The local assembly passed new regulations requiring major construction companies to equip homes smaller than 2,000 square meters (21,500 square feet) with solar panels or other renewable power sources.The government estimates that the 980,000 yen ($7,200) price of a 4kW installation can be recouped in about six years based on utility bill savings and an existing 100,000 yen ($728) per kW grant.The measure applies only to around 50 builders who supply over 20,000 square meters (215,000 square feet) to the market, so it's not clear what percentage of new homes will fall under the new rules.The measure should have a major effect, though, as the Tokyo government estimates that half of existing buildings (70 percent of which are homes) will be replaced with new construction by 2050.In France, lawmakers recently approved a bill requiring parking lots with a minimum of 80 spaces to be covered by solar panels."