Did you know that the amount of energy from the sun shining down on earth for one hour is equivalent to the amount of energy used globally for an entire year? The harnessing of solar energy is not new. However, scientists have struggled to find a way to store solar energy for use when the sun is not shining – until now. In July, Daniel Nocera, a professor of energy at the Massachusetts Institute of Technology, and a team of scientists announced that they had created an efficient and inexpensive means by which to capture and store solar energy.
Looking to photosynthesis for inspiration, Nocera decided that if he could split water into its component parts, hydrogen and oxygen, he could use solar energy to recreate energy when the sun goes down. The team ultimately created a catalyst consisting of cobalt metal, phosphate and an electrode. By placing the catalyst in water and passing electricity (provided by photovoltaic cells or other energy sources such as wind) through the electrode, the team was able to create oxygen gas. Using platinum in a similar catalyst produces hydrogen gas. Recombining these gases in a fuel cell creates carbon-free electricity.
The water by-product is filtered back into the mechanism to be split later. The process is surprisingly simple to execute and uses water at room temperature.
While assimilating this technology into existing solar energy systems is still a work in progress, Nocera is confident that everyday use of these fuel cells is on the horizon. “This is the nirvana we’ve been talking about for years,” says Nocera. “Solar power has always been a limited solution. Now we can seriously think about solar power as unlimited and soon.”
by Jim MacInnis