Small nuclear wins | Runner up: Gas

How many people can use an energy source across how many places? The answer to this question depends on several constraints. 

Land. Is enough land available to build power plants and transmission lines? Will local communities allow them to be built?

Materials. Are the right materials available in abundance? 

Climate. Can the energy source operate in all weather conditions and locations?

Time. Can the needed infrastructure (power plants, transmission lines, mines) be built in a reasonable time frame? 

Solar and wind plants are the least scalable of all energy technologies. They require more land and more materials than other energy sources. Hundreds of new mines are needed to provide enough materials to create solar panels and wind turbines. 

An energy source that can be sited near urban areas and that functions optimally in all climates is more scalable than an energy source whose location is constrained by weather or land conditions. Moving energy from the place where it's produced to the place where it’s needed can be difficult, expensive, and slow. Building transmission lines to carry electricity over long distances, for instance, is expensive and slow. The International Energy Agency estimates that it takes more than 10 years on average to build new transmission lines. Not only must construction be approved by numerous regulatory agencies, but construction efforts may also face fierce opposition from local community groups that often fight against new power lines and large wind and solar projects. Local governments in 49 states have enacted 121 policies to block or restrict wind and solar projects. Since 2015, local communities rejected or restricted wind or solar projects nearly 500 times across the US because of concerns about falling property values, ruined viewsheds, and potential loss of tourism dollars. Neighbors are also concerned about the noise pollution that is emitted by 600 foot high wind turbines.

Solar power capacity worldwide would need to increase by 20 times and wind power by 11 times to hit the 2050 climate goals set by the United Nations and the International Energy Agency. Wind and solar require 10 to 20 times more materials per unit of electricity than the other sources. That means a lot more mining to produce the equipment needed to produce solar and wind energy. The world isn’t going to run out of minerals anytime soon, but there currently aren’t enough mines operating or planned to enable the world to scale production quickly, and opening a new mine takes 17 years on average.

Consider copper—the “metal of electrification.” Copper demand is expected to soar 600% higher by 2030. Wind, solar, and electric vehicles require an enormous amount of copper. Solar power, for instance, requires three times more copper than natural gas per unit of electricity generated. Humans mined 700 million tons of copper over the last 5,000 years, and they will need to match that output over the next 22 years to meet energy transition targets using wind, solar, and batteries. The gap between copper supply and demand will stifle the growth of these technologies. 

The US electric grid would need to triple in size to transition completely to wind and solar because wind and solar plants are located far from homes and businesses. In addition, many areas simply don’t have enough consistent wind and sunlight to make projects economically viable. When we combine these constraints, scaling solar, wind, and batteries to meet the CO2 reduction goals set by the United Nations and the International Energy Agency begins to look like a practical impossibility.

Small modular nuclear plants (SMRs) are the most scalable of all energy sources. They require a tiny land footprint, few materials, and can be built almost anywhere in two to three years. 

SMRs beat natural gas in terms of land availability. They can be built close to homes and businesses and emit no air pollution. They have a small footprint, and they don’t require pipelines. 

SMRs are better than large nuclear plants in terms of land, materials, and time. The smallest reactors can operate on two acres of land compared with 800 acres for a large 1,000 MW reactor. 

Most SMRs use less water because they use other cooling methods (such as liquid metal and helium gas) to remove heat from the reactor. 

SMRs can be deployed in as little as two to three years, while large nuclear plants typically take seven to 10 years to build. But that’s the global average build time. In the US, it’s slower. Recent reactors built in Georgia took over 14 years. The new reactors came online six years late and $16 billion over budget. 

These traits combined with high energy production enable onsite SMR deployment at data centers, military bases, chemical plants, refineries, mines, and master planned communities. Large nuclear plants aren’t typically sited at these locations.

Natural gas is also more scalable than large nuclear plants, and they require fewer materials and less time to build. Typically, a combined cycle natural gas power plant can take anywhere from 18 months to three years to construct.