A breakthrough in the renewable energy industry may hold the solution to eliminating carbon emissions, while also creating new sources of clean energy. The potential revelation comes from scientists working in China and the United States in the form of a system that recaptures carbon-dioxide pollution for use in a storage system.

Energy storage has been heralded as the solution to the volatile production that comes with clean energy sources – we need a way to store energy during peak production hours for use when production ceases, such as when the sun is not out or when wind is not blowing. Compressed air is one of these solutions, and is known as one of the cheapest forms of energy storage. As it currently stands, excess energy during peak hours is used to compress air. Later, that air is blown into turbines mixed with natural gas to produce energy yet again. However, this method produces waste heat and creates a sizeable carbon footprint.

midamerican wind farm

Photo from MidAmerican Energy Facebook page.

A recent study produced in Norway by SINTEF attempted to address the issue of waste by using crushed rock to recapture the lost heat, which would be converted into energy for the next round of compression. However, this solution remains inefficient and difficult to implement. Rather, a different medium in the compression would be necessary to address these concerns. Enter CO2.

The Lawrence Berkeley National Laboratory, in conjunction with the North China Electric Power University, has proposed a system in which CO2 is captured and compressed to a fluid state. Then the liquid is pumped into a reservoir with a deep saline aquifer, a high pressure environment. When energy is needed, that CO2 will be released into a low-pressure reservoir, spinning turbines in the process. Like the normal compressed air model, this produces energy. A senior scientist at the LBL, Curtis Oldenburg, said that the idea was created when thinking of how to utilize CO2 in a closed loop system, to eliminate wasteful byproducts.

The model produced by this team was able to produce higher energy-storage density than conventional compressed air systems. This essentially means that more energy can be stored in a smaller physical space. Chinese scientists are already anticipating using the system during intermittent periods produced by wind farms in China.

The idea has been circulating as of late. Recently, a Stanford geologist, Sally Benson, cited the paper written by Oldenburg when asked during a seminar whether CO2 storage systems are possible. She continued by pointing out that CO2 energy storage has an advantage – more energy is produced when the pressure changes than was originally stored. The discussion was centered on carbon capture and potentially uses. The intersection between these scientific communities, one focused on capture, one focused on energy production, could solve a problem that has hindered the growth of many renewable energy technology for years now.

Oldenburg was also sure to address that incentives are necessary to make a system like this work. There would need to be a price or a value afforded to carbon – if carbon dioxide is valuable, it would incentivize people to make more creative uses for it. One of these potential uses would be sale to CO2 energy storage systems.