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They said it at Brainstorm Green

Here are some highlights of FORTUNE's Brainstorm Green conference, which wrapped up yesterday. I'm co-chair of the event, which brought about 300 corporate leaders, environmentalists, investors and academics to Laguna Niguel, CA, for three whirlwind days of talk about how business can help solve the world's big environmental problems:

Alan Mulally at FORTUNE Brainstorm Green

The trouble with electric cars:  Batteries remain heavy and very expensive, adding about $12,000 to $15,000 to the cost of a Ford Focus that would otherwise be priced at about $22,000, said Ford's CEO, Alan Mulally. During a q-and-a with the audience, he said:

…a battery for a hybrid vehicle is around a 2 kilowatt hour battery, weighs around 100 pounds, maybe around $2,000.  And as you move to a plug-in hybrid size, say around 8 to 10 kilowatt hours, then that weight moves up to around 300 pounds and the cost is around $7,000 to $8,000.  And then when you move into an all-electric vehicle the battery size moves up to around 23 kilowatt hours, it weighs around 600 to 700 pounds — some people actually are taking our seats to be able to carry the battery around, not us — and also they're around $12,000 to $15,000….So, you can see why the economics are what they are.

Of course, drivers who pay $39,200 for a Focus EV will save a lot of money on fuel during the life of the car, depending on gas prices and how much they drive. That's a reminder of another dilemma facing potential electric-car buyers.  Ford says its Focus can go up to 76 miles on a full charge, so it's ideal for people (like me) who don't drive much. But the less you drive, the longer it takes to recover the higher up-front costs of the car in the form of lower operating costs.

Even so, sales of hybrids and electrics were the fastest-growing segment in the U.S. auto market in the first quarter. They accounted for less than 5% of vehicles sold but Mulally said their share will grow as battery prices come down.

"We see this as continually growing," he said. "This is a long-term journey."

Lew Hay

Worries about wind: If Congress allows a production tax credit for wind-power generation to expire at the end of the year, as planned, new construction of wind farms "will go to virtually zero next year," said Lew Hay, chairman and CEO of NextEra Energy. Eric Spiegel, the president and CEO of Siemens Corp., told me that the dilly-dallying over the production tax credit had already slowed orders dramatically for the company's US-made wind turbines. Siemens is tryingto sell turbines to Canada and Mexico to avoid laying off workers at its three US-based factories.

Letting the tax break expire would be dumb. The US will install about 10 gigawatts of low-carbon wind energy this year–about 35% of all new power generation, even against a backdrop of dirt-cheap prices for natural gas. The wind industry has been growing for about a decade. GE has invested about $1 billion in wind in the last 10 years, said Stephen Bolze, president and CEO the company's power and water group.

Until the US enacts a carbon cap or tax to promote low-carbon energy, production tax credits for wind and solar are vital to keep those industries alive.

Why food costs need to rise: I'd guess that food-industry leaders Greg Page, Larry Pope and Gary Hirshberg don't agree on a lot but they all said that making agriculture more sustainable will require consumers to pay more for what we eat.

Page, who is CEO of agribusiness giant Cargill, said: "We try to get people to think about price as one of the real necessary elements for sustainability." Consumers, for example, may have to pay more for products containing soy or palm oil as Cargill and its suppliers produces those commodities  in ways that protect rainforest lands and generate fewer greenhouse gas emissions.

Pope, who is CEO of Smithfield Foods, the US's largest hog producer, said Smithfield will spend about $400 million over the next decade to improve the quality of life of the hogs in its supply chain, and improve environmental protection. "The industry proceeded to call me a traitor, but we moved forward," he said. Speaking to environmentalists in the crowd, he said: "People have thought I'm more on your side than on our side, but it's the right business decision to make."

Gary Hirshberg

Hirshberg, the chairman of Stonyfield Farm, said his organic products costs more because they are better for the environment and for the health of farmers and consumers. "There are 10,000 reasons to buy organic and one not to," he said. "That's price." It's time, he said, to "banish the myth of cheap."

The price isn't right: It's not just food, of course, that's mispriced when farmers externalize their costs in the form of water pollution or GHG emissions. Getting prices to reflect the full costs of all the things we consume was a theme that, not surprisingly, ran throughout Brainstorm Green.

Water, for example, that water is heavily subsidized in many places and not priced at all in others. Mark Tercek, the CEO of the Nature Conservancy, said: "Because water has been free, we've had some crazy uses of water in agriculture where the wrong things have been grown in the wrong places."

During a panel titled "What Is Nature Worth?" economist Pavan Sukhdev of Yale and author Jared Diamond talked about how to protect the trillions of dollars of tangible economic value in the services provided by nature, which include cleaner water and air, pollination of plants, medicines, etc. Sukhdev said: "We use nature because it's valuable but we lose nature because it's free."

As always, I left Brainstorm Green with my head buzzing with as many questions as answers.

Even after interviewing Andrew Liveris, the charismatic CEO of Dow Chemical, I'm not sure what to think about the company. Dow has a checkered past (Agent Orange, napalm) and it makes controversial products like the widely-used weed-killer 2,4-D. But the company's future will be all about sustainability, Liveris told me, as Dow develops breakthrough products like solar shingles and lightweight materials for cars and trucks. His passion for science, R&D and American manufacturing jobs was impressive.

Listening to Shell's Russ Ford and Fred Krupp of the Environmental Defense Fund talk about natural gas has just about persuaded me that fracking, if properly regulated, can be done safely. But I'm worried by the cheerleading (including some by FORTUNE) for natural gas, which is, after all, a fossil fuel. Saying that natural gas is better than coal is faint praise, as Mike Brune of the Sierra Club pointed out.

Cathy Zoi

Meantime, it's hard to know whether we are moving closer to or farther away from getting a desperately needed national energy policy. John Podesta of Center for American Progress, former EPA chief William Reilly of TPG Capital and Cathy Zoi of Silver Lake Kraftwerk joined in a great panel about the politics of climate and energy, and all said there is at least a least a possibility of a bipartisan "grand bargain" after the election that would include a mix of federal spending cuts, curbs on entitlements and tax reform and simplication that could include a carbon tax. If only.

As co-chair of Brainstorm Green, I'm obviously biased … but it felt like there was a lot of enthusiasm and optimism (and, of course, brainpower)  at the confab.  I met some fascinating people who I'll be writing about in the weeks ahead. Thanks to all of you who joined us. If you're someone who plans way ahead, we expect to be back in Laguna Beach on April 29 to May 1, 2013.

Interviewing Andrew Liveris of Dow

All photos by  Stuart Isett/Fortune Brainstorm Green. Many more here.