Scope 1 emissions are direct greenhouse (GHG) emissions that occur from sources that are controlled or owned by an organization (e.g.,
emissions associated with fuel combustion in boilers, furnaces, vehicles). One example would be a natural gas fired boiler on your site
where you directly combust this natural gas to make steam for heating one of your processes. The GHG released by this combustion for steam
heating would be a scope 1 emission.
Scope 2 emissions are indirect GHG emissions associated with the purchase of electricity, steam, heat, or cooling. Although scope 2
emissions physically occur at the facility where they are generated, they are accounted for in an organization’s GHG inventory because
they are a result of the organization’s energy use. One example would be an electrically heated tempering furnace. The scope 2 emissions
associated with this electric tempering furnace would be proportional to the amount of fossil fuels used by your local electric utility to
generate its electricity. Depending on the local electrical utility’s electrical generation portfolio and the proportion that creates GHG
during the generation of the electricity that you use, you may have a “cleaner” source of electricity or a “dirtier” source of
electricity. Your scope 2 emission levels all depend on the pie chart of fuels for generation for your electric utility. Utilities with
more nuclear, solar, wind, and hydro for electricity generation will be “cleaner.” Utilities with more coal, fuel oil, and natural gas
fired electrical generation will be “dirtier.”
Scope 3 emissions are the result of activities from assets not owned or controlled by the reporting organization, but that the
organization indirectly impacts in its value chain. Scope 3 emissions include all sources not within an organization’s scope 1 and 2
boundary. The scope 3 emissions for one organization are the scope 1 and 2 emissions of another organization. Scope 3 emissions, also
referred to as value chain emissions, often represent the majority of an organization’s total GHG emissions. This can be things like raw
materials, raw material processing, raw materials transportation, supply chain energy, capital equipment, product distribution, product
use, product disposal, etc.
Which GHG emission scopes should I be concerned about?
All three GHG emission scopes are important to an organization’s sustainability goals.
All three GHG emission scopes need to be evaluated, monitored, measured and mitigated.
An organization will have the most control over its scope 1 and 2 GHG emissions and can take immediate action to implement energy
efficiency projects to reduce direct GHG creation from onsite combustion or releases and to reduce consumption of onsite electricity which
will reduce GHG emission proportionally to the local electrical utility’s generation fuel source portfolio.
Scope 3 GHG emissions may be harder to determine and may require the engagement with other organization to implement reductions.
A carbon credit is a tradable permit or certificate that provides the holder of the credit the right to emit one ton of carbon dioxide or
an equivalent of another greenhouse gas – it’s essentially an offset for producers of such gases. The main goal for the creation of carbon
credits is the reduction of emissions of carbon dioxide and other greenhouse gases from industrial activities to reduce the effects of
global warming.
Carbon credits are market mechanisms for the minimization of greenhouse gases emission. Governments or regulatory authorities set the caps
on greenhouse gas emissions. For some companies, the immediate reduction of the emission is not economically viable. Therefore, they can
purchase carbon credits to comply with the emission cap.
Companies that achieve the carbon offsets (reducing the emissions of greenhouse gases) are usually rewarded with additional carbon
credits. The sale of credit surpluses may be used to subsidize future projects for the reduction of emissions.
The introduction of such credits was ratified in the Kyoto Protocol. The Paris Agreement validates the application of carbon credits and
sets the provisions for the further facilitation of the carbon credits markets.
Why hydrogen?
Why Hydrogen? When readily available, hydrogen is a very viable, carbon free gaseous fuel. While certainly different in its combustion
behaviors compared to the traditional hydrocarbon gaseous fuels (natural gas, propane and butane), it is not an unknown fuel to burner
manufacturers and can be, for the most part, adapted to many burner types.
What other options are there to reduce my GHG beyond hydrogen and electricity?
Other Options? Reducing GHG’s while using carbon-based fuels is done by reducing the fuel used to heat your process. So how do you do that?
Tune your combustion system: By routinely checking and optimizing your system, you will be firing at the most fuel efficient and producing
the least amount of GHG’s possible.
Burner control system: Perform an evaluation of your combustion control system and the process being fired and see if there are different
or more efficient ways to fire the burner(s). Does it make sense to move away from an old, linked valve or fuel only control system to
something that fires closer to stochiometric ratio or mor accurately controls the air/fuel ratio based on the requirements of the process.
Control methods such as ratio regulated, parallel positioning, pulse fired, or mass flow control could result in potential fuel/
CO2 savings depending on the application.
Add combustion air preheating to your combustion system: This makes sense in higher temperature applications to reduce the amount of heat
lost due to furnace stack losses where they are the most severe. By investing in a recuperator to preheat your burner systems combustion
air or switching to a self-recuperative burner system or a regenerative burner system you can reduce your fuel consumed by increasing
amounts. This results directly in the reduction of CO2 produced and could range anywhere from 5 to over 30% reduction depending
on the application and process temperature involved.
Does is make sense to blend natural gas with hydrogen?
This could depend on the method that the blend may be delivered.
Gas Grid Injection: There may be instances that hydrogen may be injected and blended into a natural gas grid making it readily accessible
to the public. The maximum percentage of H2 to possibly be injected into gas grids has been 20%. But the appliances that might
burn this blend must be confirmed to be able to use the mix with no detrimental performance implications. We have not seen the cost
implications of this situation.
Natural Gas / H2 Blending On Site: This would entail a facility doing blending at their facility, which would include a
blending station and this could be per thermal asset or possibly the entire facility. The complexity increases as the system gets larger.
In addition the thermal process itself can lend itself to a simpler system or more complex depending if the mix is to be fixed or may/will
vary, a change in air fuel ratio does or does not need to be strictly maintained that can affect product quality, burners may or may not
need to be modified or upgraded depending on the maximum percentage of hydrogen it may be able to accept, etc… There is no simple formula
that these factors can be entered into to provide black and white answers.
The percentage of hydrogen in the mix does not directly relate to the reduction in CO2 (see below).
What is the C02 reduction if you use blending versus straight hydrogen
If you consider the blending of hydrogen with natural gas, the percentage of hydrogen in the mixture is not a direct correlation to the amount
of CO2 reduction in the combustion products. This is a result of hydrogens lower heating value and very low density. You can see in
the table below that to realize a 50% reduction in CO2 emissions, you need almost 80% hydrogen in your Hydrogen/Natural Gas
mixture.
% Hydrogen
% Natural Gas
CO2 Savings/Reduction(%)
0%
100%
0%
10%
90%
3%
20%
80%
6%
30%
70%
10%
40%
60%
15%
50%
50%
21%
60%
40%
29%
70%
30%
39%
80%
20%
52%
90%
10%
71%
100%
0%
100%
What are hydrogen colors? What do they mean?
Gray Hydrogen: The most prevalent form of hydrogen and is produced from natural gas through a process called
steam-methane reforming that combines natural gas and water (as steam) that produces of hydrogen gas (H2) and large volumes of
CO2.
Blue Hydrogen: produced through same technique as Gray Hydrogen but all CO2 captured and sequestered.
Green Hydrogen: produced through the electrolysis (the separation of hydrogen and oxygen molecules by applying electrical
energy to water). This process is powered by renewable electricity such as wind and solar to be truly carbon free so zero CO2
emissions are produced.
Black or Brown Hydrogen: produced through gasification of coal with resultant CO2 emissions and other
pollutants.
Turquoise Hydrogen: Similar to blue hydrogen but produced through the thermal splitting of methane (methane pyrolysis)
that produces hydrogen and solid carbon and the carbon removed, stored and used, eliminating CO2 emissions.
Purple Hydrogen: Produced using nuclear power and heat through combined chemo thermal electrolysis splitting of water.
Pink Hydrogen: Produced through the electrolysis of water by using the electricity produced from a nuclear power plant.
Red Hydrogen: Produced through high temperature catalytic splitting of water using nuclear power as the energy source.
White Hydrogen: naturally occurring hydrogen. Gaseous diatomic hydrogen in the air is accepted to be 0.6 parts per
million making it a trace constituent in air.
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