Renewable power is set to grow far more slowly than the government has predicted, according to a new analysis of the UK’s energy mix and greenhouse gas emissions.

Renewable energy is set to provide 5% of the country’s electricity in 2010, up just one percentage point from the 4% recorded last year, says a study by Cambridge Econometrics. The government target anticipates 10% of electricity coming from renewable sources by 2010.

The study found, however, that with new policies in place, the UK could produce 12% of its electricity from renewables by 2015. This is short of the 15% Renewables Obligation target. But it is expected to reach 19% by 2020, almost meeting the government’s aspirations of a 20% share.

Next month, the government is expected to publish the outcome of a consultation on producing more renewable energy by targeting subsidies where they are most needed, rather than focusing on onshore wind farms.

Paul Ekins, senior consultant to Cambridge Econometrics, said: “It is clear that these policies that give incentives to the development of non-carbon renewable energy, particularly offshore wind, are urgently needed. However, as the proposed changes require primary legislation, it is unfortunate for the government’s 10% target that they can only be introduced in April 2009 at the earliest.”

What’s more, the government is also likely to miss its target of cutting carbon dioxide emissions by 20% from 1990 levels by 2010.

However, the UK is on course to meet its targets to reduce emissions under the Kyoto protocol.

Ekins expected emissions to be 15% lower by 2020. Carbon emissions in the UK have not fallen since 2002.

He identified the main barriers to a low-carbon economy as higher transport and household emissions. Combined, these sectors are expected to rise to just under half of the UK’s CO2 emissions by 2010.