Energy storage has a number of applications for residential and commercial customers. First and foremost, homes with solar panels could benefit from energy storage, especially if net-metering laws, which let customers use the grid for “virtual storage,” disappear. (Off-grid users with PV systems obviously need storage as well, but that’s a pretty small market right now.) Secondly, as more electric utilities incorporate smart meters and time-of-use pricing, customers may use behind-the-meter storage to reduce their consumption during peak demand hours. Commercial and industrial customers already use energy storage for load shifting and demand management. Finally, on-site energy storage can provide short-term emergency backup power when the grid goes down.
Tesla’s Powerwall works for all of those applications, but it’s not the only player in the game. Other companies - some established and some upstarts - are tossing their Li-ion batteries into the ring as well. Let’s look at a couple.
EcoBlade
Schneider Electric’s EcoBlade is a modular, scalable, and fully integrated storage system designed for homes, businesses, and microgrids. About the size of a 30” (76 cm) flat-screen TV and weighing 55 lbs (25 kg), the EcoBlade is designed to hang on a garage wall, much like its Tesla counterpart. Unlike the Powerwall, which needs a separate inverter, the EcoBlade is fully integrated: Li-ion batteries, charge controller, inverter, and energy management software are all included.
The 10 kWh Tesla Powerwall is expected to sell for $3500, but adding the cost of an inverter and professional installation brings the price tag closer to $6000, which equates to roughly $600/kWh. The 5 kWh EcoBlade, which will be available sometime in 2016, has a target price of less than $500/kWh installed. A pair of EcoBlades will provide 10kWh of storage for about $5000, including installation.
Schneider also developed a pre-engineered pod for microgrids. When fully loaded, the pod can store 1 MWh of energy and deliver up to 3.2 MW of peak power.
Verd2GO
Verd2GO (“green to go”) is a relatively new company that has an interesting take on the energy storage market: modular, multipurpose battery packs. The company is developing a line of Li-ion charging packs of various sizes. Small packs (5V, 8000mAh) with USB outputs are suitable for recharging phones, tablets, and other portable electronics. Larger units (5V 20,000mAh) can be stacked into a scalable energy storage system for home use or to extend the range of an electric vehicle.
Check out this video to see the company’s vision for the future of distributed energy:
Indiegogo from Verd2GO on Vimeo.
An electric vehicle’s primary drawback is the amount of time it takes to recharge its batteries. Quick chargers have some promise, but their current and power requirements are enormous and potentially dangerous. Tesla is proposing a robotic battery swapping station, but its application is limited.
Imagine driving into a filling station, removing batteries from a modular battery pack, and swapping them for a fully-charged set of batteries. In the same amount of time that it takes to fill a gas tank, you’ve just “refilled” your EV. That’s the idea behind Verd2GO’s modular power packs, which are designed to quickly and easily extend the range of EVs.
To be sure, a Verd2GO battery pack is not replacement for existing EV batteries; it’s a range extender. Let’s look at the technical challenges of making this happen. (There are logistical and infrastructure issues too; those are SEP - Somebody Else’s Problem.)
The first engineering problem I see with the EV range extender idea is that the rack must match the vehicle’s electrical requirements. Either a universal standard would need to be developed (good luck with that) or a “conversion kit” would have to be designed for each EV model.
Second, a battery is not exactly like an empty vessel for energy. While a 12 ounce bottle will always hold 12 ounces, a battery’s capacity changes with time, number of discharge cycles, and depth of discharge. Each battery pack would need some integrated intelligence to know how many times it has cycled and how deeply it’s been discharged each time, and would have to make reasonable estimates of its current capacity.
Related to that, it’s best not to mix and match batteries of different capacities. If a customer takes a set of batteries from a kiosk, she would need to know if they’re all the same age and all have the same wear and tear. Will the kiosk query the aforementioned on-board intelligence and sort the batteries?
Verd2GO’s concept is interesting and their vision is admirable. Can the technical issues be resolved in an economical way? Do you see problems that I haven’t addressed? Please comment below.
Images courtesy of Schneider Electric and Verd2GO respectively
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