Community-gardening advocates have sold urban farming as a sustainable local alternative to industrial-scale farming and as an educational platform for healthier living.

As design teams work toward harnessing air flows around buildings, they are producing some intriguing structures. But just how viable is wind power as a source of on-site renewable energy? Wind power is the fastest-growing source of megawatts thanks to the jumbo-jet-sized turbines sprouting en masse worldwide. But it also has a significant presence in the city, where gusts regularly send umbrellas to landfills. Rather than considering it a nuisance, architects increasingly view urban wind as a renewable resource for on-building power generation. Building-integrated wind power (BIWP)—wind turbines mounted on or incorporated within an occupied structure—may lack wind farms’ economies

A two-tier power system could deliver electricity more dependably to everyone. Blackouts caused by superstorm Sandy and other recent destructive weather events–coupled with dramatic system failures like the great Northeast blackout of 2003–have undermined confidence in the U.S. electrical grid's ability to keep homes and businesses humming. Those with means are increasingly installing their own power generation, and thus raising a provocative question: could the nation soon have a two-tier power system in which reliable electricity is a luxury, as is the case in many developing countries? Illustration © Andrew DeGraff Experts in electrical transmission tend to agree that the