Author Interview: Dr. Quanhua Liu, Solar and Wind Energy Resources

Dr. Quanhua Liu from the Joint Center for Satellite Data Assimilation along with his associates Qinxian Miao,¹ Jue J. Liu,² and Wenli Yang³ have just published their article "Solar and wind energy resources and prediction" in Issue 4 (2009) of AIP's Journal of Renewable and Sustainable Energy⁴. In the article, the researchers provide a background for their interactive website, where one can calculate the amount of wind or solar energy that could be produced in their own backyard. The authors' motivations seem clear when they note: "Energy and environmental issues are among the most important problems of public concern."

1. What motivated the research in your recent Journal of Renewable and Sustainable Energy article?

As former vice president Al Gore mentioned, enough solar energy falls on the surface of the earth every 40 minutes to meet 100 percent of the entire world's energy needs for a full year. Our study further confirmed that total annual downward solar energy at the surface is about 6,000 times more than the world annual energy consumption.

Using clean and renewable energy can ease increasing carbon dioxide (CO₂) in the atmosphere. American people support using renewable energy. According to a December 2008 poll conducted by the Washington Post and ABC News, 84 percent of Americans support requiring utilities to increase their use of wind, solar and other renewable sources of power (House Committee on Energy and Commerce, 2009). Furthermore, the U.S. government has proposed increasing renewable energy development to reduce fossil fuel burning and to reduce greenhouse gas emission. Addressing Congress, President Obama outlined his vision for a clean energy future that will not only help revive our ailing economy, but also drive new investment and job growth for decades to come.

The most challenging issues are how to provide uninterrupted and cost-effective solar and wind energy day and night. Obviously, solar radiation cannot be used during the night time and rainy days, and wind turbines cannot operate when there is no wind. Therefore, It is necessary to store surplus power in good operating conditions and release it when needed, thus making the power available on demand. To keep the electricity grid output stable and to better manage solar and wind energy operation, one needs also to know how much available solar and wind energy there will be in advance—requiring solar and wind energy forecasting.

Solar and wind energy depend on the weather near the surface, for which we have forecasts. But we don’t yet have solar and wind energy forecasting. To help with developing these types of forecasts, our paper uses weather forecasting data from the NOAA National Centers for Environmental Prediction. The preliminary result is very encouraging: the NOAA weather forecasting data can be very unique in supporting our national solar and wind energy development.

2. How do you envision this article affecting renewable energy technologies and further research?

This article shows the available solar and wind energy over the United States and the rest of the World. This geographic distribution of the solar and wind energy can help industries to consider optimal sites for solar power plants and wind farms. We used data that gave us spatial resolution of 12–40 km. Much higher spatial resolution is necessary to take into account any effects from local terrain. This study has demonstrated the capability using the NOAA NCEP data for solar and wind energy forecasting. Certainly, many more efforts are needed for accurate solar and wind energy forecasting.

With advanced Google map technology, we have developed a web site, www.renewableenergyst.org, from which one can find easily the amount of solar and wind energy for any location or area in the world. If a user type in own home address, zoom in onto own backyard, draw an area in the backyard, and provide a conversion factor value (e.g. 0.2), the user can find out how many kilowatt hours of electricity will be generated from that region in their own backyard.

3. What kind of additional interests do you have as a researcher?

My own experiences during twenty years of atmospheric science research have highlighted the need for solar and wind energy studies. Through both my official work on satellite radiance assimilation to support weather forecasting at NOAA and independent management of the solar and wind energy assessment and prediction service by Renewable Energy Science & Technology, I have perceived not only the large amount of climate information available but also the small capacity to which it is currently utilized in our national energy policy.

I am very interested in climate research. Carbon dioxide is a greenhouse gas, trapping thermal radiation emitted to space, but we need also learn more about natural variability, atmosphere, surface, and ecosystem responses to climate change. It is important that we study the impacts on weather and climate so that we can—on a large scale—efficiently use of solar and wind energy.

Dr. Quanhua Liu
Joint Center for Satellite Data Assimilation
Renewable Energy Science & Technology

¹Renewable Energy Science and Technology, Bowie, Maryland 20720, USA
²Harvard University, Boston, Massachusetts 02215, USA
³George Mason University, Fairfax, Virginia, USA
⁴DOI:10.1063/1.3168403