Germany's exit from nuclear power to renewable energy usage is on the right track despite nagging concerns over supply and the cost to consumers, the government said Wednesday as it announced more investment.

Chancellor Angela Merkel's cabinet agreed the construction of three big electricity power transmission lines, as well as a boost for steps to make buildings more energy efficient.

The German government -- in what is termed here as an ambitious "energy revolution" for Europe's biggest economy -- decided to shut down nuclear power plants after the 2011 Fukushima disaster in Japan and to reduce Germany's dependence on fossil fuels.

Instead, Germany wants to meet 35 percent of its energy needs via renewable sources such as solar and wind by 2020 and as much as 80 percent by 2050.

The government has already "come on quite a bit", Economy Minister Philipp Roesler said Wednesday as he presented the first of what will be yearly progress reports by an expert committee on the energy switch, and which covered 2011.

The experts reported that the development of renewable energy sources had advanced but warned of the need for a quicker extension of the grid to ensure that the supply is guaranteed.

Environment Minister Peter Altmaier, speaking alongside Roesler, said the jump to renewable sources "was right, is right and remains right" but acknowledged a "considerable need for action" to ensure success.

The cabinet earlier approved the construction of three major lines to transport wind power produced in the north of Germany to the west and south of the country.

Additionally it approved an annual 300-million-euro ($398-million) increase to 1.8 billion euros of a fund to improve buildings and ensure better use of energy.

Along with fears that Germany will not be able to generate enough renewable energy to supply its own power needs, a hike in costs to consumers is also shaping up to be a contentious issue as the country heads into a general election next year.

Electrical grid operators said in October that they were raising by nearly 50 percent the charge to consumers that finances subsidies for renewable energy as the country phases out nuclear power.