Energy Storage

Energy storage: public power leads the way

When Elon Musk, CEO of Tesla Motors, stepped on to a stage in Los Angeles earlier this year to unveil the company's Powerwall energy storage device for residential customers, the public's reaction was nothing short of giddy. It was as if energy storage was a brand new technology that was poised to be the Holy Grail for the energy industry.

But energy storage is nothing new for public power utilities. Take, for example, the Tennessee Valley Authority's 1.6-gigawatt Raccoon Mountain facility, a pumped-storage plant located in southeast Tennessee that was completed in the late 1970s.

Fast forward to the present day, and you can find plenty of other examples of how public power utilities are pursuing a wide variety of energy storage projects.

What has been lost in the hullabaloo over residential energy storage is the flip side of the storage coin — namely, utility-scale energy storage, which is already being deployed, along with the fact that plenty of utilities have been pursuing energy storage before it was the cool thing to do.

And putting aside the types of technology in play, energy storage offers yet another example of how diverse the public power community is in terms of both size and geography.

In California, where distributed energy resources are getting a lot of attention these days, California's Modesto Irrigation District, which serves more than 115,000 customers, is working with Primus Power on an energy storage project. In 2014, I had the opportunity to tour Primus Power's facility in Hayward, California.

Melissa Williams, a public affairs specialist at MID, told APPA on September 23 that MID is waiting for Primus Power to be ready to proceed with a two-year pilot project that includes interconnecting a 250 kilowatt flow battery to an existing MID power plant.

When ready, the flow battery will be installed at one of MID's power plants and MID will dispatch it against its power loads, she noted.

The plan is to deploy the flow battery in different ways to help determine its optimum uses and provide feedback to Primus Power on this energy storage concept. MID benefits from having the opportunity to directly test this type of technology," she said.

Another large California municipal utility, Imperial Irrigation District, has also been in the news recently. IID is working with GE to install a battery storage system for reliability and ancillary services. IID, which serves just over 165,000 energy customers, signed on to the project with the number one goal of increasing its reliability, said Bruce Townsend, the utility's superintendent of alternative energy, in an interview with Public Power Daily. It will be the first battery storage project on IID's system, he said. The 30-megawatt, 20-megawatt-hour battery storage system is GE's third lithium ion storage project.

But much smaller public power utilities are also actively pursuing energy storage projects. The public power utility in the village of Minster, Ohio, is working with other entities to install an energy storage project that, when completed early next year, is expected to be one of the largest energy storage facilities in the state. The 7-megawatt energy storage facility will use lithium-ion batteries and will be adjacent to a new 4.2-MW solar power plant. The Village of Minster serves just over 1,000 customers.

Storage — savior or death knell?

While energy storage could fundamentally shift the way power flows are managed, it is still way too early to say one way or the other whether the plans of Mr. Musk and others will ultimately pan out.

The buzz about energy storage these days raises some fundamental questions. For example, will storage ultimately deal a death blow to the electric utility industry? Some posit the idea that by capturing the electric energy produced by the sun and wind, the battery will allow customers to basically rid themselves of the grid.

Others say that storage will save the grid and the electric industry. By providing support — voltage and current to the grid when resources are tight, it will allow the utility grid to operate more efficiently and more effectively.

So is storage a death knell for the power industry or a savior? A question such as this makes one think of the famous question about which came first: The chicken or the egg?

The Wikipedia definition is listed as follows: Energy storage is accomplished by devices or physical media that store energy to perform useful processes at a later time. I for one like this definition. The key here is that I broadened the search from Battery to Energy. Electricity is one form of energy, not the end all of energy. Energy is a broader concept and one that is more important to understand. Most customers want energy to provide them with some 'useful process at a later time.'

A great example of this is using energy storage in hot water heaters. By heating the water inside the water heaters during the night when energy is more abundant, the energy stored in the water heater can be used for showers, or dish/clothes washing during times when the power is in demand, and much more expensive. The same can be said of heating bricks in electric thermal storage systems at night, and then dissipate that stored heat energy during the day when supply is much more expensive.

The key in both examples is that the consumer uses the 'stored energy to perform useful processes at a later time', and in these examples, for less money out of their pocket. It's a win-win scenario. Customers can save dollars using cheaper power and the utility can use the storage devices to load shift.

But, let's focus back down to just batteries. Is it still a win-win all around? I think the answer to that question is sometimes yes and sometimes no.

The more advance technology gets with battery storage, then the closer we get to a win-win scenario. Today we are on the cusp of this occurring, but we are still in a win sometimes, lose sometimes situation.

Regardless on which side of the savior or death knell equation you reside, it is important to understand that all parties seem to agree with the usefulness of battery storage moving forward. As batteries provide more power for their size, and the unit prices decrease, the numbers spell out future success.

But as with everything in life, a cost-benefit analysis has to be part of the equation for utilities and customers pondering energy storage options.

Customers taking a closer look at products such as the Powerwall have to make sure that they crunch the numbers before committing to such devices. While unit prices may fall over the long term, at least in 2015, buying a storage device for your home is no guarantee of money savings over the long haul.

True, for some customers in the higher tax brackets, cost may be no object when it comes to storage and other distributed energy resources.

But for the vast majority of us, it is only prudent to do our homework before making what is at least for now a major financial commitment in the form of buying a storage device."