Artificial Energy Conversion and Circuits

“Let’s assume we’re at the stage where energy production isn’t the bottleneck anymore,” says Felix Fischer, assistant chemistry professor at UC Berkeley, pointing out that the last two decades have produced huge advances in alternative energy generation. “We’re pretty close to that now. In fact, in some places, we have overproduction. Then the question becomes, what do we do with the extra energy?”

That conundrum, which Fischer calls the “reality check question,” is key to making really big changes in the way we deal with energy. It’s important to understand energy generation processes like artificial photosynthesis, he says, but points out that the technologies arising from those discoveries may be decades down the road. “Right now, we need efficient means to transport and store energy for diverse applications.” In other words, we need technologies that can be placed right now into sustainable efficient energy storage and management systems. And that requires thinking about some really big questions.

How long do you need to drive your electric car to make up for the ecological damage you’ve done somewhere else? That’s not a trivial question.
Prof. Felix Fisher

The energy problem to address is three-fold: conversion, storage, and transport. Take solar energy, for example. Any excess energy generated from solar panels needs to be converted to another form of energy that’s storable. In addition, that storage requires an efficient technology that doesn’t itself consume lots of resources. Finally, the energy must be transported to where it will be used, which might be to a turbine, an outlet, or a fueling station.

To top it off, Fischer adds, materials and resources used for these three steps must themselves be sustainable (in other words, not environmentally taxing), or they don’t offer an improvement over what we have now. 

Fischer and others like him believe that these challenges may be best met at the nanoscale, where there remain many avenues to explore with regard to increasing efficiencies across the system. He and his Kavli colleagues approach these big questions from a variety of directions. 

In the area of conversion, some Kavli researchers are striving to better understand how plants capture energy from the sun. Others are creating new types of catalysts to store that energy as plants do, in chemical bonds. 

Some researchers are even scheming new catalysts that can be used to recycle the undesirable carbon dioxide produced as our result of burning oil and gas. They’ve achieved success in the lab, and are now setting their sights on scaling the process up. Devising an efficient way to do this will not only reduce carbon emissions, but will allow us to store energy in the form of chemical bonds, a resource that we are already using today.

While obtaining and extracting energy from oil aren’t exactly environmentally friendly processes, these fuels provide an example of an efficient storage solution. “Oil is a liquid,” he notes. “You can store it easily. You can move it all around the world in ships or pipelines.” 

Fischer is one of several ENSI researchers developing other storage technologies, ones that rely on nanoscale properties or processes. Storage is vital to “bridging the night,” a term that refers to getting through the hours when a renewable source of energy—the sun, the wind, or water—isn’t present. And, he adds, “We don’t just need to bridge the night. In some cases, we need to bridge the entire winter.”

Batteries are the most familiar storage solution but they face several obstacles. We have batteries large enough to power a car, but we need safe, sustainable batteries large enough to power a neighborhood. Hydrogen fuel cells show some promise; they are efficient and clean. But, Fischer notes, “If you buy a bottle of hydrogen right now, it’s very likely the hydrogen was made from fossil fuels. That’s not a solution because you don’t get away from the fundamental problem.”

Better understanding photosynthesis will help researchers understand the conversion of sunlight into chemical energy.

Chemistry professor Felix Fischer

This is where nanoscale approaches can play a role, says Fischer. Scientists have devised ways to generate hydrogen from water, but as with CO2 conversion, the process isn’t yet at an industrial scale. Again, solutions are likely to rely on catalysts.

Fischer sees all of these potential new technologies in a larger context: what is their overall sustainability? This means not only economics and waste products like CO2 from oil and gas, but also the sustainability of obtaining materials. 

In the case of an electric or hybrid car, the battery uses lithium, which is often mined under poor working conditions in developing countries. Then the battery is shipped to different parts of the world to be assembled. “How long do you need to drive your electric car to make up for the ecological damage you’ve done somewhere else?” asks Fischer. “That’s not a trivial question.” 

Coming up with solutions that strike a balance in these sorts of dilemmas is the key to a sustainable energy future, says Fischer. Such solutions require a center like Kavli ENSI, where researchers aren’t constrained to profit-driven projects and where people across a broad spectrum of expertise can work together.

“We have to keep in mind that we’re not going to develop just one singular solution,” says Fischer. “The Kavli ENSI offers us the advantage what we aren’t limited to what’s possible today. We can strive for what can be, for sustainable, reliable energy goals.”

The lithium batteries of electric cars such as the Smart Car face obstacles: they can’t be scaled up enough for industrial use, and rely on resource-intensive extraction and shipping.