Participating in a remote meeting for one hour generates the same emissions as driving just 580 metres. That was my conclusion when someone asked me what were the relative environmental impacts of remote and in-person meetings. Here’s how I approached the question…

We’ll start by estimating the energy intensity of data communications. We know from an Ofcom study that in 2018 the average UK fixed broadband connection was using 240 GB per month, and if we assume £30 per month was the typical tariff, that works out at £0.125 per GB. Now let’s assume that this price covers the operator’s costs and that, pessimistically, 50% of that cost is for electricity which they were buying at (say) £0.15 per kWh. This implies an energy intensity of £0.125 x 50% / £0.15 = 0.42 kWh per GB.

But how much data is there in a remote meeting? Fortunately we can get a good direct estimate from the sizes of session recordings. My two-hour on-line events have typically resulted in recordings of around 500 MB, which must be the equivalent of all the data broadcast to each participant (as a sense check, that’s 250 megabytes per hour, or about 0.55 megabits per second bandwidth). To be conservative let’s add as much again for return traffic from each participant, giving a total of 500 MB (0.5 GB) per hour per participant.

At 0.42 kWh per GB that implies 0.5 x 0.42 = 0.21 kWh per participant-hour.

This only accounts for the communications element. To be fair we need to add the cost of central data processing and to do that I’m firstly going to guess that the server consumes 100 watts for the purposes of processing the meeting. Secondly I’ll assume that the meeting has four participants. That would imply 0.025 kWh per participant-hour, bringing the total to 0.235. The fact that it’s a small correction means the conclusions aren’t very sensitive to the number of participants. If we assume a grid carbon intensity of 0.3 kgCO2/kWh we arrive at emissions of 0.235 x 0.3 = 0.07 kgCO2 per participant-hour.

How does that final figure compare with car travel to the meeting? The average car in the UK emits about 0.12 kgCO2 per km, so attending an hour-long remote meeting equates, in emissions terms, to 0.07/0.12 = 0.58 km of car travel. Case closed.

–o–

This article first appeared in the Energy Management Register bulletin on 12 July, 2021. Subscriptions are free of charge: please follow this link. You can unsubscribe again from any issue.

Submitted by the Association of Midlands Energy Professionals 

The Association of Midlands Energy Professionals (MEP) invites you to join us for our FOURTH annual event for energy assessors and other energy professionals, under the title: “Gearing up for Change”.

With BREXIT behind us and the TRUSTMARK now up and running, MEES is having a significant impact on the type of work we do. WHOLE HOUSE RETROFIT, PAS2038, and THE FUTURE HOMES STANDARD are becoming even bigger drivers as the gathering momentum surrounding climate change is set to make 2021 a year of real involvement and opportunity for us in changing the behaviours of our customers.

We will be on the front line, giving advice and promoting change to UK consumers.

• We will hear from a selection of keynote speakers who will be bringing us up to date on all the above and more. The speakers will include the leading lights from the Retrofit Academy, TrustMark, and the Accreditation Bodies.
• There will be a selection of workshops to participate in. These workshops will give you tasters of the ‘state of art’ tools and techniques.
• There will be a “BBC Question Time” style session where you can put questions to a panel of experts including the Accredited Bodies

This will be a full and informative day which will provide 5 hours CPD plus valuable networking with fellow assessors and other professionals.

• Date: Wednesday 29 September 2021 (10.00 to 16.30)
• Venue: SSDC HQ, Wolverhampton Rd, Codsall WV8 1PX.

The charge for the event is £50 for MEP members, and £60 for non-members. Subscribers to the Energy Management Register newsletter can join at MEP members’ rates using their customary discount code. There will be a £10 early bird discount for those booking before the end of August 2021.  Booking forms are available from

Background

This story concerns a commercial data centre, and specifically its cooling system. The players are: (a) clients whose servers are housed in the centre; (b) a facilities operations team responsible for maintaining conditions in the server hall; and (c) a sustainability manager whose duty is to ensure that energy consumption is minimised. There is a service level agreement in place and the facilities team are contractually obliged to report regularly on the server-room temperature.

The sustainability manager regularly reviews consumption against weather-related targets, in order to detect excessive consumption. Specifically he uses the relationship between chiller electricity consumption and cooling degree days, as illustrated in Figure 1:

The story

At the end of September 2020,  weekly consumption began to deviate from expected values. The first few weeks of abnormal performance are highlighted in Figure 2:

Figure 3 is a control chart which shows that the deviation is not only statistically significant compared with anything previously observed, but it’s also persistent:

At this point the sustainability manager challenged the operations team for an explanation. The problem turned out to be the location of the temperature sensor that was used for their routine service-level reports. It was not registering the actual air temperature at equipment level, but a higher value. To get around this problem the ops team had started overcooling the building to ensure that their temperature reports were within the specification.

The problem was ultimately rectified by relocating the sensor used for reporting, and reverting to the correct space temperature set point. Figure 4 shows how consumption then came back within its normal control limits:

Thanks to Dave Covell of Clearlead Consulting for this picture of a magnet on a gas line which had grabbed hold of his steel-capped safety shoe as he was passing. We know magnets are useless, but it’s a bit rich that they make safety shoes hazardous…

Delighted to have Jan Rosenow opening our afternoon conference “Decarbonising heating – practical realities” on 8 July. Focussing on the non-domestic market, our speakers will discuss real-life experience with biomass boilers and heat-pump systems, and draw lessons for future projects. We’ll also hear from an expert on hydrogen about how that might be introduced into the national heating-fuel mix, and we have allowed plenty of time for questions from the audience.

Full details are at https://vesma.com/z200

WHEN thinking about possible energy-saving projects, you might ask yourself how radical you want them to be. There’s a spectrum from the relatively easy to the costly and disruptive. Readers may have their own views on this but I think the spectrum runs like this:

1. Make sure control setpoints and timings are correct. This is generally the cheapest and least disruptive measure one can take;
2. Enhance the control strategies. For example introduce floating setpoints on chilled water circuits, optimum start in place of fixed timers, or variable-speed control of motor-driven equipment;
3. Implement loss-reducing modifications. Examples here include zone isolation valves in a compressed-air network or thermal insulation on hot pipework;
4. Improve component efficiency. The classic case here is lighting technology (which may be cost-effective in its own right) but think also about things such as the introduction of higher-efficiency or better-sized motors (which may only be economical when replacement is necessary for other reasons);
5. Improve process layouts and integration. Here I am thinking primarily about opportunities for waste heat recovery, but there are other special cases where part-processed materials may gain or lose moisture or heat while in transit between stages to the detriment of overall energy efficiency. And finally the nuclear option:
6. Retire buildings or process plant in favour of more energy efficient replacements