Why London needs a boiler scrappage scheme

February 2, 2016

The GLA has this morning launched a Boiler Scrappage Scheme to replace old polluting boilers. In this blog I explain why this is a good proposition, particularly in terms of its potential to improve air quality, but argue that the ambition of the scheme needs to be increased.

Air pollution is the most significant environmental issue facing London. In our recent report Up in the Air: How to Solve London’s Air Quality Crisis, we documented the fact that 12% of London’s area was in breach of legal and healthy limits for Nitrogen Dioxide (NO2) in 2010. Based on this, we calculated that around 25% of schoolchildren in London and 44% of the Capital’s workforce could be exposed to unhealthy air. Little improvement in air quality has taken place in the years since. At the start of 2016, it took just 8 days for Putney High Street to breach its NO2 pollution limit for the entire year.

London’s poor air quality is often associated with road transport, in particular diesel vehicles, and the ongoing saga concerning emissions from Volkswagen diesels has only exacerbated this. As our report shows, the UK has seen a huge expansion in the number of diesel vehicles, now making up 50% of all new car sales, and 96% of all vans on the road. Diesels have much higher emissions than petrol equivalents, and have systematically failed to match up to European emissions standards on the road.



However, look at the charts and it is apparent that gas combustion (i.e. boilers and cookers in buildings) is also a very significant source of NOx emissions. London wide, gas combustion accounts for a total of 21% of NOx emissions, but in Central London the figure is 38% (domestic and non-domestic gas combustion combined).



Despite its significant contribution to emissions, gas combustion has been largely overlooked in air pollution terms until relatively recently. The focus on road transport emissions is set to yield significant results over the next decade – through policies such as the Ultra Low Emissions Zone and investment in the bus fleet. At the same time gas combustion could increase as a proportion of future NOx emissions. Modelling shows that, based on current policies, gas combustion could overtake road transport as the largest source of NOx emissions in Central London between now and 2020, and could be responsible for just under half (48%) of total NOx emissions in Central London by 2025. Therefore in order to make the deep reductions in emissions required to achieve compliance with legal and healthy limits for NO2, it is essential that policymakers focus more on how to reduce emissions associated with gas combustion.

Equally, regulations and policies related to gas boilers have largely focused on improving efficiency and reducing greenhouse gas emissions, and have only relatively recently begun to focus on the air quality impacts of gas boilers. For example, current Building Regulations require all boilers fitted to conform to minimum energy efficiency standards, but do not include any standards concerning NOx emissions. The European Eco-design Directive required all energy related products (including boilers) to be labelled according to their energy performance from 2015, but standards for boiler NOx emissions will not be introduced until 2018. The energy efficiency and NOx performance of boilers was considered under the Code for Sustainable Homes – a rating system for the sustainability of new homes – however this system was scrapped in 2015.

The problem with boilers, as with road vehicles, is that there is a significant stock of older units which perform very badly compared to the latest available technologies. The latest condensing boilers achieve energy efficiencies of around 90%, compared to 70% or lower for old non-condensing boilers. They also perform significantly better in terms of emissions of greenhouse gases such as CO2, and local air pollutants. Most of the condensing boilers currently on the market emit less than 40 mg/kWh; whilst emissions from older non-condensing boilers are many times higher at between 150-260 mg/kWh. According to DECC, there were still 12.6 million non-condensing boilers in the UK in 2012 (51% of all boilers), although this number is falling.

London has recently implemented an “Air Quality Neutral” policy which requires all major developments (e.g. 10 dwellings or more) to be assessed against emissions benchmarks, and for all newly fitted boilers to meet ultra-low NOx standards. However this policy only applies to new developments, and does not tackle the stock of existing boilers.

In our Up in the Air report we suggested the possibility of creating a boiler scrappage scheme to tackle air pollution in London. Our follow up work is exploring this and other policy proposals in more detail, and we will publish a ‘Part 2’ report in due course. Preliminary analysis suggests that there is significant potential to reduce NOx emissions by accelerating the replacement of boilers in London. We estimate that there could be around 900,000 non-condensing boilers in domestic properties alone (the number in non-domestic properties is much more difficult to establish).

Many boilers will be replaced in due course when they break down or reach the end of their useful life. There is also an economic case for replacement – households can save around £340 from replacing an inefficient boiler with a new one. There are also national policies which deliver boiler replacements – for example the Energy Company Obligation has to date delivered around 330,000 boiler replacements across Britain.

However, given the extent of the air pollution crisis in London, it is clear that additional interventions will be required, and a boiler scrappage scheme looks like a good proposition. As well as making a material contribution to reducing NOx emissions in London, replacing boilers can reduce greenhouse gas emissions, reduce household bills, and can alleviate fuel poverty. Analysis suggests that from an air quality perspective, boiler replacement is far more impactful and cost effective than other energy efficiency measures. DECC previously ran a successful boiler scrappage scheme across England in 2010, with 130,000 grants worth over £40million snapped up within a 3 month period.

The GLA has been working to develop a Boiler Scrappage Scheme over the past few months, and it was launched this morning. This is a positive step forward, but the ambition of the scheme needs to be increased in order to maximise its usefulness. The £2.6m of funding being made available will secure 6,500 boiler replacements across London, but this represents less than 1% of the stock of older non-condensing boilers across London. It could go much further.

Also, as presented the scheme is couched largely in terms of its contribution to meeting carbon targets, rather than improving air quality. It requires the new boiler to be ‘A’-rated in terms of energy efficiency, but could go further by requiring the use of ultra-low NOx boilers (which are typically available at no extra cost to the consumer). From an air quality perspective it would be beneficial to target the scheme towards the boroughs with the worst air quality, but as presented it is available across London.

Overall, it is clear that there is significant potential to reduce the emissions associated with gas boilers, and in doing so make a significant contribution to achieving both air quality and carbon targets. The move by the GLA to implement a boiler scrappage scheme is positive, but the ambition of the scheme needs to be increased, and tied in more closely to the Mayor’s work on air quality, as well as climate change mitigation.

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