Five years ago this spring, I reported on the first wave of people resisting industrial renewable energy projects in the Mojave -- solar fields covering six or seven square miles, wind farms eight or nine times that size. Over the years, I watched them start nonprofits, launch blogs, lobby the media to tell their stories. When a reporter wrote an unalloyed success story about how big solar in the Mojave would fight climate change and secure U.S. energy independence, the activists filled up the newspaper's comment section with statistics about Germany's rooftop solar, the decline of the threatened desert tortoise whose habitat these projects destroy, the desert's function as a carbon sink.

Mostly, though, opponents testified at public meetings hosted by the BLM as it weighed various projects. Local businesspeople learned to talk like biologists. "Ninety percent of the biota in the desert exist beneath the desert soil," Paul Smith, the owner of the "tiny, tiny" 29 Palms Inn near Joshua Tree National Park, said at one meeting. "So a lot of what you think is a relatively dry environment, without a lot of things growing, is actually a rich biological environment."

None of those efforts could stop the juggernaut. The BLM has approved nine solar projects on 24,000 acres of public land in California and Nevada; several more large wind farms in process will take up tens of thousands of acres. Many more proposals appear as splotches on a map, squeezed between mountains and spread across valleys that few humans have sought to inhabit. Some of the solar plants, all pricey capital investments, will fall to the vagaries of financing; others will fail to secure contracts with utilities. Some wind developers will discover that their proposed locations don't have enough wind.

Still, many more projects will go forward, buoyed by California's mandate to generate 33 percent of its electricity from renewable sources by 2020, and rushed by ephemeral tax incentives. Nor are public-land projects all there is to worry about. On the May morning I met with Brown, he talked about a 500-megawatt installation planned for five square miles of a former ranch near Pahrump, Nev., 15 miles east across a mountain wilderness from Shoshone and Death Valley. Hidden Hills, a concentrating solar thermal plant proposed by Oakland-based BrightSource Energy Inc., will deploy two circles of mirrors, or "heliostats," each two miles wide, to focus sunlight on 750-foot towers, heating fluid inside until it flashes to gas and spins turbines. It will require new transmission through Nevada wilderness, plus natural gas lines to fuel a small start-up generator. Brown expects that infrastructure "will wedge open the door to more," noting that two more projects are on the docket in the Pahrump Valley. "That whole Nevada strip will become a big industrial zone," Brown says. "Nights will be ruined; we'll be looking at tens of thousands of acres of towers."

This desert of varied elevations can swallow grazing allotments, freeways, mines and military installations. Mountains surround it: the Panamints and Sierra to the north, the San Bernardinos and San Gabriels to the south. If you climb Telescope Peak in the Panamints, braving narrow trails above thousands of feet of scree, you can take in both the lowest point in the Lower 48, at Badwater in Death Valley, and the very highest, Mount Whitney in the Sierra. Within the Mojave National Preserve, craggy hills rise to 5,000 feet and descend into gravelly bajadas that explode with pink-and-gold blooms in a good spring. Fog rolls in, snow falls, and summer thunderclouds focus dramatic beams of light. Landscapes that look barren up close take your breath away from great distances.

What the desert's vistas can't absorb are miles of wind turbines and skyscraper-high solar towers, like the ones already standing at BrightSource's Ivanpah Solar Electric Generating Station, the first big public-land solar project, now nearing completion on California's border with Nevada. Situated at the base of the Clark Mountains between segments of the Mojave Preserve, Ivanpah will generate 400 megawatts of electricity to potentially power 140,000 homes. The plant occupies six square miles, or roughly 4,000 acres -- twice the land area of Jackson, Wyo., almost the size of eight-square-mile Ogden, Utah, or the entire city of Redondo Beach, Calif.

Given that the planet's climate is already changing, partly because of carbon emissions from coal plants, we may need scaled-up clean energy to head off catastrophic environmental change. And plenty of people, good environmentalists all, consider Ivanpah a necessary achievement. The Natural Resources Defense Council's director of Western Transmission, Carl Zichella, was on board with Ivanpah from the beginning, back when he held a similar post at the Sierra Club. Local chapters were less gung-ho, but national leaders set out to convince them: Brian Brown remembers Michael Brune, the Sierra Club's national president, showing up at a meeting of the Sierra Club's Desert Committee in early February 2011. "What he said was, basically, the Sierra Club knows there are inappropriate places for solar. Then he launched right into the political speech of saving the planet."

The persuasion, however, worked the other way -- especially after biologists confirmed, in the spring of 2011, that the Ivanpah site was home to many more threatened desert tortoises than the company's surveys had predicted. By the end of that year, even Brune and Zichella agreed that future large-scale solar and wind shouldn't proceed without land and species conservation in mind. Both the Sierra Club and the NRDC filed lawsuits against a solar project in the Mojave that would have interrupted desert bighorn sheep migration; the NRDC also came out against the company's proposal to build a 500-megawatt plant in the central Mojave near the town of Twentynine Palms, a gateway to Joshua Tree National Park.

Barbara Boyle, a Sacramento-based Sierra Club energy policy analyst, says that for most environmental groups, "the focus has really shifted from chipping away at the problem to understanding how we can protect ecosystems on a landscape scale." To that end, the BLM and the Energy Department, staffed up with stimulus money in 2009, pressed forward with a plan to designate certain areas in six Western states as appropriate for renewable energy development. Future developers who choose these sites could move quickly from application to construction, confident that environmental reviews have been completed in advance.

It was, from most perspectives, an honest and vigorous effort to lessen the impact of renewable energy on ecologically sensitive lands. Two areas environmentalists had objected to, one north of Joshua Tree called Iron Mountain, and another around the Pisgah lava field south of the Mojave Preserve, were removed from the proposal's original draft. Other, more appropriate areas -- the West Mojave closer to exurban Los Angeles, the Chocolate Mountains, which abut an Air Force gunnery range -- are being considered as alternatives.

Those zones are not binding; they're only incentives. The agencies have also left 22 million acres open for development -- "roughly 13 times the 138,000 acres BLM predicts will be needed to satisfy the 20-year demand for utility-scale solar power under California's aggressive renewable portfolio (standard)," The Nature Conservancy's Laura Crane pointed out at a public meeting.

Worse, "they came five years too late," says Brendan Cummings, the Center for Biological Diversity's public-lands director. Ivanpah lies outside the zone, as do the many projects clustered around it: First Solar has put up a 60-megawatt photovoltaic field here and plans to build two more, five times the size of the first. Bechtel Corp. has applied for rights to install six square miles of photovoltaic panels a few miles south along spring-fed Soda Lake, in an area California Fish and Wildlife has already identified as bighorn sheep habitat. That project would need only a tiny amount of water, but that tiny amount of water, drawn from the local aquifer, could be the ruin of a small and locally famous fish, the endangered Mojave tui chub, which persists nowhere else on earth but in Soda Lake's small, isolated springs.

"The solar developers say to us, 'You guys always find something,' " Ileene Anderson, a biologist with the Center for Biological Diversity, says with a laugh. "And it's true, we do. Because there is always something."