SAN FRANCISCO – Growing electricity generation from by solar and wind energy is flowing into California’s electrical grid, forcing utilities here to begin integrating energy storage technologies into their systems as they seek to offset the peak midday energy generating capacity of these “intermittent renewables” with peak late afternoon energy usage.
While traditional “bulk storage” techniques like pumped hydro and compressed air remain the most cost-effective storage methods, utility executives and market analysts at the Intersolar North American conference here said promising storage technologies like zinc bromine flow batteries are being demonstrated on the grid and in utility substations. Persistently high battery costs continue to slow adoption, however.
While next-generation battery technologies like lithium ion remain too expensive for utilities, Mark Rawson, senior project manager for Sacramento’s Municipal Utility District, said technologies like zinc bromine are approaching the $400/kWh price point utilities need to begin widespread deployment of the storage technology.
While lithium ion remains one of them most promising battery technologies, it remains expensive and unproven for grid storage applications. Besides cost, the big question for utilities is whether lithium ion batteries will be “durable and reliable,” Rawson said, adding that automotive applications will likely show whether lithium ion batteries are sufficiently robust for mission-critical power grid applications. If the technology is widely adopted in electric vehicles, for example, Rawson said the resulting scaling would help reduce battery costs below the $400/kWh barrier.
The Sacramento utility is participating in several photovoltaic storage demonstrations, including a Energy Department-sponsored project with lithium-ion battery specialist A123 Systems. For now, Rawson said, “The market still has to develop to bring down lithium-ion battery costs.”
Renewable energy analysts here agreed, but argued that lithium ion and other storage technologies hold great promise as utilities search for reliable storage technologies that would allow them to use greater quantities of electricity produced by solar photovoltaics (PV).
The solar industry is currently shifting from the electricity generation phase to a new “integrated energy” phase in which renewable energy sources are being consumed where they are produced rather than transmitted to other parts of the grid, said Daniela Schreiber, an energy analyst with Germany’s EuPD Research.
“We are currently experiencing the dawn of a new era – PV 2.0,” Schreiber argued, an incremental step in which storage technologies are decentralizing the power grid and allowing consumers to directly consume power produced by photovoltaics.
Schreiber added that the integration of storage technologies into power grids also creates opportunities for new market entrants providing new power electronics and control hardware and software needed to integrate storage technologies into power grids.
It seems that one huge advantage of pumped hydro storage is that relatively little technology is required (pump / generator) and the bulk storage itself is simply water in a reservoir with a high efficiency of energy recovery. There are no batteries to maintain, repair, or upgrade. It is even possible to extend that capacity by increasing the depth of the storage pond or the surrounding retaining walls. Perhaps the Tennessee Valley Authority did something right when they built the Raccoon Mountain storage facility years ago.
The best place to put excess electricity that is generated during the day is back to the grid where it is needed. I find it commendable (although I suspect that they don't have much choice) that PGE essentially gives 100% credit for electrons returned to the grid... I certainly wouldn't want PG&E draining my car battery just in time for me to have to use gas to get home (assuming that I had an electric car, which I don't)
I support the idea of the stationary EVs being used as grid battery storage. While the utility companies save on their capital investment, the EV owners get their batteries charged at cheaper rates while their vehicles are parked in the office parking lots
If if if, might might might. You reserve how much you need for the day. If you want to be an idiot, reserve 90% of the total available range. However, if you reserve the range you need, the rest is in arbitrage, meaning you get a free car battery, 1/3 of your vehicle cost back, free energy to run it, and a free buyback/recycle of the residual battery capacity at the end of vehicle life, still useful as a static grid store. The number of useful cycles is dumb math when the battery is basically free. So, you can be an idiot dinosaur who hogs all resource "if", or a smart mammal with a plan who winds up with free transportation, only paying for the style and functionality of the vehicle shell....the choice is yours.
Of course, if your EV is in discharge to the grid mode and you need to go someplace, you may have lost too much of your range. Also, the additional charge / discharge cycles might shorten the life of your battery pack.
We've talked to folks working on new wireless nets that will require better backup power. They too shy away from lithium ion as too expensive. As we reported, the integration of Li ion batteries in EVs seems to be the best way to scale the technology and reduce cost.
The EV should be considered to be a grid element that is intermittently disconnected and moved. It spends more than 90% of its time plugged in, so the utilities need to look at the EV as a grid element, not a car. Subsidizing PEV cars will easily drop pack "costs" below $200/kWh for battery costs to utilities. An interesting, utility-centric, concept in this area is being licensed by these people www.zelentek.com