Often talked about but largely overlooked, distributed energy storage technologies have time and again proven effective and yet, in general, have not always been looked at as an integral part of the smart grid equation in the same way that large grid-scale systems have been portrayed. Perhaps it’s time to reconsider this mindset.
What if you were already using energy storage today? Well, that’s exactly the case. A domestic hot water heater is the best example for understanding the value of distributed energy storage. Nobody sizes a domestic heating element to handle instantaneous load, yet this is done with air-conditioning and it’s causing spikes in energy use and adds instability to the grid.
According to the Department of Energy, buildings accounted for 38.9 percent of total U.S. energy consumption in 2005, the most recent year in which complete data is available. Of that total, commercial buildings accounted for 46.3 percent of energy consumption, or one-fifth of all energy consumption in the country. There must be enough power infrastructure to meet the peak demand for electricity in these buildings even though the peak for electricity occurs only 1-2 percent of the year. Of course, this is costly and inefficient. Worse yet, on days of extreme heat the grid strains to provide power, resulting in brownouts and blackouts. Not surprisingly, the main cause of the peak demand problem is air-conditioning. However, by simply storing the cooling we reduce the peak demand for electricity and help stabilize the grid.
When electricity is produced during times of low demand – typically at night when large commercial buildings are mostly vacant – the electricity can be captured, stored in the form of ice, then utilized the next day when demand is higher and the strain on the grid increasing. This distributed energy storage is the key is to having a surplus to support periods when supply simply cannot support the excessive demand. Installing energy storage in or near the building further reduces power losses because power doesn’t have to travel long distances in the heat of the day.
Fortunately, distributed energy storage is getting more attention now. Take the state of California’s latest push for efficiency in Resolution E-4586, for example. Under the new resolution, the three investor-owned utilities are directed to propose a standardized Permanent Load Shifting (PLS) Program based on a standard offer with common design rules. The program will provide incentives for the implementation of ice storage and other distributed energy storage technologies. Shifting peak loads will benefit the electricity grid by reducing the need for investments in additional capacity and peaking units, and by reducing the likelihood of shortages during peak periods.
Besides California, distributed energy storage is being installed in buildings around the world. For example, the Dundalk Institute of Technology in Ireland, Durban City Hall in South Africa and the University of Arizona are all utilizing distributed energy storage technology. Smart grid projects such as the 1500 Walnut office skyrise in Philadelphia offer the potential of energy independence, allowing former consumers to become prosumers and sell the excess energy back to the grid. Storing and using what the utilities are already producing to avoid shortages of supply creates a surplus of sorts, giving large commercial structures the ability to tap into a “battery” or “virtual power plant” that sits atop its roof or even inside the building.
So let’s not ignore distributed energy storage. It is already here in various forms such as heating and cooling. Ice storage for cooling buildings is already in thousands of buildings and 37 countries. As more consumers add on-site power generation, seek ways to improve resiliency and lower energy costs the more we’ll see distributed energy storage implemented. The smart grid is anything but without distributed energy storage.