Wednesday, November 21, 2007

Eco Bollocks Award: Terminal 5

News has reached me of the fantastic efforts BAA have been making to help preserve the environment at Heathrow’s Terminal 5, due to open in March 2008. It’s taken the sustainable approach to building very seriously.

Terminal 5, which is so big that it is actually three terminals, designated 5A, 5B and 5C, will use two separate water systems, one for drinking and the other for toilet flushing and irrigation. Water for the second system will be sourced from an in-house rainwater harvesting system, topped up with a borehole supply. They hope to be able to collect and re-use 85% of the rain falling on the terminal catchment area.

In addition, all the bathrooms will have dual flush toilets, and the taps will have on-off sensors combined with aerated flow. BAA trills that it aims to reduce the demand from the public water supply by up to 70%.

Come on guys, stop trilling. It’s an airport.

Tuesday, November 20, 2007

Is Hydro the only acceptable sorm of generation

It has happened to me again. I was asked to help a client who wanted to install a solar PV system to generate their own electricity. No urgent need for it other than the clients "want to do their bit for the environment". Once I explained the probable costs involved, shockingly they quickly went off the idea. I suggested either wind or water but these did not meet with too much enthusiasm either. Turns out they are active in a protest group trying to stop a wind farm being built on the hill opposite their front door and having their own wind turbine did not sit too well. They have plenty of wind (which is why they are building the wind farm opposite) and it was possible to see the cogs turning - was it possible to do it and avoid being hung by their mates?

A bit of further investigation dug out that uncle, who owns the farm next door, has "a bit of a stream. Probably too small". A swift survey showed that the stream has the potential to support a 2kw turbine - enough for 3 houses. The clients, their uncle and the guy next door are now looking to club together to put the turbine in, and have free electricity for the next 20 years.

Every time I do a seminar I tell the audience to check their stream, however small it may seem. But they never do. They always think I don't mean them because their stream really is too small. But I do, and it probably isn't.

Wednesday, November 14, 2007

Are flourescent lamps efficient

I have been asked a few times lately if it is better to leave fluorescent lights switched on as they use so much energy to start up? And, are fluorescent tubes (and by extension compact fluorescent lamps – low energy lamps)really efficient?

Fluorescent lamps, be they standard strip lights or compact fluorescents, use gas discharge technology and it takes 3 to 15 minutes (depending on the type of lamp) to vapourise the gas, get up to temperature and reach full luminosity. It takes no extra power to do this, just a bit of time. So the argument for leaving lights on relates to time rather than energy. If you are popping in and out of a room all day you probably want to leave it on. Otherwise turn it off. To put it simply a light left on uses more energy than a light turned off.

Fluorescents are more efficient than incandescent lamps by a factor of about 4. To be technical, they produce around 90 lumens per watt compared to about 20 watts for incandescents (these figures vary with the type of lamp but are broadly accurate). It is why incandescents have been banned in Australia and are being phased out here. They give a different quality of light, which is what leads to the idea that they are not as bright and therefore you need more of them. My Grandma said the same when her gas lamps were replaced with nasty electric bulbs, but she got over it.

While we are on the subject, I have also been asked if fluorescents have nasty chemicals and gases in them, and the answer is yes! They have 5mg of mercury in a 40w tube. It is a tiny amount, less than the size of a pin head – but poisonous nonetheless. They also have a phosphor coating to the glass (which is what fluoresces and produces the light) which is not pleasant, but not poisonous. The gas in the tube is usually argon which is inert and harmless.

There are new lamps about to hit the market that use xenon gas – no mercury and no phosphors – which are even more efficient. These will produce over 120 lumens per watt.

Monday, November 12, 2007

Pumping heat

Spent the weekend dispensing bon-mots and advice in Harrogate at the Homebuilding & Renovating show, one of six held throughout the UK each year. This year I have been delivering a short lecture on sustainable homebuilding and it has sparked some interesting questions and comments from the audience. However this Sunday it all got a little fiery when someone asked about the difference between air source and ground source heat pumps and whether either made sense for his building project. Rather like the output from these heat pumps, my response was just a little lukewarm.

What I specifically said was that heat pumps don’t make much sense if mains gas is available but that there should be a reasonable payback against oil. “You are doing well if you get a Coefficient of Performance of more than 3.0,” I said. I have been consistently saying this for some time now and at least one heat pump manufacturer, Kensa, seem happy to agree with me.

But up stands this man in the audience who said that heat pumps could now deliver over 6.0 — i.e. twice as much heat output for the power input. Before I could stop myself, I blurted out “That’s rubbish.” It obviously hit a nerve, because he stood up and started getting shirty with me. “What do I know about it” sort of stuff. I have no idea who he was but can only guess he was working for one of the many heat pump suppliers exhibiting at the show.

This made me go all defensive and I started quoting a couple of studies back at him that showed that heat pumps often don’t deliver what manufacturers claim. If only to prove that I do know something about it, if not exactly ranking at world expert status. This of course made matters worse and our man turns around and walks out of the seminar theatre in an act of brazen defiance.

You could have heard a pin drop. Normally, these events pass by without any rancour at all and everything is sweetness and light from start to finish. Here there was a definite feeling that someone thought I that I was being out of order and should be upbraided.

What I think this shows is that the heat pump market is maturing fast, perhaps a little too fast. By all means consider the merits of using a heat pump, but don’t get sucked in by the hype, and beware claims of extraordinary efficiencies achieved.

Thursday, November 01, 2007

How sustainable are the sustainable suppliers?

It occurred to me the other day that my local builder’s merchant is selling a range of sustainable and eco-friendlier materials in an entirely unsustainable and non-eco friendly shed. At first this seems a bit of an anomaly. If he is going to pretend to be eco-friendly then he should at least make some effort to make the shed LOOK eco-friendly. If we are to be completely right-on then everything up to and including the gas that was used to cook the breakfast for the driver of the lorry that delivers our sheep wool insulation should be from a sustainable source. If not it just adds to the carbon footprint and negates the whole point of trying to build sustainably.

But life ain’t like that. The builder’s merchant operates from a building that was erected some years ago and he is not going to change that. Should I bleat about the building not being sustainable or be grateful that the scales have fallen and he is seeing that there is a market for sustainable materials?

Take my own case. As a sustainability consultant it might be expected that everything about me is ecologically sound. The truth is that I run a oil-fired boiler to heat my house. It is fast approaching the end of its useful life and that will be the time to switch to something more sustainable – possibly wood pellet or a log-burning stove with back boiler I have just found at less than £1,500.

Changing before now would mean throwing away a perfectly good machine with life still in it and adding to the carbon overhead with a new piece of kit.

Similarly, I drive a beat-up old car. Some say it is because I am too mean to buy a new one. I say it is because the carbon overhead of a new car is too big to think about and an old car has no embodied CO2 left in it.

So maybe the answer is - all we can do is what we can do. There is a clear and growing movement to building sustainably. It may still be slow movement, but if we do what we can it will get quicker.