Frank Jensen, the lord mayor of Denmark's capital city, spent the last week looking forward to Friday night's state dinner for President Hu Jintao. But the food and handshake at Queen Margrethe II's summer palace, he hoped, was just the beginning of a new relationship with China.

Jensen said he will be heading for Beijing later this month to finalize a sister-city agreement with the Chinese capital. While some cities collect sister-city relationships like postcards, it's a rarity for Copenhagen, whose officials have historically preferred to network from within organizations such as the C40. That group of the world's largest cities includes 20 percent of the global GDP.

"I look forward to visiting Beijing," Jensen told China Daily last week. "The sister city agreement is the first long-term agreement that Copenhagen makes in many years, and I am very honored that Beijing pays such great attention to Copenhagen."

Jensen said both cities have a mutual interest in cooperating to enhance sustainable urban development, such as efficient use and supply of water.

One way Copenhagen has capitalized on this idea in recent years: the Harbor Baths, a recreation area that revitalized a once-shabby waterfront district. Now on a summer's day, the water park teems with kids diving off the piers and adults who sunbathe or swim as their fancy takes them. Merchants have followed the people there. Classic old buildings have been renovated, and hip galleries, cafes and restaurants cluster around that part of the harbor. A blue sky sparkles over the inviting water, and a boat taxi takes commuters up the inlet to busy new commercial centers where parking is at a premium.

"The investments we have made within the area of sustainable urban development in Copenhagen have solved problems with pollution, improved the quality of life and generated economic growth," Jensen said. "I look forward to sharing our innovative green solutions with the city of Beijing."

One of those green solutions is an old one: The bicycle. Bike culture has a long history here, getting a lot of new media attention during the climate change summit of 2009. Jensen gets to work on two wheels every day. So do Crown Prince Frederik and the butcher, the baker and the candlestick maker.

The Danish embassy in Beijing has aggressively promoted bicycles at its public events for many months. Ambassador Friis Arne Petersen, now in the Danish capital for President Hu Jintao's state visit, said recently that bicycles are old friends for residents of Beijing and Copenhagen. "They have always been part of our lives as transportation, not recreation," he said recently while hosting a "climate race" in the Sanlitun area of China's capital. "In today's world, where we try to reduce our carbon footprint, bicycles can have a bigger part to play than ever."

In Copenhagen late last month, Jensen unveiled what the city called a "holistic vision" to achieve its goal to be carbon-neutral by 2025. The ambitious plan would reduce CO2 by transferring energy production away from coal and toward biomass, wind and solar - all of which Denmark has been a global leader - while also reducing consumption and improving energy efficiency in transportation, housing, heating and industry.

The targets include a 20 percent reduction in heat use, a 10-percent reduction in household electricity use and a 20-percent reduction in electricity use by businesses. That will cost the city about 2.7 billion kroner ($458 million) - including 600 million kroner for improvements in the cycling infrastructure. It will also require additional private investment of at least 20 billion kroner, the city estimated.

"The investments will ensure jobs now," Jensen told the media in late May, "and the new solutions will be an opportunity to create economic growth".

Contact the writer at michaelpeters@chinadaily.com.cn