By Jason Deign
Systems integrator Powin Energy could gain an award today for a seemingly bizarre energy storage application: using batteries to charge batteries.
The Oregon, USA-based company is among those shortlisted for a 2016 Energy Storage North America Innovation Award for an electric vehicle fast-charging station at the headquarters of microprocessor firm Intel.
The installation, in Santa Clara, California, uses Powin Energy’s Battery Pack Operating System (bp-OS) to manage 30kw and 43kWh of lithium iron phosphate storage linked to 15 SolarWorld PV panels with a capacity of 4.1kW.
The use of batteries for electric vehicle fast charging avoids the need for standard three-phase 208/277/480V AC connections and helps avoid high demand charges, said EV4, the firm that designed and manages the station.
The technology also makes it possible to place charging stations in areas where three-phase AC is hard or costly to obtain.
Using patented technology
Danny Lu, Powin Energy’s vice president of sales and marketing, said the company has sold five other electric vehicle (EV) charging station setups, all in Oregon, using the patented technology in place at Intel.
Because of high demand charges in parts of the US, “a lot of times the economics of fast-charging doesn’t really work if it’s a privately owned EV system,” he told Energy Storage Report.
“If you add battery backup to it, you can pretty much discharge the battery any time the charger turns on, and keep that charger under the demand threshold so the privately owned EV station can make some profit.”
EV chargers typically deliver power at 50kW while demand charges kick in above 30kW, Lu said.
“We discharge 30kW of power for 30 minutes while the charger can stay below that 30kW-threshold, so you can eliminate a lot of those demand charges,” he explained.
Storage delivered six months ago
The Intel storage, which is linked to OpConnect charging software and an Ideal Power conversion system, was delivered six months ago.
Powin Energy also has an agreement to supply battery packs that will be built into the charging stations being developed by an unnamed large Portuguese converter and transformer manufacturer, Lu confirmed.
Since most European markets do not have punitive demand charges like those seen in the US, the main attraction for this and other charger makers is likely to be the ability to place charging stations beyond the reach of three-phase power.
Electric vehicle charging is only a minor part of Powin Energy’s overall focus, though.
Lu said the company’s bp-OS used sensors to determine the charge in each battery cell and adjust it to keep all the cells in a system at a uniform level, maximising the capacity.
Installation and product costs
“Some of the issues we’re seeing in other [systems] is that installation and product costs may be a little elevated because of the amount of DC connectors associated with transferring energy between packs,” he said.
He claimed bp-OS can connect 36 battery strings onto a single DC bus of a centralised inverter, whereas competitors often require inverters and transformers for each string.
Powin Energy’s approach means the company can roughly halve the current cost of battery system installation, according to Lu. It can also reduce battery management system costs by about 10%, he said.
These advantages do not have much of an impact on small systems but could shave about 5% off overall costs for a 50MWh system, said Lu. It has taken the company a while to gain acceptance in the market, however.
Powin Energy originally trialled its technology with Bonneville Power Administration and Pacific Northwest National Laboratory, assembling a 120kW, 500kWh mobile system that was put through its paces in a range of settings.
Over a period of two years, the setup was tested for wind power integration, solar firming and smoothing, and demand response, the latter as part of an award-winning programme with Energy Northwest.
In late 2014, Suntech investor Shunfeng International Clean Energy Limited paid USD$12.5m for a 15% stake in Powin Energy, adding to about $3m in seed funding obtained over the previous three years.
The company initially struggled to win projects in US utility and commercial and industrial-scale energy storage markets, Lu admits. But the Intel deal seems to have signalled a change in fortune.
Last month, for example, Southern California Edison selected Powin Energy for a 2MW, 8MWh project in Irvine, California, which is due to be commissioned by the end of December, using Chinese-made prismatic batteries.
Powin Energy has also been awarded a 1MW, 1MWh project with Bonneville Power Administration and National Renewable Energy Laboratory, which is due for delivery in February or March 2017.
“Aiming for 75 to 100MWh”
The systems integrator is now “aiming for 75 to 100MWh” of capacity to be installed in 2017, Lu said.
Around 75% of that volume is likely to be installed in the US, he said, and almost all of it will be stationary storage. Powin Energy can call on up to 200MWh a year of production capacity in China, said Lu.
The company is now seeking additional investment to fund its growth, targeting mostly Chinese backers with a fundraising target of between $5m and $12.5m.
The funds should be enough to take the company into positive cash flow within two years, Lu said.
Being an awards finalist at today’s US version of the Energy Storage trade fair, alongside prestigious entries such as the Stone Edge Farm Microgrid featuring technology from Tesla and ESS, certainly won’t hurt its chances of succeeding.