Japan can meet a 2020 goal of cutting greenhouse gas emissions by 25 percent from 1990 levels solely by policies that spur households and businesses to adopt low-carbon technologies, according to an environment ministry report.

The report, released last month, is aimed at provoking a wider debate as the ruling Democratic Party seeks feedback from the public as it seeks to pass a climate bill and enhance voter support ahead of a mid-year poll.

The report shows more than half of the pledged cut to 946 million tonnes of CO2 equivalent by 2020 can be met by changes by households, offices and the transport sector instead of solely relying on industry.

Suggestions include building low-carbon houses or remodeling existing domiciles by spending on devices like solar panels that would be paid off by lower fuel costs in about a decade.

The report says, for example, it costs up to 4.2 million yen ($46,000) for an owner to remodel a house into a low-carbon building, a cost that could be redeemed in 11 to 13 years.

Other points in the report include:

- Manufacturers, such as steel and chemical companies, could replace outdated factories with energy-efficient ones.

- Push a policy for hybrid and electric cars to account to half of new sales by 2020.

- To boost solar power capacity to 50 million kilowatts by 2020 and make energy from carbon-free renewable sources in total to exceed 10 percent of the country's primary energy supply.

- To accelerate the usage of nuclear power with nine new reactors and a jump in the average nuclear plant operation rate to 88 percent by 2020, against just 65 percent in 2009.

($1=92.15 Yen)

(Reporting by Risa Maeda; Editing by Ed Lane)