From the 2000s through the 2010s, it looked like America’s demand for electricity had peaked. But starting in 2021, demand began to tick up, and it’s projected to increase by 50% in the next 25 years. This trend is driven by the electrification of vehicles and buildings, which shifts heating, cooking, and transportation away from fossil fuels and onto electricity, and by rapid growth in data centers, particularly for AI and cloud computing. Ultimately, the power grid is limited by physics: We simply can’t move enough electricity from Point A to Point B on our current grid. We need more transmission lines to meet rising demand.

Climate change makes extreme weather events more frequent and more intense. From hurricanes to heat waves to winter freezes to wildfires, extreme weather events mean that people demand more energy (i.e. turning on the air conditioner during a heat wave), while the power plants and transmission lines simultaneously under-perform in the less-than-ideal conditions (i.e. a cold snap knocks out gas plants). Together, unusually high demand and unusually low output mean more rolling blackouts and expensive energy bills if affected regions can’t import electricity. We need more transmission lines to create the redundancy that keeps power reliable.

The clean energy transition is underway, but renewable energy sources like wind and solar farms or hydroelectric dams are often located far from the cities and industrial areas that use the most electricity. Without the long-distance, high-voltage transmission lines to connect these energy generation sources to the grid and to export the energy to the regions of the grid that need it most, we can’t bring the projects online. Indeed, transmission constraints are a top reason why new clean energy projects aren’t getting built faster. Developers across the country have already secured land, financing, and permits — but are stuck in what’s called “the interconnection queue,” waiting for permission to connect to the grid. There are 2,000 gigawatts of generation and storage in the queue — the same capacity as the entire U.S. gridtoday – which you can visualize here: interconnection.fyi.

In fact,  slow grid build-out is one of the biggest threats to meeting national and state-level climate targets. Modeling by Princeton’s REPEAT Project has shown that the full benefits of recent federal climate legislation (like the Inflation Reduction Act) depend on expanding transmission capacity by at least 2.3% per year. Yet in the last decade, growth has averaged just 1% per year.

Just like highways for cars, transmission lines can get congested – i.e. they’re transmitting as much electricity as they can each second, and they can’t transmit any more. This pushes consumer prices up, as utilities in many markets pass on transmission congestion charges — fees associated with navigating crowded parts of the grid. 

Moreover, there are relatively few transmission lines that connect the regions of the grid. When those lines are congested, it means one region with higher-than-normal demand won’t be able to import enough power. When this happens – even for a couple of hours on a hot summer afternoon, for example – rid operators fire up  older,  less efficient, and usually fossil fuel-based backup generators. On the flip side, many regions have periods of the day where they generate more power than they need, often via cheap renewables. If the transmission lines are too congested, they can’t export this cheap, clean power, and grid operators are forced to turn off (or ‘curtail’) those solar farms, wind farms, etc. When consumers are forced to buy dirty, expensive power and are blocked from clean, cheap power, prices go up and lack of transmission capacity is to blame.