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Love them or hate them, liquid biofuels are increasingly being put forward as a renewable fuel for CHP. Currently they’re eligible for ROCs and so appear to be considered renewable by BERR and OFGEM.
But when I spoke to the SAP team at BRE, not only did they confirm that liquid biofuels aren’t considered under SAP, they also said that “because of mounting doubts over the extent of emissions from biofuels”, you have to use the emissions factor for oil when carrying out your SAP calcs. Did they expect the treatment of biofuels to change for the 2010 review of SAP? Adamantly, they did not.
Then I called the BREEAM helpline. They told me that liquid biofuels also aren’t considered under the Code for Sustainable Homes. So no help in scoring points under ENE1 or ENE7.
So liquid biofuel CHP is eligible for ROCs but will do little for your Part L and Code requirements. Without achieving these requirements, the case for biofuel CHP for new buildings is severely undermined. Obviously this situation could change. With CLG on the lookout for ways to meet the 2016 zero carbon homes target, there might be considerable pressure applied in favour of making biofuel renewable under SAP. But for now the official line is that biofuels are not a solution for carbon reduction in new build.
If you build to Passivhaus standard, there’s no point in putting in a wet heating system. In fact, the key to the economics of Passivhaus design is that a conventional heating system is rendered redundant: you’re supposed to use the resulting savings to help fund the efficiency measures. Instead of a boiler and radiators you might only need a small electric heating coil in your mechanical ventilation system.
Level 6 of the Code for Sustainable Homes is modelled on the Passivhaus standard. As a result, until the Code changes, you’re likely to see more and more developers trying to move towards electric heating systems. You might argue that given the quantities of electricity we’re talking about (15 kWh/m2.yr), even if you source the electricity from the grid, it’s no carbon catastrophe. Unless you consider the bigger picture.
Making new buildings zero carbon is an excellent requirement, but by focusing our efforts (and a hell of a lot of money) on ratcheting down the heat demand from new buildings, we throw away the huge opportunity of using new developments to slash emissions from existing stock. Read the rest of this entry »
My first day back in London and I’ve spent the morning schmoozing at a publication launch just off the Mall. Five minutes out of my cattle stall and I’m already moving and shaking. It was an event to publicise the TCPA’s new document, Community Energy: Urban Planning for a Low Carbon Future, and it attracted quite a crowd including MPs Nick Hurd and Keith Hill.
During the presentations and panel discussion, most people in the room seemed to feel that local authorities have the pivotal role to play in the creation of low carbon distributed energy networks. I totally agree, but I think we were missing part of the picture.
Today Lord Turner’s panel met for the first time to discuss a concrete strategy for fufilling the UK’s commitment to reducing emissions by 60% by 2050 (and to consider upping the target to 80%). With around a third of UK emissions coming from housing, this sector will inevitably play a key role in their strategy. You might think we could rely on the Code for Sustainable Homes to get us there - after all, if all homes from 2016 are Code level 6 then there will be no net emissions from new housing. But unfortunately new homes are only a small part of the problem.
The graph below illustrates the predicted emissions from the housing sector by age of housing stock for the period 2002 to 2050. It shows that the overwhelming proportion of emissions will continue to come from houses built before 2002. The dotted lines represent the emissions from all housing required to achieve a 60% and 80% reduction in emissions vs 1990 levels. Emissions from each band decreases over time due to demolition.
Figure 1. Carbon emissions from housing sector by age of housing stock, 2002 - 2050
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. Read the rest of this entry »
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.
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.
[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:
Over the summer there was a debate between some big names in engineering over whether combined heat, cooling, and power (CHCP) using absorption chillers actually saves carbon. The theory goes that because engine size is usually dictated by the base summer heat load, the additional heat load from the chillers allows you to upsize your engine and generate more low-carbon electricity throughout the year.
However on a current project, we’re looking at the feasibility of installing a district heating and cooling network, including installation costs. And one thing is clear: regardless of whether CHCP saves carbon, the capital cost of cooling is unaffordable.
The Draft Statutory Instrument (DSI) for Stamp Duty Exemption for Zero Carbon Homes, announced at the last budget, will undermine the majority of attempts to deliver the greenest of housing. The DSI doesn’t appear to be available online, but the link is to a copy we acquired from the Treasury after badgering them.
The DSI is to be laid before Parliament at the end of next week for Committee approval by the end of the month. It is at best a misguided piece of well-meaning legislation that will do more harm than good, or at worst a genuine attempt by central Government to limit the loss of stamp duty receipts from too many zero carbon homes.
David Orr’s comments at the NHF annual conference last Friday have sparked off a row with the Homes Builders’ Federation. In response to Orr’s suggestion that developers won’t hit the governments target of all new homes being carbon neutral by 2016, head of the HBF Stewart Baseley said oh yes we will.
But given that it appears the Treasury is trying to make it much harder (and more expensive) to officially go carbon neutral, it’s likely that developers will have to pay up or change their tune before long. Maybe to one of the old protest songs - We shall overcome perhaps?
In Building yesterday, a study by London South Bank University says a quarter of schemes in London are exceeding the 10% target. The article states:
In total the study, undertaken by London South Bank University, looked at 113 detailed energy statements for schemes that had been given planning approval.
Erm, but none of those scheme has been built yet. And currently there’s no mechanism for enforcing adherence to the commitment by developers - unless it’s written into a Section 106. This enforcement mechanism is a tricky issue that hasn’t been resolved as far as I know. The study also finds that:
…the most effective technologies at cutting carbon are CHP and CCHP, particularly where biomass fuel is used.
Fantastic, and I’m looking forward to seeing more biomass in London. We’ve specced it on a number of jobs, the first of which is up and running. But I can say that using biomass heating (never mind biomass CCHP) brings its own logistical tangles. It’s one thing to tot it up on a spreadsheet and another entirely to bring to fruition.
Without succumbing to the pessimism that seems de rigeur when blogging about the government’s or the GLA’s green policies, I’d just like to add a note of caution. The schemes have been granted planning permission but are by no means home and dry. A follow up survey is needed to see what’s actually built.
(Spotted by Mel at Elemental) Cyril Sweett have published their research into the potential for improving energy performance of existing building stock. The importance of greening existing buildings is brought home by two facts:
- 44% of all CO2 emissions in the UK comes from energy use in buildings
- According to one of the report’s authors, in 2050 60% of Britain’s buildings will still pre-date the 2006 revisions to Part L
So we can look forward to the carbon reductions required by Part L being ratcheted up in future, but the overall effect will be modest, even in the long term. If we want to save carbon NOW then energy consumption in existing buildings is too important to ignore.
Predictably, the report’s top recommendation is for “brave decisions” by the government. But in a political climate where politicians would rather engage in creative accounting than be decisive on climate change, it’s hard to be hopeful.
What’s going on?
There’s been a fierce debate among energy bods this summer over the environmental effectiveness of combined heat and power (CHP) and CHP with cooling (CCHP) – a debate closely tied to assumptions about the carbon emissions associated with grid electricity in the UK.
What happened?
As noted in this blog in May, Arup associate director James Thonger opened up with a broadside aimed at the GLA policy of requiring CHP and CCHP on new developments. In particular he refuted LCCA claims that gas CHP saves 54% of carbon relative to grid electricity. The LCCA is headed up by Allan Jones, former green god of Woking and now darling of the London Mayor, who didn’t take the criticism lightly.
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 another Hopkins scheme - this time the Gibbs Building owned by the Wellcome Trust. Like Portcullis House, it’s an office building kitted out with plenty of green gear. And like its cousin, the Gibbs Building is consuming more energy than predicted at design stage. So is the green office building just a myth?
Via zerochampion, the Guardian’s architecture commentator suggests that buildings
…should only really be offered prizes 20 years after their completion. While we can comment on the merit of the design, look and feel of a particular building when new, and celebrate the intentions of its designers, there is no guarantee that it might not prove to be a failure.
I know we ought to be happy that architecture is being discussed on TV at all. Having said that, if I were in charge of the Stirling Prize I’d consider actual measured energy use and give occupants a vote on whether they think the building is a success.
Client (on seeing the staircase dominating his hall): But I didn’t want a black marble staircase, I wanted an oak one!
Lutyens: What a pity.
This is driving me nuts. There’s now a huge emphasis on sustainability in architecture but some architects still don’t get it. Aflame with good intentions at the start of projects, they enthusiastically buy into sustainability concepts. But later in the design when there’s a perceived conflict between the energy performance and the architecture, the energy performance is chucked out the window.
Next year we reach a milestone unprecedented in history when more than half of all people will live in cities. This comes from the UN’s new State of the World Population report, which strikes an interesting tone. The authors acknowledge the huge risks of increasing rates of urbanisation, particularly for the poor, but also maintain that if we get our urban planning and public administration right, we can design out the worst of our environmental and social problems. And anyway, urbanisation is inevitable because you can’t have economic growth without it.
You could argue that here in the developed world, we’ve got enough urban planning experience under our belts to allow us to meet the challenge. Except that the developed world is not where the real expansion is set to take place. Most of the shift will occur in Asia and Africa where “the accumulated urban growth of these two regions during the whole span of history will be duplicated in a single generation.” So to describe the pace of expansion as breakneck is putting it mildly.
Just heard from the folks at the Carbon Trust who are doing the micro-CHP field trials. The release date for the next interim report has been pushed back to the end of August with the methodology to follow some time after. Advise not holding breath.
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:
Via Tom N, a great article in BSJ on whether CHP (and CHP + cooling) actually has as much potential to reduce carbon emissions as the industry (and Ken Livingstone) would have you believe.
In general, I agree with James Thonger’s conclusions. However… Read the rest of this entry »
A London borough used thermal imaging from the air to help identify properties with high heat loss and they’ve put the results online for anyone to see. Here’s the article in the The Times. And here’s the map showing the results.
I think it’s fantastic, provided the council follow it up with constructive advice to the worst homes and other buildings. Now what we need is a thermal version of Google Earth.
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