According to the Energy Information Administration (EIA) 67% of the energy generated in the United States in 2015 was from fossil fuel sources. There are several reasons for this percentage including economic reasons, existing infrastructure reasons, legacy reasons, and an abundance of these resources in our own country. Another reason why fossil fuels make up such a large portion of our generation is because we have an inherent problem with some of the most well-known renewable resources. For Solar (.6% US energy) and Wind (4.7% of US energy) the problem is storage.
As everyone knows, the sun is only up for a certain number of hours each day. Unfortunately wind tends to also have patterns of high speeds and low speeds. In America we like our TVs and lights to turn on any time day or night, and we don’t want to be held prisoner to the cycles of the sun. That’s where storage comes in to play. If we really want these technologies to make up a larger portion of our energy then we have to be able to store the energy when we can collect it.
Recall from my second blog post we can’t create or destroy energy so if we want to store energy we have to convert it into a form that can be stored. One popular method of storing energy these days is in the form of lithium-ion batteries. These batteries are great for storing energy, but it is difficult do to it on an industrial scale. In other words it would be difficult to store enough energy to power a city with our current lithium-ion technology. Tesla is now producing a Lithium-ion battery that could be used for individual use in people’s homes. This might be one work around for the industrial scale problem.
There have been several other methods proposed that could be used to store energy. Some of them include pumping water up a hill during the day time and using it to power a hydroelectric dam at night time. You can compress huge amounts of air during the day time, and release it across wind turbines at night time. You can also use electricity to separate water into hydrogen and oxygen and later burn the hydrogen to create thermal energy. The reason that we don’t see more of these technologies being used commercially is that they all have really low efficiencies. Every time we convert energy from one form to another, we lose some energy due to inefficiencies. In the current market, companies are better off just selling the solar power when the sun is shining.
If you have some thoughts on this post or energy storage in general I would love to hear about them in the comments section below.
Photo credit: http://berc.berkeley.edu/wp-content/uploads/2015/02/energy_storage_2013_11-13-1.jpg