By: Mark MacCracken, CALMAC
| May 28, 2014
Renewable energy sources like wind and solar are by nature inconsistent: solar is not available at night and the wind is not always blowing. This poses a challenge since our power grid is designed to create and provide electricity as we consume it. Most likely, the air blowing through the vents of a building at any given time was powered by energy that was just generated by the utility company. If the utility relied solely on renewable sources for that power generation, it would not always be able to meet our energy demands.
Energy storage can help solve this problem by capturing renewable energy sited at a facility or away at a power plant when it is available and saving it for use when it is needed, therefore dramatically increasing the viability of cleaner sources of energy. Thermal energy storage technologies can store the energy created by wind, solar and geothermal energy. Case study
The Dundalk Institute of Technology in Ireland is a perfect example of this application. The campus uses ice-based thermal energy storage to more effectively utilize the renewable energy produced by its on-campus wind turbine.
Originally built in the late 1960s as a cigarette factory, the 191,000-square-foot PJ Carroll Building is considered one of the finest examples of Miesien architecture in Europe. Approximately 118,000 square feet of the facility were remodeled in 2010 as part of a college expansion project, which included the incorporation of thermal energy storage technology.
The installation of ice-based thermal energy storage helped smooth out the electricity grid demand profile by allowing more renewable wind energy to be used on site. The thermal energy storage tanks provided a way for the campus to capture the excess nighttime wind energy created by the campus turbine in the form of ice. The facility can then melt the ice as needed to cool the building during the day, thus, evening the peaks in demand and meeting the campus' electrical energy requirements.
In 2012, the wind turbine equipped with energy storage was able to produce 1,440 MWh, 79 percent of which was consumed by the university and the remaining sold back to the grid. In 2013, the turbine was generating 40 percent of the campus’ electrical energy requirements. With 64,000 square feet of the facility yet to be occupied, the benefits of energy storage will continue to increase over the next few years. According to energy modeling calculations, in the near future energy storage working in tandem with the wind turbine could provide 96 percent of the cooling load.
Technological advances allow energy storage
Renewable energy technologies are getting more efficient and lower priced. However, most of these technologies have only considered the first piece of the low carbon energy story: collection of energy. However, to effectively lower our dependence on fossil fuels, which are forms of “stored energy” we must couple this collection with storage so that energy can be deployed when needed.
Thermal energy storage technologies are filing some of that gap, allowing buildings to harness renewable energy and dispatching it to cool buildings the following day. This reduces the on-peak demand on the grid while enabling the use of clean, renewable energy, reducing dependence on the carbon-intensive energy that is currently powering much our lives.
NOTE FROM BLOG MANAGER: Read more on thermal energy storage in the May/June issue of FMJ.