What is Decarbonisation?
The global imperative to mitigate climate change has spotlighted the need to decarbonise buildings. As significant contributors to greenhouse gas emissions, buildings offer substantial opportunities for emission reductions through energy efficiency, renewable energy adoption, and innovative building technologies. if you are a large business you may be one of 400 RE100 members and have shareholders and employees who expect you to care about the planet. If you are a small business, you may form part of the scope 3 emissions of a larger business which may force you to start engaging with decarbonising. Here, we outline a comprehensive guide to decarbonising buildings in 4 steps, encompassing both new constructions and existing structures.
1 Measure Performance
In order to begin decarbonising your building and reducing energy use, you first have to know how energy efficient it is. There are a range of tools and techniques that you can apply to do this.
“You can't improve what you don't measure.” Peter Drucker
Energy Benchmarking
Remote Optimal™ Energy Benchmarking Calculator is an online tool that provides an estimate of your likely energy use (thermal energy and electricity) based on the type and size of your building, without having to set foot inside it. This can be compared with your energy bills to determine how energy-efficient your building is. If it indicates that your building is not efficient, and research shows that 75% of non-domestic buildings are not energy-efficient, then there are many options open to us to help you eliminate waste and reduce your energy demand.
ISO 52120 Survey
There is an International Standard for Building Automatic Control Systems (BACS) aka Building Energy Management Systems (BEMS), specifically designed to assess BACS/BEMS performance. It was created by the European (CEN TC 247) committee in 2006 under its Energy Performance of Building Directive, and has been independently verified by the Technical University of Dresden. It was awarded an ISO accreditation in 2021 and was incorporated into the latest UK Building Regulations Part L2 in 2022.
Like the energy efficiency rating on a refrigerator, the Standard rates BACS/BEMS systems into efficiency classes from A to D. Energy efficiency Class C is the baseline for buildings with a standard BACS/BEMS. Buildings in which the BACS/BEMS is not operating efficiently are rated as Class D and typically use 35%-50% more energy than those in Class C, depending on the property type.
Changing the control to a demand-led, rather than a time-based strategy, can result in an average energy reduction of between 18% - 39% when moving from a C to an A rating, depending on the building type.
Asset Audits
A review of all of the assets in the building can be carried out. In addition to plant such as boilers, air handling units (AHU) and chillers, the fabric of the building will be reviewed from the perspective of insulation, and potential locations for future behind-the-meter assets such as solar/PV panels.
AM&T
Automatic Monitoring & Targeting (AM&T) sub-metering systems are specifically designed to measure energy usage, record metered energy data, and analyse and report on energy consumption. BEI is SSE’s in-house Energy AM&T Solution.
By having a complete picture of your energy, carbon and other services, can make a huge difference. Engagement with an AM&T platform, such as SSE’s Business Energy Intelligence (BEI), alone can drive down carbon and costs by up to 10%. BEI, as with many AM&T systems, can be customised to give you an overview of not only your energy consumption but also water, EV, carbon, heat, and steam. It can record virtual, e.g. internally derived meters, and sub-metering. With this knowledge, you can make changes to cut your energy wastage, your bills and your carbon footprint.
Fiscal and Sub-Metering
Want to gain a deeper understanding of specific areas of your building or even specific assets? Whilst Fiscal meters can give an overall view of energy use on-site Sub-metering can provide invaluable information about energy use associated with specific high-energy demand plant or discrete areas of the building. Tennant billing is a particular area of interest which is covered by the Heat Metering and Billing Regulations 2014.
2 Eliminate Energy Waste
Once you know how and where energy is being used, you can start to eliminate areas of wasted energy. Research shows that these methods can save between 18% and 39%, depending on the type of building and installed systems.
Control Optimisation
An effective control strategy is one of the simplest and most cost-effective ways to eliminate waste. The correct use of timer controls can prevent energy from being consumed when it is not required, such as at night. Preventing heating and air conditioning from competing with each other, or preventing occupants from manually overriding set points, all of which can be result in wasted energy but, are easy fixes.
Sensors and Zoning
Building on from timers, to achieve an ISO 52120 Class A rating, it is necessary to apply a demand-driven strategy, whereby building systems, such as HVAC and lighting, are only used when a room or zone is occupied which may require additional sensors. In addition to commonly used outside air temperature sensors that are used to switch off heating when temperatures are high, occupancy sensors ensure that HVAC is only activated when rooms are occupied.
Many modern lighting systems use occupancy sensors to turn off lights in unoccupied rooms. By linking these systems to the BACS/BEMS, the Heating, ventilation and Air Conditioning (HVAC) can also be turned off, the underlying principle of the ISO 52120 standard. Rather than heating or cooling a large area uniformly, the addition of zones allows more selective control of the space with HVAC being used only in occupied zones.
Space Management
Through leveraging the insight from sensors and zoning, space management strategies can be developed, utilising data to inform conversations. For example, live data on water usage in showers can encourage people to use less, or monitoring occupancy levels in rooms can help to select the appropriately sized meeting room. Unified booking systems combined with space analytics data from lighting or dedicated sensors can help to deliver direct savings and support a wider behavioural change through internal campaigns.
Edge analytics
Edge analytics provides cost savings, increased efficiency, and improved decision-making through capturing and processing data instantly, enabling real-time data and decision-making on the premise or via remote access. Data can be harmonised from different systems and protocols to provide what is commonly referred to as a “single pane of glass”. It is achieved by displaying the data in a common, easy-to-read format.
Digital Twin
A digital twin is an electronic model of a building or a system within a building. It can be used to evaluate new strategies and control systems or solutions without disrupting the actual operation of the actual building. New plant and equipment can be “installed” digitally and its effectiveness evaluated without incurring capital costs on potentially inefficient solutions.
Digital Twins are also used by cloud-based AI control solutions to maximise energy savings in buildings. This is achieved by directly interfacing the AI with the on-site BACS/BEMS control systems to predict the building's energy needs and make pre-emptive adjustments to the controls. The effect is to maximise the benefit of casual and solar gains to the benefit of the building.
3 Reduce Site Demand
Unless you have an understanding of the energy efficiency of a building and have taken steps to reduce wastage, there is a very great risk of over-specifying plant when installing low-carbon solutions, and of putting a strain on electricity generation networks in densely populated areas with increased demand. reducing site demand through technical solutions reduces demand, energy cost and carbon emissions.
LED Lighting
Compared to fluorescent bulbs, LED lights are up to 80% more efficient because, unlike fluorescent lights, LED lights convert 95% of their energy into light and only 5% is wasted as heat; this is all while still using far less power to provide a strong and consistent light output at a lower wattage.
In addition, LEDs last 25 times longer than incandescent bulbs and up to 5 times longer than compact fluorescent lamps. Therefore, the facility team will not need to replace or maintain them as often, lowering overall maintenance costs.
Solar PV
The installation of solar or photovoltaic (PV) panels on your site means that, in addition to reducing cost and demand from the grid, your organisation can also get paid for excess electricity that you don’t use.
Battery Storage
Whilst renewable energy is carbon and cost-free after the cost of installation, the sun doesn’t always shine, the wind doesn't always blow and usage patterns don't always align with electricity generation. It is therefore necessary to use a form of electricity storage for these occasions to ensure continuity of supply and to reduce or mitigate electrical energy supplied by the grid. Batteries are the most reliable and commonly used storage method and are almost always used in conjunction with on-site renewable energy assets.
Low carbon CHP
Organisations with a requirement for high heat and high electricity demand in their manufacturing can reduce energy costs by up to 40% by switching to a Combined Heat and Power (CHP) systems. Whilst these are low carbon, rather than zero carbon, it may be seen as a step on the road towards net zero.
Demand-Side Flexibility
If your organisation is able to change when peak energy consumption is taken from the grid, it may benefit from demand-side flexibility. By reducing energy consumption at peak times, you can be rewarded with rebates or cheaper energy. The supplier or network will flag high demand periods and your system will reduce consumption accordingly. This type of control will need an integrated BACS/BEMS or other automaic control function to manage the process.
4 Decarbonise
Finally, all that remains is to decarbonise your energy
Heat Pumps
Unlike a boiler, where one unit of energy produces approximately one unit of heat, a heat pump delivers more heat than the energy supplied, typically up to three times the heat per unit of energy, and provided that the electricity is from on-site renewables or guaranteed 24/7 green electricity, the heat will be net zero carbon. There are different types of heat pumps from individual building or room-based units wand can be either air source or water source. The efficiency of air-sourced pumps will vary depending on the outside air temperature but are easy to install. Water-sourced and Ground-sourced heat pump efficiency is less dependent on the outside air temperature but is more complex and costly to install, but delivers on average, higher conversion efficiencies.
EV
A major source of carbon emissions in any organisation is transport so hybrid and all-electric vehicles represent an important path to decarbonisation.
Biomass
Organic material, such as wood chips, wood pellets or organic waste is burnt in a biomass boiler or furnace to produce heat. This can be used to provide heat and hot water and, whilst considered by some to be renewable, does still produce carbon dioxide and so is not net zero.
24/7 Green energy
It is essential at this stage in decarbonisation to ensure that the energy you purchase is 100%, 24/7 renewable electricity. All of SSE’s 100% renewable electricity is sourced from our own UK wind and hydro assets.
CPPAs
Corporate Power Purchase Agreements (CPPAs) are becoming an increasingly popular choice for companies wanting to reach net zero, as they offer up to 100% renewable power and much-needed addition to the grid. A CPPA is a long-term energy contract (typically between 10-15 years), between an electricity corporate consumer and a generator or developer of renewable power. Typically, a CPPA would be between one generator and one corporate off-taker, however, to allow flexibility and greater uptake, a portfolio arrangement for off-takers is now also an option.
