Greg Davies: Preserving Our Natural World

Back in Australia, Greg Davies, ‘17, called it bushwalking. Being raised in a city that was bordered on all sides by national parks, he spent many days hiking and mountain biking with friends. Those early treks, he says, are what first fostered his interest in the natural world.

Since then, Greg has carried his passion for the environment across the globe. After graduating college with a degree in physics and mechanical engineering, he went to work for BHP Billiton Petroleum. From the construction and commissioning of offshore oil rigs in China to working in a drilling group in Western Australia, Greg says working for an oil and gas company gave him a fuller and more practical perspective on the energy crisis. Today, as a graduate student in Mechanical and Aerospace Engineering at Princeton he works on a problem that is universal to all nations: renewable energy solutions.

“I grew up enjoying the environment and one of the important questions that has always driven my studies and research is, ‘how we make sure future generations have the same opportunity to experience a pristine natural world?’ At this time, the answer for the most part comes down to our reliance on energy and where it is sourced. These factors will play a major role in what our environment will look like in the future,” explains Greg.


One of the most important applications for renewable energy solutions is in the electric grid. Every time a light turns on or a thermostat is adjusted to cool, it taps into this network of energy. For nearly a century, these grids have been powered predominantly by fossil fuels; and even today, only a small fraction comes from green sources. While solar and wind power have become more cost competitive, they are can be unpredictable and intermittent, due to changes in cloud cover and wind speed and direction.


Greg’s team is trying to increase that percentage by working on large-scale battery storage systems. “Energy storage solutions like batteries could increase the reliability of wind and solar power,” he explains. “Capturing excess energy while the sun is shining and the wind is blowing, storing it on the grid system, and then releasing it at a later time when generation is low, is one important step towards a grid with an increased proportion of renewable energy. However, batteries can also do much more for the grid.”


Batteries could be particularly helpful in population dense cities like New York and San Francisco, where there are increasingly limits on transmission capacity. “Battery energy storage has the potential to save a lot of money, greatly reduce greenhouse gas emissions and infrastructure expenditure, improve overall grid performance, and offer an alternative for power in emergency situations,” adds Greg.


The challenge is finding a way to make these battery systems cheap and reliable enough to be adopted on a wide scale. “When it comes to turning on your air conditioner or running your dishwasher, you do not want an intermittent supply of energy, or to have to pay a lot of money on your electric bill to get that reliability,” says Greg. “That is why fossil fuels continue to dominate the energy network, because they can be dispatched at any time for low cost.”


So how do you lower the cost of an enormous battery? It starts by tinkering with its chemical formula and physical package. In the laboratory, Greg’s team manipulates the architecture of various battery designs using different materials and forms that change the energy density, power, and longevity of the product. Changing the chemical makeup can also allow the batteries to be more reliable and rechargeable.


In particular, Greg specializes in testing these new battery designs using a process known as the ultrasonic method. “We apply a similar technique to batteries that a doctor would use with an ultrasound machine when someone is pregnant,” he explains. “By sending ultrasonic pulses through the batteries we can track the changes in the acoustic image over time. This tells us something about the physical and chemical changes happening inside the battery, and allows us to understand the charge state and health of the system, or even when the battery is being overcharged.”


The technique can also help identify when a battery is going to fail and should preemptively be taken out of operation. “We know relatively little about why batteries fade and fail. If breakthroughs on this front can be made, batteries for renewable applications will have enormous potential,” says Dan Steingart, PhD, a Professor in Mechanical and Aerospace Engineering and the Andlinger Center for Energy and the Environment, who serves as Greg’s advisor.


Dr. Steingart adds that Greg’s experience in the oil and gas industry has been a tremendous advantage in the laboratory setting. “Most researchers, myself included, begin working on batteries not fully appreciating how good gasoline is at what it is supposed to do. The fact that Greg started knowing the inherent limits of batteries, and still decided to work on them, indicates both his passion and dedication to the environment,” he says.


Greg is also a member of the Princeton Energy and Climate Scholars—a student organization interested in energy and climate-related issues—and is working on a certificate in Science, Technology, and Environmental Policy (STEP). In the future, he hopes to work in a position where he can impact future energy strategy, and hopefully make an impact on environmental legislation. 


Today, as he did as a teenager, Greg continues to spend his free time running or walking outdoors. On the weekends, he enjoys exploring new parks. Through his work, Greg hopes he can, in some small way, help future generations be able to enjoy the same beautiful natural world. 


-Caroyn Sayre