Building Measurement and Verification in Lockdown
Building Services Engineering, Maintenance Engineering, EMEA, Sports & Leisure, Retail, Environmental Management, United Kingdom
Mark Gifford, Technical Services Manager with global building performance specialist IES, considers the implications of Zero Running Buildings for Energy Services and FM teams during COVID-19.
The last few weeks and months have brought unrecognisable changes to society. The announcement of shutdowns and lockdowns by Governments around the world has seen the unprecedented closure of cities across the globe and a freeze on life as we knew it.
At a building level, this has resulted in the complete closure of a vast number of buildings of all functions and sizes. The range of building types which have been affected seems endless; schools, offices, shopping malls, stadiums, hotels, factories, cultural venues... the list goes on. Entire university campuses have been shut down and many thriving city centres are empty. In this piece, I wanted to explore how this unprecedented lockdown is panning out from an Energy Services perspective.
As the majority of us are in isolation at home, a number of Facilities Managers (FMs) are still out there silently working behind the scenes, taking their buildings through a series of shutdown procedures and/or functional adjustments. This could be as simple as turning off non-essential HVAC equipment through the adjustment of BMS time-clocks on Air Handling Units (AHUs) for example, but for other more critical buildings out there such as data centres and scientific laboratories the FM's mission may involve the maintenance of more critical equipment.
A number of active FM clients I have spoken to in recent weeks have been very busy supporting their respective organisations in the implementation of the necessary building services adjustments which are needed from an operational perspective. This could involve closing and making secure/safe 100+ schools within a portfolio or, in the healthcare profession, it could involve the re-purposing of entire facilities (the transformation of the Excel London events venue to the new NHS Nightingale hospital is a perfect example). Needless to say that major re-purposing of facilities on this scale does not happen on its own and there are a number of hidden FM heroes out there playing their part.
As the initial surge of building shutdowns and re-purposing has passed, however, some FMs are finding themselves alone in near empty facilities. If smart meter power traces are the 'heart-monitors' of our buildings then they should be able to tell us a lot during this unprecedented period of shutdown, so I've been doing some investigation.
As an example, I have included a plot from a utility grade electricity trace from a medium sized UK retail/leisure/cultural facility below. The trace runs from 1st Jan 2019 until 15th April 2020. The green area to the right of the chart illustrates just how much the electricity trace has dropped off in recent weeks.
Zooming in on the most recent range (Fig 1), it is possible to conduct a comparison of the 2019 electricity trace vs the current 2020 trace from the range 17th March - 15th April. The red line below indicates a 'business-as-usual' approach in the normal 2019 operating year. The green line however illustrates the implementation of shutdown procedures from 25th March onwards. Initially the energy reduction looks vast but as always in the field of data visualisation and analytics it is worth exploring further to validate the full extent of this perceived reduction.
First we convert the half-hourly data to a cumulative sum (CUSUM - see Fig 2). In this way we can zero-base the starting point of both the 2019 and 2020 calendar years and compare against each other. It can be seen that in Jan-Feb the green 2020 line closely tracked the red 2019 CUSUM line. This would be expected in a normal operational FM environment, with a pro-active Energy/FM team who are making reasonable efforts to obtain year-on-year savings within their facility in-line with Corporate Social Responsibility (CSR) and evolving policy targets. However, from mid-March a distinct change in the slope of the green CUSUM ramp can be seen as it flattens out. This corresponds to the same time period when implementation of shutdown procedures began.
None of us know how long the current shutdown might last but for purposes of this analysis and simplicity in my messaging let's assume that the shutdown lasts for the remainder of the 2020 calendar year (Fig 3). Assuming no significant change to the building's electrical power profile it is possible to extrapolate the CUSUM ramp for the remainder of the year using linear regression. This would give us a reasonable approximation of the likely total 2020 energy use. In a normal 'business-as-usual' 2019 year this particular facility uses somewhere close to 2,500,000 kWh. In its 'shutdown' mode of operation we predict the annual 2020 electricity consumption to be close to 800,000 kWh.
Now let's consider these numbers in a bit more detail. Assuming a £0.12/kWh per unit electricity rate puts the annual electricity cost in the £300k per year range (Fig 4). Using this same rate on the 2020 forecast it is closer to a £100k per year cost. The calculations are fairly rough (excluding transmission, distribution and other supply side charges) but they give a reasonable approximation. In this way we have evaluated an annual cost reduction of nearly £200k which is close to a 66% reduction in electricity use when expressed as a percentage.
Looking further still we can analyse the building's baseload in both the 'business-as-usual' and 'shutdown' modes of operation (Fig 5). The overnight 2019 baseload was in the 70-80kWh range. After implementation of the 2020 shutdown procedures the baseload is closer to the 30-40kWh range. Again, significant numbers indicating that the building's baseload has been reduced by nearly 50%.
In this short workflow we have completed a conceptual Measurement & Verification analysis (Fig 6). The numbers on the surface appear good, a 66% reduction in total annual energy consumption and nearly a 50% reduction in baseload achieved as a direct result of targeted shutdown procedures, but the story doesn't end here.
Final Thoughts & Discussion
- The organisation in question has completely lost its 2020 operating revenue which was mainly based on occupancy footfall, ticket sales and associated retail sales. Basic economics allow them to pay the £300k / yr energy bill quite easily... if energy costs get too high they simply increase ticket prices and tenant rates/rents to offset. The £100k / yr energy bill however is a major challenge to cover in the complete loss of 2020 operating revenue.
- As such any form of backlog maintenance budget which the FM had in place (that rainy-day fund!) will now most likely be stripped and re-distributed to cover the immediate energy and operating revenue crisis. In doing so, when the building does become fully functional again and comes back online, the backlog maintenance fund may be left empty. Any energy conservation projects that had been pending will now be left in a period of uncertainty. For ageing HVAC equipment such as boilers, chillers, AHUs, pumps, etc. this is not good news. Instead of taking ownership of that new and shiny energy efficient equipment that was promised for the 2020-2030 decade, a lot of building FMs may have to make-do with their ageing assets for a period of time yet.
- Where does the above dilemma leave us in pursuit of 2030+ climate targets? How does policy evolve and adapt in light of the current crisis? The global Energy Services Contracting (or ESCo) market could prove to be more valuable than ever for cash-strapped FMs as we finally do come out of the current pandemic crisis, but public procurement rules on 'borrowing & lending' of private money backed by guaranteed savings (many based on hedge fund models) are still limiting the ESCo model from making the in-roads in the market which are needed.
- Needless to say that currently active ESCo Contracts based around 8-10 year contract terms and mid-way through will need very careful policing at the moment to ensure that those achieved 'guaranteed' savings are in fact a result of the installed Energy Conservation Measure (ECM) itself and not disguised as a bi-product of the functional building shutdown. Given the extent of the global economic crisis the very state of the energy fund itself may not be in great shape.
- From a Design-side perspective we can also learn from the above example. It's never been easier to brandish around predicted % cost savings for energy cost savings in built environment projects. 10-15% from new LED lighting, 20% for these new VSD fans/pumps, 30% for a new turbo-core Chiller, 50%+ combined savings, etc! The above documented M&V example is testament to the true nature of the Energy Services industry and the fact that achieving sustainable energy savings with good ROI in the built environment is not an easy process and should be left to qualified professionals backed by accurate modelling.
- If it takes a complete shutdown of a facility and the total loss of its primary function as a building in order to achieve a 66% energy reduction then you may want to reconsider some of the inaccurate engineering advice which may be out there and some of those 'guaranteed savings' promises which may have been made as part of pending ESCo contract works. Are they really that achievable?
- On a more positive note current energy-saving opportunities do exist right now. It could be the perfect time to conduct deep-dive analytics activities within shutdown facilities whilst they lie unoccupied with a skeleton FM team in place. There's never been a better time for over-worked FMs who are normally used to daily 'fire-fighting' to get that long awaited look at some of those historical energy trends and sub-metering records which have been gathering dust.
- It may also be a good time to consider the installation of portable and temporary CT power loggers and rotate for 2-3 day cycles on various Distribution Boards within electrical switch rooms. Small scale and low cost steps such as these could allow operational intelligence to be gathered within facilities that's been impossible until now for busy FM teams.
- A final consideration is how 'connected' is your building and how easy it to access your BMS and Energy data remotely? As we are all confined to our home environments, that up-front investment from the pro-active FM teams out there with remote connectivity already in-place is paying dividends. More traditional and archaic FM teams with zero connectivity to their building systems will have been wishing they had acted sooner as they are now left picking up the pieces and dealing with the magnitude of the crisis they currently face.
It will be interesting to see how the Energy Services industry continues to adapt as we move through this strange period of time.