February 11, 2008 by Casey Cole
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:
Continue Reading »
Posted in climate change, energy, engineering, heat pumps, renewable energy, sustainability, utilities | Tagged ground source heat pump, GSHP | 12 Comments »
February 4, 2008 by Casey Cole
[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:
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. Continue Reading »
Posted in chp, climate change, Code for Sustainable Homes, energy, engineering, micro chp, renewable energy, sustainability, utilities | Tagged Brian Anderson, iSBEM, SAP, SBEM | 5 Comments »
January 21, 2008 by nickdevlin
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. Continue Reading »
Posted in climate change, Code for Sustainable Homes, energy, house, london, renewable energy, sustainability, uncategorized | 2 Comments »
January 21, 2008 by nickdevlin
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.
Posted in Code for Sustainable Homes, energy, renewable energy, stamp duty exemption, sustainability | 1 Comment »
January 4, 2008 by Casey Cole
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.
Posted in climate change, energy, engineering, london, renewable energy, sustainability, utilities | Tagged clean coal, E.On UK, Kingsnorth, Medway Council | 2 Comments »
January 3, 2008 by Casey Cole
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.
Continue Reading »
Posted in architecture, chp, climate change, Code for Sustainable Homes, energy, engineering, micro chp, renewable energy, stamp duty exemption, sustainability, utilities | Tagged Barratt Homes, House Builders Federation, UKGBC | 5 Comments »
November 27, 2007 by Casey Cole
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.
Posted in chp, climate change, Code for Sustainable Homes, energy, engineering, micro chp, stamp duty exemption, sustainability, utilities | Tagged BRE, Brian Anderson, SAP | 3 Comments »
November 22, 2007 by Casey Cole
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.
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 | 2 Comments »
November 19, 2007 by Casey Cole
[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:
Continue Reading »
Posted in biomass, chp, climate change, Code for Sustainable Homes, energy, engineering, london, micro chp, renewable energy, sustainability, utilities | Tagged BRE, Brian Anderson, Housing Corporation, SAP | 6 Comments »
November 2, 2007 by Casey Cole
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.
Posted in climate change, energy, engineering, renewable energy, sustainability, utilities | 1 Comment »
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