Saving water to save energy

When there's a drought, Californians start thinking about saving water, but did you realize that saving water - all the time - is one of the most effective ways to save energy and thus prevent global warming?

California's state authorities concluded last year that water-use efficiency and conservation is the most potent source for meeting new water demand, and that a major portion of the solution lies in closer coordination between the water and energy sectors. (See "California's Water-Energy Relationship", an excellent overview of energy-related water use in California.)

Several agencies are giving new attention to the relationship between water and electricity.

• Last year the California Energy Commission issued "Integrated Energy Policy Report" with a host of recommendations to break down artificial barriers to water/energy savings.
• The state's Public Utilities Commission is tentatively beginning to consider how to increase water/energy conservation. It is trying to get water and energy utilities to think about how to cooperate better on their efficiency programs. Unfortunately, though, the commission is considering "shareholder incentives" (extra profit) to reward utilities for water savings. This mechanism tends to waste funds without improving performance.

As much as 20% of California's electricity consumption goes into moving water around the state, for urban use and agriculture, and into water-related end uses in appliances and irrigation. California's electrical grid is "cleaner" than most but still depends more than 60% on dirty fossil fuels. So cutting water use saves the climate.

We need to make sure that our local water and wastewater districts have greenhouse-gas reduction plans. Marin Municipal Water District was the first such agency to join the Climate Protection Program of ICLEI - Local Governments for Sustainability (formerly the International Council for Local Environmental Initiatives and others will follow suit. Water districts are potentially important "anchor tenants" for Community Choice Aggregation. Water conservation best management practices, though, are mostly old and dated. Look for new, more radical methods that bridge established jurisdictions and function regionally.

For example, Sonoma County has projected a 39% increase in water needs in 15 years. It has a major choice:

• accept this forecast and build $100 million of new water-supply infrastructure plus spending another $300 million for restoring the Eel and Russian River watersheds, leading to a 63% increase in greenhouse-gas emissions; or
• reduce water use by 11% below 2005, thus avoiding new capacity costs and reducing greenhouse-gas emissions up to 44%.

Hard data are emerging that show how large-scale conservation is the cheapest long-term way to meet needs. Water planners and administrators need to pay attention.

Indoor residential usage, typically a large end use along with warm-season outdoor irrigation and landscaping, can be reduced by more than 40% in an average home (saving money too) through use of toilets that use only one gallon per flush, premium clothes washers, high-quality aerators and showerheads, and smart hot-water plumbing. The "Pay As You Save™" implementation system, already proven by electric utilities, enables developers, building owners, and tenants to install such cost-effective improvements without debt or initial costs and gaining net savings of hundreds of dollars per year. This system makes efficiency offers so attractive that traditional rebates are not needed.

Looking ahead, bright soft-path innovations are appearing. One of the most dramatic is the advent of on-site wastewater treatment that supports reuse for all indoor non-potable end uses. When coupled with efficient end-use equipment, this can reduce net water demand tenfold, thus making on-site rainwater harvesting and storage a viable strategy for general application. This could soften many of the negative impacts now associated with municipal water, wastewater, stormwater, and related energy infrastructure.

Ed Mainland, co-chair, Sierra Club California Energy and Climate Change Committee