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Energy management is defined by the VDI (Verein Deutscher Ingenieure, or Association of German Engineers) as follows: “Energy management is the proactive, organized and systematic coordination of procurement, conversion, distribution, and use of energy to meet the requirements, taking into account environmental and economic objectives.” (VDI-Guideline, 2007, p.3).
When taking into account the business administration field of facilities management, energy management seeks to reduce a building’s energy requirements, effectively distribute energy throughout the building, and procure that energy from sources beneficial to the building’s environmental and economic bottom lines. With photovoltaic (PV) technology and innovations in batteries, the requirements for effective procurement, conversion, and distribution of energy can be met within the building itself, reducing the overall demand on the electric grid.
The important measurement for energy management in buildings is kilowatt-hours per square meter per year (kWh/m²a). This describes the amount of energy (kWh) required for every square meter in the building over the course of a year. One kWh unit equates to 3.6 megajoules and is a composite measure equivalent to an hour of sustained power at 1 kilowatt (kW).
Coordinating energy usage in buildings with batteries and photovoltaics follows similar guidelines as buildings without these technologies included. A construction that minimizes heat loss, makes use of natural light sources and incorporates well-designed passive venting systems all helps to reduce the energy requirements of the building.
Occupants’ behavior also has an effect on energy consumption, and this can be optimized and automated with the use of Internet-of-Things (IoT) connected devices in a so-called “smart” building. For example, lighting can be automated so that rooms are never left with lights on when not needed, or appliances can be automatically turned off when not in use.
Smart systems can also work in conjunction with PV and battery technology in buildings. In this way, energy can be stored when it is gathered but not needed (for instance, in homes when occupants are at work but energy is generated by the sun, or in office buildings at weekends or holidays). Appliances that do not need to run when the building is occupied can also be managed by a smart device, for example, washing machine cycles can be set to run during the day using solar energy.
In buildings with PV technology installed, ensuring the energy generated can get to its end-use destinations efficiently is an important factor for facilities management. As above, this element of energy management in buildings can be automated. For instance, SCADA (supervisory control and data acquisition) systems can be installed in industrial buildings – or even numerous facilities – to efficiently manage the distribution of energy throughout the building or complex. This results in lower energy demands and less energy wasted, an important factor in preserving energy stored in batteries.
In building-integrated photovoltaic (BIPV) systems, solar panels and other PV technologies can be installed anywhere on the envelope (outer shell) of the building. Using various chemical or electric methods of converting solar energy (photons) into usable electricity (electrons), these systems ultimately enable a renewable power source for the building. They can be incorporated on a domestic as well as industrial or commercial scale, and, while this is subjective, many occupants and investors prefer the aesthetic of PV-clad buildings to other, passive kinds of traditional cladding.
When all of these aspects of energy management in buildings are added up, they combine to drastically reduce the amount of energy that a PV and battery-powered building requires from the national electric grid and gas pipelines. This energy is almost entirely generated by burning fossil fuels, which releases harmful carbon dioxide into the atmosphere and the planet’s water systems, and is a finite resource which, when over-relied on, poses risks to national security as well as planetary ecosystems.
Well-managed energy plans in buildings with batteries and PVs not only reduce this requirement on national grids and gas pipelines but also in some cases enable the building managers to sell surplus power back to the electric grid. In this way, the environmental and economic benefits of well-managed buildings with batteries and PV are aligned.
- VDI-Guideline. (2007). Berlin: Beuth Verlag, p.3.