Consider This

What does a day without power cost a business? How much of a headache is even a short power outage? How long does it take to restart operations? Facility managers are tasked with finding solutions to ensure uninterrupted operations and reduce energy costs while also meeting company environmental goals. These duties are often at odds with each other.

Stand-by generators are a common solution but certainly not an optimal one. Generators need time to start up before carrying the load, and that means a power interruption that a facility’s IT and other important electronic infrastructure cannot tolerate. Use of uninterruptible power supplies (UPS) is mandatory to ensure the availability and reliability of this important electronic infrastructure and prevent loss of data. Besides the power interruptions, generators require regular maintenance, on-site fuel storage, and are costly to maintain and operate, while UPS have their own maintenance issues and requirements. Emergency generators are inefficient – only 30-40 percent of the input energy is output as electricity; the rest is wasted as dissipated heat. They are also an environmental nightmare, spewing toxic exhaust into the air, which is why most are only permitted to be used for emergency back-up use. How can FMs ensure that their facility has a reliable supply of the power required to maintain uninterrupted operations, lower operating costs and reduce the operation’s environmental impact?

A viable solution may be a microgrid system.

The benefits of implementing a microgrid rather than relying on stand-by generators alone include reduced cost of operations and carbon footprint while ensuring an uninterrupted flow of power to maintain business operations no matter the situation. A microgrid not only guarantees energy resiliency in case of emergencies but can reduce overall energy costs while helping to meet company carbon reduction and sustainability goals.

What is a microgrid?

A microgrid is a facility’s own energy grid with on-site control and energy production capabilities. A microgrid can disconnect from the utility’s grid when necessary and operate autonomously (island mode). Energy is produced primarily by on-site renewable resources, whatever is appropriate for the site, backed-up by batteries and/or generators (distributed energy resources) as well as the utility grid. Utility power is used when economically advantageous to do so. Depending on design and requirements, a microgrid could run indefinitely in island mode.

A microgrid connects to the utility’s grid at a common coupling point maintaining the voltage at the same level as the utility’s grid unless there is a problem on the grid or other reason to disconnect. An automatic transfer switch separates the microgrid from the utility’s grid when the utility’s power is out. At that point, the microgrid functions autonomously. It can also send excess energy generated by on-site resources back into the utility’s grid, further enhancing the economics of installing a microgrid.

Some entities will help subsidize the cost of installing a microgrid with grants or other incentives.

On-site renewable energy assets supplement the utility’s power to reduce a facility’s dependance on power supplied by the utility. Organizations may use on-site energy production resources when utility rates are high and utility power when rates are low. For example, a facility may charge the batteries at night using the utility’s power when the cost of electricity is lowest, then use that stored energy to reduce peak demand charges during the day. These techniques are especially beneficial in peak-demand shaving and time-of-use billing scenarios enabling organizations to time shift reliance on the utility’s energy. It is a win/win for the consumer and the utility, lowering energy bills for the consumer and lessening demand on the utility’s resources.

While microgrids have been around for many years, the technology and components have been evolving to make them smarter, more efficient and economically viable for many more applications. Early systems were mainly for off-grid use and other special applications such as military and prisons. Today there are commercially available microgrid systems available to meet varied needs, even systems that can be delivered to the site fully assembled and tested. These plug-and-play systems can greatly reduce the time needed to install a system and keep operational interruptions to a minimum. Advances in controls and software have given microgrids the ability to prepare for and/or react to changing conditions such as extreme weather events, time of use or peak-demand shaving. A smart microgrid can optimize efficiency and economic payback while ensuring uninterrupted business operations with reduced environmental impact.

Depending on requirements, a microgrid may support the entire facility and all its systems. This may not be economically feasible because the huge demand for power means that the microgrid’s on-site resources must be able to meet the peak demand electrical load of the facility. A more economically palatable way is to design the microgrid in such a way as to support only those loads that are critical to safety, security and specific ongoing operations.

In a well-designed system every load connected to the microgrid is always powered by the microgrid, even when the energy is being supplied by the utility. The power the microgrid delivers is clean and stable, with no sags, glitches or spikes. The supported load’s clean power is always on, without interruption, known as blinkless. When the utility’s grid has a problem or outage, the microgrid’s own energy resources carry the load without incident. In effect, all the loads supported by the microgrid are powered by a sophisticated UPS. This enhances the connected equipment’s reliability, lifespan and reduces the time it takes to get back to normal operations. For absolute reliability, critical control systems should be powered by their own nano-grids, further isolating them from any potential electrical problems and ensuring up-time.

Traditionally, microgrids have only addressed the electrical power needs of the facilities they supported, which can leave a big gap in many facilities’ energy needs. Many businesses use more thermal energy (BTUs) than electrical energy (kWhs). There are microgrid systems available that can also provide for thermal as well as electrical energy needs by incorporating a thermal grid, which uses pipes, valves and pumps to distribute thermal energy much the same as an electrical grid uses wires and switches to distribute electrical current. Leveraging the efficiency of combined heat and power systems (CHPs or cogenerators), heat pumps and thermal energy storage with a thermal grid can increase the facility’s overall energy efficiency. Natural gas-powered CHPs are efficient and relatively clean with fuel cells becoming clean alternatives with very low to zero carbon footprint.

Thermal storage – storing heated (or cooled) working fluid in insulated tanks for use when needed – is less costly than batteries with the added benefit of much longer life. It enables the production of heat (or cold) when energy is expensive. Designed and implemented in an integrated system further reduces the cost of operations and increases return on investment.

Controlling the facility’s various energy infrastructure components (HVAC, heat pumps, boilers, distributed energy resources (DERs), etc.) and loads as a comprehensive integrated system using a microgrid system’s overarching control system can yield even more benefits. An overarching energy infrastructure control scheme acts like an orchestra’s conductor, always determining the best and most economically efficient energy production resources to power operations and how best to leverage the use of that energy.

With proper security measures, the microgrid, and the infrastructure components integrated into the system, energy production and use can be monitored, controlled and problems diagnosed remotely via any authorized connected device from anywhere. The ability to use remote diagnostic capabilities can enhance up-time by reducing the mean time to repair. It can even alert FMs to impending equipment failures before they cause a real problem. Having this kind of visibility into a facility’s infrastructure is especially valuable in eliminating finger pointing if a problem does occur.

Real-time and remote monitoring of energy production from all sources and energy use at each supported load, as well as cumulative and historical data provides valuable insights, helping FMs understand how the microgrid is performing and control energy costs.

Real-time alerts and remote-control capabilities can help FMs adapt to changing conditions, avoid higher utility bills or disruptions to operations enabling the ability to intervene when nature does not cooperate or an equipment failure is detected.

It is also important that the microgrid system can adapt to and utilize energy from multiple sources. Different DERs produce energy in different voltages and currents. Billions of dollars are spent in the search for better, cheaper, more efficient clean energy systems and battery tech is evolving rapidly. Solar panels from 10 years ago were more expensive and much less efficient than what is currently available. Future-proofing a microgrid by ensuring that whatever comes in the way new energy technologies can be utilized will increase the life expectancy and ROI of the entire system.

Implementing a microgrid system is not cheap; but a comprehensive and well-designed system pays for itself over time in energy savings alone, not to mention tax incentives and utility grants that may be available. The added bonuses of ensuring that critical business operations are never threatened due to power interruptions while helping to meet company environmental goals are priceless.