So many organisations are committing to targets for greenhouse gas emissions, yet very few building owners or operators know exactly where they are starting from, or which areas to focus on for the most impact, or even what it means to arrive at net zero carbon buildings.
Starting Point: Where Are You Right Now?
There’s an often-told anecdote in Ireland that goes something like this:
A man stops for directions and asks a local how to get to his destination. The local replies: “Well, I wouldn’t start from here…”
So where are you? How can you accurately calculate your building’s carbon footprint? What are you going to measure?
There are protocols for how deep you can go to assess your greenhouse gas emissions. The approaches fall into one of three scopes, largely based how directly you can control the emissions:
- Scope 1 offers the highest degree of control, such as burning coal or gas on-site and releasing emissions through a flue or chimney. The emitter owns the source and has complete control over whether the fuel is burned and creates emissions.
- Scope 2 encompasses grid electricity or off-site heating/cooling sources, including purchased electricity, steam, or heated/chilled water. Users can control the amount of energy consumed, but they do not control how the energy is produced or its emissions intensity.
- Scope 3 accounts for emissions with the least control or ownership. Examples include employee travel and commuting, vendor supply chain, or embodied energy in building products.
How to calculate carbon emissions
The simplest calculations fall into Scope 1 and 2 and this is therefore where most start. A ballpark estimate of your carbon footprint can be calculated by converting utility consumption of oil, gas and electricity into equivalent weight of carbon dioxide. There are conversion tables such as this one that can give you the carbon equivalent of your energy use.
So, what does that tell you? It is equivalent to measuring the flow of water into a tank. But where is it all going? Are there any leaks? How often do you measure it and over what time period? Did you use more today than yesterday, or even this day last year? Does your neighbour use more or less than you? Where do you rank in a benchmark of equivalent buildings?
Do energy ratings matter?
The idea of an energy rating is not new. In Ireland, the LEED and BREEM Certifications have been in place for many years. However, these standards were not designed to accurately predict building performance. For example, at Crowley Carbon, we took a Platinum LEED certified building and reduced its energy consumption by over 30%.
These standards are being updated and now contain operational modelling along the lines of the Australian NABERS system. A NABERS 6-star rating targets very low levels of energy intensity and equates to over 70% less energy consumption compared to a current equivalent best practice building. The focus of NABERS is on operational performance and the rating can change every day with environmental and other factors. The system also assesses sustainability of water and waste.
Key Performance Indicators for Net-Zero Buildings
Now you have established a rough baseline for your carbon footprint. By dividing the weight of carbon by the floor area of your building you can get a simple key performance indicator – KPI (kgCO2e/m2) of your building. The next thing you need to do is establish a plan for how to improve it and other important KPIs.
You are unlikely to achieve net zero carbon in one step, or even several. Although by spending money on carbon offsets or by procuring energy from renewable sources, you can influence the negative side of the equation. This is a way to achieve a net zero carbon sum, even though the building may be performing badly from a sustainability perspective. The planet will not forgive you if you rely on this method. The best approach is to continuously improve the performance of your building by targeting certain assets and systems such that they operate more sustainably over time. In order to achieve this, you can follow this approach:
- Collect data to allow you to automatically assess your KPIs on a regular if not continuous basis
- Implement a method for presenting this information in a format that easily shows improvement or degradation
- Perform regular checks that identify opportunities for reduction of energy or increased efficiency
- Take action to make changes or swap equipment that influences carbon emissions
- Measure performance gains for activity you undertake
The steps above form a continuous improvement workflow. This is a method employed by Crowley Carbon’s Clarity team when supporting customers on their path to net zero carbon.
Are you comfortable with this?
You shouldn’t lose sight of the fact that buildings are occupied by people, and you need to keep its occupants comfortable and healthy. This means your KPIs should include comfort-based indicators not just for thermal comfort, but ventilation (CO2), noise and light.
It would be easy to reduce energy by turning off boilers or chillers, but if this means a compromised environment then you are not achieving all goals and your employees will not thank you. A large proportion of support tickets that facilities managers face are based around comfort factors, so having proof of performance and a clear strategy can help deal with any complaints.
Little steps, big gains – A five step plan to get to Net-Zero Carbon Buildings
Some of the simplest approaches to energy efficiency in buildings can have the largest gains. Your Building Management System (BMS) is the key to implementing strategies that will effectively turn the asset into a smart building. By combining this with a monitoring system such as Clarity you can get insights into what changes you should make as well as measuring their impact. These few recommendations are some of the easiest to implement:
- Assess baseload of the building at night and ensure non-essential services are switched off when not occupied
- Determine ideal start and end time for HVAC services to ensure comfort levels during occupied hours. Shoulder periods should ideally be sympathetic to ambient conditions
- Eliminate simultaneous heating and cooling in shared zones. Local thermostats can cause 20% additional load where conflict occurs
- Use free cooling as much as possible. Fresh air can meet supply needs for make up air during most seasons in some countries with only recovered heating
- Use demand-based controls for pumps and fans where variable speeds can be set
Path to net zero carbon
More significant changes are necessary where legacy systems are not easily optimised or can be replaced with carbon free equivalents. Where lower grade hot water is required then an air source heat pump can be used.
Dry coolers can be enhanced by evaporative cooling that works at higher temperatures. Solar arrays will contribute to daytime running costs and possibly contribute to the grid outside occupied hours.
The opportunity to make such capital investments and achieve significant energy and carbon reductions should be modelled to determine the return on investment and the associated impact on the net zero target. Validating that this impact on the target has been achieved is an important step that often gets missed.
Death and taxes
The impacts of climate change are already hitting us hard. Loss of life is happening at an increasing rate and the impetus to do more is becoming critical. Legislation at a local, EU and Worldwide basis is coming into effect already.
The benchmark carbon price in Europe is increasing at a phenomenal rate having gone from 20/tonne pre-COVID to over 50/tonne in May-2021. This will translate to penalties for poor performing buildings in the form of carbon taxes. These changes are now inevitable and increasing.
Making a net zero carbon commitment is now not just a publicity play, but an essential characteristic of top performing companies that own and operate buildings. Investors, tenants and occupants are demanding their spaces are built and operated sustainably. Make your steps along this path from an informed and accurate basis by working with Crowley Carbon to achieve net zero carbon.