A Conversation About Water: To Spin a Turbine

The Upvoters that cared:
This is a community post, untouched by our editors.

A three-part article of the Conservation Conversation series, tentatively extrapolating the seemingly simple and straightforward idea of water conservation. The first part, “Resource Philosophy“, discusses the nature of resources. The second part, “To Obtain Freshwater“, discusses freshwater, their sources, and desalinization. The third part, “To Spin a Turbine“, discusses energy production for desalinization, and the pros and cons associated with the major forms of non-combustion electrical generation.

The Sun

A full-disk multiwavelength extreme ultraviolet image of the sun taken by the Solar Dynamics Observatory. False colors trace different gas temperatures. Reds are relatively cool (~60,000 K); blues and greens are hotter (> 1,000,000 K). Courtesy of NASA.

The images of this Sun (Dec. 7, 2011) taken at almost the same time are shown in various wavelengths in various temperatures and layers of the Sun. In addition is added a superimposed illustration of the Sun's magnetic field lines to the view. Courtesy of NASA.

To Spin a Turbine

Photovoltaic solar panels on the International Space Station. Courtesy of NASA.

The Sun is an awesome, often underrated object. It contains virtually all of the Solar System‘s mass and energy. Because its lifetime is equal to the lifetime of the Solar System (for obvious reasons), it is a long lasting energy source. While sunlight is present on 50% of the Earth’s surface at any one time, meteorological phenomena currently prevent simple and, more importantly, constant access to this resource for electrical generation purposes.

There is more than just one solar power paradigm. There are projects to utilize the vastness of the Sahara desert to power much of Europe and the world. However, not all solar power projects deal with massive surface area and multinational projects. They can be smaller, more local (geographically speaking), like the Andasol power plant, in Andalusia, or powering artificial satellites in orbit, or powering boats. They can be photovoltaic projects, utilizing the photovoltaic effect to create current directly from photons, or solar thermal, utilizing the radiation to directly heat a fluid, which spins a turbine. They can be private domestic projects, like installing solar panels upon a roof for personal use. They can be even more particular, like photosensitive plastic polymers. One often thinks of solar power plants because of the idea of power plants. Location of a power plant is fundamental, however, and more important for an open-to-the-elements solar power station than for a closed building power plant.

An enhanced geothermal system. 1: Reservoir, 2: Pump house, 3: Heat exchanger, 4: Turbine hall, 5: Production well, 6: Injection well, 7: Hot water to district heating, 8: Porous sediments, 9: Observation well, 10: Crystalline bedrock. Sourced by Wikimedia Commons.

The larger and more branches something obtains, the more useful autonomy in those branches is. Solar power is not necessarily most ideal as a massive project, but can also be advantageous as a private, regional and local alternative or complimentary source. Solar power is also a fluctuating resource, and not ideal for a constant supply of energy, unless there were sufficient surpluses to prevent shortages, which would imply obscenely large amounts of surface area utilization. As stated earlier, sunlight is a vastly contested resource, requiring large amounts of surface area to maximize production, and, as such, would not be the most philosophically ideal energy source.

Geothermal energy is also an energy source that would last the lifetime of the Solar System. Mostly caused by the radioactive decay of heavy elements in the Earth’s core, and partially the remnant heat from the formation of the Earth, the geothermal gradient of Earth is 22.1º C per 1000 meters of depth, meaning that, on average, one is 4525 meters (4.525km) away from matter warm enough to boil water, warm enough to produce steam, and spin turbines. Unfortunately, at this time such mining to reach those depths is prohibitively expensive, and unless one is near geological activity, where the Earth’s heat rises relatively close to the surface, geothermal energy is not actively sought. Were it not so costly, it would possibly be the ideal energy source for humans. It is a virtually uncontested energy source among organisms, with the exception of undersea vent environments, which, fortunately, would not be contested by humans, and, as it would be far underground, the power plant would be apart from virtually all natural ecosystems.

Sketch of Boulder (Hoover) Dam site. Sourced by Wikimedia Commons/U.S. Public Domain.

Hydroelectric energy is the utilization of flowing water to spin something, in century most often a turbine generator. It is a non-carbon emitting source of energy, though it does has its disadvantages. Ecologically, it interferes with the local habitat and hydrological cycle. Dams create reservoirs—lakes that have no business being there—which interfere with local ecosystems—and stymie river flow, interfering with flora and fauna transportation within the river.  The reservoirs cover areas of land many times larger than the surface area of the host river itself, inundating the river’s banks and shore, affecting not only the animals and plants located on its banks, but affecting human populations located on the shore of the river, as was famously the case with the creation of the Three Gorges Dam. Heavy utilization of river water, coupled with the damming of the river, can eventually cause the river to no longer reach its final destination, as the Colorado river now famously does not. It also, famously in the case of the Nile river, prevents sediments from traveling downstream. The farmers of the Nile once relied on the river to deposit new sediments every year for their agriculture to prosper and their soil not be depleted of nutrients and minerals. Unfortunately, after the completion of the Aswan Dam, flooding no longer occurs in the lower Nile, and farmers are obligated to use artificial fertilizers to maintain productive land.

Three types of wind turbine. Sourced by Wikimedia Commons/Ssgxnh.

Wind energy is the utilization of airflow to spin something, nowadays most often a turbine generator. Wind turbines are relatively innocuous to the environment, with the exception of bird and bat strikes. Wind turbines utilize relatively little Earth surface (base of tower contacting Earth’s surface), as opposed to solar power, in which its energy output is proportional to the surface area used—however, wind turbines, to be effective, must be placed in wide, open locations with reasonable airflow, and they do take up a certain volume of airspace. Wind is also a force that is not constant, and variation in access to a resource is not a virtue of the resource. While electrical grids do not suffer a constant and fixed amount of demand, and electrical demand of the grid depends on time of year and time of day, in principal one should not base one’s electrical demands on an intermittent generating source, unless there is a confidently safe surplus of electrical generation from other locations to provide the grid with.

Artistic rendition of nuclear fission, depicting Uranium-236 splitting into two smaller nuclei and releasing 3 neutrons. Sourced by Wikimedia Commons/IgniX.

Nuclear fission is the utilization of radioactive decay and instability of certain atoms to provide thermal energy, which heats a fluid, and spins a turbine. As it does not produce any pollutant that is released directly into the environment as a waste product (aside from waste heat), it seems a very attractive energy source from an environmentalist’s standpoint—up until something goes wrong. And things will always go wrong, as gloriously demonstrated by Fukushima and Chernobyl. Pollution caused by fossil fuel burning—carbon oxides, nitrous oxides, sulfur oxides—to me, at least (and I should reiterate that this is my opinion), is far inferior than uncontained nuclear waste, or radiation leaks due to nuclear core meltdown. And while deaths per year due to pollution caused by fossil fuel power plants, both direct and indirect, is greater than deaths per year by pollution caused by nuclear power plants, the fact remains that carbon dioxide, no matter how harmful it may be to current ecosystems and climate change, will not sterilize those ecosystems as ionizing radiation can.

“Life, uh”, as Ian Malcolm so eloquently put it, “finds a way.” Carbon dioxide during the Cambrian period was estimated at 7,000 parts per million (ppm); far, far greater than today’s 390 ppm, which is, still, at 390 ppm, the highest it has been in the past 20 million years—and, as carbon dioxide dissolves in water to form carbonic acid, the oceans presently are acidifying faster now than during any point in the past 300 million years. The point is, however, that “life will find a way”, regardless if the carbon dioxide ppm is 1 or 7,000. Life will evolve; its DNA shall mutate, and a most apt configuration shall be found, and it will survive. However, it will not, and cannot, find a way in the face of the destruction of its DNA.

Greatest painting in the history of Art. "Ian Malcolm: From Chaos", by Brandon bird. Sourced by Huffington Post. Click for slide-show.