Net Zero in existing buildings

Net Zero in existing buildings

Net Zero in existing buildings 1061 572 Greengage Environmental

With ever increasing focus on delivering net zero carbon buildings and lots of attention on developing new buildings that meet design and operational performance, it is important to recognise that a over 80% of the building stock is existing. This creates a huge opportunity to identify means to reduce operational energy and carbon from properties already in use and active.

Greengage have a five step method for working towards operational net zero in existing buildings:

  • There is a lot of data and information needed to understand your carbon base line for scopes 1, 2 and 3 emissions as a starting point. This will enable you to identify the areas of high operational impact and begin to set your trajectory to net zero carbon.

    Review your building activities and environmental impacts. Understand where they lie and where there is significant usage and risk. Understand your data flows, do you have the information you need, what is relevant to capturing the data to calculate your baseline.

    Review how the data is captured, how it is provided, who is involved and the data type, this will be important for ongoing monitoring as well. Identify data gaps and establish means to resolve, albeit with a consistent approach to estimation until you can get actual data.

  • Now you have your baseline and pathway, it is time to tackle operational energy and carbon. Using both consumption data (e.g. half hour electricity consumption kW) and contextual information on performance (e.g. Plant start up times, out of hours activity) review daily energy profiles to investigate actual performance, interrogate BMS and HVAC control strategies and understand occupant behaviour patterns to fine tune and implement measures to make marginal gains on operational energy consumption. These add up over a period of time and will contribute to reducing operational net zero carbon.

    Utilising actual data is important, estimated data can distorted month on month comparison and impact ongoing monitoring. This is the same with physical meter readings. Where there is no other option for meter readings, it is important to set up a structured approach to ensure readings are taken at a consistent date each month. This ensures data quality and the ability to monitor month on month consumption, avoiding consumption slips and misrepresentation of seasonal performance, especially with gas.

    Data normalisation will help compare property portfolios and identify the highest consuming buildings (based on intensity) for targeting. The most common is floor area (m2), this can distinguish the poorer performing buildings for their size, enabling a prioritised approach and targeting resources to make the largest impact on existing building energy use. Using industry benchmarks such as the Better Building Partnerships REEB can help to compare to similar building types and give a broader indication of performance.

    Although there are new technologies constantly coming to the marketplace and we have the schemes and process in place to implement good practice. We need to proactively engage building users and occupants. The impact people have in our buildings through behaviour and improved awareness on sustainability will help them make informed decisions, supporting us operate energy efficient and sustainable buildings. Harnessing tools such as Post Occupancy Evaluation can help understand people interaction with buildings and how the building systems are performing in relation to utilisation. Using this to capture lessons learned and improve performance is going to be invaluable.

  • Review your buildings potential for onsite renewable energy generation. Be realistic, tall offices in a city centre are going to have limited or no real onsite opportunities. Whereas large flat roofed data centres and distribution centres out of town are ideal candidates for solar PV or Bio solar (Green roof and solar PV) for example. If it is not feasible now, consider reviewing CapEX budgets for future, scalable installation.

    The UKGBC net zero framework supports onsite generation and potential for battery storage as it encourages increased renewable energy generation development and battery storage provides opportunities to support the grid with peak demand.

  • It is now increasingly critical to review energy procurement contracts and switch to agreements with environmental benefits.  The UKGBC sets out 3 principles to support the quality of electricity procurement:

    • Energy Attribute: exclusive ownership of onsite renewable energy generation and consumption or via Renewable Energy Guarantees of Origin Certificates (REGOs).
    • Renewable Sourced: Purchased electricity must be from 100% renewable REGO supplies.
    • Additionality: Must be applied. This is where a when a consumer installs, self generates and consumes energy from their own facilities or agrees an electricity purchasing contract that contributes to the construction of new renewable energy facilities.

    Currently, there are only 3 energy supplies (Good Energy, Green Energy and Ecotricity) recognised to provide additionality. Due to market limitations, a phased approach can be adopted, requiring electricity consumption on contracts without additionality, offsetting using location-based emission factors. As the market evolves this approach will be phased out.

    Gas has a number of ‘green’ products in the market place and hydrogen is expected to play a role in the future. However, of the 115m tonnes of Hydrogen generated each year 98% is considered grey as it is generated from coal and gas means. This emits 830m tonnes of CO2e per year, equating to 2% of  global carbon emissions. So hydrogen had a long way to go to become a viable low carbon solution!

    In addition, the current market does not facilitate gas equivalent to REGOs as there are no market-based emission factors as there are for electricity. This is currently being reviewed.

  • There are 8 key principles to consider for offsetting:

    • Real – Emissions associated with the offset project must be proven to have taken place
    • Avoid leakage – The offset project has to demonstrate that it has accounted for any indirect emissions.
    • Measurable – All emissions should be quantifiable using recognised measurement tools against a credible baseline.
    • Permanence – The carbon credits must represent permanent reductions or removals.
    • Additional: The offset project could not have happened without the finance from the carbon credits and that the carbon reduction/removal is additional to what would of occurred had the project not taken place
    • Independently verified by a recognised, accredited 3rd party
    • Unique – Only one carbon credit per ton of carbon with no double counting
    • Avoid social and environmental harm – the project must not contribute to any social or environmental harm.
  • A key part of achieving net zero carbon, is verification and monitoring. One of the challenges faced here is the performance gap between design and operational performance. We need to move away from a design for compliance mentality to a design for performance one.

    This is where I believe soft landings can help, bridging the gap from inception and design, through construction and handover into operation. Through collaboration, thinking about the building in whole life terms from the outset and bringing forward consideration around operational use can help to improve, design and construction as well as refurbishment of existing buildings. Harnessing lessons learned through building performance evaluation and post occupancy evaluation can identify opportunities and innovations to improve not only occupant satisfaction and wellbeing but also building system optimisation and improved energy efficiency. All contributing to lower carbon emitting existing buildings.

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