The Dry Garden: Want to save energy? Start by saving water

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Week before last, more than 1,000 climate experts from around the world gathered in Stockholm for World Water Week. If you didn’t read about it or hear about it on TV, it’s not necessarily because of the crisis besetting modern journalism. It could easily be the subject. If there is anything that can clear a room faster than a plague of toads, it’s discussion of climate change and water.

Peter Gleick, a MacArthur fellow and president of the Pacific Institute in Oakland, was in Stockholm for the meeting. He is, above any Californian, our man on the unmentionable.

So are there ways to address this topic, I asked Gleick recently, without leaving everyone feeling utterably depressed and helpless? Absolutely, Gleick responded. “If you want to save energy, save water.”

Aha, logical. Energy saved amounts to greenhouse gas emissions prevented. Energy is a hidden cost of water. In 2004, Gleick published a report with the Natural Resources Defense Council on the subject. As the date of the report suggests, the knowledge isn’t new, but comprehension is so low, thousands of climatologists still feel compelled to sing the message in Stockholm.

It may be the stealthy quality of water. It simply seems to flow naturally into our sprinklers, garden hoses, toilets, baths and washing machines while it’s actually moved to us. This takes so much power that the pumps that convey and treat California’s water account for roughly 20% of the electricity consumed in the state.

Southern California, particularly, drives that figure way up. We are so far away from the sources of our water in the Sacramento Delta and Colorado River that the energy cost for bringing water to us is 50 times higher than for Northern Californians and five times the rate for average Americans. Why so high? Water is heavy. In the case of the State Water Project coming from the Sacramento Delta, Southern Californian supplies must be pumped 2,000 feet over the Tehachapi Mountains. This is “the highest lift of any water system in the world,” according to the Pacific Institute and Natural Resources Defense Council report.

Numbers making you dizzy? Me too. Time to switch to a map. This one comes from the section of the recent White House report on global climate change in the U.S. that pertains to the Southwest.

Scroll down the page until you find the twin maps of California, Nevada, Utah, Arizona, Colorado and New Mexico. This is the tale of two futures projected by federal climate modelers. The most optimistic model, the “Lower Emission Scenario” on the left, shows that in the last two decades of this century, Southern California will be lucky to lose only 20% to 30% of its current precipitation.

If we fail to restrict our energy consumption and cap our carbon emissions, the map on the right shows precipitation falling by 40%, not just here but also in the places that supply our water.

Gleick said saving hot water has a double benefit because it saves the energy to move as well as heat the water. But he isn’t picky about where we find the savings.

“If you can, if you’re replacing your washing machine, buy a high-efficiency water machine and you save a huge amount of energy and water and in the long-run money,” Gleick said. “But even if you’re saving cold water, that’s water that doesn’t have to be pumped over the Tehachapi Mountains or water that in the future doesn’t have to be desalinated.”

This column being about gardening, an observation: About 40% to 60% of our water goes outdoors, depending on our climate zone. There’s no time better than now to kill your lawn and go native. What Gleick was telling us, and what those maps were underscoring, was that we could act now to arrest global warming and plant gardens fit for the future.

Rebates are still being given by major water authorities for all manner of water-saving devices: washing machines, dishwashers, garden sprinkler and drip systems, toilets, shower heads. To find out details, look up BeWaterWise.com.

Recommended reading: ‘California’s Water-Energy Relationship’ from the California Energy Commission and ‘Energy Down the Drain: The Hidden Costs of California’s Water Supply’ from the Pacific Institute and the Natural Resources Defense Council.

-- Emily Green

Green’s column, The Dry Garden, which covers low-water gardening, appears here weekly. She also blogs on water issues at www.chanceofrain.com.

Note: A previous version of this post incorrectly said the pumps that convey and treat California’s water account for roughly 20% of the energy consumed in the state. The correct term is electricity, not energy. California’s water-related energy consumption includes 30% of the state’s natural gas and 88 billion gallons of diesel fuel annually, according to the California Energy Commission.