Net-Zero Carbon Heating
Net-Zero Carbon Home
In the July/August 2022 issue, ICM profiled an initiative
to demonstrate that homes can be net-zero emitters of
atmospheric carbon.
Here is an update on the project.
The need to lower carbon emissions
has driven many industries to find
alternative methods to minimize their
contribution to a warming planet.
The liquid fuel heating industry
is no exception. For decades, it
has been reducing petroleum fuel
use through increases in heating
system efficiencies and since the
early 2000s, has been working to
develop and adopt a renewable
and sustainable low-carbon fuel. The use of
biodiesel has been identified as an effective and reliable fuel
to replace fossil-derived heating fuels. Due to research by
the National Oilheat Research Alliance (NORA) and efforts
by heating system manufacturers and fuel marketers, the
use of increasing blends of biodiesel with No. 2 heating oil
has increased rapidly over the past few years.
NORA’s goal is to create demonstration homes that are
net-zero emitters of carbon. Labeled the Net Zero Carbon
Home Project, the homes will replace standard heating
fuel with 100% biodiesel (B100) while relying on solar PV
roof panels to generate renewable, carbon free electricity
for non-heating uses. Since biodiesel is not yet fully carbon
neutral, the solar PV system needed to be sized to produce
more energy than the home requires. The excess carbon-free
electricity could then be transferred back to the grid and offset
the small amount of carbon emissions from biodiesel.
A calculator created by NORA utilizes a number of parameters
such as fuel usage and electricity consumption to calculate how
much oversizing of the PV system is required to make the home
carbon neutral.
The first of these demonstrations is the home of Dr. Thomas
Butcher, Director of Research of the NORA Liquid Fuels
Laboratory in Plainview, NY. Dr. Butcher’s home was already
using B100 for heating and subsequently solar PV panels were
installed for the non-heating energy needs.
Using biodiesel consumption (due to hot water production),
electrical usage and power generated by PV system, it was found
that Butcher’s home was Net-Zero (and beyond) for the months
of July, August and September 2022 (see Table 1). Figure 1
shows the carbon emission comparison for Butcher home with
and without proposed changes (B100 and solar PV).
Despite a significant air conditioning load in the summer,
as shown by the blue bars, each of the summer months contributed
to a lowering of the carbon intensity of the grid by
producing more energy than was used in the house, as shown
by the orange bars.
The question is—as we enter the Winter and biodiesel consumption
increases, will the solar on his roof and the savings
from the summer be enough to make his house a Net Zero home
for the entire year? Preliminary calculations say “yes,” but look
forward to an update in the spring of 2023.
NORA is working with various State energy organizations
to find additional suitable homes for this project. ICM
Table 1: Sample calculations that show how a home
can be carbon neutral using biodiesel and solar PV
Heating Energy Required (mmBtu)
approximately 650 gallons 90
Annual Boiler Efficiency (%) 86
No. 2 Oil Carbon Emissison (lbs CO2/mmBtu) 228
Carbon Score of B100 (%) 90
Annual Non-Heating Electric Load (kWh) 10000
PV Sizing as % Annual Load 121
Grid Carbon Score (lbs CO2/kWh) 1.17
Annual Heating Carbon Emission (lbs CO2) 2386.047
Annual Non-Heating Electricity Carbon Emission
(lbs CO2) 11700
Annual PV Emissions Savings (lbs CO2) 14157
Net Annual Carbon Emission (lbs CO2) -70.9535
Figure 1: Carbon emission comparison for Butcher home with and without
proposed changes (B100 and solar PV)
18 ICM/November/December 2022