by Karen Telleen-Lawton, Noozhawk Columnist (read the original in Noozhawk by clicking here)
Two-year-old Henry is staying with us, which is why I’ve been thinking about energy systems. He, along with his 2-month-old sister and their parents, are our guests while they search for housing before Henry’s mom begins a post-doc teaching fellowship at UCSB. Henry asks about everything, including the purple stains on our patio.
The grape arbor over our tile patio is currently loaded with ripe purple fruit. It gives the patio a little Italian villa look, but it’s also proved highly attractive to birds, mice and rats. We decided to make Vitus californica grape juice, in part to reduce this “attractive nuisance.” I favored making wine, but none of the rest were willing to wait the requisite fermentation time.
We started plucking bunches while Henry napped, choosing the food network TV method of saving just a portion of each activity for his ephemeral involvement. We picked about four gallons of succulent bunches, so ripe that some were moving towards raisins.
After soaking the bunches, we de-stemmed several mixing bowls worth. It was about this time that a rat had the gall to breach the patio, despite our presence. It made me wish for a BB gun, but Henry (and maybe I) would have been devastated.
After rewashing the grapes to remove woody bits, we fed them through our decades-old vegetable juicer, which has sat unused since we got tired of cleaning all the moving parts. Henry is a lover of trucks, so I thought this would be his favorite part. But in his post-nap blues, the mulching cacophony didn’t impress him. The part he liked best was hauling the empty stems and grape pulp up to the compost pile, to feed next year’s grape harvest.
Overall, this project seemed pretty ecologically sound: harvesting the grapes, drinking the juice and using the pulp for next year’s harvest. The electric juicer may have ruined the equation. But it reminded me of a recent Los Angeles Times article by Tiffany Hsu, about Ralphs’ grocery chain. They have devised an amazing “brown food to green energy” system.
Ralphs uses a process known as an anaerobic digester system to funnel food that can’t be donated or sold from Southern California stores into electricity, water and organic fertilizer. Ralphs claims the 359 stores’ worth of garbage annually provides 13 million kilowatt hours of electricity (enough for 2,000 California houses) and enough nutrient-rich organic fertilizer for 8,000 acres of soil.
Their process involves pulverizing food waste — packaging included — in a massive grinder. A pulp mulcher then filters out inorganic materials such as glass and mixes in hot wastewater, creating sludge. Then it’s stored in a silo, where, devoid of oxygen, bacteria convert it to methane gas to power three on-site turbine engines.
According to parent company Kroger, this project has reduced waste by 150 tons per day. That’s the environmental bottom line. The economic bottom line is copacetic: an expected 18.5 percent return on investment, saving it $110 million over the life of the plant.
The Natural Resources Defense Council reported in the last year that 40 percent of U.S. food goes uneaten; the waste shuttled to landfills contributes 25 percent of our methane emissions. This project represents an alternative that is both environmentally beneficial and economically viable.
Ralphs’ project has sweet rewards. We reaped a reward from our harvest, too — close to a half-gallon of the sweetest, richest grape juice I’ve ever tasted. It stains like heck, but it’s sweeter than wine. Henry likes it, too.
Karen Telleen-Lawton, Noozhawk Columnist
Karen Telleen-Lawton is an eco-writer, sharing information and insights about economics and ecology, finances and the environment. Having recently retired from financial planning and advising, she spends more time exploring the outdoors — and reading and writing about it. The opinions expressed are her own.