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We need lots more power lines. Why are we so bad at planning them?

transmission towers (Shutterstock)

One of the fastest and easiest ways to boost renewable energy is to improve and expand electricity transmission, i.e., power lines. Smart transmission, in addition to its many other benefits, reduces both the engineering challenges and the cost of integrating renewables.

(For a recent example, check out this post on a new power line across the Midwest, which is unlocking Oklahoma wind power.)

Unfortunately, the way transmission is planned today threatens to squander many of those potential benefits. Transmission planning badly needs to be reformed if the US wants to hit its ambitious carbon targets for 2030 and beyond.

I realize "electricity transmission planning" isn't exactly a subject of fascination for most people (I wish Donald Trump would say something stupid about it!), so I'll be brief. For the longer version, check out this new report from the Brattle Group, which I'm drawing on here.

The way we plan transmission is narrowly focused, missing important factors

Today's transmission planning is somewhat blinkered and myopic. It:

  • usually takes place within a single region;
  • focuses on a five- to 10-year horizon;
  • focuses almost exclusively on reliability;
  • does not take into account the risks of insufficient flexibility;
  • considers only a small sliver of benefits.

To the extent there's any interregional planning, it replicates these mistakes and makes them even worse.

This is bad. It guarantees piecemeal, incremental, uncoordinated growth in the transmission system. It misses long-term policy and technology trends and sacrifices the potentially enormous benefits of a more holistic vision.

Such a vision would take into account all the benefits of transmission. Here's a chart!

transmission benefits (Brattle)

When all benefits are considered, it can make the difference between a project penciling out or not. Here's an illustrative example, using the Devers-Palo Verde 2 line in California to make the point:

transmission benefits (Brattle Group)

In short, transmission planners need to evaluate projects in the context of the larger US electricity system, not purely in terms of meeting a base case of regional needs.

Transmission planners urgently need to take a longer view

Better planning would be better than worse planning any time, of course (that's why they call it "better"), but the need for better planning is particularly urgent at the moment.

First, it takes five to 10 years for transmission to go from planning to construction. If current market and policy trends in electricity continue or accelerate, as they are widely expected to, the landscape is going to look very different in 10 years, and even more different in the years following.

Policy-wise, the US carbon reduction goal for 2025 is challenging, but getting 80 percent reductions by 2050, which the US has also pledged, is exponentially harder. The power sector is entering a period of accelerated decarbonization that will continue until it hits zero carbon. Planning assumptions based on an extension of the status quo are disastrously off-base.

Technology-wise, there's going to be more distributed, small-scale generation on the grid, more electric vehicles, more smart energy management, more microgrids, and fewer big coal and nuclear plants.

The grid of the future, according to Georgia Tech.
The grid of the future, according to Georgia Tech.
(Georgia Tech)

When those changes roll around, we will very much appreciate having a smart, flexible, integrated grid — or rue not having one, which will mean higher than necessary costs for ratepayers and more difficulty than necessary meeting policy goals.

Second, much of US electricity infrastructure is nearing the end of its useful life, which means a big new round of investment is getting underway. It would be a shame to waste that new investment on poorly planned projects.

That smart, well-planned transmission projects can reduce costs for ratepayers has been demonstrated by dozens of studies, both in the US and abroad. (See the paper for a capacious list.) But what does smart planning look like?

Plan for multiple scenarios, maximize flexibility, and minimize risk

The Brattle paper proposes a "scenario-based" planning process, for both regional and interregional purposes. It goes like this.

  1. Identify the trends, drivers, and uncertainties shaping the electricity system over the next few decades. (One of the biggest: Obama's Clean Power Plan.)
  2. Develop a range of plausible scenarios based on those trends.
  3. Translate each of those scenarios into a set of planning needs and assumptions.
  4. Use modeling to simulate power flows and grid performance under each scenario.

Interestingly, Brattle analysts recommend against attempting to assign probabilities to the scenarios. Basically, we're fooling ourselves if we think we can predict the electricity system decades out.

Instead, the goal of developing a range of scenarios is to discern what kind of transmission projects can address multiple needs across multiple scenarios; which ones offer long-term flexibility in addition to meeting short-term needs; and which ones avoid low-probability but high-cost risks like sudden loss of power plants or more-severe-than-expected climate impacts. (Current planning tends to revolve around a single "base case" that excludes so-called tail risks.)

For an example of how this mode of planning works in practice, check out Brattle's work with ERCOT, the Texas grid planning authority.

The benefits of better transmission planning

Smarter transmission planning will result in better performance, better reliability, more renewable energy, and lower greenhouse gas emissions. But perhaps most importantly, it will save US ratepayers lots and lots of money:

[W]e estimate that the net savings associated with a proactive transmission planning and development process in the U.S. would range from (a) $30–70 billion of savings in total generation and transmission investment costs through 2030 for compliance with current regulations to (b) $47 billion/year of savings in annual customer bills under an even more environmentally-constrained future in which a well-planned grid significantly reduces generation investment and operating costs. [Emphasis in original.]

Since it is all but certain that a post-2030 world is going to be "more environmentally constrained" than today's, the need for smart grid planning is enormous; $47 billion dollars a year for US ratepayers is no small thing.

Even if you have no interest in transmission planning as such (there's no accounting for taste), it's worth noting that the kind of planning Brattle describes — scenario-based, iterative, cognizant not only of immediate needs but of long-term resilience and tail risks — is well-suited to all planning in the coming era of climate instability. That's everyone's concern.

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