UPDATE 1-GE, Conoco, NRG set $300 mln fund for energy tech

* To invest in 30 countries over four years

* Initial investments in solar, coal, biomass conversion (Updates source of story)

BOSTON Jan 27 (Reuters) - General Electric Co (GE.N), oil company ConocoPhillips (COP.N) and power group NRG Energy Inc (NRG.N) said they are pooling $300 million to invest in emerging technology companies.

The three did not say how much each would contribute to the Energy Technology Ventures joint venture, which will fund about 30 young companies over the next four years.

The first investments are in Alta Devices, a maker of solar energy equipment; Ciris Energy, which is developing a way of converting coal to methane; and CoolPlanetBioFuels, which is working on a method of converting low-grade biomass to high-grade fuels.

The news was first reported by the Wall Street Journal. (Reporting by Scott Malone in Boston and Fareha Khan; Editing by Jon Loades-Carter and John Wallace)