Thursday 14 May 2009

Green energies give rise to 'eco-bling'

ATTEMPTS TO make buildings more energy-efficient by installing expensive “green technologies” have resulted in the rise of “eco-bling”, a symposium in Trinity College heard yesterday.

Academics and practitioners of sustainable energies said much money was being spent on micro-renewable energy systems when extra insulation and draught-proofing would be more effective.

The symposium heard some expensive technologies such as photo-voltaic cells, which take energy from sunshine, can take up to 50 years to pay for themselves in saved energy costs. However, photo-voltaic cells often have a useful life of just 20 years, making them effectively “eco-bling”.

Howard Liddell of Gaia Architects, which has been working on eco-design in Scotland and Norway since 1984, said heat pumps, photo-voltaic cells, solar panels, even in some instances wind turbines, were types of renewable energies which frequently did not stand up to “crunching the numbers”.

In his lecture, “Nega Watts – the antidote to Eco-bling” Mr Liddell said preventing heat loss was by definition among the best ways to achieve energy efficiency.

He said he had never seen a heat pump in operation which offered a return as good as three units of energy output for each unit which went in, yet these were regularly advertised as “four units of output for one unit in”.

Photo-voltaic cells which make energy from sunshine offered a 50-year payback, but all too often have a 20-year useful life.

He was critical of new housing schemes which advertised “10 percent of energy from renewables” when research showed clearly the best way to achieve energy efficiency was simply to reduce waste.

The optimum measure was “super insulation”, making a house air-tight, “instead of heating the sky”. However, he asked, “How do you make insulation and air-tightness sound as sexy as 10 per cent from renewables?”

He said “green” buildings with micro-renewable energies tended to be lived in by environmentalists, and cost more to build. Super-insulated buildings with only air tightness and passive solar gain tended to be lived in by “ordinary people” and did not cost more to build.

In his address, “Sustainable Energy – Without the Hot Air” Prof David MacKay of the department of physics at Cambridge University, England, asked whether renewable energy has the capacity to meet society’s demands. He concluded that Britain, as an example, could survive on renewable energies alone – but only with massive societal changes and most of its land mass utilised by biofuel crops, alongside tidal, wind and wave energy farms.

Irish Times

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