Though the cost of renewable energy has plummeted in recent years, traditional power sources are still very much the rule in the energy industry today. That might look like an issue of simple inertia, but it’s actually the result of the last major barrier to a real energy revolution: energy storage.
With fossil fuels, energy already comes stored in a stable form, ready to be released. Renewables capture energy, and have to either put it to use immediately or find a way to store it with expensive and complex batteries. Unfortunately, those batteries have developed at an agonizingly slow pace compared the other energy technologies. In recent years, however, investment into battery technology has ramped up, and new ideas are finally being developed.
What’s driving the change
The rapid improvement in solar and wind technologies in the last two decades have driven their cost down to a level that’s comparable with oil. While this has certainly made a difference with investors, the major catalyst for change is the auto industry, and the emergence of competitive electric cars.
Tesla Motors and its founder, Elon Musk, have brought attention to the issue of energy storage, and are working hard to find ways to resolve it. Seeing the potential, universities and other businesses are now pouring far more effort and investment into solving the problem. The issue is that batteries are extremely heavy, and last for only a limited amount of time before they need to be replaced. This makes them the biggest hurdle for creating more energy efficient, and much more inexpensive vehicles in the future. Incidentally, resolving those problems, particularly the issue of longevity, would also drastically drive down the long-term cost of storing and using renewable energy in private homes.
Battery improvements are on the horizon
In recent years, a number of important improvements have been made in battery technology and the larger industry. Here are just a few notable examples…
Economies of scale
Though Elon Musk is a fan of reinventing entire industries, Tesla is taking a more traditional approach to battery development. They’re doing this by producing the Powerwall and Powerwall 2, which are enormous modular battery storage devices designed to be installed in, and provide power for private homes. By creating a mass-producible product that can be brought to market quickly, Musk hopes to drive down cost, bring on further investment, and develop a natural feedback cycle to encourage faster development.
One exciting technology is the lithium air battery. Unlike regular lithium ion batteries, it only has 20% of the weight of a regular battery for the amount of electricity stored, and works through a series of electrochemical reactions that use oxygen. In the past, these types of batteries didn’t charge efficiently, losing nearly 30% of the energy to heat. They also incorporated oxygen from the atmosphere, which required converting oxygen into a solid form, and releasing it again as a gas, which stressed the materials and limited the battery’s lifetime. MIT’s new lithium air battery remains in a permanent solid state, and loses just 8% of its charge to heat generation. Preliminary tests suggest that these kinds of batteries have a very long lifetime, and that they’re significantly safer than existing technologies.
Gold nanowire batteries
Nanowire batteries make batteries more efficient by vastly increasing the surface area of one or both electrodes. They have a far larger capacity than traditional power cells. Researchers at the University of California Irvine have worked out how to do this using gold nanowires in a gel electrolyte solution. Gold is an ideal material, and when combined with a manganese dioxide shell, the power cells showed absolutely no noticeable degradation after 200,000 cycles. This is a very big deal, because it suggest that batteries that practically never wear out are a real possibility in the near future.
One of the major benefits of the centrally supplied power grids that we use today is that the flow of electricity can be adjusted in real time to ensure that customers are properly supplied, and that the grid doesn’t become overloaded.
To accommodate a more complex user-supplied system, grids need to become smarter. A sufficiently smart grid would need to track the supply and demand of energy in its system in real time, and be empowered to draw on and redistribute energy resources to ensure steady service and to minimise blackouts. Building a durable and robust system that will manage this effectively is a major infrastructure hurdle that will likely not be crossed in most countries until market pressures intervene to force the issue. Fortunately, with the better battery, that change is now on the horizon.