Comment Log Display

I am writing to comment on the Discussion Draft for the 2030 Target
Scoping Plan with respect to water-related use of energy for
pumping, conveying, treating and heating water.

Nexus eWater is a San Diego-based company that manufactures
residential-scale solutions to recover and reuse valuable resources
that are in the “grey water” discharge that leaves every home – the
water itself, and the energy that is in the water.  Ours is an
emerging technology category that can play a positive role in the
achievement of the goal of significant Greenhouse Gas Emissions
reduction.  However, it is critical that the Plan be able to adapt
to challenges that are sometimes presented by new technologies.

I would like to emphasize two points that are illustrated
particularly in the water-related use of energy:

1.	Conservation, efficiency and recycling are the shortest paths to
cutting GHG emissions, not to mention directly engaging all
Californians in the achievement of these goals.

2.	The Plan must be open to switching between fuels, and to
switching from one technology to another, if that results in
system-wide reductions in energy and GHG emissions.  In particular,
I am referring to two technological paradigms:  Electric vs. gas
water heating; and distributed (on-site) vs. centralized water
recycling.

Water-related Greenhouse Gas Emissions – the Impact of Conservation
and Onsite Water Reuse


The Scoping Plan correctly identifies the water sector as a major
user of energy, and thus a major source of greenhouse gas
emissions.  The Discussion Draft notes that 10% of the State’s
energy use is associated with water-related end uses, and water and
wastewater systems account for an additional 2% of energy use (page
76).

The energy-intensity of water can be addressed at many different
points in the long water supply, process and treatment chain.  The
most effective way to reduce the GHG impact of water use (page 77)
-- bar none -- is to reduce water use.  This, of course, is the
well-worn concept of conservation or efficiency. 

The second most effective way to reduce the GHG impact of water is
to switch our reliance from high-energy sources of water to
locally-sourced water.  The best example of this is the use of
on-site sources of water such as grey water and rainwater as a
replacement for potable water (for appropriate uses).  Generally,
this Is known as on-site water reuse.
In order to achieve the GHG emissions goals of the scoping plan
with respect to water, we need our policies to appropriately
prioritize water conservation, water efficiency, and water reuse in
our policy portfolio.  Without an appropriate policy mix, we will
instead be forced, over time, to move to more energy-intensive
sources of water such as desalination or centralized wastewater
treatment for potable reuse.

Fortunately, in California we have already begun to move toward
more on-site water reuse.  Jurisdictions such as the City and
County of San Francisco, the City of Los Angeles, and the service
area of the Santa Clara Valley Water District have policies, or
draft policies, which will encourage more and more residential and
commercial buildings to make more effective reuse of grey water and
rain water in the future.  

On-site sources of water can be used in California for landscape
irrigation and toilet flushing, which are two of our largest
residential uses of water.  When homeowners are reusing their own
water, they become more closely engaged with the process of
producing and using water, rather than simply “consuming” water.  A
citizenry that is engaged in the process of conserving, using it
efficiently, and recycling it for their own reuse is a citizenry
that better understands and appreciates our climate policies and
goals.

Building-Level vs. System-wide Efficiency – Addressing Perverse
Policy Incentives when Technologies Change

Each scenario presented in the Discussion Draft reflects the
State’s known commitment to double building-level energy efficiency
by the year 2030, as required under AB 350 (see page 41).  One
means to do so is the replacement of inefficient space heating and
water heating appliances with more efficient appliances, such as
electric heat pumps.   A number of participants in the review
process have called for ending the use of fossil fuels in buildings
on the pathway to achieving our GHG emissions reduction goals.

On-site water reuse is an example of an emerging solution that can
simultaneously contribute to the doubling of energy efficiency of
the broader system, but not necessarily at the level of the
individual building.  It is obvious to see how it can contribute to
this goal when the embedded energy in a home’s grey water is
harvested and reused on site, which is already possible but not yet
common.  It is less obvious when on-site water treatment results in
a new appliance power demand that currently is handled off-site at
a centralized facility. Even if the net energy use is lower to
treat and move water around at the building level than it is at a
centralized treatment facility, it is not uncommon for policy-based
calculators to create perverse incentives that may result in less
efficient outcomes at the system level.  This should not be allowed
to happen. 


As was the case of rooftop solar, on-site water reuse solutions
have the potential to transform a portion of water treatment from a
centralized to a distributed solution.  When this can happen, we
need our policies to adapt to the technological change and not
create perverse incentives that may perpetuate less efficient
pre-existing technologies.



The potential water and energy impact of on-site solutions for
water is nothing short of transformational, and can have just a
great an impact as the move from a centralized to the distributed
power grid.  

Let us make certain that the Scoping Plan has the flexibility to
anticipate, adapt to, and encourage such technological
transformation that may be critical to our achievement of the goals
of the plan – the 40% reduction in greenhouse gas emissions by the
year 2030.