Archive for November, 2007

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.

Read Full Post »

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.

Read Full Post »

[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:


Read Full Post »

Rather than taking action to meet its commitments on renewable energy, Brown’s government is actively wriggling out of them. Even more pathetically, it’s trying to persuade other governments to soften their line, let the targets slide a bit, don’t worry so much about climate change. Why? Because in the view of Brown’s advisers (in which we might include the CBI), the targets just aren’t realistic. We’ve done all we can and it just won’t work.

Over a year ago, the Carbon Trust were sending up warning signals about the inefficiency of the Renewables Obligation (RO), the Government’s primary method for supporting renewable energy technology. They found that the RO is the worst of all possible options. Yep, of the methods they considered, the RO is the least practical and cost effective method of achieving renewables targets and carbon reduction. And the best? Feed in tariffs similar to those that sparked the PV boom in Germany and that you find in Italy, Spain, Greece, and other countries.

So why does the UK stick to a doomed policy? Probably a number of things: Government inertia, the nuclear lobby feverishly presenting themselves as a silver bullet, utilities hoping to maintain current margins. But little in the way of valid argument. There’s no excuse for shirking responsibility on this issue.

Read Full Post »

%d bloggers like this: