(T) We have many non-fossil alternative energy available to use today. If you consider all of them, the list is pretty long and include at least solar, wind, nuclear, hydroelectricity, biofuels, biomass, geothermal and ocean waves energy! There are many factors that are likely to make one of those renewable energies more appropriate to satisfy our energy requirements than another one. Namely, the energy of the future must be plentiful and scalable to meet our growing worldwide energy consumption. And, it needs to produce abundant electricity in a cost-effective matter. Ideally, you might want to add that its source, generation, and distribution shall be equally spread worldwide to mitigate any geopolitical risk regarding its supply and pricing.

Biofuels and biomass are not the best solutions

Biofuels are mostly produced from crops such as sugar cane in Brazil or corn in the US Midwest. There are two major challenges with biofuels. The first one is that they require too much soil and water that must be preserved more than ever to feed a crowded planet. The second one is that they keep us dependent on liquid fuel for transportation. Or transportation is roughly a third of our energy consumption and we need ideally to move as quickly as possible to electrical-based transportation. In addition, corn-based biofuels require fossil fuel from the corn fertilizer to the processing of the corn and the transport of ethanol that makes the net carbon reduction of corn-based ethanol nonexistent.

Biomass generates electricity from plants through a process called photosynthesis that converts the solar radiations into the stored biomass energy. But photosynthesis is not efficient. Plants can only capture 1% of the solar energy while solar photovoltaic (or PV) cells can capture up to 15% of the solar energy hitting a given surface (more on that soon).

Wind, hydroelectricity, geothermal and ocean waves are local solutions

Wind, hydroelectricity, geothermal and ocean waves energy might be competitive in certain regions. But each of them depends on favorable local conditions and has limitations to be produced in large quantities. They will likely contribute to producing the energy of our future but in a marginal way and cannot be considered as a global replacement for oil and natural gas. Wind power has been growing recently worldwide annually by 45% a year and represented 1.5% of the worldwide electricity production in 2008. And, in most cases, wind is cost competitive.

Nuclear energy is a second choice after solar energy

The only two sources of energy that can be the large-scale non-fossil fuel alternatives are nuclear and solar energy. Simply put, both of them are plentiful, scalable and cost-effective and can directly produce electricity. However, nuclear energy has many disadvantages that make it a second choice after solar energy.

The fears of nuclear proliferation have always been a major security constraint to the development of nuclear energy. No solution has been found yet to the disposals of nuclear waste from the nuclear reactors. And, that is both an environmental and political challenge that is still waiting for a solution.

Solar is The energy of the future

Solar energy has now the potential to be our largest, safest and longest-lasting energy source. Yes, the Sun is the energy of our future! Emerging solar technologies exist already that will make large-scale production of solar energy to be a viable and cost-effective alternative energy source on a worldwide scale. There is a vast amount of solar energy to harvest, and we need to start urgently heading down that route.

We can capture 1000% more energy from the sun than we are consuming! The total solar energy absorbed by the Earth in a few hours is more than a year of the total worldwide consumption of energy. The amount of solar energy reaching the surface of the planet is so vast that in one year, it is about twice as much as the energy that will ever be obtained from all of the Earth’s non-renewable energy sources including oil, natural gas, coal, and mined uranium combined.

Sunlight can be converted into electricity using photovoltaics (PV) cells that are being presently improved from many start-ups to deliver the ultimate solar electricity cell and panel. PV cells have mainly been used to power small and medium-sized applications, from the small calculator powered by a single solar cell to off-grid homes powered by a photovoltaic array.

Multi-megawatt PV plants that convert the sun’s rays directly into electricity using semiconductor technologies such as the 20 Mega Watts site in the Spanish province of Alicante are characteristic of the trend toward larger photovoltaic power stations both in Europe and the United States. The Alicante solar power plant has now 14 hours of solar storage that enables the generation of solar power over a non-stop 24 hours period.

Today electricity prices, for instance in California from PG&E, are increasing on an annual basis on an average of 6% due to the increase in gas pricing. Solar energy prices are currently decreasing by 20% a year. So, we should expect soon – maybe as soon as in the next 2 to 3 years that solar energy will be as cost effective as gas to generate electricity.

Yes, definitely the Sun is the energy of our future!

Note 1: This article is based on the talk “State of energy address? Are we are on the right track?” from Professor Gerritsen from Stanford University on July 23rd at the Cantor Museum of Art at Stanford University and from the talk “Physics for future presidents” from Professor Muller from UC Berkeley at Kepler’s bookstore in Menlo Park last summer.

Note 2: The picture above is a sunset from Brittany, France.

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