Scientific American’s Solar Grand Plan
Scientific American has a thought-provoking proposal in its January 2008 issue. The magazine proposes a massive, far-reaching plan to get solar power generating 69 percent of America’s electricity 35 percent of our total energy by 2050, thus replacing all of our foreign oil needs and slashing global warming emissions. Below are some of the highlights of that “solar grand plan.”
Technology
The American Southwest would be the home of massive amounts of solar power needed for this clean energy conversion. Specifically, two types of solar power would be employed: Photovoltaic (PV) cells and concentrated solar power.
According to the solar grand plan, 30,000 square miles of PV cells would provide 3,000 gigawatts (GW) of energy. The “30,000 square miles” part made me flinch, but already existing solar installations indicate that the land needed for each gigawatt-hour of solar energy in the Southwest is less that the amount of land needed to run a coal plant and mine the fossil fuel for it.
Concentrated solar power would supply about one-fifth of the solar energy in the plan. Concentrated solar power uses long metallic mirrors that focus the sun’s rays onto a pipe filled with fluid. The fluid is heated and runs through a heat exchanger that produces steam that turns a turbine. Nine plants like this already exist in the in U.S.
Storage
The solar grand plan recommends compressed-air energy storage for PV energy: Electricity from the PV plants compresses air and pumps it into empty underground spaces like caverns, abandoned mines, aquifers or depleted natural gas wells. The air can be released on demand to turn a turbine and make electricity, aided by burning small amounts of natural gas. Compressed-air technology has been used in Germany since 1978 and in Alabama since 1991.
To store the concentrated solar power, pipes could be run into a big insulated tank containing molten salt that would retain the heat. At night when the sun isn’t shining, the heat could be extracted to create steam. Of course, the salt doesn’t retain heat indefinitely and so the stored energy would have to be tapped within a day. The first commercial installation with this molten salt storage technology is being built in Spain and has seven hours of storage, so this technology would still have a ways to go.
Transmission
Our existing grid of AC power lines isn’t up to the job of efficiently carrying solar power from the Southwest to consumers around the country (it would lose too much energy over that distance). Rather, the plan proposes a high-voltage, direct-current (HVDC) transmission backbone for the nation.
Studies have shown that an HVDC line loses less energy than AC lines over long distances and are less expensive to build. The lines would end at converter stations, where the power would switch over to AC and then be sent along already-existing regional transmission lines. About 500 miles of HVDC lines already exist in the U.S. and companies are eying them up for their renewable energy projects: Southwest Power Pool of Texas is designing a system of DC and AC transmission for a wind farm in Texas and TransCanada proposed 2,200 miles of HVDC to carry wind power from Montana and Wyoming down to Las Vegas and beyond.
Cost
The cost of this plan is admittedly large, as any major change in the nation’s infrastructure would be. The plan estimates $420 billion in subsidies are needed from 2011 - 2050 to fund the infrastructure and technology advances to make solar power more cost-competitive. Economies of scale and continued efficiency milestones will also help:
A report by the Solar Task Force of the Western Governors’ Association found that concentrated solar power could cost 10 cents per kWh or less by 2015 if four GW of plants were constructed.
The cost would be well worth it. The writers argue:
The infrastructure would displace 300 large coal-fired power plants and 300 more large natural gas plants and all the fuels they consume. The plan would effectively eliminate all imported oil, fundamentally cutting U.S. trade deficits and easing political tension in the Middle East and elsewhere. Because solar technologies are almost pollution-free, the plan would also reduce greenhouse gas emissions from power plants by 1.7 billion tons a year, and another 1.9 billion tons from gasoline vehicles would be displaced by plug-in hybrids refueled by the solar power grid. In 2050 U.S. carbon dioxide emissions would be 62 percent below 2005 levels, putting a major brake on global warming.
The biggest obstacle to the solar grand plan may not be the money or the advances in technology, but rather the political will to get it done. And while I personally appreciate and recognize the need for grand plans to demonstrate how we can get this done, I question whether solar power is really the best technology or if it’s being billed as the silver bullet answer to our energy problems. At the same time, the arguments for efficiency and a modern transmission system are on-target. Whether our clean energy future employs a majority of solar power or is a mix based on the local resources of the region (solar in the South, geothermal in the West, wind in the Midwest, etc.), our obsolete electric grid and advancements in storage capacity will be crucial for expanding other renewable energy systems.
The amount of sunlight the earth receives in 40 minutes is enough to power the globe for a year. With the 250,000 square miles in the U.S. Southwest suitable for solar power plants, a large amount of this resource must be a part of a 21st century system.
The subsidies question is going to be a tough one, as we saw with the recent Energy Bill compromise. The argument is that alternatives should stand on their own and let the market decide.
I’m not sure this is feasible at the current energy conversion rates and efficiency. One can reasonably assume from this standpoint that other energy sources are not subsidized in some way (either through tax breaks or direct payments). This simply isn’t true.
Should we kill one subsidy just to start another? I worry about that.
However, if consensus is ever reached on shifting the subsidy, we might insist on a term-limit. Say, 5 years, to generate a time-bound incentive to rapidly scale production and reduce the costs of producing alt-energy. Or better still, invest the savings from one pork not in another pork, but into an investment fund for new technologies, creating new jobs that are linked to both new energy development and new technological fixes to energy conservation.
Wouldn’t it be easier to line the east-west highways with solar cells; considering that Interstate 10 covers over 2500 miles by itself. If you setup 4-8ft panels facing south on both sides of the road the only thing you would block would be noise. Then add in the land covered by the other freeways such as interstate 40 which is anouther 2400 miles, you quickly begin to cut down the amount of open land used for this project and you can use the money made for power to fund the roads.
Just thinking
You state that conversion stations would be at transmission-line endpoints. What about data centres, where most of the equipment runs on DC? Why have a wasteful DC->AC->DC conversion cycle? For any loads that require AC, why not just use an invertor?
thinking_hard - you have it half right: it would be better to build the solar cells into the road itself, and make the entire thing one giant solar collector. We would need a lot of work getting the materials right, but think of it: every new mile of road would be that much more electricity produced. The electricity could even be used by cars, so there would be no need of ‘refueling’ stations. But it would be a lot of work….
I wish they would drop the solar idea. Well actually cant these idoits thing of new ways of energy that having sun light heat to warm some chemical to produce steam. I bet theres some elements when mixed together produce massive heat. Many people still trying to convert solar to power- move on. I wonder why gun powder is not even considered as a mechanism to produce electricity, sure launches and keeps a bullet for miles in the air, more power than comparable gasoline used to launch a bullet.
I just found 44,000 square miles of space that wouldn’t even be missed:
http://www.futurepundit.com/archives/002185.html
Roofs. Shopping centers, malls, corporate offices, homes, apartments, etc. Throw in another 10 to 15k square miles of land in the southwest that is not being used and there ya go. Also solar stirling is 45% efficient at conversion, throw in biodiesel for cars (algae farms) and a bit of nuclear or natural gas to cover the gaps, wind for giggles, and tidal, wave, hydroelectric, and we are off to making energy, getting off oil and supporting an incredible economy with more than enough juice to take us into space and beyond. (Electrolyzing hydrogen for rocket fuel), increases in technology could constantly upgrade the solar panels (IE if 1 square mile produces 60kw now, and is gradually upgraded even 10% we have a path for growth. I mean seriously do we have to choke to death and pay 100 bucks a gallon for gas before we get it. This should be on the scale of building the highway system, as it impacts are national security in a HUGE way. M1A1 tanks, F16’s F22’s B52’s B1B, A10, etc defend our nation, but without fuel (read could be fueled by biodiesl made here) we are at the mercy of nations with oil, not all friendly. Think about it, call your representive and lets spend 500 billion here instead of pay that much every month for foriegn oil (no didn’t check that number but I know it is a LOT)
I see 3 problems with panels by the roads. Theft, dirt and vandalism.
[...] tip here to Maria Surma Manka at sustainablog, where I came across this story. Manka made what I think is the critical point when we talk about [...]
Roadside solar power is a bad idea for more reasons.
Ever hear of “that house on the corner that has had a car smash through it’s front door on more than 1 occassion”?
I am pretty sure they are trying to reduce the costs of solar power, and part of that is reducing repair and upkeep costs. Building it in an accident prone area (I.E. adjacent to a highway) sort of defeats the purpose of reducing costs, besides the already mentioned theft, dirt and vandalism. It is probably easier (cheaper) to plan clear and build large areas with garunteed sunlight, not thin highway segments.
Covering 19% of the southwest in solar panels just won’t fly from an environmental standpoint. It’s not barren lands, it’s a delicate desert ecosystem out there and if you shade all the plants and tear up the land building roads you’ll wreck it.
Far better to have solar panels on every building leave the electrical generation to a decentralized approach rather than these huge centralized projects that would be vulnerable to site outages. What happens if climate change makes the southwest unsuitable because of cloud cover or something like that?