It seems that every utility is either considering or already installing energy storage systems. In fact, the Energy Storage Association notes that, in terms of MWh, the U.S. market grew 284% in 2016 and is set for another year of near exponential growth. The reasons for it are well known: energy storage helps to integrate renewables; enables frequency and voltage control; ensures power quality, and enhances the value of microgrids, to name just some of the benefits. “But before you rush to install an energy storage system on your grid in hopes of making it more reliable, secure, and resilient, there are eight things you should ask your provider,” cautions Troy Miller, Director, Grid Solutions at S&C Electric Company. “Taking some time at the outset to gain a full understanding of what your provider can and cannot do will reap huge savings in time, money, and, yes, stress over the life of the system.”
According to Miller, “Everyone knows to ask about the first four of the eight core competencies necessary to design, build, and operate an energy storage system.” These include all the normal technical and cost details about: 1) the batteries; 2) the power conversion system or inverter; 3) the energy management system or the software that makes it work; and 4) EPC or engineering, procurement, and construction – actually getting it built. “But, the other four questions can really be revealing and can make a critical difference,” adds Miller. They are:
No. 5 – What’s included in your power system engineering and analysis?
Ideally, this process involves an in-depth look at what type of energy storage system you require, where you need it, and why you should install it there. It should also include a short-circuit analysis, as well as grounding, load flow, fuse coordination, and power quality studies to make sure it will be safe and reliable. “If this process involves a number of different companies, each of which is engaged in a variety of activities, then the risk that things will get missed – or will not be done as thoroughly as required – rises considerably,” warns Miller, who cites an S&C project in Minster, OH, as an example. “In Minster our detailed analysis revealed a hardware design mistake by a sub-vendor that, if undiscovered, would have caused a two-month project delay,” he says. “This process works.”
No. 6 – How thorough did you analyze your switching and protection?
Energy storage systems are not like traditional generation. “Their fully charged batteries contain a tremendous amount of embedded energy, at low circuit impedance, that can be released instantly,” says Miller.” As such, when analyzing the potential impact of connecting an energy storage system to the grid, it’s absolutely vital that the engineers ensure the system is protected from the grid – and that the grid is, in turn, protected from the system. In fact, notes Miller, S&C adopted this approach when installing a 2-MW PureWave® Storage Management System and a 2-MW/2-MWh lithium-ion battery system at a Powercor location in Victoria, Australia.
“The utility’s engineers required an energy storage system that could power the line during grid outages and peak-shave during times of high demand to reduce stress on the network’s assets,” adds Miller. “The switching and protection was extraordinarily complex on that job.”
No. 7 – Do you have the capability of running full-system tests?
This should seem pretty obvious, but many energy storage suppliers only do representative tests and only test the complete system after everything arrives at the site. “They will typically only test the software – or perhaps a small piece of the overall storage system – as opposed to looking at the whole system in full operation before it gets to your site,” Miller says. “By contrast, we connect the entire system and run it under full power prior to shipment. That does not happen with most suppliers. “In fact,” adds Miller, “we’ve seen others have project delays of up to nine months because the system wasn’t fully tested in advance.”
No. 8 – What level of post-installation support do you provide?
Predictive monitoring and preventive maintenance are absolutely key to ensuring your energy storage system will be operating as originally intended a decade from now. “It takes a holistic approach – one that includes 24/7 remote monitoring – to catch small problems before they turn into big headaches,” says Miller. “Even a slight temperature rise in part of the system could be a predictor of potentially costly problems on the horizon, and your installer should be your partner in this approach.”
Of packagers, developers, and true integrators
How to tell whether your energy storage system supplier is an energy storage system packager, developer, or true integrator – and why you should care:
Packagers – These are specialists in one area that partner with other suppliers to deliver a system. “Typically, they cannot deliver on all eight competencies,” notes Miller.
Developers – These are primarily project managers who focus most often on “first cost,” not the total lifetime cost of the energy storage system.
True integrator – These are specialists in all eight core competencies. “They understand total system costs, have no conflicts of interest, and won’t ever compete with you,” says Miller.