Wind and sunlight have many advantages as fuel sources, but one big drawback is that they aren't portable. You can't carry them to a power plant. You have to build the power plant wherever you find them.
That puts the US in an awkward situation, because the most intense wind and sunlight tend to be found in remote, low-population areas — think the sunny desert Southwest or the windy Great Plains.
In order to exploit that wind and sunlight, the US needs some way to carry the power generated there to the population centers where it's needed. That is to say: The US needs new high-voltage, long-distance power lines.
Big infrastructure like that is notoriously difficult to build in the US, but it can still happen. Last week brought heartening new evidence.
A transmission line to unlock Oklahoma wind energy
On Friday, the Department of Energy approved the Plains and Eastern Clean Line, a new high-voltage direct-current (HVDC) power line that will extend from western Oklahoma to western Tennessee. It is meant to bring the abundant wind power of the sparsely populated Oklahoma Panhandle to dense population centers to the east.
The project is being developed by Clean Line Energy Partners; it is privately funded, paid for by energy producers and utilities that want to make use of it.
In addition to the poles and wires, the project will involve three conversion stations.
Wind turbines in the panhandle will generate alternating current (AC). It will be transformed to direct current (DC) at one station, near Guymon, Oklahoma, then sent over the line. There will be a station in Russellville, Arkansas, where power can be offloaded into the midwestern AC grid, managed by the Midcontinent Independent System Operator (MISO).
And there will a third station in Memphis, where power will be converted and fed into existing AC grids serving Southwestern and mid-South states.
(Clean Line CEO Michael Skelly told me that roughly one-sixth of the energy will go into the MISO grid; the rest will continue on to the final station.)
Clean Line claims the line will unlock $7 billion in new investments in wind energy and bring 4,000 megawatts of new wind capacity into the system.
That power will help clean up some of the dirtiest grids in the country (I'm looking at you, the South), which currently have the least access to renewable energy.
HVDC lines are pretty cool
DC lines (in which electricity runs in one direction) are more effective and economic over long distances than AC lines (in which currents alternate either direction).
HVDC lines, in particular, are crucial for connecting remote renewables with electric loads, as this Siemens video explains:
"Today," Clean Line notes, "there are more than 20 HVDC transmission facilities in the United States and more than 35 across the North American electric grid."
One of the advantages of HVDC is that it only requires one pole rather than two side by side, so it takes up much less land (around 170 feet wide, versus around 400 feet). Here's one of the structures used, a monopole rather than lattice structure:
And here's an interesting video on the construction process:
Because HVDC infrastructure is tall and narrow, it allows for a range of land uses, most notably agriculture, to proceed more or less unimpeded around it. And landowners get other benefits too, which brings us to...
How this HVDC line got approved
The process this line had to go through to get cleared is rather epic. It began in 2009 and involved years of reviews, community meetings, and regulatory approvals from multiple agencies, including DOE and the Tennessee Regulatory Authority.
In the process, much scrutiny was given to "potential project impacts on existing resources, including but not limited to, homes and structures, heavily populated communities, recognized tribal lands, areas with high resource value, recreational areas, known cultural resources, water resources, and federal and state protected species." (Makes you wonder about the "not limited to.")
Clean Line submitted a route, DOE responded with amendments, community feedback resulted in more amendments, and DOE finally cleared the final route on Friday.
Part of how approval was won is that Clean Line offered local benefits all along the line.
On the Oklahoma end are new economic development and new jobs from wind power (and eventually, Clean Line expects, about 1,000 MW of solar power as well — the panhandle is also very sunny).
Along with that is "$13 million in ad valorem taxes to Oklahoma counties and rural communities where the electric transmission project is located" in the line's first year. That tax revenue will continue annually as long as the project operates.
In Arkansas, landowners will receive annual payments from Clean Line for every pole on their land; those in-state payments will total about $5 million the first year and $140 million over the first 40 years.
In addition, much of the wire itself, along with numerous parts for wind turbines, will be manufactured in Arkansas.
In Tennessee, Memphis gets to become an energy hub (it's already a shipping hub), and the whole region gets an influx of cheap, clean energy.
And of course, all three states will see thousands of (temporary) jobs created by construction of the line itself, along with reductions in air pollutants that come with a shift to cleaner energy.
It took seven years, but it all lined up just right. Construction is expected to begin next year and conclude by 2020.
There are lots more HVDC lines proposed, but approval is always a challenge
The Plains and Eastern line is only one of five that Clean Line has in various stages of the approval process. Here are the others:
They are all meant to carry wind energy from where it's generated (purple) to where it's needed (green).
It's never easy. As this Bloomberg Business story notes, Clean Line has already had a few setbacks:
Clean Line ... asked Iowa regulators to suspend review of its 500-mile Rock Island line last year as the company plots its course through the approval process amid opposition from landowners. In July, Missouri’s Public Service Commission voted to block the company’s 780-mile Grain Belt Express line, saying the developer hadn’t proven the need for the $2 billion project.
The company is going to resubmit plans to the Missouri PSC and expects to eventually win approval. And it expects to eventually win over landowners in Iowa as well. But it is a slog.
Bloomberg points to a few other companies that also have HVDC lines in some stage of the approval process.
Anbaric has proposed a Maine Green Line to carry wind energy from northern Maine to the Boston area.
TDI New England has proposed a New England Clean Power Link line that would bring Canadian hydro down to Vermont population centers (almost entirely underground or underwater).
SunZia is proposing a Southwest Transmission Project to carry solar power from Arizona and New Mexico to population centers in the desert Southwest. The Juan de Fuca Cable Project would link Vancouver Island, British Columbia, with Port Angeles, Washington, enabling better balancing of renewable and hydro energy in the region.
And so on. It's too little, and too slow.
Transmission is key to renewable energy growth in the US
A much-heralded report last year from the National Renewable Energy Laboratory (NREL) concluded that the US could integrate up to 30 percent wind and solar "via transmission expansion and largely understood changes to system operations."
But that means a lot of transmission expansion. Here's a kind of US supergrid proposed by the American Wind Energy Association (AWEA) back in 2008:
This is just a speculative sketch, obviously, and it doesn't even show any of the offshore wind, but it gives some sense of the scale involved. It's the kind of thing that would be required to fully unlock the power of wind and solar in the US.
Assuming it's completed on schedule, the Plains and Eastern Clean Line will have taken 11 years from proposal to reality. All the processes and reviews, the multiple overlapping regulatory authorities, the varying and unpredictable timelines — they create substantial uncertainty for investors, as Clean Line's EVP explains in this 2012 letter to the DOE. That makes them more difficult to finance and build.
Something needs to be done to streamline the process. If every piece of the US supergrid takes 11 years to build, it's going to be a long time before American wind power reaches its potential.
Bonus brain stretching
Here's a proposal for a global renewable-energy grid (GREG), making use of HVDC lines and centralized storage:
And here's another one, part of an excellent overview in IEEE Spectrum:
Imagine all the people...