There's a common narrative about the "solar panels" that Jimmy Carter installed on the White Hoose. The narrative is that as part of the fossil fuel industry killing renewables, Reagan removed the panels when he got into office, and we are much worse off because of that one action. In fact Reagan did make major policy decisions to deprioritize research into renewables. Perhaps the panels are a symbol of the path into ubiquitous renewable energy. I would suggest they are not, and the issue of renewable research, which I strongly support, needs to be completely separated from an objective analysis of any installation of any particular technology in any particular location.

These were not solar panels as commonly understood, but solar-thermal panels. With any alternative energy we need to look at Energy Returned on (Energy) Investment (EROI). If a fuel or energy source requires almost as much or more energy to create it as we get during its lifespan, then using it is not going to lower CO2 and help solve the problem of too much CO2. The issue of whether a particular technology makes sense in a particular situation needs to be analyzed objectively. Quite often the cost of a product or fuel, including maintenance costs, can be used as a proxy for energy investement.

Lower EROI can be ok as explained in https://www.buildinggreen.com/news-article/energy-return-investment A lot of the usefulness depends on the location. Solar heating of hot water has decades of popularity and use in California, Florida, Israel, and other mild locations. We also need to look at how the warmed water is used. Is warmed water, mostly in summer, universally useful? Unfortunately, no. We can glean that conclusion from the results at Unity College, near the coast of Maine, which is not a good location.

A Scientific American article starts with: The SciAm article laments that some, in fact, all, of the panels are now in museums or storage as Carter "feared". The article explains that the publicity director of Unity College in Maine wrote to Carter in 1991 who wrote back "It would please me very much to see those panels in use again." From the SciAm article: This document states exactly where we would be: https://www.osti.gov/servlets/purl/6334779 We would be poorer and have 10's of millions of solar-thermal panels in warehouses or more likely in landfills. Or we would need a lot more very large museums. The panels were only marginally cost-effective on the White House (at $28,000 plus maintenance compared to relatively cheap gas water heating) and certainly were not cost-effective in Maine.

In fact omitting any EROI analysis is a major deficiency in the Sci Am article, especially considering the apparent short lifespan. Thermal panels are not economical in Maine or even on the White House roof due to its gas water heating. Even the solar thermal greenhouse at Unity College is now covered over since it provides only unwanted heat in the summer and very likely net negative heat in the winter. The claim that the panels were too big to fit the roof in Maine is an outright falsehood. Also claiming they work in winter.

Solar thermal water heating is much like that attached greenhouse, shown in the pictures below, now missing or covered. It provides plenty of heat in the summer when you don't need as much, and not much (or zero for these water-filled panels) in the winter when you need more heat. It may be untrue that panels were removed from the White House for no reason. They were removed during roof repair in 1986 and not reinstalled possibly because they were not cost-effective. From https://americanhistory.si.edu/press/releases/white-house-solar-panel-acquired-smithsonian Did it really take more than $150,000 to refurbish "perfectly good, working" panels and operate them from 1992-2005? From https://www.ecomall.com/greenshopping/solarwhitehouse.htm (SOLAR ENERGY IS BACK AT THE WHITE HOUSE): In other words, even some current panels may have negative EROI. The WH roof is flat and the panels were angled at about 45 degrees. That means the backs of the panels were completely exposed to cold and therefore much less effective in cold but nonfreezing weather. The panels were removed from the WH in 1986 during roof repair, left in storage until 1991, refurbished and installed at Unity in 1992 and taken out of service in 2005. That's three decades of service at Unity according to Bill McKibben:

(click to enlarge photo) https://e360.yale.edu/features/a_symbolic_solar_road_trip_to_reignite_a_climate_movement From the New York Times June 21, 1979: Let's assume the panels operating in Maine had 50% solar energy collection efficiency, with the rest of the system at 50% efficiency with pumping and cooling losses. For DC see (1). The insolation at Washington DC is 4.5 kWh per square meter per day. Assume the system can be run for 7 months before being drained for freezing temperatures.

Annual energy collection for Washington, D.C.:
7 months * 30.5 days * 4.5kWh/day/m² * 300 square meters * 0.31 = 89,350 kWh
From 1979 to 1986 the average price of electricity was 7 cents / kWh.

After being installed in Maine the annual energy collection is:
5 months * 30.5 days * 4.2kWh/day/m² * 150 square meters * 0.25 = 24,000 kWh
From 1992 to 2005 the average price of electricity was 8.5 cents / kWh.

Location	Energy saved annually	Annual savings	YRS	Total savings	Cost of system
Wash. DC	89,350 kWh	$6,254	7	$43,781	$28,000+
Maine	24,000 kWh	$2,100	13	$27,000	$150,000+

Note that the savings in the table above assume resistive electric water heating. Natural gas water heating at the White House in 1980 was three times cheaper, see (1) above for costs. Gas was 3.5x cheaper but gas was only 85% efficient versus 100% for electric hot water.

If the $28k is accurate the panels could have positive EROI with less than five years to return the energy costs of electrical resistive heat with energy from the sun. But the Maine numbers don't look as good. Also we would need to know why the panels needed refurbshing after just 7 years on the WH roof and 6 years in a warehouse. Were they damaged? Specifically, we need to know how much energy was required to restore and maintain them for their lifespan. Finally do they only operate for 20 years? That seems too short.

Symbolism is not going to save the world from too much CO2. Misrepresenting what the panels what the panels did and what they can do is not helpful. They did not work in the winter for example. They did not work for three decades in Maine. I conclude they were essentially useless in Maine with negative EROI. Reducing our fossil use is good. But pretending we are reducing is not.

1992:

"too big to fit in an area that is much smaller than the White House roof" (click to enlarge)

Currently: panels have been removed. Roof faces ESE.

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