As consumer preferences continue to shift toward purchasing locally sourced and organic produce, demand is growing for commercial greenhouses, or controlled environment agriculture (CEA), as the industry is labeled. This shift in preference to locally grown food is changing the way supermarkets and restaurants source their fruits and vegetables, writes Erik Svanholm, vice president of Non-Wires Alternatives at S&C Electric Company.
The push for more locally sourced produce is not a fad but an enduring trend among increasingly discerning consumers. As a result, reinforcing the supply chain for produce is a growing concern. When the arrival of the COVID-19 pandemic quickly resulted in empty grocery store shelves in the spring of 2020, the need for increased food security became painfully obvious. A widely distributed food-supply infrastructure with short delivery distances would provide much stronger resilience.
Per square yard of land, CEA facilities can support up to 20 times the volume of produce compared to traditional farming, but greenhouses still require substantial real estate to deliver the volume of fruit and vegetables necessary to meet consumer demand. It shouldn’t be a surprise the plots of land suitable for CEA sites aren’t found in the urban areas they will ultimately serve. Rather, good locations for industrial agriculture are most frequently found in rural areas at the very edge of the electricity grid, where utility capacity is often constrained and outages may be frequent.
Meeting demand with infrastructure
Pairing the CEA energy demands with the suboptimal electrical infrastructure typical for rural locations on the grid can lead to disasters for greenhouse owners if not adequately mitigated. A sustained power outage wouldn’t just knock out the lights, it could destroy an entire crop.
Utility-driven improvements at these locations are often possible but can be expensive and time-consuming. For many utilities, reliability improvements and capacity increases at specific CEA locations benefit only a small fraction of their customers, making it difficult to justify the cost when compared to service improvements in more populated areas.
Thankfully, there is another way to support these facilities’ energy needs that augments and enhances existing utility electrical service: microgrids. Microgrids have the potential to service these remote locations without major investment by the utility, and they can offer a more reliable and resilient energy supply.
Microgrid systems can be designed to support industrial-scale loads of both heat and electricity, and they can be tailored to meet the individual needs of each commercial greenhouse. Because the energy needs at CEA sites involve both heat and electricity, the most common microgrid solution for these facilities includes combined heat and power (CHP) plants with natural gas-fueled engines. These systems can be optimized to provide the required heat output needed for ideal growing conditions and can be outfitted with scrubbers to extract carbon dioxide and feed it back into the greenhouses, enhancing photosynthesis and increasing crop yield.
Not all microgrid integrators have the level of experience needed for demanding environments such as commercial greenhouses. Finding a partner skilled in turnkey designs, renewables integration, utility experience, and sophisticated microgrid controls is crucial for getting a microgrid done right on the first try.
Read the complete article at www.powermag.com.