Shifts to renewable energy can drive up energy poverty, PSU study finds
Efforts to shift away from fossil fuels and replace oil and coal with renewable energy sources can help reduce carbon emissions but do so at the expense of increased inequality, according to a new Portland State University study
Microgrids can help maximize efficiency of renewable energy consumption
A group of Italian researchers has developed a method that enables more efficient use of energy by smart homes that are connected to a microgrid -- a web of individualized units that are connected to one another and one common energy source.
Renewable energy generation with kites and drones
A group of researchers at Universidad Carlos III de Madrid has recently developed a new software aimed at the analysis of energy generation systems based on kites and drones.
A powerful catalyst for electrolysis of water that could help harness renewable energy
An international collaboration of Scientists at Dongguk University developed a novel nickel-based hydroxide compound that can be used as a powerful catalyst for the electrolysis of water.
'Sun in a box' would store renewable energy for the grid
MIT engineers have come up with a conceptual design for a system to store renewable energy, such as solar and wind power, and deliver that energy back into an electric grid on demand.
More Renewable Energy News and Renewable Energy Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.