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Hospital microgrids: going beyond backup generators to ensure resiliency

In the face of increasing power demand on the grid, aging electrical transmission infrastructures, and increasing numbers of violent storms worldwide, the subject of resiliency keeps many hospital administrators up at night. I’m sure many in the U.S. are aware of the backup generator failures that occurred at hospitals during hurricanes Katrina, Irene, and Sandy. It’s clear there’s a need for an onsite energy solution that delivers higher reliability, over longer periods, to the entire facility.

In addition, Deloitte notes “Global health care expenditures are expected to continue to rise as spending is projected to increase at an annual rate of 5.4 percent between 2017-2022.” Energy costs will continue to put pressure on operating budgets, given hospitals use up to 2.5 times the amount of energy as similar sized commercial buildings, and electricity costs are expected to trend upwards. Anything hospitals can do to reduce energy consumption will also make it easier to meet environmental regulations.

The arrival of the hospital microgrid

Microgrid solutions have been around for a long time, helping educational campuses, military bases, industrial plants, and other types of facilities intelligently coordinate a variety of onsite, distributed energy generation assets to optimize 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. The overall cost of installing microgrids has dropped an estimated 25 to 30% since 2014, and the market is expected to continue to grow by more than 20% a year. Many hospitals have already adopted microgrid technology, and it makes sense, given their need for large amounts of continuous, clean, and affordable power.

In this post I’ll give a quick overview of what makes up a typical hospital microgrid. In the following three posts in this series, I’ll list out some key benefits, as well as running through some considerations for the optimal design and financing of microgrid projects.

The smart microgrid architecture

Hospitals typically have – and regulations require – some form of backup power system, usually one or more diesel generators, supported by an uninterruptible power supply. In recent years, many hospitals have adopted combined-heat-and-power (CHP) systems, which are highly 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. A microgrid control system coordinates the use of all DER, but also manages safe and reliable transition to island mode in the event of a utility grid outage. A microgrid can also integrate with the facility’s building and energy management systems to enable even greater flexibility to optimize costs and reliability.

What DER options can a hospital choose from?

Diesel generators are ubiquitous for hospital backup applications, but they have potential weaknesses, including: limits to how much fuel can be stored (which limits runtime), and less than 100% confidence they will start reliably when needed. In contrast, CHP systems are often fueled by natural gas, which is an infrastructure not typically impacted by severe weather. And a CHP system usually run continuously, meaning it is ready and able to provide power in the event of a blackout.

Renewable energy is another option worth consideration, depending on availability and costs, policies and incentives, and electricity pricing and regulations. A number of renewable options are worth considering: solar panels, wind turbines, and biomass energy. The viability of each will depend on available optimal locations and other factors, with solar being a particularly good fit, as roof space is often plentiful.

Fuel cells are another DER option that is growing in market share. They can provide primary power, backup power, or combined heat and power. Fuel cells need hydrogen, which is most commonly produced from natural gas or biogas (methane). However, it can also be produced from water using a process powered by a renewable energy source, such as solar or wind. In this case, the resulting hydrogen fuel can be considered a renewable resource.

Finally, energy storage is an important part of a microgrid solution, supporting resilience in coordination with backup generators, CHP, and renewables. Storage also helps maximize the value of renewables by saving excess energy for use when photovoltaic panels or wind generators are not producing electricity output. Stored energy can also help reduce the amount of energy consumed from the utility grid during periods when energy is more costly.

In my next post, we’ll look closer at the broad scope of benefits that microgrids offer hospitals. To learn more, download the white paper “How new microgrid designs help hospitals increase resilience, cut costs, and improve sustainability.” Schneider Electric provides complete microgrid expertise and integrated solutions for hospitals. Discover these at our microgrid solutions page.

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