How Dense Can They Get?

When it comes to power, energy density is the key. Solar power, wind power, and ethanol are so expensive because they are derived from very diffuse energy sources. It takes a lot of energy collectors such as solar cells, wind turbines, or corn stalks covering many square miles to produce the same amount of power that traditional coal, natural gas, or nuclear plants can on just a few acres.

Each of these alternative energy sources is based on mature technology. Agriculture and fermentation have their roots in prehistory; windmills date back at least to 65 B.C.; the photovoltaic effect was discovered in 1839. Yet nowhere in the world are these technologies serving as primary energy sources without significant government subsidies. While incremental improvements can be expected, it would take an order-of-magnitude increase in productivity for them to become viable. As old and as well-researched as the technologies are, such improvements are possible but unlikely. As significant future energy sources, these technologies are dead ends, which is why the government, and not the private sector, is funding them.

Industry is more than willing to risk research dollars on technologies that show real promise, but it is not willing to flush shareholder money down a rat hole. Politicians, however, operate from different incentives. When a crisis, real or imagined, makes headlines, they want voters to see them “doing something” about it, and they must move quickly because election cycles and constituent attention spans are short. Funding long-term research in promising technologies doesn’t meet politicians’ needs. Solar panels, wind turbines, and ethanol refineries are all current technology and can be erected quickly with fanfare and photo ops. By the time these alternative power sources prove to be financial and, possibly, environmental busts, the politicians will have been reelected and voters’ attention will have shifted to the next crisis.



By contrast, consider the significant oil-industry investments in researching biofuels made from algae. Unlike ethanol, biofuels are chemically similar to fuel made from petroleum and, like petroleum-based fuels, have a significantly higher energy content than ethanol. Biofuels can also be handled by current fuel distribution systems and can be burned in today’s vehicles.


Biofuels are carbon-neutral because the carbon dioxide released when they are burned is extracted from the atmosphere by the algae. Unlike burning petroleum-based fuels, then, burning biofuels will not result in a net increase in atmospheric CO2 levels.

With algae’s vast potential, it is easy to understand why private industry is interested and why no government subsidies are needed to encourage investment. Moreover, if algae-based fuels do not prove viable, the companies now researching them will have no “status quo” problems with ending their investments and shifting scarce resources to more promising technologies—where “promise” is measured in density.

A previous version of this article originally appeared at