The EU's Waste Electrical and Electronic Equipment (WEEE) directive, which has been enforced by Roche's department since 2005, adds an extra 50 cent to the price of each CFL bulb sold in the state to cover disposal costs.

CFL bulbs fall under the directive because each one contains a tiny electronic energy-saving device that regulates electricity flow into its coiled fluorescent tube, making it environmentally preferable to ordinary bulbs.

Simple incandescent bulbs, which have no such energy-saving element, do not attract WEEE charges.

The minister, however, has promised to attach an as yet unspecified levy to the bulbs in an effort to get consumers to abandon them in favour of longer-lasting, less wasteful CFL bulbs. He claims such a change could save consumers 32m a year and eliminate "hundreds of thousands of tonnes" of carbon dioxide emissions.

The proposal is only one element of a much larger anti-global warming strategy, but the department considered it significant enough to devote a press release to the issue to coincide with the publication of government's white paper on green energy.

But the cost incentives are stacked against Roche's plan. An Irish-made 100-watt incandescent Solus bulb sells for 76 cent in supermarkets, while an equivalent CFL typically costs more than 5. Again, the minister is up against European regulations: the EU has placed a 66% tariff on cheap CFL bulbs made by several Chinese manufacturers, while Dutch firm Philips takes a 33% hit on its Asian-manufactured bulbs.

Even setting aside the WEEE charge on CFL bulbs, Roche's levy on incandescents would need to be about 600% to overcome these extra costs and achieve price parity.

The minister, however, is counting on the fact that CFL bulbs offer long-term savings by using less energy and lasting longer than ordinary bulbs.

Ireland's only light bulb manufacturer, Solus, is sceptical about Roche's plans. While an estimated 10% of Solus's 8m light bulb revenue comes from its CFL range, sales director David Reynolds says CFL equivalents do not yet exist for increasingly popular . . . and energy-intensive . . . ceiling spots and reflector lights. Also, CFL bulbs explode if used with dimmer switches.

"The technology just isn't there for decorative lighting, even if it is there for bog-standard lighting, " Reynolds said.

Reynolds said Solus is working on CFL replacements for decorative lighting . . . precisely the sort of activity Roche's levy is expected to encourage . . . but pointed out that CFL products are costly to make and yield low margins compared to incandescent bulbs.

He favours eliminating the WEEE charge and VAT on CFL bulbs instead of adding a tax to incandescent bulbs.

"Nobody has even asked us for an opinion, " he said. "I don't think Dick Roche is aware of where the market is."

A statement from the Department of the Environment said the amount of the levy would be set following consultation with stakeholders. A spokesman declined to comment on the WEEE charges or tariffs.