transmission: what's breaking the grid (part 2)

transmission! the middle child of the energy stack. part 2 in a series on transmission, bottlenecks, & solutions

Jun 11, 2025

In part 1 of this series, I explained what energy transmission is: how electricity moves, and why it’s one of the most under-appreciated ingredients of the clean energy sandwich.

In part 2, we’re diving into the bottlenecks in transmission: why new transmission development is so slow and how billions of dollars in clean energy projects are stuck waiting to connect.

In part 3, we’ll cover what’s being done about it and who’s working on solutions.

Welcome to part 2!

Here are some alarming facts I came across while doing research on transmission:

New transmission lines take 5 to 20 years to develop. Since the 2005 Energy Policy Act, new projects have taken over 10 years on average to complete.1 Interstate lines often take even longer.
As of the end of 2023, 2,600 gigawatts of energy and storage capacity were waiting in interconnection queues. Solar, wind and battery storage projects account for 95% of active capacity in queues, with most of the remaining 5% being natural gas projects.2
While global investment in power transmission grew by 10% in 2023 to reach $140 billion, this figure would need to exceed $200 billion annually by the mid-2030s to meet rising electricity demand.3

Basically, new lines take forever to develop, there are billions in renewable energy and storage projects waiting in the interconnection queue, and not enough investment into the sector. What’s the problem?

The 7 bottlenecks

There are 7 key bottlenecks facing the transmission sector:

interconnection queues
supply chain constraints
regulatory barriers: planning, permitting, & siting
aging infra
cyber + physical attacks
integrating renewables

interconnection queue

As we know, there’s about 2,600 gigawatts of mostly renewable capacity stuck in interconnection queues today. For context, that’s more than double the total electricity generation capacity currently installed in the U.S. (which is about 1,279 gigawatts.) To put this in perspective, 1 gigawatt is 1000 megawatts. 1000 megawatts can power between 500k to 1 million homes. So theoretically, if all were approved, this queue could power 1.3 billion homes.

Quick reminder: the interconnection queue is the process new projects (solar, wind, batteries, and sometimes transmission lines themselves) must go through to connect to the grid. Projects submit detailed applications, then undergo a series of grid impact studies to ensure they won’t destabilize the system. These queues are managed by regional grid operators, and they’ve become one of the most significant chokepoints in the clean energy transition.

To learn more about this complicated process, see these deeper dives on interconnection: part 1 (what is it + bottlenecks) and part 2 (solutions in progress + companies building here).

The huge barrier here is that rate of new transmission construction has slowed, and much of the existing grid doesn’t have the capacity to absorb this flood of new projects. Even when a project is technically ready to go, it often gets stuck waiting years for study results or is forced to fund expensive transmission upgrades on its own. Permitting, siting, and building new transmission lines can take a decade or more, but demand for clean energy keeps rising.

Basically, we want to be generating gigawatts, but the grid isn’t ready to receive it.

supply chain constraints

Utilities have identified supply chain constraints as one of the most pressing challenges. These constraints include long manufacturing lead times, limited manufacturing capacity, and labor and material shortages.

An IEA survey of industry leaders found that procurement takes 2-3 years for cables and up to 4 years for large power transformers, which is twice as long as in 2021. Specialized components face even longer delays, with lead times for direct current cables extending beyond 5 years. The price increases for components are equally concerning. In real terms, cable costs have nearly doubled since 2019 while power transformer prices have increased by around 75%.4

Supply chain constraints come at a particularly challenging time, with more than 1,600 gigawatts of solar and wind projects in advanced development stages awaiting grid connections. As I mentioned above, while global investment in transmission grew by 10% in 2023 ($140 billion), we would need to exceed $200 billion annually by the mid-2030s to meet rising electricity demand. To add insult to injury, we also need to hire ~1.5 million people to construct, maintain, and operate grids by 2030 to meet this demand.

regulatory barriers: planning, permitting, and siting

As I highlighted above, new transmission lines take 5 to 20 years to develop - most new projects since 2005 have taken over 10 years on average to complete.

High and extra-high voltage projects in the US face permitting timelines alone that are up to 6 years longer5 than in other countries because of the fragmented way our system approves projects.

I briefly mentioned this in transmission: part 1, but since FERC’s authority over transmission is limited, this leaves states primarily in charge of permitting, making the process fragmented, inconsistent, and often painfully slow.

As an example, state criteria6 for approval typically includes:

demonstrated need through analysis of the transmission system
comparison of project benefits to costs
land use and environmental effects

As such, transmission is inherently prone to controversy given that lines are long, highly visible, and have wide rights-of-way. This attracts local resistance on aesthetic, land use, and environmental grounds.

Furthermore, determining transmission needs and benefits is highly technical. Adjusting plans to account for public objections is difficult.

Most public utility commissions (PUCs), which are state government agencies that regulate utilities like electricity, gas, water, and telecom, care mostly about intrastate public needs, and want to make sure their states’ ratepayers are not paying for projects whose benefits manifest elsewhere.

Thus, state policy is biased and tends favor local, low-voltage projects over the multi-state, higher-voltage projects.

The cherry on top is that permitting authorities act independently of one another, so multi-state projects must receive approvals from each state and locality.

aging infra

Much of our electric grid infrastructure was built in the 1960s and 1970s. As of 2023, 70% of lines and transformers deployed on the grid were over 25 years old.7

There are many symptoms of our aging infra, and many accompanying risks:

reduced load carrying capacity = increased maintenance costs, fire hazards
line heating + sagging = outage potential
increased demand placed on generators worsened by high transmission energy losses
long queues for interconnection limiting renewables expansion
extreme weather events causing premature failures of the infra = broken lines, damaged transformers, compromised substations, and overextended generators

To make matters worse, 2023 set a record for billion-dollar weather and climate disasters in the United States. Our systems were simply not built for this level of demand, or weather volatility.

cyber + physical attacks

In 2023, US utilities saw a nearly 70% increase in the number of cyberattacks.8

Because utilities depend heavily on IoT (Internet of Things) and ICS (Incident Command System) technologies, the grid is very susceptible to cyber attacks.

The expansion of this, including interconnections to new customers like the hyperscalers’ data centers for AI, create even more potential points of, and incentive for attack. In fact, NERC reported that the number of susceptible points on our electrical networks increases by about 60 per day.9

Defending the grid is not an easy task, and utilities are struggling to find and retain the skilled workers needed to upgrade system security.10 As DERs (distributed energy resources like solar and battery systems) that are less secure and harder to monitor at scale decentralize the grid, security from such attacks become even more complex.

And not only is the grid at risk of cyberattacks, physical attacks on the grid have taken place as well. In late 2022, there were physical attacks11 on substations in North Carolina and Washington state that left tens of thousands of people without power.

integrating renewables

I discussed in my generation series part 1 on solar and wind that unlike coal + gas that consistently generate power, renewables are intermittent and variable based on weather conditions. This strains transmission lines that were designed for one-way, consistent electricity flows. As a result of more solar and wind coming online, curtailment is a growing concern. Curtailment happens when there is too much power on a line at a given point - solar curtailment is happening in CA,12 and very much on the rise.

Not only are renewables intermittent, but renewables projects are also often located in places that aren't necessarily close to existing transmission lines. The cost required to build out transmission to reach these areas is often high, and falls on the project developers.

How close are we to the inflection point for the grid-enhancing technologies (GETs)? — just a few of the challenges coming transmission’s way

what can we do about it?

Sometimes I get a headache thinking about all the bottlenecks here. There’s a reason a lot of people interested in building in energy tend to avoid transmission - it’s very thorny, complicated, and heavily tied to bureaucracy.

But that means it’s also ripe for innovation. In part 3, I’ll explore the solutions and companies working on untangling these wires.

this is going to be electric

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