California’s clean
energy mandate
will require their
electric utilities
to get 60%
of their wnergy
from renewable
sources by 2030.
SoCalGas calls
cow manure fuel
“renewable
natural gas”.
"Renewable Gas "
is a renewable
that's not getting
enough attention.
It has three advantages:
(1)
Cow manure is "free".
(2)
It can replace fossil fuel
natural gas, and
(3)
It makes use of a
powerful greenhouse
gas, methane,
that would otherwise
get released into
the atmosphere.
So, how does a
"dairy digester"
work ?
Hold your nose !
A towering contraption
separates cow manure
into solid and liquid parts.
A conveyor belt deposits
the brown solids at the top
of a stinking mound.
The fluids are filtered through
narrow slits in a metal screen,
before continuing down
a concrete channel.
The liquids will eventually
reach a double-lined
holding pond, larger than
a football field, and covered
by a thick black tarp.
A stew of gases
— mostly methane
and carbon dioxide —
bubble up under the tarp,
creating enough pressure
that you can walk across
the undulating surface
like it was a trampoline !
Left untouched,
decomposing
cow manure might
spend months sitting
in open lagoons,
getting broken down
by bacteria in a
reaction that
would releases
methane gas,
a very powerful
greenhouse gas,
into the atmosphere.
Growing crops specifically
for use in methane production,
( or for ethanol production )
does not make economic sense.
Capturing methane at sewage
treatment plants, where the gas
is a byproduct of wastewater
processing, would be kess
expensive.
The least expensive source
of renewable gas starts with
"free" cow manure !
When fossil fuel natural gas
is burned in a furnace, or
a kitchen stove, it will
generate carbon dioxide.
But if a natural gas
was captured from
cow manure at a
dairy farm, where
it otherwise would
have been released
into the atmosphere
as methane, there's
a greenhouse gas
emissions reduction.
One loud cheerleader
for renewable gas
is SoCalGas,
a subsidiary of
San Diego-based
Sempra Energy.
SoCalGas hopes to replace
20% of the fossil fuel natural
gas in its pipelines, with
renewable gas, by 2030.
SoCalGas’s preferred use
of renewable gas is selling it
to homes and workplaces
for use in heating and cooking.
But for now, SoCalGas’s
renewable gas pipeline
is NOT going to homes.
State and federal programs
incentivize cleaner vehicles,
So methane is being supplied
to fueling stations for use in
heavy-duty trucks, that run
on compressed natural gas,
as an alternative to diesel fuel.
Nearly all of the 120
"dairy digesters" operating,
or in development in California,
are targeted at transportation,
not hone heating and cooking.
A recent report from
Lawrence Livermore
National Laboratory,
a federal research
institute, concluded that
California can achieve
“carbon neutrality”
— removing as much
carbon dioxide from the
atmosphere as it emits —
at a cost of less than
$10 billion per year.
That would require
producing and using large
amounts of renewable gas
from dairies, landfills and
sewage treatment plants.
A May 2019 report funded by
SoCalGas, and fellow Sempra
subsidiary San Diego Gas
& Electric, found renewable gas
has the potential to replace
9% of current statewide
gas consumption by 2030.
A December 2019 report
commissioned by the
American Gas Foundation
concluded the United States
is likely to produce, at most,
enough renewable gas by 2040
to supply just 14% of current
U.S. natural gas consumption.
Environmentalists say the
limited quantities of renewable
gas should be dedicated
only to fossil fueled activities,
where electric power would be
too expensive, such as
cement and steel production,
aviation or electric power
generation.
They say using the fuel
for heating and cooking
is not sensible, because
electric alternatives are
increasingly affordable.
In a recent report for the
California Energy Commission,
the consulting firm Energy
and Environmental Economics,
known as E3, concluded that
renewable gas would be
too expensive for home use.
“Electrification of buildings,
and particularly the use
of electric heat pumps
for space and water heating,
leads to lower energy bills
for customers over
the long term,” E3 wrote.
SoCalGas has pushed back,
arguing that the electric grid
has become unreliable,
with utilities shutting off power
to reduce the risk of deadly
wildfires.
Calgren Renewable Fuels
captures that methane
before it enters the atmosphere,
then injects it into the pipeline
network owned by Southern
California Gas Co., a utility
that serves over 21 million
people, from Fresno to the
U.S.-Mexico border.
Our nation’s
natural gas
pipeline system
is 2.6 million miles
of existing energy
infrastructure that can
deliver renewable
natural gas today.
One big problem is that
California state officials
embraced electricity
as the best strategy for cutting
CO2 emissions from homes
and workplaces --
not fossil fuel gas
or "renewable gas".
Over the past year,
30 California cities
and counties have required,
or encouraged, construction
of all-electric buildings.
Environmentalists also say
renewable gas has many
of the same problems as
fossil fuel gas: It leaks
from pipelines, and requires
consumers to keep paying
for the upkeep of aging
pipeline infrastructure, that
caused the deadly San Bruno
gas pipeline explosion, and the
Aliso Canyon methane blowout.