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Archive for the ‘sustainability’ Category

Greenpeace model town

Posted in biofuel, biomass, chp, climate change, energy, engineering, renewable energy, sustainability, utilities, tagged , , on February 19, 2008| Leave a Comment »

Greenpeace has created their version of a model town, stitching together examples from all over the UK. It’s a very cool combination of flash pages with lots of case studies, animations, and videos. Worth a wander.

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ground source heat pumps not so green

Posted in climate change, energy, engineering, heat pumps, renewable energy, sustainability, utilities, tagged , on February 11, 2008| 12 Comments »

At first glance, the green credentials of ground source heat pumps (GSHPs) look unquestionable: because you’re harvesting free heat from the ground, you can get up to four times more energy out of the system than you put into it. Sure, it runs on electricity, which is more carbon intensive than gas, but because of this favourable ratio of output-to-input (called the COP for coefficient of performance) the system should still emit less carbon than a gas boiler – in theory.

But the claimed benefits are reliant on incorrect assumptions. A new house will emit about the same carbon using a ground source heat pump as with a new gas boiler. Here’s why:

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emissions from CHP: the standard method is wrong

Posted in chp, climate change, Code for Sustainable Homes, energy, engineering, micro chp, renewable energy, sustainability, utilities, tagged , , , on February 4, 2008| 5 Comments »

[update March 20: I’ve looked further into how SAP treats CHP and written it up here. So while the method described below is being used elsewhere in the industry, the criticism doesn’t apply to SAP.] 

I’ve written on this topic before but maybe I didn’t succeed in making clear just how far off the mark the standard method is when estimating carbon emissions from CHP. Why does it matter? Here are some reasons:

  • Right now, big developers and the Housing Corp are assuming CHP can get them to level 4 under the Code for Sustainable Homes and this may not be true.
  • These emissions figures can determine whether or not a scheme gets planning permission or passes building regs.
  • The nascent micro-CHP industry (expected to be worth £2billion per year across Europe) is using this flawed method to back up its sustainability claims. Changing from a commonsense approach to the much more forgiving “standard” approach explains why the first Carbon Trust interim report on the micro-CHP field trails was so bleak and the second was so rosy.   

There’s a good chance that, if I’m right and the standard approach is flawed, when the CLG and BRE realise their mistake, the rules will change, leaving public and private sector developers and the micro-CHP industry with a very costly mess to clean up. (more…)

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Lies, Damn Lies and Statistics

Posted in climate change, Code for Sustainable Homes, energy, house, london, renewable energy, sustainability, uncategorized on January 21, 2008| 2 Comments »

I’ll keep this short to ensure that it does get posted, but I suspect that I could rant on this till closing time on Friday night. For a recent renewable energy assessment for a client I finally took the time to review the potential for air source heat pumps to deliver carbon reductions and I don’t like what I found. (more…)

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Off-site Renewables Update

Posted in Code for Sustainable Homes, energy, renewable energy, stamp duty exemption, sustainability on January 21, 2008| 1 Comment »

I posted extensively last year about the no off-site renewables issues enforced by the Treasury. There is little to report on this as yet, except that as a direct result of the blogging and discussions with Paul King by myself and Julian Brooks we were invited to join the Green Building Council Task Force to review the issues and report to Government.

Can’t say anything about progress, but it’s exciting stuff and we are pleased to be involved.

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new coal? you’re joking

Posted in climate change, energy, engineering, london, renewable energy, sustainability, utilities, tagged , , , on January 4, 2008| 2 Comments »

If the government backs up Medway Council’s inane decision to allow a new coal fired power station in Kent, I’m going to pack it in. The superfluous runway at Heathrow is bad enough, but new coal? The squabbling we all do over saving a tonne of CO2 here and a tonne of CO2 there – and Gordon Brown is going to give us the first new coal plant in 30 years?

Seriously, I’m going to put my feet up, club a baby seal, hit the hash pipe, and join the national guard. Who knows, I might even become the next prime minister.

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without action, the plan for zero carbon homes by 2016 will fail

Posted in architecture, chp, climate change, Code for Sustainable Homes, energy, engineering, micro chp, renewable energy, stamp duty exemption, sustainability, utilities, tagged , , on January 3, 2008| 5 Comments »

The requirement for all homes to be zero carbon by 2016 is going to fail unless we take action now. In particular, a set of interim requirements under the Code for Sustainable Homes must be imposed on private housebuilders. In addition, the Code must allow more flexibility in how zero carbon is achieved.

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Carbon Trust micro CHP interim report finally out

Posted in chp, climate change, Code for Sustainable Homes, energy, engineering, micro chp, stamp duty exemption, sustainability, utilities, tagged , , on November 27, 2007| 3 Comments »

Much later than planned, but here it is. In summary, micro-CHP saves 5% to 10% of carbon in large inefficient houses but only if you use a flawed methodology and give yourself extra-extra credit for displacing grid electricity. A few of the key findings:

  • The trial has demonstrated that the carbon and cost savings from Micro-CHP are generally better for buildings where they can operate for long and consistent heating periods.
  • In small commercial applications, the field trial has shown that Micro-CHP systems can provide typical carbon savings of 15% to 20% when installed as the lead boiler in appropriate environments.
  • The domestic Micro-CHP systems monitored in the trial have the potential to provide typical carbon savings of 5% to 10% for older, larger houses with high and consistent heat demands (over 20,000kWh/yr).

So since the last report, the Carbon Trust has toed the industry line that the 0.568 figure should be used.

There’s some very interesting output from the boiler field trials in the report as well. In particular, the boilers they’re monitoring are generally performing 4% to 5% below their SEDBUK rating.

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confused about policy changes? Phil’s crib sheet is the answer

Posted in architecture, biofuel, biomass, chp, climate change, Code for Sustainable Homes, energy, engineering, london, micro chp, other stuff, renewable energy, stamp duty exemption, sustainability on November 22, 2007| 2 Comments »

Phil Clark and Fulcrum have put together a fantastic list of upcoming proposed policy changes relevant to construction. Though I couldn’t find the attached doc he talks about: Fulcrum’s housing chart – where is it? Phil’s promised to keep the list updated as more information is released.

That’s just saved me a pile of research this morning, Phil. Thanks.

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SAP and CHP – a dangerous muddle?

Posted in biomass, chp, climate change, Code for Sustainable Homes, energy, engineering, london, micro chp, renewable energy, sustainability, utilities, tagged , , , on November 19, 2007| 6 Comments »

[Update March 20 – while it’s true that SAP gives misleadingly high emissions savings for CHP, I got the methodology wrong. See an updated post here. Points 3 and 4 below are still valid.] 

The SAP results for dwellings using CHP are badly skewed. This may cause large developers to formulate strategies for meeting the Code for Sustainable Homes which fall well short of the targets.

Doing some research this week, I read the Housing Corporation’s report on the estimated costs of meeting various levels of the Code for Sustainable Homes. It’s an interesting document, but at a certain point I was confused by their claim that you can meet the carbon reductions required by code level 4 (i.e. a 44% reduction in DER relative to TER) just by using gas CHP. In fact, when I looked closer I found that in some cases, they were claiming an emissions reduction of over 50% – an extremely high figure. Something closer to 10 and 15% is much more reasonable, unless you want to get Orchardesque.

The source of these wild claims is the Government’s Standard Assessment Procedure for dwellings – SAP 2005. As hinted at in the CHP debate running in the BSJ over the summer, SAP does some funny things when it comes to CHP. Have a closer look at the SAP worksheets and you find that SAP:

(more…)

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