﻿Learning from the London Plan
How effective has the London Plan been in reducing carbon emissions from one of the largest cities in the world? We have the answers.
It is over six years since the London Plan was published early in 2004. One of its objectives being to address the issue of climate change and reduce energy consumption and carbon emissions using the planning system. It has become a fact of life for the construction industry, and information about its effectiveness has emerged from studies carried out by London South Bank University and presented to the recent CIBSE Conference by Tony Day, professor of energy engineering at London South Bank University.
The aim of the work by London South Bank University (LSBU) was to examine in detail the various approaches used to reduce carbon emissions and draw conclusions about what works in practice.
The study has three stages and involved LSBU conducting an evaluation of planning applications submitted to the Mayor of London.
The first stage looked at 113 developments during the period 2004 to 2007 to assess overall CO2 savings.
The second stage covered 147 detailed energy statements from November 2006 to June 2009, out of 340 approved.
The third phase will also look at examples of buildings completed or under construction.
The first stage of the project was during the heyday of the ‘Merton rule’ requiring the use of 10% renewable energy on site to reduce CO2 emissions. Merton Council adopted the rule in 2003, and the Mayor of London and many councils have also implemented it. The rule has also become part of national planning guidance.
Despite the fervour, the contribution of renewables to reducing CO2 emissions was quite low for the period 2004 to 2007. The additional contribution by renewables after the benefits of energy-efficiency measures and CHP was just 5.8% — i.e. 5.8% renewable energy.
During that period of the study, energy-efficiency measures alone, before CHP, were responsible for reducing CO2 emissions by 10.3%. compared with baseline emissions CHP was responsible for a further 12.3%.
The CO2 proportion of actual CO2 savings achieved by energy-efficiency measures and CHP were over 4.6 times more than from renewable energy, with renewable energy accounting for 17.8% of CO2 savings. The chart in Fig. 1 puts the whole thing into perspective.
The low proportion of CO2 reductions due to renewables over the period is the result of a learning curve that saw only about 3% of CO2 savings due to renewables as the end of 2003 approached and passing the 10% mark being met, on average, by the middle of 2005. In the interim, the London Renewables Toolkit was released and additional staff joined the GLA planning team.
The headline figure was a 25.8% reduction in baseline emissions for the 113 developments studied in the period 2004 to 2007.
Tony Day explains that virtually all the early savings were from CHP (Fig. 2 in download below), with very little coming from energy efficiency, passive design and renewable energy efficiency. By the end of the period, however, the contribution of energy-efficiency measures almost matched that of CHP, with renewable energy providing a thick slice of icing on the cake.
He says, ‘CHP and energy efficiency make the largest savings. The greater these savings, the less the investment in renewables needs to be. The expense of renewables led to getting energy efficiency as good as it could be, and
the energy-efficiency component was driven even harder in 2008/09.’
The next stage of the study looked at CO2 savings from 147 developments over the period 2007 to 2009. The headline figure here was a reduction in CO2 emissions of 30% against the baseline figure, and there was a marked shift in the makeup of the CO2 reductions.
Energy-efficiency measures boosted their proportion of the savings by 14% to 45.5% of the total. The proportion due to renewables shot up by over 50% to 27.2% of the total. The sector that saw a fall was CHP, with its share of the total down by over a third to 27.3% of the total — virtually the same as the contribution from renewables.
The accumulation of reductions in CO2 emissions in the second 3-year period was quite different from that of the first period (Fig. 3 in download below). There was much more emphasis on energy efficiency and passive design and renewable energy — and much less on CHP. With concerns about future supplies of natural gas, this is probably a good thing.
Tony Day highlights the success of this second period by pointing out that by mid-2007, 35% of projects exceeded the requirements of the Building Regulations by 35%, with 23% of developments achieving 40% better.
The contribution of renewables in reducing emissions is now in decline, but those from CHP continue to climb. Such has been the success of the London Plan that Tony Day comments, ‘If we can get 30% better than Building Regulations, renewables don’t matter.’
By far the largest savings from renewables is due to biomass — both biomass boilers and Biomass CHP (Fig. 4 in download below). In terms of cumulative CO2 savings, fuel-cell CHP is closing the gap with biomass CHP, despite a late start.
The large CO2 savings achieved by biomass boilers were due to many installations (74) with relatively small annual savings per installation (an average of 158 t/year per installation). The reported and estimated installed capacity was 50 MW, giving an CO2 reduction of 234 t/MW/y.
The six biomass CHP installations had an installed capacity of 1.5 MW and delivered average annual CO2 signs of 1158 t per year — which works out at massive 4632 t/MW/y.
There were 10 wind-turbine installations, with an average saving of 274 t/y — giving annual CO2 savings of 1054 t/MW/y for 2.6 MW of installed capacity.
Photovoltaics were a popular source of renewable energy, with 55 installations averaging 31 t/y of CO2 savings. The specified capacity of 3 MW averaged 568 t/MW/y.
Solar thermal produced smaller CO2 savings than solar PV. The figures are 26 installations giving average savings of 22 t/y. The 3.5 MW of installed capacity giving savings of 163 t/MW/y. Is there a case for using solar PV to produce domestic hot water rather than solar thermal — with excess electricity fed into the Grid?
Finally, ground-source heating/cooling was used in 31 installations and reduced CO2 emissions by an average of 108 t/y. The total reported/estimated installed capacity was 14.7 MW — giving CO2 savings of 228 t/MW/y.
Summarising the results of the study, Tony Day said. ‘The London Plan has been responsible for estimated savings of over 750 000 t of CO2 per year since its introduction in 2004.’
However, the savings would doubtless have been very much smaller if the planning process had not been slashed from 700 days in 2004 to 100 days by 2007.
Tony Day’s view is that the planning system is a very effective way of forcing developers to introduce low-carbon technologies into new developments. The policy is unpopular with developers, but it is driving the market and reducing planning and capital costs. He also believes that good regulation can lead to innovation, provided engineers are not overly constrained, and that planners and developers have a better understanding of what is needed.
The implementation of the London Plan has seen engineers becoming involved at the earliest stages of projects, vastly improving the possibilities for carbon reduction.
The London Plan has led to the development of some world-class knowledge, which Tony Day believes should be sold around the world. ‘There are cities that need to know this now,’ he asserts, and he has already made presentations to four cities in China
Final conclusions? Regulation has succeeded, while the market is imperfect.