Read the below extraction from articles about "feed-in tariff scheme in Hong Kong and answer the following questions. Hongkongers can apply to sell renewable energy into the grid as early as next week, officials from the larger of the city's two power companies said on Monday as they presented details of a new "feed-in tariff" scheme to lawmakers. Under the new scheme, households and businesses that install renewable energy facilities, such as rooftop solar panels, would be able to sell the clean electricity to the city's power grid at higher than market rates of HK$3 to HKS5 per unit of electricity (compared to 0.84 HK to HK$1.79 rate for residential user), depending on capacity. A typical village house solar project occupying a third of a 700 sq ft roof could cost HK$90,000 to HK$150,000 to install, and see the investment returned in six to 10 years, according to CLP. Lawmakers welcomed the move but urged the Environment Bureau and two power companies to provide more details of how they would remove red tape (bureaucracy from government), while urging officials to issue clear installation and safety guidelines. "We do not want to repeat the experience of green roofs before when proper guidelines were only issued after something happens," The mainland encountered problems after government incentives sparked a boom to install wind and solar farm installations a few years ago. Many projects were unable initially to sell power to the grid because of insufficient infrastructure. Other problems included an inability to absorb too much renewable power at any one time, otherwise the stability of the system would be threatened. a) Assuming that the market of solar panel board is perfectly competitive, how does the new scheme affect the profit and number of solar panel sellers in the market? b) Hong Kong government aims to reduce the carbon emission (by 26% to 36%) by using renewable energy in next 10 years. Is the "feed in tariff scheme a command approach or market approach to the environmental problem? Evaluate the effectiveness of the scheme in reducing pollution.