By Nina Chestney
LONDON (Reuters) - Dwindling supplies of metals, water and biomass could slow the deployment of clean energy technologies by 2035, a study by research organization the Stockholm Environment Institute and by business initiative 3C showed on Tuesday.
Governments and companies are increasingly developing low-carbon technologies to reduce their dependency on fossil fuel-based energy sources and to cut greenhouse gas emissions.
The International Energy Agency forecasts that the share of renewables from non-hydro sources in power generation will increase to 15 percent in 2035 from 3 percent in 2009.
Several clean technologies depend on metals that are becoming scarce, hindering large-scale deployment, the report said.
Photovoltaic solar technology uses indium and tellurium in thin film, while the wind industry uses neodymium in permanent magnets for wind turbines, and plug-in hybrid and electric vehicles use lithium and cobalt in batteries.
The study found a "severe risk" of indium and tellurium deficits by 2020 and 2035, a moderate risk of neodymium scarcity by 2020 and a severe risk by 2035, and a limited risk of cobalt and lithium deficits by 2035 due to a mixture of limited availability, environmental regulation and trade policies.
China has restricted the export of some rare metals, citing their rapid depletion and environmental concerns.
"Such shortfalls could indeed hinder the transition to a low-carbon global economy," the report said.
A separate study has estimated demand for dysprosium - used in electric vehicles - and neodymium could rise by as much as 2,600 percent and 700 percent, respectively, by 2035.
WATER AND BIOMASS
Some low-carbon energy sources such as solar thermal and geothermal require so much water that development on a large scale might not be possible in a world where the water supply is constrained or uncertain, the study said.
Cutting emissions and saving water are not always compatible. Low-carbon geothermal, hydro power and biofuels can all use far more water than conventional fuels.
Under California's renewables policy, the state's share of renewable electricity should rise to 34 percent by 2020 from 25 percent, reducing greenhouse gas emissions but increasing water consumption, the study said.
If California used more photovoltaic solar and less solar thermal energy, water consumption would be reduced. But the adjustments necessary to technology systems would make plants less efficient, offsetting cuts in emissions.
Adding carbon capture and storage technology to natural gas plants would lower emissions, but that would use more water, the study found.
Biomass energy accounts for 77 percent of world renewable energy, and wood biomass makes up the majority of that. But demand for wood looks set to outstrip supply by up to 600 percent in some countries, according to some estimates.
"Biomass is a renewable but limited resource. Biomass production is constrained by land and water availability, by soils' ability to produce biomass, and by the need to return some biomass to the land to retain nutrients and soil moisture," the report said.
Using land for biomass can conflict with food production, and some forms of biomass could actually increase emissions.
"In most of our scenarios, more land is needed and as ... estimates suggest that highly productive land is already occupied, any expansion will be onto less productive land," the study said.
(editing by Jane Baird)