Achieving zero carbon emissions

The government has set the health sector a target – yes, another one but this time to do with its new buildings. By 2018 all new and refurbished buildings will have to be ‘zero carbon’. Until now, though, there has been no accepted definition of what this actually means. So a new consultation paper from Communities and Local Government puts forward some proposals that will form the basis of an official ‘definition’.

Key aim
A key aim of the proposals is that new buildings do not add to the existing carbon emissions total, which would compound the problem of reducing them by at least 80 per cent by 2050. By making them zero-carbon in the next few years, the government hopes to ‘future-proof’ non-domestic buildings so that the country is not faced with expensive retrofit programmes later on.
    
In its 2007 consultation on domestic buildings, ‘Building A Greener Future’, the government proposed that all new homes built from 2016 should be constructed in such a way that, after taking account of:

• emissions from space heating, ventilation, hot water and fixed lighting
• expected energy use from appliances
• exports and imports of energy from the development (and directly connected energy installations) to and from centralised energy networks the building would have net zero carbon emissions over the course of a year.

There was, however, a great deal of debate about the third element and the use of the phrase ‘to and from centralised energy networks’. It was generally understood that this meant renewable energy, either on the development site (in the case of micro-generation district heating for example) or ‘near-site’ renewables connected by private wire.

New consultation
The new consultation, which also deals with non-domestic buildings, spells out more clearly how the government expects zero-carbon structures to be achieved. In this the third condition has changed significantly. Buildings should:

• be built with high levels of energy efficiency
• achieve at least a minimum level of carbon reductions through a combination of energy efficiency, onsite energy supply and/or (where relevant) directly connected low carbon or renewable heat
• choose from a range of (mainly offsite) solutions for tackling the remaining emissions.   

ESTA is concerned that this option of using offsite solutions should only be available after all the options for onsite mitigation have been explored and implemented as fully as possible. If developers and site owners are offered the option of using as much offsite renewable power as they wish, there will be no reason to reduce consumption – in fact, it could even increase.
    
While that may address the specific issue of climate change, it does not tackle the wider sustainability agenda and specifically the need for sustainable consumption. If allowed without any restraints, such a policy would drive a coach and horses through related energy efficiency policies.

Controlled services
The main way of ensuring that new buildings are energy efficient is through the building regulations. However, these currently only cover a proportion of the actual energy demand. The ‘controlled’ services include heating, cooling and lighting for example, but many other energy-consuming pieces of equipment, such as lifts, escalators, small power loads, etc, are not covered at all.
    
There really needs to be a ‘whole building’ approach to energy-consuming equipment. Tackling only a part will not deliver the kind of reductions in consumption and emissions that are needed to achieve a zero-carbon status.
    
Table 1 shows the average energy demand for health sector buildings compared with the average of all non-domestic buildings. Energy consumption in equipment accounts for half the total emissions – but this is not covered by the building regulations or any statutory regulations. The impact of the EU’s Ecodesign of Energy-Using Products Directive will be felt gradually as the most inefficient pieces of equipment are banned, but how many health sector procurement teams specifically include energy efficiency when buying equipment?
    
Returning to Table 1, energy consumption in the health sector is well above the average for non-domestic buildings and while this may in certain areas be inevitable, it certainly presents the sector with a challenge.
    
ESTA believes that for reasons of cost-effectiveness, security of supply and sustainability, we must reduce energy consumption to a minimum before we look anywhere else for solutions to the challenge of climate change.
    
After that, we should consider on-site or near-site energy generation using low-carbon, or preferably zero-carbon sources. Renewables can be building-integrated – for example, photovoltaic (PV) arrays on roofs or curtain walling, solar water heating on roofs, wind turbines on site.
    
Combined heat and power (CHP) technology has been successfully used in hospitals for decades, but smaller, microgeneration systems can be used in other locations as well within the health service. And although CHP has always been presented as a low-carbon technology because it produces usable heat and power, an increasing number of biomass-powered systems are becoming available. Given the size and available space of the larger health sector establishments there is much potential for achieving very low and perhaps even zero carbon sites.

The ‘remainder’
In many cases, it will not be possible to eliminate carbon emissions altogether and there will be a residual energy demand. This may have to be supplied over the grid from renewable sources or tariffs. But it should only be as a last resort – energy efficiency and on-site (or near-site with private wire connection) renewables should be exhaustively explored first.
    
Indeed, we think that designers should be required to assess the total likely energy demand of the building and all its systems, to assess what the site potential is for renewables (a city centre will be very different to a greenfield site) – and then to realise a large proportion (perhaps 80 per cent or more) of the site renewable potential through designed-in features of energy efficiency and on-site renewables. Only once this has been achieved should grid-connected supplies be permitted. This would allow for situations, such as inner-city areas, where the land is just not available for extensive renewable technologies, while encouraging designers to make the maximum use of existing opportunities.

Design or operation?
A key issue, and one which is not directly addressed by the consultation, is how to ensure that buildings minimise their carbon emissions but also their overall environmental footprint. This is a matter of operation as much as design.
    
Most larger health sector organisations have to produce Display Energy Certificates to show stakeholders how efficiently the building is being operated. We feel that this, rather than a purely designed-based measure, is the true yardstick for zero-carbon buildings. And to achieve the most environmentally-friendly and efficient buildings, the government needs to focus more on the management and operational aspects of buildings.

About ESTA
The Energy Services and Technology Association (ESTA) represents over 100 major providers of energy management equipment and services across the UK. For more details visit the website at: www.esta.org.uk

For more information
The consultation document is available at: www.communities.gov.uk/publications/planningandbuilding/zerocarbondefinition