By John Mott-Smith From page A4 | July 16, 2015

Cross posted from the Davis Enterprise | Photo Credit: Davis Enterprise

This is the second of three (I think) columns on the topic of energy storage; specifically, electrical energy storage. Why so much time spent on a seemingly mundane topic like energy storage?

One reason is that energy storage is a necessary partner with development of photovoltaic (PV) and wind energy: These sources of energy are susceptible to fluctuation when the sun doesn’t shine or the wind doesn’t blow. This intermittency can be made up for by storing energy that either is electricity or can be converted to electricity when needed.

And PV and wind are increasingly providing a greater proportion of our electricity. To give you some idea of the pace of this, a September 2014 report calculated that about 500,000 homes and businesses in the United States had PV systems on their rooftops in June 2014. By March 2015, this number had increased to 700,000, with more than half of all new electrical generation capacity in the U.S. coming from PV.

This also can be seen locally, where the number of rooftop systems installed on Davis homes and businesses, as well as other Yolo County cities, is just about doubling each year.

Another angle on this is that the state’s ability to rely on hydroelectric power has been dramatically curtailed due to the drought, with electricity from this source making up only roughly half in 2014 the “normal” amount.

According to the Energy Information Administration, the explosion in the number of PV installations was able to make up nearly 85 percent of this loss. Ironically, solar PV is making up for the “intermittency” of hydroelectric power.

As a result of all this, many experts are predicting that energy storage will be the next big thing, and there is a tremendous amount of research and testing going on to develop cost-effective storage technologies.

The U.S. Department of Energy estimates that pumping water uphill and then letting it flow downhill to generate electricity accounts for more than 90 percent of current storage capacity. But DOE is aggressively funding research and development of other, less costly storage technologies.

California is on the leading edge in this effort through its requirement that utilities develop 1.3 megawatts of storage capacity by the year 2020, but it bears mentioning that this is not just a Left Coast effort. The rest of the country, other countries, and many of the planet’s largest companies, are racing to capture what they see as a quickly emerging market.

The state of New York, for example, is funding seven pilot programs to test various technologies to increase battery efficiency, reduce manufacturing costs, or to come up with brand-new approaches to energy storage.

In Georgia, a project is underway to construct a 1-megawatt storage system as a beta test for integration of renewables into its electric grid.

General Electric is testing “liquid air” as a storage system, in effect compressing, cooling and liquefying air that can generate electricity in the process of decompression.

Hawaii’s “Energy Research Systems” is installing “vanadium flow batteries” in two homes, a science center and with a micro-grid to test and evaluate how these and other sites like them potentially could operate off the grid.

Stanford University is testing aluminum batteries that are expensive but that could last much longer than the lithium-ion batteries now ubiquitous in cars and smartphones.

Speaking of aluminum, a company in Germany is has designed a system to capture electricity from its manufacturing process that can be stored and used when the price of electricity is highest, thereby offsetting one of its largest production costs.

Japan’s Ministry of Economy, in addition to seeking about a billion dollars to increase energy efficiency in homes and factories, is also looking for almost $750 million to construct energy storage systems that make it possible for the further development of renewable energy supplies.

Just to drive home the point that interest in energy storage is not unique to places and populations that might be expected to push the envelope on renewables, the city of Turlock, our neighbor down the valley, has installed a “grid-scale, iron-chromium redox flow battery” system that gets its electrons from a dual-tracking PV system in an almond orchard.

All this adds up to one thing: The energy storage industry is developing very quickly. How quickly, you might ask?

Way back in 2013 (ancient history) the Edison Electric Institute, identified as “the trade group for investor–owned electric companies,” referring to home battery systems (see next column), warned its members that: “One can imagine a day when battery storage technology or micro turbines could allow customers to be electric grid independent” and compared this to how rapidly the world changed from land lines to cell phones.

Finally, with all the talk and action related to energy storage there is one aspect I am very excited about and which will be the basis for the next column: the role of cars and homes in energy storage and the implications of this for the future of the electrical system overall.

— John Mott-Smith is a resident of Davis; his column is published on the first and third Thursdays of each month. Send comments to