Energy Storage Options
Why does energy need to be stored?
Many alternative energy options, such as solar and wind power, do not produce a consistent output. Meaning that the produced power fluctuates throughout the day. For example, solar panels produce very little energy at night, and wind turbines produce more energy on windy days. Because of this, it is just as important to store the generated power as it is to generate it in the first place. There are many feasible storage solutions today. From lithium-ion batteries, like what powers your phone, to turbines spun by water pulled by gravity. The table on this page compares several of these options.
Top 3 Storage Options
| Option | Discharge Time | Lifetime | Density | Energy Loss |
|---|---|---|---|---|
| Hydro Pumps | 4-16 hr | 30-60 years | 0.2-2 W-hr/l | 15-30% Loss |
| Compressed Air | 2-30 hr | 20-40 years | 2-6 W-hr/l | 30-40% Loss |
| Li-ion Battery | 0-8 hr | 1,000-10,000 cycles | 200-400 W-hr/l | 5-15% Loss |
| Source | ||||
Summary
From the table, Lithium-ion batteries are by far the most efficient storage option. With significantly lower energy loss, and much higher energy density than either of the other options. However, Lithium-ion batteries do not last as long as the other options. Assuming each is discharged only once a day, then on average, either of the other options would last many years more than a lithium-ion battery. The other two options, Hydro pumps and Compressed air are much more even in their efficiency. A hydro pump takes up more physical space than compressed air, but is has lower energy loss and lasts longer.