The renewable energy sector continues to grow worldwide, with 2017 seeing a record increase in generation of 8.3 percent. However, as more companies, cities and state governments adopt renewable power goals, they all face an unshakeable obstacle: energy storage.
Storage is essential for renewables’ survival
Reliance on renewable energy sources, especially on wind and solar, is increasing across the country; Massachusetts is considering a bill to source 100 percent of its electricity from renewables by 2047, California is close to achieving its goal of 50 percent renewable power sourcing by 2020 and Ohio plans to invest $25 billion in energy innovation. Unfortunately, none of these ambitious goals will succeed without a scalable, affordable solution to energy storage.
The purpose of energy storage technologies is to collect excess, unused energy produced from wind farms or solar arrays and store it for a rainy day – i.e., when there is no sun or wind. Producing enough extra renewable energy is not a problem; California, for example, produces more than eight million megawatt-hours (MW) of surplus energy during the summer. But, with only 150,000 MW of installed energy storage, most of that surplus goes to waste.
Lithium-ion batteries are not a cost-effective solution
Long-lasting and power-dense, lithium-ion batteries are already the top choice in today’s electronics, including iPhones and Tesla electric vehicles. As such, many renewable energy experts have turned to lithium batteries as the energy storage solution of the future – a strategy with which the experts at MIT disagree.
On a small scale, lithium-ion batteries seem like an effective storage method for excess energy created by renewables. However, building enough lithium-powered storage to bring California to 100 percent renewable power, at its current cost, would equate to roughly $2.5 trillion. At one-third of today’s price, lithium battery storage would cost $1,612 per generated MW. Considering these costs would be added to ratepayers’ electricity bills, it is unfair, unnecessary and unsustainable to pursue large-scale lithium battery storage.
Alternative energy storage methods
In addition to being prohibitively expensive, lithium batteries are also not environmentally friendly; lithium is flammable and very reactive, and often end up in landfills rather than recycling plants.
There are several eco-conscious and affordable alternative energy storage methods in development across the globe. A few promising projects include:
- Ammonia production: Researchers in the U.K. are trying to turn electricity, water and air into carbon-free ammonia. The ammonia can be stored in tanks and later burned to generate electricity.
- Sodium-ion batteries: Sodium-ion batteries, or Na-ion batteries, simply replace expensive lithium for cheap and abundant sodium. The main drawback to this type of battery is that the energy density is much lower than in its lithium-based counterparts.
- Liquid air storage: Using off-peak electricity, air is cooled to -196 degrees Celsius, turning it into a liquid. The liquid air can then be stored and turned back into a gas for electricity.
- Saltwater batteries: Prototypes of the “Blue Battery” are already being tested, but the basic design consists of a saline solution passing through a series of membranes to store energy.
Gabriella is a North Carolina-based writer covering topics related to the energy industry and the environment. A Sunshine State native, Gabriella graduated from the University of Florida in 2017 with a bachelor’s degree in English.