Marin Clean Energy (MCE) has just issued this document (which you won't find on the
MCE
website).
In it you will find every possible category of energy generation
AND then you will find category 'OTHER'
AND also- "40% Unspecified Power" ?
Where is this "UNSPECIFIED" power coming from? (See below).
Look for MCE to work so much better when they put
solar
panels and a wind turbine on every roof.
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Source:
http://pge.com/includes/docs/pdfs/myhome/customerservice/energychoice/communitychoiceaggregation/gen%20portfolio.pdf
2012
Electric
Power
Generation
Mix*
|
Percent of
Total
Retail
Sales (kWh)
|
PURCHASES |
PG&E |
MCE
Light
Green |
MCE Deep
Green
|
Renewable |
19% |
53% |
100% |
• Biomass & Biowaste |
4% |
12% |
0% |
• Geothermal |
5% |
0% |
0% |
• Eligible hydroelectric |
4% |
2% |
0% |
• Solar electric |
0% |
1% |
100% |
• Wind |
6% |
38% |
0% |
Coal |
0% |
0% |
0% |
Large hydroelectric |
18% |
7% |
0% |
Natural gas |
25% |
0% |
0% |
Nuclear |
22% |
0% |
0% |
Other |
1% |
0% |
0% |
Unspecified
Power |
15% |
40% |
0% |
TOTAL |
100% |
100% |
100% |
*2012 data
is from
the “Annual
Report
to the
California
Energy Commission:
Power
Source
Disclosure
Program.”
PG&E
data is
subject
to an
independent audit and
verification that
will
not be
completed
until
October
1, 2013. |
Note that the 12% on Biomass/Biowaste burning is not included in the
CO2
emission calculation |
2011
Total
CO2
Emissions from
Electricity
Sales
per
Megawatt-Hour**
PG&E
"Unspecified Power" plus
Natural Gas |
MCE
Light
Green
All
"Unspecified Power" |
MCE
Deep
Green
|
393
pounds |
389
pounds |
0
pounds |
**The CO2 emission rates reflect the energy generation purchased
by an energy provider.
For the purposes of this chart, renewable
energy, hydroelectric and nuclear resources
have been considered Green House Gas
(GHG)-free.
MCE’s purchases of unspecified power make up
the entirety of the 389 lbs/MWh of CO2, as
all other energy purchased by MCE is zero-emission.
Likewise, the emissions from PG&E are primarily a result of its
natural gas generation and its own
unspecified power usage.
The emissions rate for unspecified system
power is determined by the California Air Resources Board, (CARB) which
is .428 metric tonnes CO2e/MWh, or 943.58 lbs CO2e/MWh. This emission rate is
made publicly available and can be referenced in section 95111(b)(1) of the
Regulation for the Mandatory Reporting of Greenhouse Gas Emissions:
http://www.arb.ca.gov/cc/reporting/ghg-rep/regulation/mrr-2012-clean.pdf
The calculation generally works by taking the resources in the entire California
system and subtracting electricity purchased and reported by utilities and
electricity used by certain entities for on-site use rather than retail sales.
The same methodology is applied to both providers. These standards were
discussed and agreed to by both MCE and PG&E, as this mailer was designed and
financed with agreement from both parties as was required by state law. Please
also note that 2011 emissions data was used as it was the most recent data
available at publication. Based on PG&E’s power supply changes for 2012, their
emissions factor will actually be much higher.
MCE's ANSWER:
MCE and PG&E both use the same methodology for calculating their greenhouse
gas emissions reported to the Climate Registry.
Unspecified Power is the new terminology for California System
Power, which is electricity purchased from the California
energy grid itself,
where the fuel type is unknown.
MCE relies on this to provide its conventional (non-renewable or
hydroelectric) energy, rather than contracting directly with gas or nuclear
power plants.
Other utilities, such as PG&E, rely on a combination of unspecified
power and conventional power plants. PG&E, for instance, used a mix of 25%
natural gas, 22% nuclear, and 15% unspecified power to meet its
conventional power needs in 2012.
Bioenergy is a renewable resource certified by the State of California
which takes natural waste and utilizes it to generate power without adding
additional carbon to the carbon cycle.
As an example, MCE contracts with a biogas
facility in Placer County which is attached to the regional
landfill. Prior to the facility’s
construction, the waste material would generate significant quantities of
methane (a greenhouse gas about 14x worse than CO2!) which would be released
directly into the atmosphere, sometimes through “flaring” where they burn it
to reduce the impact a bit; there’s actually a diagram of how this flaring
process works on their wall in their offices!
In contrast, the biogas facility takes that methane and utilizes it to make
electricity and converting the methane into CO2. This is actually a net
reduction in GHG that redirects something already going into the atmosphere –
decomposing carbon – into making electricity as part of its life-cycle. All
utilities report these facilities as “biogenic energy”, which typically
is considered to have an emissions factor of zero.
We absolutely encourage customers to learn more about the power sources we
use.
There’s a great piece of information on what Unspecified Power is on
the state website at
http://energyalmanac.ca.gov/electricity/total_system_power.html.
Wikipedia also has good information on bioenergy on its website at
http://en.wikipedia.org/wiki/Bioenergy.
We encourage people to look at objective information from credible websites on
energy where possible.
The information provided was provided according to the template specified by
the California Energy Commission.
Just over 3% of MCE’s total power supply
in 2011 came from biomass, with about
9% from biogas
(landfill methane). You’d have to contact PG&E about
what their breakdown is, as they currently report it entirely as bioenergy,
but historically their bioenergy has leaned almost entirely on biomass
(I think about 22 out of 23 bioenergy facilities contracted by PG&E in 2010
were biomass).
Most biomass in California is actually
from decomposing wood waste, and the only site that MCE purchases
biomass-based power from (a wood waste site) is actually also contracted by
PG&E for another portion of its power. I cannot speak to the facilities used
in PG&E's power mix, as I have no idea what the specifics of those other
facilities are.
Biomass has no GHG associated with it according to just about every
standard of GHG reporting. Some life-cycle based assessments to rate biopower
emissions, but usually actually consider it lower than solar or geothermal
power. Again, keep in mind that you're taking material which is already
decomposing organic waste which will be added to the carbon cycle regardless.
Feel free to check out the Intergovernmental Panel on Climate Change's
report on life-cycle carbon emissions at
http://srren.ipcc-wg3.de/report/IPCC_SRREN_Annex_II.pdf.
(And Biomass and Biowaste need to be
separately reported when Biomass is from a non-waste source .)
The emissions factors of unspecified power
are publicly published by the State and should be available online. Both MCE
and PG&E use the most current factor published by the State at the time of
publication, 0.428 tonnes/MWh. Again, these are State of California standards
calculated according to the methodology that was discussed previously.
However, please note that I'll be unable to follow this threat any further; if
you have any additional questions please feel free to email us at
info@mcecleanenergy.com .
It’s also important to note that no fuel source, strictly
speaking, is entirely zero emission, although renewable sources are generally
considered zero-emission because they utilize sources that do not add to the
otherwise occurring carbon cycle. The Intergovernmental Panel on Climate
Change in 2011 found that the
Lifetime (including construction) Emissions
of:
-
solar are about 45g/kWh,
-
biopower (including biomass and biogas equally) is about 18g/kWh,
-
natural gas is about 469g/kWh, and
-
coal is about 1001g/kWh.
Biogas is a growing source of dependable renewable energy, that you
can read more about at
http://en.wikipedia.org/wiki/Biofuel.
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