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Featured Article
| Part L Revealed |
Since the announcement last September by the Minister for the Environment of substantial improvements to be made under Part L of the Building Regulations, speculation has been rife in the construction industry about what the details of the updated regulations would entail. Jeff Colley examines some of the key parts of a regulatory improvement that will help the Irish construction industry to modernise and meet the demands of a rapidly changing world.
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Part L Revealed |
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Page 4 of 4
Renewable energy
In addition to the 40% reduction in primary energy consumption, all new dwellings must provide a proportion of their heating or power from onsite renewable energy sources – a minimum of 10kWh/m2/a by utilizing solar thermal panels, heat pumps or either biomass boilers or stoves, or alternatively a minimum of 4kWh/m2/a from solar photovoltaic or wind turbines. It is reasonable to assume that the setting of a lower figure for renewable electricity is due, in part to the carbon intensity of grid electricity. One unit of delivered electricity from the grid requires roughly 2.7 units of electricity to be generated by Ireland’s grossly inefficient power stations. Therefore, roughly the same amount of carbon is displaced by 4kWh/m2/a of renewable electricity as would be the case with 10kWh/m2/a of thermal renewables.
There may be some concerns in the industry that solar thermal is counted towards reducing primary energy consumption, whilst the other thermal renewables are not. The reason for this distinction is two-fold. Firstly, it is consistent with DEAP. Secondly, it recognises the differences in terms of how the different renewables generate energy. Whilst heat pumps and biomass boilers and stoves rely substantially on the use of external energy sources – electricity in the case of heat pumps and biomass in the case of biomass boilers and stoves – solar panels require little in the way of external energy in order to operate. “Effectively the distinction is that solar is not imported energy” Healy states. “What we’re looking at is the requirement to import energy on to the site”.
As a result of the distinction between the various renewable energy options, there may be concerns that uptake of solar will start to greatly outstrip that of heat pumps and biomass systems. Such a notion starts to dissipate upon further consideration.
Solar undoubtedly has certain advantages. The cost of a solar thermal system can be relatively low. From a regulatory point of view, solar can both contribute to the 40% reduction and achieve the 10kWh/m2/a requirement. However solar thermal cannot alone meet the combined space heating and domestic hot water requirement, and compliance would therefore require investment in an additional heat source.
Heat pumps and biomass boilers may be at a disadvantage in that they won’t be counted towards reducing primary energy consumption, but they do possess their own advantages. Not only do they satisfy the 10kWh/m2/a requirement, they can exceed this to the point of delivering every kWh required by the household, thereby negating the need to invest in an additional thermal energy source.
It will however be possible to comply with Part L without specifying renewable energy systems at all, by using a combined heat and power (CHP) system. In high density developments, such as apartment developments, where the provision of 10 kWhr/m2/annum from renewable sources to each dwelling may be difficult to achieve, the provision of space and water heating utilising a small scale combined heat and power (CHP) system can be specified as an alternative.
Whilst oil and gas based CHP systems have the drawback of using carbon intensive fuels, they also have the advantage of using those fuels efficiently to produce both heat and electricity. As they can help to take substantial loads from the grid and Ireland’s overburdened, inefficient power stations, CHP systems are justified not only in reducing carbon dioxide emissions, but also in terms of taking pressure off the grid, and reducing the risk of power shortages at peak times.
All in all, the changes to Part L are an immensely positive step in improving the performance of Irish buildings. The options available to building designers are sufficiently broad to enable a variety of methods of fulfilling the new requirements. Given Minister Gormley’s pledge to further improve the energy performance requirements of Part L by 60% relative to current requirements by 2010, it’s very much in the industry’s interests to seek to exceed the minimum requirements to the greatest extent possible. The timeframe from planning to completion for bigger developments can be so lengthy that developers would be prudent to think ahead. “For large schemes still on the drawing board developers need to look at the overall programme and probably design to meet the 2010 regulations now.” concludes Jay Stuart.
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Jeff Colley |
| About the author: |
| Jeff
Colley has been the editor of Construct Ireland, Ireland's pioneering
sustainable building magazine, since 2003.
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