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Archive for the ‘renewable energy’ Category

ill wind from Warwick carries important lessons for us consultants

Posted in engineering, london, renewable energy, wind turbines, tagged , , on March 9, 2009| Leave a Comment »

As flagged up by Tom at XCO2e, the Warwick wind trial final report (pdf) is out and the results aren’t good. Keeping in mind that the trials included only sub-2kW turbines, there are some important things to take away from the report:

  1. We consultants must be cautious – it’s not enough to take an average wind speed or a predicted output from the London Plan and think it has any relationship to reality. It’s becoming even clearer that a lot of site specific analysis is required before considering micro-wind.
  2. NOABL isn’t applicable in the built environment – the study found that the NOABL database consistently overestimated wind speeds by around 16x relative to measured data. The study recommends scaling factors for NOABL data that bring the predictions in line with measured data (these are based on a limited sampling period so should be treated with caution – but it’s a good start).
  3. Manufacturers can’t be trusted – using measured wind speeds and manufacturers’ power curves overestimated power output by 170% – 340%. As the report points out, there are other reasons why this might be: accuracy of monitoring equipment, response times, etc. But check out the graphs on page 30 of the report showing sampled power output vs. manufacturers’ Cp curves. OUCH!
  4. Micro-wind in the built environment may be a bad application of a good technology.

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dear god another consultation

Posted in energy, engineering, renewable energy, tagged , , on February 16, 2009| 3 Comments »

I spent a fair chunk of the weekend going through the CESP and HES consultations and it’s sucked the life right out of me. I think I may have consultation blindness. The worst part is, there’s a chance this might be a game-changing shift we’re witnessing here but 200 pages later it’s almost impossible to care.

Luckily I also spent a chunk of the weekend making a kick ass leaf hut with my 3 year old son. That may be the only reason I’ve survived.

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2050: housing, heat, and how we’ll hit the target

Posted in biomass, chp, climate change, energy, engineering, renewable energy, sustainability, zero carbon on February 5, 2009| 4 Comments »

In the last post, I argued that we’ve got to strip the carbon out of almost all of our existing stock in order to hit the 2050 target. That’s a huge challenge. Phil Clark summed it up in a comment:

I would consider it a near impossibility to upgrade every old leaky house without some massively radical action.

I completely agree: it’s going to take radical action. But what kind? The picture gets a bit clearer if you take a look at where the carbon is coming from.

Looking at the graph from my previous post, we can take a snapshot of where the emissions will come from in 2050 under a business-as-usual scenario.

carbon-from-houses-by-end-use-in-2050

The pie chart above shows that of the emissions from houses in 2050, almost 2/3 will come from heat. Electricity, on the other hand, will only make up just over a third of emissions. Without radical action to decarbonise heat, we won’t get anywhere near the 2050 target.

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Climate Act requires all homes built after 1917 to go zero carbon

Posted in climate change, energy, renewable energy, sustainability, zero carbon on February 2, 2009| 9 Comments »

Sounds crazy but it’s true.

Here’s a graph I put together showing the number of houses of various ages up to 2050. It clearly shows that, using current demolition rates, the vast majority of the homes in use in 2050 have already been built. Details on how I put the graph together can be found in a previous post.

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zero carbon must not depend on private wires

Posted in Code for Sustainable Homes, private wire, renewable energy, SAP, zero carbon on January 19, 2009| 8 Comments »

In a blog post earlier this month, Mark Brinkley wrote that the zero carbon agenda is dependent on private wire networks, which he contends are anti-competitive. While I have a lot of respect for Mark, in this case his arguments aren’t valid. Here’s why.

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sadly, another nail in the coffin for small wind

Posted in energy, engineering, renewable energy, wind turbines, tagged , , , on January 14, 2009| 3 Comments »

According to the Guardian, most domestic turbines are only generating 5-10% of the manufacturers’ claims. Dramatic stuff but maybe not a huge surprise. I think there’s been a growing realisation among professionals in the built environment that small wind in built up areas rarely works.

But it’s important to remember that in most cases this poor performance is not the fault of the turbines themselves; they’ve just been placed badly by designers and over-hyped by manufacturers.

Located somewhere with decent wind (on the back of a sailboat, on top of a tall mast on a windy hill, etc) they’ll do the job. But bolted to the chimney of a Victorian semi in Surbiton? Almost definitely not. Even Ashenden House, a 13-storey tower in Elephant and Castle, hasn’t proved to be a salubrious place for turbines.

So blame the engineers and architects, blame manufacturers for short-sightedly over-hyping their own products, but don’t blame the turbines. It would be a mistake if we were to dismiss the technology as a result. Small wind still has an important role to play, even if that role is more limited than many people hoped.

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zcc IV: what does 70% mean?

Posted in climate change, Code for Sustainable Homes, renewable energy, sustainability, zero carbon, tagged on January 9, 2009| 1 Comment »

CLG drop quite a few hints in the zero carbon consultation that they’re prepared to set the carbon compliance requirement at 70%. In other words, new schemes would have to achieve a reduction of 70% in regulated emissions relative to 2006 regulations. But if you look a little closer, it soon becomes clear that this figure isn’t what it seems.

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zcc III: onsite, offsite, and the role of private wires

Posted in biomass, chp, Code for Sustainable Homes, energy, engineering, private wire, renewable energy, SAP, sustainability, wind turbines, zero carbon, tagged on January 8, 2009| 2 Comments »

From the zero carbon consultation, you can see that CLG has accepted that we need to resolve the onsite / offsite question. They have also moved away from the requirement for private wire networks or “direct connections” between generators and homes since it caused all sorts of problems.

So positive moves from CLG, but there is still a huge amount of confusion over what onsite and offsite actually mean. This is a crucial issue since only onsite energy will count towards carbon compliance, while offsite energy is only likely to count as an allowable solution.

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zero carbon consultation II: summary

Posted in Code for Sustainable Homes, energy, engineering, private wire, renewable energy, SAP, stamp duty exemption, sustainability, zero carbon, tagged , on December 30, 2008| 3 Comments »

In case you don’t fancy wading through it, this is a brief summary of the zero carbon consultation doc. While nothing will be finalised until next summer (after they’ve ruminated over the responses), the document does give some insight into the way CLG is leaning on some issues.

At the core of the document is the government’s preferred framework for reaching zero carbon. In order of priority:

  1. A minimum standard of energy efficiency will be required.
  2. A minimum carbon reduction should be achieved through a combination of energy efficiency, onsite low and zero carbon (LZC) technologies, and directly connected heat. This is referred to as achieving carbon compliance.
  3. Any remaining emissions should be dealt with using allowable solutions, including offsite energy.

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Zero Carbon consultation published

Posted in climate change, Code for Sustainable Homes, energy, private wire, renewable energy, sustainability, tagged , , on December 17, 2008| Leave a Comment »

Just under the wire! The CLG has published the consultation on zero carbon. Big hat tip to Mr Devlin. Comments to follow shortly.

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