Commercial Energy Storage
Commercial Energy Storage is the current buzzword heard these days when discussing energy, energy savings and energy management. But what is exactly is “energy storage?”
Energy storage can be any technology that captures energy from an available source and stores it for future use. The energy is converted from its captured form, to its “stored” form, and then converted to another form (not necessarily its original form) for later use.
In a very real sense, coal is a form of energy storage. Millions of years ago organic material decomposed. A combination of heat and pressure caused the chemical and physical changes we recognize today as coal.
Coal however is not regarded as renewable, since what we have is all we have - at least for a few million years. In that sense it's not very efficient either.
The holy grail of energy storage is being able to store energy very efficiently (limiting losses in the conversion process) and very quickly, and then discharging the energy efficiently over whatever time period is required.
One of the earliest forms of energy storage used in the commercial industry is thermal storage (ice). Thermal facilities used grid electricity to make ice at night during less expensive (off peak) times. This ice was then used to provide space cooling for offices and buildings during the day when grid electricity was most expensive (on peak).
Commercial Energy Storage Explained
Another common type of storage is used by water municipalities which pump water to high elevation reservoirs during the night. Then, during the day, the water is allowed to flow back downhill and gravity forces the water through turbines that drive generators to generate electricity.
Today, the most common form of energy storage is based on some form of battery storage. Battery technology has advanced significantly in the last 10 years and the inefficiencies of charging DC batteries with AC power (which inverts back to AC electricity) have been greatly reduced.
Energy storage using advanced battery technology is becoming a popular energy management solution in the commercial sector, especially when combined with Solar PV. The use of battery storage is usually designed around one of two strategies; demand shaving, or solar PV over production.
How is Commercial Energy Storage is used?
The use of battery storage is usually designed around one of two strategies; demand shaving, or solar PV over-production. Demand shaving is a strategy which uses the selective discharge of stored battery energy to reduce or ‘shave’ the peak demand of utility power. Cutting down the maximum demand or peak during the billing month lowers the demand charge portion of the utility bill. Storing energy for PV overproduction functions as a way to capitalize on the energy produced by a solar PV system in excess of what is being used by a facility. The stored energy can then be used when facility demand exceeds PV production rather than credited by the utility at a low rate or not at all.
Currently the lion’s share of battery storage systems installed at commercial facilities are designed with the intention of reducing the monthly peak demands. Sophisticated battery controllers monitor energy demands and model expected demand requirements. These systems use complex predictive analytics to optimize the amount of energy discharged, and consequently demand reduction, within the limit of the battery capacity. Many systems are capable of “learning” expected facility demand profiles so they discharge at the right time and cut down the worst peaks, ignoring lesser peaks and consequently conserving battery energy for only those times where the highest electrical demand is predicted to occur.
As technology advances both for batteries and predictive analytics, we can expect to see more and more applications of energy storage coupled to solar PV.