A new law on energy-efficient construction issued on Wednesday, the first of its kind in China, will go into effect on November 1. The law sets out that all new residential buildings under 12 storeys must install solar water heating for residents.

Current technological limitations mean that only 12 storeys can be guaranteed 24-hour hot water, according to an expert with Shenzhen Construction Bureau (SCB).

Projects that are unable to collect solar power will require special permission from the government, otherwise they cannot be put on the market. Offenders will be fined 50,000 yuan (US$6,250) to 500,000 yuan (US$62,500).

"It's an important law that will ensure the wider application of solar power in the city, a sign the municipal government is putting more emphasis on renewable resources," said Gao Erjian, an official with SCB, in an interview with China Daily yesterday.

The city has submitted to the Ministry of Construction 19 construction and reconstruction projects that will make full use of solar power.

"They will pave the way for the city to become the national leader in the utilization of solar power in construction," Gao said,

One of the projects is a government-funded software building, which will provide nearly 59,000 square metres of floor space to small and medium-sized software companies.

Builders will place 900 single silicon solar cells on the roof and another 3,654 non-silicon solar cells on the southern and western walls of the building.

The solar cells will increase costs by about 13 million yuan (US$1.6 million), but they will generate roughly 320,000 kilowatt-hours (kWh) each year, meaning annual savings of 285,000 yuan (US$35,625) at the current rate, according to a feasibility study by SCB.

"The government should subsidize developers who use solar power to generate electricity since the cost is two or three times that of regular generation," said an SCB official surnamed Xu.

In Germany, the government encourages people to use solar power by purchasing unused solar electricity at three times the normal price, Xu said.

The central government is considering a similar subsidy method but no details have been released yet, said Gao.

With nearly 2,000 hours of sunshine each year, solar power has significant potential in the city, but by 2004 only 110,000 square metres of buildings used solar power, according to official figures.

The city consumed about 44 kWh of electricity last year, compared with 19 billion kWh in 2000. It still needs a further 800,000 to 1 million kWh each year to meet demand.

SCB in July worked out a blueprint for the city's energy-efficient construction between 2010 and 2020 in July.

By 2010 half of the new buildings in the city will install solar water heating systems, and 20 per cent of the new buildings will use solar power to generate electricity.

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