Microgrids: The Way of the Future?

“It keeps the customers out of the game,” Kelly notes. “But utilities are missing the fact that customers will invest their own money in renewables or power generation. Their ability to produce power reduces peak load in their neighborhood, which is mutually beneficial for the utility and the client.”

If your region faces regulatory hindrances for microgrids, become an advocate on behalf of your site. Your area leadership may not be aware of the vast advantages of grid independence for commercial clients.

“The primary benefit boils down to reliability for both the customer and the utility,” Dohn says. “Because commercial buildings are such large consumers of energy, it may be financially favorable to the utility to allow a client to produce its own energy to alleviate the demand on the grid and ensure reliability for all customers.”

For example, there may be times when the utility requests that a microgrid to come online to avoid a brownout. “In the case of a large disturbance to the main grid, the utility can take a large customer out of the mix. While that microgrid takes care of its own needs, the utility can worry about restoring service to other consumers,” explains Smith.

A network of on-site power generation also reduces the total output required of the utility. “The closer the energy consumer is to the source of power generation, the less you lose in line loss,” posits Puffer. “If you have to run lines 100 miles from the power plant to the user, the utility has to produce more energy in order to deliver the amount needed to the location.”

The Building Blocks of a Microgrid
Microgrids aren’t a plug-and-play technology – they are a multi-phase project with specific actions that must be tailored to your site’s unique energy profile.

“A microgrid includes generation, a distribution system, consumption and storage, and manages them with advanced monitoring, control, and automation systems,” explains Dohn.

The first step is to get a clear picture of your demand needs. Without data in hand, you cannot make effective decisions about on-site generation requirements and load shifting strategies.

“The next step is a permanent reduction in consumption for electricity, water, and gas,” Dohn says. “This will give the consumer near-term cost savings driven by measured and verifiable conservation measures.”

These initiatives commonly take the form of lighting retrofits, envelope improvements, the use of advanced metering, and upgrades to HVAC and other energy equipment. Make sure to build in active load management automation, as demand response functionality is a key cornerstone of a microgrid.

After energy efficiency projects, target on-site generation and storage equipment. Renewable energy will be a significant component of this phase as one of the goals of a microgrid is to draw electricity from more sustainable sources than the bulk grid can offer. Cogeneration (engines, turbines, fuel cells) and power storage options (chilled water or ice, batteries, flywheels) will also serve as additional power providers.

Extensive metering is necessary to keep all elements in communication with each other. “A microgrid requires meters at the point of the load, on the individual pieces of generation equipment, and at the interface between the utility and the site,” explains Puffer. “You need to meter at the interface between your campus and the utility so you can tell how much electricity is going which direction and at what time of the day. You also want to know how much your loads are – you don’t want to serve more load than you’re capable of because that will bring your on-site generation down very quickly.”

With these phases complete, your site is ready to become grid independent in one of two ways. “If the microgrid has internal combustion engines with reactive power compensation within the system to provide voltage and frequency regulation, the power system can connect or disconnect via relays, switches, and breakers,” Dohn explains. “Alternatively, the microgrid generation and storage assets can connect to the main grid via a series of inverters, allowing for more advanced control of power in both directions between the main grid and the microgrid – this is a more elegant yet expensive option.”

Throughout a microgrid’s development, it is imperative to assign a dedicated team to its creation and operation. It must be clear who will oversee and maintain the system. “Someone has to be in charge – you can’t form a microgrid and just walk away,” stress Dohn.

Looking to the Future
Broad acceptance of microgrids, just like the national smart grid, will likely be realized down the road. With the push for renewable energy capacity, the grid’s increasing vulnerability to cyber attacks, the rise of global competitiveness, and the need to blunt the impact of fuel price fluctuations, more solutions like microgrids will be required to keep power quality in check. In the interim, microgrids provide building owners with a flexible operating model that enables grid independence on short notice.

Jennie Mortion jennie.morton@buildings.com is associate editor of BUILDINGS.

 


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