Method for Analyzing the Value of Distributed Energy Storage at the Facility Level – Step 3: Select Energy Storage Devices

Figure 1 shows the current step in the evaluation methodology…

Figure 1 Showing the current step in the methodology for evaluating a facility level energy storage deployment.

Building on the example of the facility housing the software company as the example, the next step is to select energy storage devices that are considered viable. Considering all known factors it is now possible to select energy storage technologies that meet the energy and non-energy requirements of the facility. The economic, environmental and energy impacts and benefits of deploying each selected energy storage technology will be evaluated to get a general understanding as to which technology is most appropriate for the facility. For the purpose of this study the following three technologies will be selected.

• The LightSail RAES V1 – an adiabatic, CAES energy storage device that stores the air in a series of filament wound air tanks that occupy a shipping container form factor that can hold 1 MWh of energy. Though the RAES V1 is not yet available in production, LightSail Energy claims that the system will have a power rating of 250 kW, with a round trip efficiency of 70% and the ability for repeated, deep discharge over a 20 year life span  (Lightsail Energy, 2012).
• Prudent Energy’s Vanadium Redox Battery Energy Storage System (VRB-ESS®) - a vanadium redox flow battery with a footprint slightly longer and taller than a 30 foot shipping container (30.5’ x 6.6’ x 9.3’) (Shipping Containers 24, 2013). The system has a DC round-trip efficiency of up to 85%, with the response time < 50 ms. The power rating starts at 250 kW and can be scaled up by combining power modules. The energy rating is also scalable by increasing the volume of the vanadium electrolyte tanks. 1 MWh of energy requires 61.6 m³ of vanadium electrolyte. The system is rated at 100,000 full discharge cycles (Prudent Energy, 2013).
• Ice Energy’s Ice Bear – Thermal storage device that produces ice at night that is used during the day to augment building AC equipment. The energy benefits realized by deploying an Ice Bear are equivalent to a 7 kW reduction in peak power demand and a total of 35 kWh of energy shifted to off peak. Used daily, the Ice Bear is expected to have a 25 year life span (Ice Energy, 2012).

Works Cited

Lightsail Energy. (2012). Technology. Retrieved January 14, 2013, from Lightsail Energy: http://lightsailenergy.com/tech.html

Prudent Energy. (2013). Prudent Energy’s Vanadium Redox Battery Energy Storage System (VRB-ESS®) Product Brochure. Retrieved January 29, 2013, from www.pdenergy.com: http://www.pdenergy.com/pdfs/Prudent_Energy_Product_Brochure_2011.pdf

Shipping Containers 24. (2013). 30 Foot Shipping Containers. Retrieved January 29, 2013, from Shipping Containers 24: http://www.shippingcontainers24.com/dimensions/30-foot/