ONE TOWN SQUARE: at the intersection of peak oil, climate change, and land use

The biggest effect of Sunday’s conference in Jeddah was to bring to the world’s attention the stark reality of the immanence of peak oil.  So what if Saudi Arabia is able to increase production to 12.5 mbd within a couple of years?  Nearly verybody else’s production will still be declining.  The net effect, at best, would be to maintain current levels of production for a few more years before the final descent begins. Coal and oil aren’t far behind on the depletion curve, and (safety and cost problems aside) neither is nuclear.  What to do?

Ted Nace at Gristmill reminds us that an area of about 100 x 100 miles (10,000 square miles) of solar thermal power – utility-scale arrays of mirrors that create heat and then electricity – could supply 100% of US electric power, day and night.

That’s not an insignificant amount of land – but it’s a lot less than we currently use for other purposes. Robert Rapier has calculated only about half that amount of land would be required – an area about the size of Los Angeles County.

Joseph Romm has posted photos at Climate Progress  showing what a solar thermal array looks like:

click to view image

Gar Lipow at Gristmill does a quick back-of-the-envelope calculation and concludes that solar uses far less land than coal.

“Nevada Solar One takes up about 400 acres, mostly for mirrors and heat engines. You would have to mine about 5,300 acres to feed a coal-fired powered plant producing the same amount of electricity.”

His calculations are based on a 20-year period. But the need to mine coal goes on forever, whereas a solar facility can occupy the same footprint forever. And then you have to also consider the environmental impacts.

A new DOE report – “20% Wind Energy by 2030: Increasing Wind Energy’s Contribution to U.S. Electricity Supply” - concludes that it’s feasible for wind energy to contribute one-fifth of the total U.S. electricity supply by 2030.

Joseph Romm at Climate Progress lists the key conclusions:

• Annual installations need to increase by only a factor of three from current levels by 2018.
• Costs of integrating intermittent wind power into the grid are modest. 20 percent wind can be reliably integrated into the grid for less than 0.5 cents per kWh.
• No material constraints currently exist. Although demand for copper, fiberglass and other raw materials will increase, achieving 20 percent wind is not limited by the availability of raw materials.
• This would require 300,000 MW of wind, delivering electricity for about 6 to 8.5 cents per kilowatt hour, unsubsidized (i.e. no federal tax credit) and including the cost of transmission to access existing power lines within 500 miles of wind resource [new nuclear is currently about 15 cents/kwh (see here)].
• The 20% Wind Scenario could require an incremental investment of as little as $43 billion NPV [net present value] more than the base-case no new Wind Scenario. This would represent less than 0.06 cent (6 one-hundredths of 1 cent) per kilowatt-hour of total generation by 2030, or roughly 50 cents per month per household

Romm says that key benefit is that carbon dioxide emissions from electricity generation by 25% in 2030. But this isn’t such good news after all – avoided emissions would merely “nearly level projected growth in CO2 emissions from the electricity sector.”

In other words, emissions would continue to grow – just not as much as they otherwise would. We would be far from on track to meet the 80% reductions necessary to keep atmospheric CO2 at ~450 ppm, much less the level of reductions necessary to stabilize CO2 at 350 ppm, the level necessary to avoid an unacceptable risk of climate catastrophe.

Robert Rapier at R-Squared Energy Blog has undertaken to calculate whether it would be feasible to use solar power to generate enough energy to offset all U.S. gasoline consumption. He concludes that it will take about 444,000 megawatts of electrical generating capacity. Current U.S. generating capacity is over 900,000 megawatts – but there’s little to spare.

He calculates that to generate 444,000 megawatts with solar PV would require just under 1,300 square miles (a 36 mile by 36 mile square) of just PV surface area. To generate that much power with solar thermal – including supporting infrastructure – would require 4,719 square miles (a 69 mile by 69 mile square).

A large area, but not impossible to envision. That’s almost exactly the area of Los Angeles County – and we’ve easily covered pretty much all of that area with built environment.

A couple of weeks ago I wrote a piece suggesting that concentrated solar thermal power (CSP) could prove to be the answer to our energy (and climate) crises.

Now Joseph Romm has a long article on CSP in Salon, “The technology that will save humanity: The solar energy you haven’t heard of is the one best suited to generate clean electricity for generations to come.” He has a brief summary and these photos at his blog Climate Progress.

click to enlarge

Romm gets to the bottom line of why CSP is so important:

“Because it’s the only form of clean electricity that can meet all the demanding requirements of this century . . “

Five solar-thermal power plants – capable of generating 900 megawatts of electricity, enough to power 540,000 homes each year, are slated to be built in the Mojave Desert. BrightSource Energy will build the plants, and Pacific Gas and Electric has contracted to buy the power.

Nine solar plants were built in the Mojave Desert between 1984 and 1990 and are still operating.

The inherent problem with conventional photovoltaic cells is that they are composed of silicon. Although abundant in the form of silicon dioxide (say, from sand), the pure element requires considerable energy to extract. Analysts differ somewhat in their estimates, but the consensus is that it takes about three years for a conventional silicon photovoltaic panel and the equipment associated with it (the rigid frame used to mount it and the power-conditioning electronics that attach it to the grid) to produce the amount of electrical energy required to manufacture this equipment in the first place—assuming that it is set up in a reasonably sunny spot.

Fortunately, alternative strategies exist for making photovoltaic cells using much less energy, and one promising example is now beginning to be made in significant quantities.

“Dye-sensitized” solar cell uses a combination of titanium dioxide (a component found in many paints) and an organic dye molecule, often a compound containing ruthenium, which are together immersed in a liquid electrolyte. Instead of coming off the assembly line in discrete, rigid units, the dye-sensitized cells are placed on half-mile-long rolls of flexible metal foil.

ECN Solar Energy, an independent photovoltaic-research firm in the Netherlands, has estimated that such dye-sensitized cells installed in southern Europe would have an energy payback time of only a half-year or so.