A New Place for Solar Energy: Highway Right of Way
Editor’s Note : This is a guest post from William Ellard, an economist specializing in energy and renewable energy markets. He is currently working with national solar energy firms to bring distributed solar power to municipalities in the American Southwest.
During a recent work meeting with the Western Renewable Energy Zones Initiative, it became clear that the recent push for renewable energy in the western US has major wildlife and environmental implications. As an alternative energy economist, my contribution in the meeting was to present some of the new solar energy technologies and explain how distributed solar could be deployed without disturbing wildlife ecosystems.
The main issues for public land managers and wildlife stakeholders are the new roads and infrastructure placed on previously undisturbed public lands. The western US has huge potential for renewables such as solar, wind, and geothermal. , but the rush to build these renewable power systems on public lands could adversely effect wildlife corridors and ecosystems.
These issues have me thinking more about the economic and environmental benefits of the distributed nature of solar technology. Wind and geothermal power only work in particular areas of the US—in most cases far away from the end electric user. Also, wind and geothermal resources are mainly on public lands.
Solar, on the other hand, can work anywhere. Some solar application work best in high, hot, light areas like the desert Southwest, whereas other solar applications work best in cooler, diffused light areas of the country. I’ve started to think about all the land masses in the US that are already disturbed or used, and could be levered as solar energy resources.
Commercial Rooftops
New solar firms like Solyndra produce thin film solar technology especially for commercial rooftops. If we installed solar systems on these rooftops we could supply the US with 150 gigawatts of electricity. Solyndra has entered into a contract with ENERGY STAR®-certified cool roof systems from Carlisle Construction Materials. This combination of the reflective roofing membrane with Solyndra’s solar systems increases the output of the Solyndra PV system up to 20%.
The above estimate of 25% of the US electric grid is based on the approximate efficiency ratio of 15% for Solyndra’s PV system. These solar thin film technologies are still in the early stages of development, so over time we should see significant improvements in efficiency and cost.
Solar thin film firms can already produce solar energy at grid parity. These cost breakthroughs in solar have been achieved by focusing on the cost side, not the efficiency side. New thin film solar technologies are less than half as efficient as silicon based solar cells, but can cost 80-90% less to produce. My article on solar economics describes in more detail the different solar technologies and the economic considerations.
So with commercial rooftops, the US could replace more than 25% of the grid. What about other brownfield land solar development? While driving many hours across the desert southwest on interstate I-15, it hit me.
Highway right of way solar - ROW solar
On both sides of I-15 all one can see is scrub, weeds, debris, and power lines. Highway departments must keep their right of way clear of invasive weeds such as Russian thistle(tumbleweed), cheat grass, etc. Mowing or pesticide spaying operations are the most common methods. Instead of spending all those tax payer dollars trying to control photosynthesis, why don’t we use photosynthesis to create electricity along these highways?
By designing the proper alignment of solar systems along highways, land managers could also funnel wildlife away from dangerous highway crossings and into safe wildlife corridors. In the desert Southwest, miles of small fences are built along highways to protect the desert tortoise from getting killed by cars. Larger structural solar systems could also protect larger animals such as cattle, deer, and antelope. These larger animals also cause many serious accidents and human deaths on our highways.
How much acreage are we talking about? The first estimate to consider is the amount of land that highway departments currently manage. This is a small subset of all right of way highway acreage. Road Ecology: Science and Solutions written by Richard T. Forman in 2002 is a good source of information on managed right of way land along our nations highways.
Forman’s book states that California manages 230,000 acres of right of way on 15,000 miles of highway—about 15 acres per mile of highway. In the US we have about 4 million miles of roads, or 60 million acres of right of way to manage. On many sections of highways in the western US, the highway right of way is contiguous to federal land like the BLM (Bureau of Land Management). By using a small amount of this BLM land, we could easily double the amount of land available for highway solar energy.
Depending on the particular solar technology, one needs 2-4 acres of land to place a 1 megawatt solar power system. So a conservative estimate for US highway solar would be 20 million megawatts of total capacity.
In 2006 the existing US capacity for electricity was about 1 million megawatts. For example, in just the disturbed land along our nation highways, we could have almost 20 times more capacity then currently installed. Here are some energy figures from 2007:
The U.S. electric power industry’s total installed generating capacity was 1,089,807 megawatts (MW) as of December 31, 2007.
Total U.S. electricity generation was 4,159,514 gigawatt-hours (GWh).
The capacity of different power plants will produce different amounts of total electric generation. A coal or natural gas fired plant can run almost all the time. A solar power plant may only average 8 hours a day of energy generation. So the real effective electric generation for the 20 million megawatts of highway solar capacity would be about 7 million megawatts of full generation capacity. This is 7 times the electricity we currently consume in the US.
In summary, right of way highway solar could be a solution to our nation’s energy needs and could also reduce costs to manage these right of ways. Another benefit would be to help wildlife managers create wildlife corridors for both human and wildlife safety. Let’s preserve our undisturbed public lands by implementing solar technologies on these existing managed lands.
Photo CC-licensed by Flickr user threecee
A decent idea but have you thought about the effects on drivers? Light poles have a tendency to make people dead when they hit them and im sure there would be similar effects on those hitting solar panels, not to mention the cost of replacing said panel when it’s been shattered from the impact. And as others have stated there will be thievery eventually, and that will cost far too much.
It’s good to try and reuse land where we can to make what we have more productive but there is a cost/benefit to everything.
Think about how many more technicians you would need to hire because cell 2318 in sector B2 is down but happens to be 4 hrs from the nearest tech.
@JR - there is a black market for solar panels, a big one. It would be difficult to police even a small fraction of the 20 million miles of road. Stolen panels would also shut down strings of power along their corridor.
@Phillip & Rojello (& William) - Transmission is indeed a major issue here. It depends on the grid but 40% isn’t unusual for wasted capacity in long-range transmission and grid distribution. Solar highways would likely lose more. One of the key benefits of solar is that it can be installed demand-side on rooftops. Federal funding for a nationwide highway solar system would be much better applied (first) to building on-site renewables.
@William - Thanks for the article. One of things you touched on in your response is much more likely to see development first and that’s solar-powered fuel centers for electric cars. The battery swap program underway in Israel will be watched closely. Potentially, roadside stations could use solar power to charge stores of batteries to be swapped in for drivers’ depleted ones.
It would be good to mention companies beyond Solyndra in your articles. They’ve put an interesting spin on solar but they’re still ramping up production and they haven’t established their panels as a reliable, trusted design yet. Also, they aren’t viable for just any commercial application as they require large, flat roof areas that can be retrofitted with the reflective membrane. You mention that Si-based solar is too expensive but there’s a reason it is still prevalent despite 30 years of thin film development: it’s reliable and produces more power. It would not, as you mentioned, create the thievery issue. That issue will remain regardless of whether Si or thin film modules are used. Giving a figure of “80-90% less to produce” is misleading; much of the cost of a solar system is in the design and installation and, further, producing a thin film cell is not the end of the production process. The reduced cell cost represents a fraction of the overall cost of solar.
20 million MW of capacity would produce between 22 and 28 million GWh of energy, depending on siting and alignment - hope that helps
I imagined the utilization of our black roads (currently passive uncaptured solar energy) a few weeks ago. We could just plug our houses into the road! I had heard of those solar building materials and paints that could possibly be used. The biggest difficulty I can see is channeling the energy, as well as using materials that are resilient enough to drive on.
I also like the road-side solar idea too, though it has limited application. Where I do see it being successful is in small towns (there are many of them) scattered across rural America with a major road vein running through.
Like the commenter posted (same as author?), they had an idea for using charging stations along the roads in the boonies. This idea illustrates the point that solar IS LIMITED and while some applications are suitable for operation solely during sunlight hours, there is still a fairly clear need to store generated power. I’m finding it hard to support anything but hydrogen. I’ve been thinking about powering my car with it and mounting a mini-zeppelin on my roof.
One last point I would like to throw out there is that I had this wonderful vision that solar energy is pretty much the best solution, even if it means that our power only works during the day. Many people might have a hard time with this concept (not using power at night), but I rather embrace returning to the days of yore when the nights were candle-lit and people actually slept at night. I think that a return to living more syncopated with nature would do wonders for our society.
I wish the red man beat the white man.
William, I like the idea. Economically it would seem to make sense to follow existing powerline transmission routes. As you point out, roads and powerlines sometimes coincide. Where they diverge, it would seem to make more sense to follow existing powerlines. Any idea what the percentage of convergence between roads and the powerline routes in the Southwest?
They already have highway solar on the sides in Switzerland and Oregon. A guy in Idaho wants to embed solar cells on top of the road surface too, with a durable translucent cover. You act like no one has ever thought of this. There is a company in Vancouver BC that wants to put underwater current turbines under bridges. I saw a picture of a guy that won a contest by combining overhead highway signs with horizontal axis windmills. Sidewalks could have solar built into them too with less likelyhood of damage. All these renewables are not baseline power however. Hyperion mini-nukes are baseline power. But I would combine them with underground power trunks to make the grid impervious to windstorms and only use them as emergency power. These mini-nuke batteries provide power 28 times cheaper than wind. I love the renewables I say go for all we can, but let’s be smart, and back it up with cheap emergency mini-nukes.
You don’t have to protect long wooden power poles from cars and trucks because they are inexpensive and easily replaceable. To even consider putting solar system in right of ways would require at a minimum full guardrail protection along all highways.
The costs would be astronomical and using the total national right of way in your calculations is a poor decision. It is implausible that 1/3 of all right of way acreage could be used. A more likely figure would be 5%, with the increased cost of crash and theft protection. Much right of way is currently wooded as well, would you deforest these areas?
Limit your proposal to a more feasible solution for isolated interstate communities and you might win some backing, but pretending this is a national solution weakens your argument. We can use our Uranium for the next thousand years without making up science.
Mike;
I was thinking that one could design roadside solar projects that could work also to lower traffic deaths, and reduce accidents.
Bryan;
I do track many new solar firms(about 50). For commercial rooftop, Solyndra looks the best. I will be writing more articles in the future about some of the other new firms and their applications. I am not a fan of Si based solar because of the high cost to refine the Si. I do like the economic dynamics for thin film, CSP, CPV. I did not intend to say the TOTAL cost would be 90% less for thin film, but installation cost would also be cheaper with light weight flexible planar type materials IMHO.
Tony;
I was going to put a link in about Oregon’s highway solar, but the article was already getting too long. I know I did not invent this concept. Maybe Al Gore invented this along with the Internet!
Thanks for the response, William. I keep an eye on developments in solar as well and was pretty excited when I first learned about Solyndra. The fact that they’ve pre-sold $1.2 billion in capacity already is great. Their results still haven’t been verified by third parties yet, though, and they haven’t been installed in enough locations to even consider them for large-scale public works projects. What I do like is their high wind load tolerance but, again, those numbers are based on their testing.
In the long run, thin film will likely (and almost has to) become cost-competitive with Si. In the short term, it allows for more creative or durable designs. It still has a higher cost per watt (end system cost) than run of the mill Si modules. Sunpower, Sharp, Evergreen, Suntech, etc all produce crystalline modules that cost less per watt to install than any commercial thin film supplier. Installation cost with thin film is actually higher (currently) because of increased balance of system costs. Thin film modules cost about 25% less per watt than Si modules but require much more roof area (and structural support) for a given wattage which, in the end, pushes the cost over that of Si.
Details aside, you’re right on with your predictions/recommendations. Looking forward to your upcoming articles, would be great to pick our brain sometime before then if you can see my email.
The real question is if people will steal the solar cells from the ROW. With all of the theft of metal by the local drug addicted folks - will the tax payer be providing another item to steal? We can not keep the animals from stealing now, what makes us think we can in the near future?
Feel free to check out the Oregon site. The team installed the panels 4 weeks ago. I drive by it every day. The array sits at the convergence of two main highways and is on the center meridian. It is surrounded with large barb wire fencing.
http://www.oregonlive.com/environment/index.ssf/2008/08/oregon_installs_first_highway.html
Mark