January 18, 2017
Recently, the Massachusetts Department of Energy Resources (DOER) determined it will set a specific structure for energy storage targets for electric companies by July 1, 2017. Energy storage is a key factor in enabling companies to utilize their renewable energy sources to their full potential – by allowing them to bank power during peak production periods and use it when their energy generation systems (whether renewable or non-renewable) aren’t producing.
There are a number of options for storage, depending on what size and type is right for your business or organization. Let’s investigate a few of these solutions at work in our own backyard and see what they can do to optimize energy use and efficiency.
Energy from pumped hydroelectric is stored by pumping water from a reservoir at a lower elevation to one at a higher elevation. When electricity demand is high, the stored water in the higher elevated reservoir is released to the lower reservoir through turbines, creating energy. When energy demand is low, low-cost electricity from the grid is used to pump water from the lower reservoir back to the upper reservoir to be stored. For example, New England’s largest pumped hydro battery is found in Massachusetts at Northfield Mountain—a “5-billion-gallon battery”. Deep inside the hollowed-out mountain is where you will find the generating facility, which is reached by a tunnel that leads into the mountain. Pumped hydro is generally considered the most cost-effective way to store energy.
Compressed air energy storage (CAES) is similar to hydro in terms of its output and storage capacity. However, while hydro pumps water from a lower pond to an upper pond when there is excess power, compressed air storage compresses ambient air and stores it under pressure in an underground cave. Then, when energy is needed, the pressurized air is heated and expanded in an expansion turbine, which drives a generator that produces power. This type of storage is considered very reliable and economically feasible. General Compression, one of the leading innovators in the CAES industry is located right in local Newton, MA and has been working to develop a system that bypasses the need to regulate temperatures as compressed air is stored or extracted.
Thermal energy is useful because it allows you to reserve both heat and cold energy for later use. Boston’s Moakley Courthouse, for example, uses thermal storage tanks to cool the building in a way that is energy efficient. Through the use of pipes filled with glycol antifreeze, the tanks are essentially frozen into ice cubes, converting the courthouse basement into a farm of frozen batteries. These “batteries” can be charged when the cost of energy is low, and used when the building needs to be cooled. Because energy is much less costly at night, in most cases, these tanks are cheaply storing the courthouse’s energy system at night in the form of ice; that energy can then be used in the daytime to produce air conditioning in the building. Thermal storage can be very effective for commercial facilities and their energy costs, as they can release large amounts of energy with minimal waste.
Lithium Ion Battery
These batteries are rechargeable, solid-state batteries that have recently been developed into larger-format cells for company storage use. This form of energy storage is most commonly paired with solar. NEC Energy Solutions, for example, has unveiled its own battery system called the Distributed Energy Storage Solution (DSS) that is self-contained in controlled enclosures, made for both outdoor and indoor installation. It was designed in a way to enable commercial facilities interested in affordable storage something that is easy to use and install. In comparison to other forms of storage, lithium ion batteries are considered advantageous in their power density and usable life.
While we have identified a few viable types of energy storage, there are plenty of others that can be explored as well. However, what is most important is the bottom line: that your organization will be able to utilize its renewable energy as much as possible and reduce energy costs by cutting peak demand.