Last week, Ecocem, the 'green' cement company founded by former CRH executive Donal O Riain, announced it had persuaded four of Ireland's biggest construction firms to use carbon-neutral concrete in a range of high-profile developments.

According to O Riain, the company was surprised by the enthusiastic response from developers. He believes it reflect the fact that "the construction industry in recent years has been exposed to a lot of pressure to do something on the green front".

"Developers now understand that the more they do, the more receptive planners are, " he said. "The developers know that people do want sustainable development and climate change to be taken into account when it does not involve excessive cost."

O Riain said Ecocem had developed carbon-neutral concrete as an extension to its low-carbon cement business, which produces cement using slag, a by-product of iron production in northern Europe.

The concrete is produced using a mixture of low-carbon cement, with the remaining carbon footprint neutralised using independentlyverified carbon offsets sourced on behalf of the developers by Ecocem.

According to O Riain, despite the cost of purchasing offsets, the resulting concrete is only 2% more expensive than its less environmentally-friendly competitors.

He admitted, however, that Ecocem did not include the cost of transporting the raw materials used to produce its cement in its carbon calculations. The company claims the manufacturing of its cement emits 16 times less carbon dioxide than standard cement.

"We make the comparison between emissions at the cement plant compared with emissions at our plant. In neither case, do we take into account the shipping of our raw materials nor the quarrying of raw materials in the case of standard cement, " he said.

"The reason we do that is that the standard procedures for estimating carbon dioxide emissions in the cement industry require you to do it that way to gain comparability between sites."

Many of the projects where carbon neutral concrete will initially be used are flagship developments such as the National Convention Centre in Dublin and the new headquarters of the Department of the Environment in Wexford. O Riain said this was partly due to a desire among developers to publicise their green credentials.

"If you take the National Convention Centre, the pouring of concrete started a few weeks ago. That was the first time that carbo- neutral concrete has been poured anywhere in the world.

The centre will have bragging rights on that forever more. That's very positive publicity for them, " he said.

O Riain rubbished reports that the world's largest building materials firm, Saint Gobain, had bought a 30% stake in the company. He said the prospect of Saint Gobain buying a stake was one of the possibilities the firm discussed with its shareholders but that no deal had been done.

"It didn't come from us. We discuss with shareholders, as we do on a regular basis, what possibilities there are. So I think it's part of the price you pay for being so open with your shareholders."

O Riain also admitted that the green cement sector's growth would be restricted by the limited availability of slag.

"There's a limit: it's limited to 18 million tonnes a year in Europe. Each tonne of slag is equal to one tonne of cement. So it's never going to be 50% or 60% of the European cement market, " he said.