Experts are at odds over whether Whitcoulls' launch of e-books this week will be good or bad for the environment. From Thursday, two million e-books will be available from the Whitcoulls website. Whitcoulls will also sell the Kobo e-reader, a device designed for reading electronic books, but the e-books can be downloaded and read on personal computers, smartphones such as the iPhone and tablet devices such as the iPad. A study by United States research and media firm Cleantech Group found carbon emissions from electronic books were far lower than from traditional book publishing. On average, the carbon emitted in the lifecycle of an Amazon Kindle e-reader would be fully offset after the first year of use, and any additional years of use would result in net carbon savings of about 168 kilograms of carbon dioxide a year, it said. That assumed people would otherwise buy 22 new books a year. However, the study found e-readers were not squeaky clean. Production of a Kindle created 168kg of carbon dioxide compared with 7.46kg for a book. But e-readers also require electricity to run and are not as environmentally friendly to dispose of as paper-based books. A New York Times "life-cycle assessment" of books and e-readers found traditional books were by far the greener option. One e-reader required the extraction of 15kg of minerals and 265 litres of water to produce its batteries and printed circuit boards, it said, while a book used 0.3kg of minerals and only 7.5 litres of water. Manufacturing an e-reader consumed 100 kilowatt hours of electricity and generated 30kg of carbon dioxide, while a book consumed two kilowatt hours and produced 100 times fewer greenhouse gases. People who enjoy reading in bed at night would be better off with an e-reader — which typically has an energy-efficient screen — because lightbulbs consume more energy. Other studies sit on the fence, but generally recommend visiting a library or a second-hand bookstore as the greenest way to get a literary fix. Borders in Australia, also owned by Whitcoulls owner, the REDGroup, launched an e-book service last week. It is selling the Kobo e-reader for A$199 (NZ$249), and e-books cost between A$10 and A$15 (NZ$12.50 and NZ$18.70). The Australian Publishers Association told the Sydney Morning Herald the "competitive pricing" would feed the appetite for e-books, but the death of the paperback had been overstated.