Hospitals are reliant on continuous energy supply and cannot afford the potential disaster that could ensue if power fails within the infrastructure. This is why microgrid systems are globally being instituted within the healthcare industry to provide large amounts of continuous, clean and affordable power.
“Load shedding, aging infrastructure and generator maintenance issues all put a strain on healthcare providers in South Africa,” says James Shirley, Segment Leader for Hospitals, Hotels & Critical Buildings, Schneider Electric South Africa.
“Rising energy costs will continue to put pressure on operating budgets, given hospitals use up to 250% of the amount of energy to similar sized commercial buildings, and anything hospitals can do to reduce energy consumption will also make it easier to meet environmental regulations.”
According to Shirley, Microgrid solutions intelligently coordinate a variety of onsite, distributed energy generation assets to optimise power stability and costs. They also include the option to ‘island’ from the utility grid to avoid exposure to outages or disturbances. The technology has reached a high level of maturity, with the overall cost of installing microgrids dropping an estimated 25-30% since 2014.
“Hospitals typically have some form of backup power system, usually one or more diesel generators, supported by an uninterruptible power supply (UPS). However, without a microgrid, the combination of traditional diesel backup generators and UPS can supply critical circuits, but only for a limited time. In addition, there is a risk that those generators may fail to start up,” he says.
“Many hospitals have adopted combined-heat-and-power (CHP) systems, which are efficient solutions for supplying (at least partially) the electricity needs of the hospital, plus useful heat. They can operate at a combined heat + electricity efficiency of up to 90%. CHP systems can be configured as microgrids, but a more comprehensive solution can encompass a variety of distributed energy resources (DER), including CHP, renewables, fuel cells and energy storage.”
Shirley notes that microgrid can also integrate with the facility’s building and energy management systems to enable even greater flexibility to optimise costs and reliability.
“The microgrid controller has a few important responsibilities,” says, adding that if there is a utility grid outage, it will safely disconnect to ‘island’ from the grid, support critical loads and then reconnect after the event. The controller also ensures facility-wide electrical network protection is maintained in grid-connected or island mode.
“When connected to the utility grid, DER is managed so that renewable energy is consumed as much as possible or saved to the storage system. In island mode, onsite energy production is balanced against consumption. With enough onsite resources, the entire hospital can be powered for an extended period.
“Advanced microgrid solutions can provide proactive protection by ‘looking ahead’ to approaching conditions (such as a storm) and prepare to island from the grid, giving facility personnel enough time to take precautionary measures. Islanding from the grid can also be enacted to avoid poor power quality conditions, such as transient spikes from lightning that might affect sensitive hospital equipment,” Shirley says.
“If the facility is equipped with renewable energy sources, backup generators will still be engaged as a first line of defence against a grid outage. However, if backup generators fail or reach their runtime limit, the microgrid controller can engage renewable sources and energy storage to supply critical circuits. While backup generators are supplying critical loads, renewables can also be used to supply additional circuits.”
Saving on utility bills
According to Shirley, a microgrid system can intelligently help avoid utility bill demand penalties by temporarily reducing the amount of energy consumed from the grid to avoid a demand peak. This can be done by consuming more onsite energy from renewables, storage, or CHP. Though options may be limited, another strategy is to turn off any non-critical loads, such as EV charging.
“Finally, a microgrid offers a great opportunity to optimise sustainability. Self-consuming low-cost, renewable energy helps reduce energy-related GHG emissions. The microgrid can be programmed to maximise the use of renewables by intelligently managing solar and wind generation, as well as energy storage,” Shirley concludes.