Power storage is a sort of missing link in a chain that connects wind farms to load centers. Without storage, unneeded wind power is lost and more often, needed power is unavailable. Sufficient storage would give utilities more control of their power characteristics such as frequency control. And it might solve the problem of rapid power ramps from solar farms when clouds move by. Things are changing.
A few years ago, utilities with high renewable-energy sources, such as Pacific Gas and Electric, weren’t installing much battery-based storage due to high costs. More recently, the budding electric vehicle industry is increasing battery manufacturing volumes and that is helping bring costs down. The cost declines in the battery industry, coupled with some of the regulatory pressures indicate that the day for storage has arrived.
Now with so many batteries to choose from, utilities can turn to companies such as Greensmith (www.greensmithenergy.com) to size a rack of batteries, apply controls and an inverter, and provide useful service to utilities with renewable-energy sources. The company has been in the energy storage business for about six years, “which is a lifetime in energy storage,” says its senior VP Andrew Tang. “We’ve been perfecting our software platform and have deployed 35 successful implementations of it across 19 different customers including both utilities and non-utilities,” he says.
Power developers, and wind and solar developers are on his list. “By year’s end, we will have deployed projects that total about 23 MW. One of them was just commissioned recently for San Diego Gas & Electric and we have a large 20 MW frequency-regulation project being deployed that goes live in November. That will be bidding into PJM on a daily basis,” add Tang.
While mitigating ramp rates is a big issue in the solar industry, there are similar issues on the wind side. “Renewable energy is not a completely firm resource. It introduces voltage variations across the grid and controlling those is a large portion of our market. But as I look at how the market is going to develop over the next five to ten years, a large percent will move toward what the industry calls transmission and distribution deferrals,” says Tang. For instance, in previous years, a utility would have to upgrade a troublesome substation or transmission line. Today, it may be possible to solve their problems by placing energy storage closer to load pockets.
Tang says the company is battery agnostic. “I’d go a step further and say we are nearly technology agnostic. That means we will pair with anyone’s battery and with anyone’s inverter or power conversion system. To date, the company has integrated eight different battery manufacturers, and based on products that we will close out this year, that number will rise to 12,” he adds.
The company has also worked with most lithium-ion chemistries including the lithium-manganese-oxide batteries from Samsung and LG Chemical. “We’ve integrated lithium-iron phosphate, and we are integrating an aqueous-ion hybrid battery from Aquion, along with one from Vizn. We’re trying to match the right battery and the right inverter for the application or use case,” he says.
The company’s secret integration sauce is its control software, GEMS 4. “There are three fundamental components to it. The first is a physical or device connectivity layer. This is the interface to the physical world, the part of the platform that plugs into batteries and inverters, and most importantly, into SCADA systems and market signals,” says Tang. So if we were designing a PJM frequency-regulation system, we would also plug into PJM’s regulation signal.”
The second is the platform layer that does the core computations. It’s where the algorithms run and where the complex input and output takes place. The analytical computing layer makes it easy to develop additional applications.
Applications are the third layer. These would be specific to the use cases such as
frequency regulation, capacity shifting, or ramp-rate control for solar firming. That’s how a utility or a power developer actually monetizes the asset – how it gets paid.
Systems also provide a black start capability, says Tang. That refers to starting an induction generator when no other power is available. Such generators need a power source to energize their coils.
Tang says the company is working with about five of the top 20 wind and solar developers in the U.S. “These are companies that have built large wind and solar projects. A lot of them are looking at energy storage as kind of the next frontier – the next opportunity. Many are looking at building energy-storage-development businesses in addition to their wind and solar businesses. For instance we’ve had a handful of battery companies actually respond to utility RFPs, and they needed a software control layer. So they ask us to partner with them,” adds Tang.
Filed Under: Energy storage, News