The south-facing roof of one 16-storey apartment building in Shanghai’s Shenzhuang district stands out from its neighbours. It is covered with 22 photovoltaic panels wired up to an electricity meter.

The roof’s owner is Zhao Chunjian, a professor at Shanghai University of Electric Power, who last winter climbed up and installed his self-designed “domestic power station”. On December 15, 2006, Zhao’s solar power plant produced its first watt, and to date it has produced 2,750 kilowatt-hours (kWh). In fact, the clean energy the panels produce is enough to power Zhao’s entire apartment below.

This set-up has run smoothly for 10 months, allowing for seasonal fluctuations. August was Zhao’s record month, with 352 kWh produced, while gloomy January managed only around half of that.

Electricity generation also fluctuates over the course of a day. In daylight hours, the solar panels produce more electricity than is needed, and any excess is fed back into the city grid for others to use. After sunset, a small amount of power is drawn back from the grid to keep things ticking over. Early indications are that the installation will produce around 3,000 kWh over the year.

Zhao is clear about the implications of his power shift. “It works out as 1.14 tonnes of coal saved, and 3.6 tonnes of carbon dioxide emissions avoided,” says Zhao. Besides these benefits, it also brings Zhao energy security in a city that experiences frequent power shortages. Even on the hottest summer days, his family do not worry about the air-conditioning suddenly coming to a halt.

But the outlook for solar power is not all that bright. The rooftop solar cells generate power at a far greater expense than that drawn from the city grid. Says Zhao: “The system cost me over 140,000 yuan (US$18,890). Even if it produces 100,000 kWh over its lifetime, that’s 1.4 yuan (US$0.19) per kWh.” Power from the grid costs only 0.62 yuan (US$0.08) per kWh. “Who is going to spend that kind of money for the sake of the environment?”  

Put another way, Zhao’s installation costs could buy almost a quarter of a million kWh of energy from the grid – enough to sustain an average household for 81 years. But the solar cells only have a lifespan of only three decades. And if it wasn’t for government subsidies for solar power, that gap would be even greater.

Moreover, the electricity that Zhao feeds back into the grid during the day brings him no benefit. In fact, he pays for the privilege. To prevent the theft of electricity, the power company uses meters that only turn in one direction. The numbers go up, regardless of which way the electricity is flowing, even for Zhao.

Zhao pulls out an electricity bill. “Look, in March we paid 400 yuan.” In Japan, he says, households with solar power cells have two meters: one for power that is used, one for power sold back to the grid. If you produce more power than you use, your rooftop can turn a profit. 

Zhao studied for his doctorate in Japan, and has worked in the solar power industry ever since. “Domestic solar power is very popular in Japan,” he says, “600,000 households have already installed solar cells.” When his family moved house last year, Zhao took the opportunity to build China’s first domestic solar power plant of its kind. But the costs involved mean that his endeavour cannot be popularly recreated in China.

China’s Renewable Energy law came into effect on January 1, 2006, which encourages businesses and individuals to use solar power. But there are not the concrete measures that are needed. How can power be sold back to the grid? What preferential pricing will the energy companies offer people who switch to green electricity? China is in urgent need of economic measures – both carrots and sticks – to encourage the use of solar power.

A country’s solar power potential relates directly to its land area – and this means that China is potentially very rich in solar energy. Over the past few years, the industry has boomed. In 2006, China produced solar cells with capacity of 370,000 kWh, 15% of the global total and the third largest producer in the world. Solar power entrepreneurs have attempted to follow the lead of Shi Zhengrong, founder of Suntech Power, in appearing on the country’s rich lists. During September’s World Solar Congress in Beijing, Torben Esbensen, chair of the International Solar Energy Society, told Chinese journalists that the country was already an important player in the sector. But these successes hide the fact that China produces most of its solar panels for export. China is still in the early stages of developing its own solar power infrastructure.

A feasibility study of large-scale domestic solar power generation, carried out by Cui Rongqiang, from Shanghai Jiaotong University’s Solar Energy Institute, found that if one-tenth of Shanghai’s 200 million square metres of rooftop was used to generate solar power, it could produce 3 billion to 4.7 billion kWh every year. Today, these estimates are being backed up by the professor Zhao’s own experiment. But it is unlikely many will follow his example.

So why is this? Besides the cost, government policy is also a determining factor. In some developed countries, local electricity distributors will buy solar-generated electricity at cost, plus a reasonable profit margin. Government subsidies – for generators or distributors – and growing environmental awareness are combining to popularise solar power. But China has no similar policies, meaning the country’s market has yet to take shape. As of the end of 2006, China had less than 80,000 kWh of solar power capacity – very small when compared to the total power generation capacity of 600 million kWh. For most Chinese people, solar energy is still a very remote possibility. 

Zhao, however, has high hopes for the future of his rooftop power plant. He is keeping detailed records of the electricity he generates. Next year, this data will be published to help inform government decision-making.
 

Kan Zhe is a Shanghai-based reporter for chinadialogue