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As summarised in earlier posts, license light is pretty much the only tool in OFGEM’s toolbox to allow small scale generation schemes to get value for the electricity they generate. It’s nothing to do with subsidies or guaranteed prices or feed in tariffs. Instead license light is trying to redress the fact that our electricity market just isn’t a level playing field. The big companies can afford to play, while small time (usually low carbon) generators are squeezed out.

I noted in the earlier post that the GLA were working on a pilot to trial license light. They had hoped to get the license light toolkit and sample contracts published by end of March 2012. This hasn’t happened.

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On-site generation only works if you get good value for the energy you produce. For example, the viability of CHP (and the resulting cost of heat) depends on the price you get for the electricity you generate.

So what are your options? You could export to the grid under an offtake contract with a licensed electricity supplier. But as a small generator your electricity is almost worthless to them so they won’t pay much for it: maybe 2 or 3p. So unless you’re able to negotiate a particularly sweet contract, this is usually a non-starter.

The obvious route should be to sell energy directly to people on the site where the energy is generated. That’s supposed to be the point of distributed energy, right? (more…)

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Following on from discussion about planning reports last week, here’s a chart I put together showing roughly how much PV you can fit on a flat roof. It’s based on the formulas described by Volker Quaschning, the German Godfather of Sol (Thank you! I’ll be here all week. Try the crab).

Solar-shading

The shading angle is the angle from the bottom of the panel behind to the top of the panel in front. As a rule of thumb, you can use the height of the sun at noon on the winter solstice – for London, this is about 15°. Utilisation factor is the ratio of panel area to roof area.

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For consultants, energy reports for planning are fantastic: a bit of SAP, a few benchmarks, some spreadsheet magic, and hey presto you’re sending an invoice. But the contents of the energy report can have huge implications, in some cases committing the scheme to commercially or legally impossible strategies, causing delays and increasing costs later in the programme. Here are a couple of examples:

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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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Made it in the paper this week.

Casey Cole of low carbon consultant, Fontenergy, said the unregulated nature of heat has led to some “questionable practices” and needed outside regulation: “Both a technical standard for heat networks and a customer charter for heat are very welcome developments and we’ll be helping LEP with their work alongside the CHPA.

“While many buildings in London are now “district heat ready”, to date there’s been no common standard to ensure these schemes are actually able to connect to each other. In addition, rules for the provision of heat will give greater protection to customers and hopefully unify the many disparate methodologies in use at the moment.”

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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.

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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. (more…)

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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.

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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.

carbon emissions from housing by age of stock

Figure 1. Carbon emissions from housing sector by age of housing stock, 2002 – 2050

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