Phil Clark at Zero Champion sent a request under the Freedom of Information Act for figures on CO2 emissions for Portcullis House, the office building for Members of Parliament across the road from Big Ben. When he received a response he wasn’t sure if performance was good or bad. It’s bad:
Ignoring the figures for 2006-7 given in Phil’s blog entry because of uncertainty about the source of electricity (discussed below), I looked at 2005-6. For that year, Portcullis House used 7,230,601kWh of energy and emitted 630.2 tonnes of carbon. They don’t specify a breakdown for fossil fuels and electricity.
So doing a bit of maths, the figures look like this (see end of entry for details on the calculations):
total kWh | kgCO2/kWh | kgCO2 | kWh/m2 | Econ19 standard aircon office | Arup target | |
electricity | 4,035,284 | 0.422 | 1,702,889.7 | 194.8 | 128 | 39 |
gas | 3,195,317 | 0.19 | 607,110.3 | 154.3 | 97 | 51 |
I added in two sets of figures for comparison:
- Econ19: this has been the standard reference for energy consumption in offices in the UK for the last 18 years. It’s badly out of date and the figures are too high (worse luck for Portcullis House), but it’s all we have. It’s based on measured figures from the 1990’s and the targets I used were for “good practice” in a standard air-conditioned office.
- Original Arups target at design stage – this comes from the BSJ article quoted by Phil, but the numbers look really low so I may have misinterpreted the article.
So the building uses 50% more electricity and 60% more gas than a crappy 1990’s air conditioned office block. And 500% more electricity and 300% more gas than the Arups predictions.
But this isn’t a standard air-conditioned building! Wavy precast concrete ceilings and high admittance surfaces allow cooling using thermal mass; borehole cooling; displacement ventilation; heat recovery via thermal wheels; light shelves; lighting that dims according to available daylight, and so on. This is state of the art green and it’s gone wrong somehow. Is it the IT power loads? Is it the select committee rooms that double as television studios? I don’t know.
According to the Parliamentary Answer:
All electricity consumed on the parliamentary estate has come from renewable sources since 1 February 2007, therefore there will be no carbon emissions resulting from electricity consumption in future. This has contributed to the reduction in carbon emissions for the year 2006-07.
The comment in the P.A. about electricity being carbon neutral because it comes from renewables is a slippery one. If they mean they’re using a green tariff, it’s definitely not carbon neutral electricity. Even on those tariffs that buy one unit of renewable energy for every unit they sell, typically less than 10% of the ROCs are retired. While the end user might consume a unit of renewable electricity, the corresponding ROCs are sold to other electricity suppliers who might use them to prove the credentials of their own green tariffs. It’s double counting. So at best that might be 50% carbon neutral. But anyway, the GLA won’t let developers claim green tariffs as carbon savings so why should Portcullis House get away with it?
Whichever way you cut these figures, it’s not good. We need to figure out what went wrong.
Here’s how I got to the above figures. First, convert the carbon to CO2 (multiply by 44 and divide by 12) to get 2310.7 tonnes. So now we know how many kWh they used in total and what their total CO2 emissions were. Using carbon intensities for mains gas (0.19kgCO2/kWh) and mains electricity (0.422kgCO2/kWh) and a little excel magic, we get a solution for annual electricity and gas consumption. The total floor area you get by working backwards from the figures in the P.A. (7,230,601kWh divided by 332 kWh/m2 gets 20,712m2).
Somewhat scary. Could it be that far from asking CIBSE to do a RIBA and give people a Building Services engineer for a few hours, we should line all architects, BSE’s and environmental scientists up against a wall and shoot them with recycled bullets?
I remeber the BRE Office of the Future performing equally badly. Is it just big buildings in general, grand schemes and the like that are beyond the ken of anyone.
As EF Schumacher said, ‘Small is beautiful’. Maybe its our only hope
I’d love to know where the predicted figures come from? I’m a big advocate of BIM and running a model with data for a year’s typical model should pop out realistic answers. The problem comes when the target has been set prior to the model and then it is ‘adjusted’ to fit the target. Then when the building goes into the ‘real’ world and humans get their hands on it, the numbers don’t quite match. It’s easy to sit at a screen and kid yourself that everyone will turn their screens off at lunchtime when they pop out for an hour, but if that isn’t what you do yourself in real life, then what’s the consequences?
That said, the Portcullis numbers are quite disturbing. Even with the erratic working hours of MP’s, (almost 24 hour operation I understand), they should be better than that…
How do REGO’s fit into the green tariff issue? If one is signed up to a REGO, rather than a plain green tariif, shall we award them points for it?
The building benchmark for electricity fails to correctly identify the electrical load that modern server rooms consume. I suspect that all those heating and cooling systems are constantly fighting each other 24/7 also!
Hi Casey,
Still over here in blighty?
If you’re interested I’ve just found some numbers on another Hopkins building for the Wellcome Trust – see my post. I stress this is not a one-man campaign I’m waging against the efficiency (or otherwise) of the Hopkins output. In actual fact I’m a fan of his buildings from a design perspective.
Keep up the good work on the blog.
Phil
Thanks for the tip, Phil. I’ve just got back from a mountaineering course in Wales. Now all I need to do is set aside a few hours to catch up on the blog!!
[…] sustainability, london, architecture, energy Following our recent blog conversation about the energy consumption of Portcullis House, Phil at the Sustainability Blog has pointed out the recently published consumption figures for […]