We often hear that massive carbon emissions reduction is either technically impossible or financially unfeasible. However, through a feasibility-level analysis of eight commercial and industrial buildings, I arrived at a conclusion that surprised even me.
Massive net carbon emissions reduction is not a technological issue, nor is it a financing problem.
It is a question of mindset.
An 80% CO2 net emissions reduction can be achieved in commercial and manufacturing buildings using existing off-the-shelf technologies, and with a payback on par with what is generally accepted for CAPEX projects.
All without grants, special tariffs, or subsidies.
At today’s energy prices.
Without accounting for carbon taxes.
In a place as cold as Edmonton.
On an electrical grid as carbon-rich as Alberta’s.
Let me show you how…
Project scope and tool
In early 2021, GreenQ Partners (among other consultants) was contracted by Natural Resources Canada to come up with financially reasonable, massive emissions reduction measures for eight commercial and manufacturing buildings. These were not specific buildings, but rather prototypes of typical buildings pre-modelled in RETScreen.
The buildings varied from a medical clinic and a commercial printer to a chemical plant and an industrial bakery.
My task was to bring net emissions reduction to 80% in jurisdictions as diverse as Edmonton and Montreal at the “Scope 2” emissions accounting level; that is, to account not only for emissions generated onsite, but also for those in purchased energy.
Some measures had already been modelled by RETScreen engineers, resulting in a net reduction ranging from 20% to 35%. Since RETScreen calculates emissions reductions and the financial impact of measures, my task was to come up with commercially available technical solutions and model them.
Below, I present both the pre-modelled solutions, and those I have introduced.
Measures and results
Given the variety of buildings, there was no “one size fits all” solution, so I adopted a 3-step approach:
1. Apply building-specific solutions to the main sources of emissions in each building.
2. Apply solutions to systems that are common in every building.
3. As a last resort, offset the remaining emissions through solar PV generation and switch the heating fuel to wood pellets. (This last step is trivial, and I will not discuss it in detail in this article, except to say that this measure did not kill paybacks.)
Across the portfolio of buildings I analyzed, reaching 80% net reduction through energy use reduction and offsets can be achieved with paybacks of 7 to 15 years. The further you go into reductions, the more expensive they become.
(Not surprisingly, net emissions reduction is easier and more profitable in Montreal than Edmonton because Quebec’s hydroelectricity has low carbon content.)
Building-specific measures varied widely from building to building or, rather, from industry to industry. This list does not cover all possible solutions—only those I modelled as part of this project. In no particular order:
• Microwave technology can be used for drying materials and products, from pills to bread.
• A baking oven with a reflective internal surface uses 25% less heating energy directly, while a microwave baking oven uses 80% less energy directly. Both reduce the demand for A/C and ventilation for the amount of unwanted heat emitted into the building.
• The heat rejected at production can be used for either office heating or pre-heating boiler makeup water, thereby reducing overall energy consumption.
• Replacing hydraulic plastic moulding machines with all-electric ones reduces direct energy consumption by 80%, and reduces the load on the cooling system by 80%.
• A hanging ceiling is a surprisingly effective way to reduce heating and A/C energy use, especially at the top floor where it reduces air volume and increases ceiling R-value. A 300-mm air cavity created with a 16-mm polystyrene sheet increases R-value by almost 4 m²•C/W (22 sf•F•h/BTU). Reduced noise, simplified cabling, and a reduced demand for lighting are bonuses.
• Lowering ceiling light fixtures from 6 metres to 5 metres reduces demand for lighting at the source by 25% to 50% while keeping the same lighting at eye level. In many places, this leads to an A/C load reduction, too. Who knew that a metal chain could be such an effective energy efficiency measure?
• Low-hanging duct can provide conditioned air directly to manufacturing workstations, thereby dramatically reducing the need for conditioning the whole building. Automation reduces the number of people on the production floor to a level where conditioning an entire building becomes unnecessary.
Common energy use reduction measures
While the measures above are building-specific, here are some that apply everywhere:
Lighting and HVAC
Although the energy efficiency (and maintenance) benefits of LED lighting are now pretty well understood, they are still worth mentioning.
Appropriate temperature settings, night/weekend setbacks, and appropriate timing for switching between heating and cooling constitute the simplest and the cheapest ways to cut down energy waste in HVAC systems. You enjoy instant payback with no CAPEX, and the energy savings are often accompanied by improved conditions for occupants.
As much as everybody likes fresh air, adding more fresh air after a certain level only adds cost. On the other hand, excessive exhaust may add sanitation issues atop of HVAC costs, particularly in an industrial food production environment. Bringing air supply in line with ASHRAE recommendations can save 20% to 40% of energy use between ventilation and conditioning. Adding heat recovery can further reduce energy use in air-conditioning by 60% to 80%, with a payback of 3 to 4 years.
Natural air infiltration is often overlooked. Addressing those cracks in walls, and around doors and windows, may present an excellent opportunity for a 2x to 5x reduction in heating and cooling costs, with a payback of 2 to 4 years in industrial environments. These energy savings are often accompanied by an improved sanitation condition.
Affinity laws can be put to work in ventilation: a 2x oversized premium efficiency VFD-controlled fan motor uses 3x to 5x less energy while delivering the same air flow.
Compressed air systems
Compressed air systems often present excellent opportunities for energy cost reductions. Unfortunately, these opportunities are routinely tackled from the wrong end. Instead of first reducing demand then optimizing supply, customers are often convinced to buy new compressors and skip optimization altogether.
I once visited a plant where two 300-hp fixed-speed compressors were replaced with two 300-hp VFD compressors—to great applause, I might add. But were they even necessary? Nobody so much as looked at compressed air leaks which, when not dealt with, waste at least 30% of air flow.
A much more profitable and environmentally responsible approach to compressed air systems starts with fixing leaks, eliminating improper use, ensuring schedules are followed, untangling the distribution network, bringing in cold outdoor air and rejecting hot air outside or, better yet, using rejected heat for onsite heating.
While these measures are not as glamorous as new compressors, they bring more benefits, including energy use reduction. At our client’s injection moulding plant, these low-cost, low-tech measures not only solved the puzzle behind the unstable production of two $1.2-million, freshly installed all-electric moulding presses, but reduced demand at the compressor by a whopping 35%! In addition, by freeing compressor capacity, we eliminated the need for the owner to buy a new compressor to support a planned expansion.
Switching from a natural gas boiler to wood chips (pellets) may not seem like a net emissions reduction measure, as both produce CO2 emissions, but when those wood chips come from a construction waste sorting company, for example, the emissions picture changes dramatically.
Waste wood can be either burned under controlled conditions in a boiler or trucked to a landfill, where it will rot uncontrollably and emit a much more poisonous mixture of gases. The emissions profile between these two processes constitutes a significant reduction. The European Union has, in fact, decided that wood chip boilers are carbon neutral. (Granted, a wood chip boiler has its limitations, but its use reduces emissions.)
With the current cost of solar PV systems below $2 per installed Watt of capacity, onsite and offsite electricity generation become viable paths for offsetting emissions with a decent payback. (We could have a lengthy conversation about the difference between emissions reduction and emissions offset but, in my opinion, an offset contributes to overall reduction.)
Show me the money in carbon reducing retrofits
Now it’s time for the fun part: the financials!
Within the range of buildings I modelled, and based on budgetary quotes I obtained from different vendors, the 80% net emissions reduction can be achieved with a payback of 7 to 15 years, without accounting for tax breaks, grants, carbon tax avoidance, and emerging technologies.
If a 15-year payback sounds like a showstopper, consider this…
The average stock market return over the last 30 years was 8.3%, from which taxes must be deducted, whereas a 15-year payback equates to a 6.6% return, to which tax breaks shall be added. But, even if there were no government supports (grants, tax avoidance, etc.), investing in carbon emissions reduction is more profitable than investing in the stock market.
The first 20% to 40% of emissions reduction are highly profitable, and new technologies continue to come to market. Meantime, carbon taxes are here to stay, and they will continue to grow—as will the cost of energy.
Add it all up, and you can see how investments into carbon emissions reduction are a very profitable proposition.
This article was first published by Energy Manager Canada after extensive editing by Anthony Capkun