It’s time to rethink what ‘energy efficiency’ means for buildings. Energy efficiency is the most powerful tool we have for accelerating progress to Net Zero Carbon (NZC), but as the California Energy Commission explains in its Energy Efficiency Action Plan:

“… it is no longer sufficient to utilize energy efficiency only as a static resource. Energy systems – new homes, replacement heating and cooling equipment, industrial processes and the like – must be both highly efficient and flexible to the maximum extent possible. Flexibility means interactivity with the grid: the ability to manage energy usage, proactively and situationally, to minimize both its cost drivers and its carbon content.”

Energy efficiency is at the front and centre of most property owners’ NZC plans. For most, this simply means ‘use less energy’. However, if buildings can interact with electricity grids intelligently and dynamically, then they can support much higher penetration of renewables and reduce the entire energy system’s dependence on fossil fuels. They can also save money. This article summarises how Buildings Alive can support leading building owners and operators in achieving their next wave of emissions reductions as they move towards NZC.

Emissions factors are not static

The market price and carbon intensity of electricity supplies varies by the minute in proportion to the amount of renewable energy in the supply mix. When renewables go up, greenhouse gas emissions (CO2-eq) go down and so do wholesale prices – sometimes even to below zero. On the flipside, electricity generated from fossil fuels contributes more emissions.

This can be easily observed in the following chart which shows the carbon intensity of the electricity grid in South Australia for a five-day period in May overlayed with Buildings Alive’s forecast. The emissions from one kilowatt-hour of electricity vary from almost zero to more than 600 grams.

Forecasting the carbon intensity of electricity supplies is complex yet crucial for informing actions aimed at driving down emissions. In this example, the variability is explained by the combination of demand on the system and the contributions of wind and solar power.

National greenhouse gas accounting standards do not account for this variability – they just take an annual straight-line approach which simply glazes over the opportunities and costs. Recognising this limitation, companies such as Google, Microsoft, Vattenfall and pwc are getting behind the independent EnergyTag Initiative “to define and build a market for hourly electricity certificates that [will] enable energy users to verify the source of their electricity and carbon emissions in real-time”; however it is only in its early stages of development.

Accurate forecasting is the key

Buildings Alive has spent years of R&D effort in developing our forecasting competency which has focused mostly on automated forewarning of peak electricity demand events to help building operators minimise network capacity charges. We have adapted this 7-day-ahead forecasting to be ‘carbon aware’, the first building block for “active efficiency” strategies to support NZC.

If we take a 24-hour forecast for a building’s electricity demand, illustrated by the blue shaded area below, and overlay the forecast carbon intensity of the grid for the same period (red line), it becomes immediately obvious that the hourly carbon intensity profile is very different to the energy consumption profile.


Support renewables, don’t starve them

In this example, it would make little sense, from a carbon point of view, to focus on reducing consumption in the middle of the day, especially when investments in solar energy rely on there being maximum demand when the sun shines.

This is more clearly illustrated in the plot below which overlays the building’s true carbon impact (blue line) with the approximations produced by applying the National Greenhouse Account (NGA) factors for the electricity grid – in this case, South Australia.

Active efficiency strategies applied in this situation could dramatically reduce greenhouse gas emissions by trimming loads at the beginning and/or end of the day and potentially increasing loads in the middle, for example by increasing the building’s indoor air quality or thermal comfort using solar power distributed through the grid. We have published numerous articles showcasing successful approaches, see for example our paper “Buildings as Batteries” presented at the 2020 ACEEE Summer Study on Energy Efficiency in Buildings.

We acknowledge active efficiency is a very new concept and it might sound daunting. Right now, government-run measurement systems can’t account for it and energy performance rating schemes are not able to reward it. However, active efficiency strategies are cost cutting strategies. They are price-aware, they drive smarter investment, enable higher penetration of renewable generation sources, and are arguably the most important contribution that buildings can make to a Net Zero Carbon future.

If you would like a demonstration of how easy this technology is to deploy and use, or how it integrates with our other products and services, please get in touch.