How much does U.S. population growth cut gains made by solar energy to reduce carbon emissions?

Here's my stab at answering that question.

Photo by the American Public Power Association

In Memory of Herman Daly, pioneer steady-state economist, 1938-2022

THERE’S A NASTY FIGHT underway over plans to convert a large area of Indiana farmland for solar energy generation. A recent article in The Guardian describes the project, its ugly politics and its environmental and economic pros and cons.

The chief selling point is that the "Mammoth Solar Farm" would, while replacing an agricultural area the size of Manhattan (NY), supply 1.3 gigawatts of energy to meet the needs of more than 200,000 households.

Each year, the U.S. requires about 500,000 extra households to keep up with population growth (see footnote). That means about 2.5 solar developments the size of Mammoth are needed annually to keep pace with household energy use from population growth (about 3.25 gigawatts.)

The U.S. Energy Information Administration expects utility-scale solar generating capacity to grow by 21.5 gigawatts in 2022. So, population growth would take about 15% of that for household use.

But there's also non-household energy demand tied to a yearly addition of 1.3 million people to the U.S. population. Residential energy use on average is only about a fifth of the total energy needed to support someone. The rest is connected to industry, transportation and commerce.

So, population growth may use 75% of new solar capacity that comes online in 2022. Considering that there's a shortfall of about 5 million housing units in the U.S., the population effect becomes even more significant. Home construction has apparently not kept pace with population growth over the past 20 years.

The Guardian article points out that, "If the US really is to zero out its carbon emissions by 2050, researchers at Princeton University have estimated that solar production could have to grow more than 20-fold, occupying an area that, put together, would be equivalent to the size of West Virginia."

Obviously, that vast amount of land for the solar industry has to come from somewhere, most likely from farmland or wildlife habitats such as forests, grasslands, and desert. So expect more conflict over land use, along with potential global supply chain, economic, and political issues, that could prevent solar energy expansion anywhere close to that 20-fold extent. (China is by far the largest producer of solar panels; its relations with the U.S. are in decline to the point of halting bilateral talks on climate change.)

An alternative to large land-altering projects like Mammoth would be to place most solar infrastructure on rooftops and along highways. I like that approach. But it’s unclear if it can surmount technical, economic, and political constraints to become the main player in solar energy generation for the U.S.

Getting a massive renewable energy network up and running in time to avert the worse of climate change is problematic given growing human numbers, rising energy demand, pushback from local communities and many environmentalists, and uncertain political and economic stability.

The U.S. should cut energy consumption to help meet climate policy goals while softening environmental impacts from so-called “green” industrialization. That could be done by reducing overall energy consumption (including that by the military) and by stabilizing population. The fertility rate in the U.S. may have flattened but immigration is likely to increase, especially if economic, political, and environmental conditions worsen around the world. An honest national discussion is needed on how population growth affects carbon emissions and more broadly the environment.

Sources: Reuters and Macrotrends

The overgrowth problem of the U.S. is, of course, not only about energy consumption and climate change. The bigger we get, the more buildings, roads, traffic, commercial centers, and just about everything we'll need. All of that takes additional resources — to be extracted from nature at home and abroad (sometimes at the expense of other people as well as at great cost to nonhuman life). Our society, for the time being, seems perfectly fine with more resource exploitation. Frankly, that’s insane. The tragedy of overconsumption will continue until we as a society come to terms with limits to growth.

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If our ethical understanding of the value of “sustainability” (longevity with sufficiency) is to “maximize” cumulative lives ever to be lived, subject to a per capita consumption level sufficient for a good life, then we must limit the load we place on Earth at any one time. Fewer people, and lower per capita resource consumption, facilitated by more equitable distribution, mean more (and more abundant) lives for a longer, but not infinite, future. There is no point in maximizing the cumulative number of lives lived in misery, so the qualification “sufficient for a good life” is important, and requires deep rethinking of economics and a shift of focus from growth to sufficiency, including sufficient habitat for other species. It also requires a rethinking of the traditional pro-natalist dogmas of the fundamentalist branches of most religions, including Christianity, Islam, and Judaism. The modern secularist religions of Marxism and Scientism likewise proselytize for the Ecumenical Church of Growthism while ignoring population. — Herman Daly

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Footnote: The US population is growing by about 1.3 million people (based on 2021-2022 data). If that remains constant, about 500,000 extra households are needed annually (given an average of 2.6 persons per household).