Net-Zero, carbon footprint, carbon capture, carbon sequestration, greenhouse gases – the internet is awash with terminology related to climate change. But what does it all mean and where should you start your journey to carbon neutrality? We break it down.
What is a carbon footprint?
Earth’s atmosphere lets in some of the energy from the Sun. This heats up the planet and provides energy for plants to grow and weather to happen. Heat from earth is radiated back out, but the atmosphere reflects some of that heat back, a bit like the glass in a conservatory / greenhouse. Some gases (droplets and particles) are better at reflecting the heat than others. Carbon dioxide (CO2) is a key one of these Greenhouse Gases (GHG’s). Others include methane, nitrous oxide, and many refrigerants.
CO2 is used as a metric, because it’s the most impactful of the anthropogenic greenhouse gases today. Other gases are therefore compared to CO2 to get the Global Warming Potential (GWP). CO2 is stable in the atmosphere, but other greenhouse gases can break down over time which makes this comparison somewhat open to interpretation. For example, methane is moderately reactive, so breaks down within a decade or so; carbon tetrafluoride, on the other hand, is very stable and can persist for millennia.
Greenhouse gas emissions are therefore commonly quoted in terms of equivalent CO2 (eg kg CO2e). The Carbon Footprint is the greenhouse gas impact of a particular activity or product.
What makes up the CO2 footprint?
Equivalent CO2 (CO2e) is broken into 3 categories:
Scope 1 – direct production of greenhouse gases. For example, making silage releases methane, burning natural gas to make heat (e.g. for steam) releases CO2 and converting malt into beer releases CO2 during fermentation.
Scope 2 – indirect consumption of energy that releases greenhouse gas elsewhere. For example, consuming electricity that was produced in a coal-fired boiler and dispatched through the grid.
Scope 3 – Greenhouse gases embedded in the raw materials or downstream use of your products. For example, the food you throw away may turn into CO2 and methane in landfill, and the steel used to support the building embodies greenhouse gas for mining, refining, forming, and transportation.
Carbon Neutral – My process consumes as much carbon as it produces. For example, processing trees into charcoal, and running the process on “waste heat”.
Net Zero – I can’t get to carbon neutral, so I’ll pay someone else to absorb it. For example, planting trees or capturing methane from a landfill.
Carbon Footprint Reduction – My process still produces carbon, but less than it used to do. For example, covering an anaerobic sludge pond and capturing the methane as biogas.
Carbon Sequestration – Capturing CO2 and then storing it for geologically relevant timescales. For example, pumping it underground into an aquifer or old oil well.
Strategies to reduce your carbon footprint
- Reduce your own Scope 1 / Scope 2 carbon (and encourage your supply chain to do so).
- Replace carbon heavy products / processes within your plant. E.g. use solar power in place of coal.
- Carbon Capture (and Storage). This can be point source capture (concentrated CO2 from a burner exhaust or a cement plant) or direct air capture (dilute CO2 capture from ambient air).
- Pay someone else, either directly or through tradable carbon credits or taxes.
Read the fine print
Net Zero concept is riddled with loopholes
The offset schemes could be imaginary, or could go bust, or be tough to audit. They often refer only to Scope 1 / Scope 2 levels and are sometimes based on “expected future benefits from research”.
Carbon Reduction Goals
Look at the baseline year and understand what was happening. Do they consider Scope 3? If as a nation you offshore your heavy industry and import raw materials, your Scope 1 and Scope 2 numbers look much better. As a company, you can buy rather than make carbon-heavy intermediates and achieve similar results (if you only track Scope 1/2).
Similarly, there can be “penalties” for your organisation in reducing the overall footprint – converting soybean meal into higher protein animal feed by leveraging waste heat may reduce the Scope 3 CO2 overall, but will increase the site’s Scope 1/2 footprint.
The Bottom Line
Urgent action is needed to address climate change. Reducing greenhouse gas emissions is the critical step to make that happen.
While there’s a lot of complexity and debate in the scientific details, and there are all sorts of games that one can play (Scope 3 allocation, carbon offsetting, …), improving the efficiency of your process will almost always move the needle in the right direction.
Crowley Carbon can help you identify and implement direct, tangible changes through:
- Replacing equipment with more efficient designs (e.g. coal boiler to gas fired CHP).
- Helping to redesign your processes for greater efficiency (e.g. installing a heat pump to recover heat).
- Developing solar, battery and operating strategies that can both lower your power bill and help you integrate your facility more efficiently into the more variable, but greener, power grid of the future.
- Identifying operating conditions that are more efficient (eg adjusting setpoints to use raw materials more efficiently).
- Applying software tools and new manufacturing practices to make efficient operation easier and cheaper to maintain.