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August 19, 2014 was not only important for those who celebrated their birthday. It also marked a milestone for the planet, or rather a sad day. It marks the date when humanity had already consumed the entire planet’s natural annual budget or in other technical words, when humanity’s ecological footprint exceeds the ability of the Earth to replenish those resources and the capacity to absorb carbon dioxide, which is called nature’s biocapacity.

That day is also known as Earth Overshoot Day. It is as if we had started the day with money and then had gone into debt, knowing that we could never pay back the money. The worst news is that the day happens earlier and earlier each year. In 2000, it was still in the month of October, and in the 70s it fell in December. What has happened is that since the early 70s, the energy, food, and water consumed by our cities, with their economic and demographic growth, accounts for a much larger quantity of resources than the Earth can regenerate. World cities consume 67% of the energy produced on Earth and are responsible at the same time of 70% of global energy-related CO2 emissions contributing in this way to the negative effects of climate change.

Although it seemed at first to have nothing to do with Earth Overshoot Day, something very interesting occurred that same day in August as well. A Swiss bank, which is not known to take many risks when it comes to advising clients where to put their money, circulated a document that explained how it made good financial sense to invest in companies that manufacture solar photovoltaic systems, batteries, and electric vehicles. If a bank that has US$ 1.5 trillion in assets says this, surely they know something about investments.

The main argument is that the cost of these technologies have fallen so much in recent years that we are on the verge of a revolution in the electricity system. While the costs of solar panels have fallen by 80% since 2008, the Swiss bank’s own estimates show that the price of batteries could drop by 50% in 2020. This will not only lead to an increase in the sale of electric vehicles, but also an increase in the possibilities of storing surplus energy with stationary or vehicle batteries. These two aspects are very important to help mitigate the variability of electricity production with renewable energy sources like wind and solar.

energía lunarPhoto: Rawlemon

The impact on utilities and energy consumers in cities will be huge. This is a revolution that offers opportunities for all. While the falling costs of solar systems make traditional electricity consumers become generators, utilities may generate greater value in new business units that address the evolving needs of the modern consumer, for example through intelligent energy distribution networks, special services to end consumers, and the management of small reserve units.

We hope that Earth Overshoot Day will occur later in the year, and that we can adapt more to what the earth has to give us, not vice versa. Of course, there is no shortage of pessimists who think that there is no revolution and that we will never store energy efficiently. For those who are impatient, innovation has an answer. What if we could produce electricity with the light of the moon and did not even need to store the energy produced during the day with the sun?

This is not the crazy idea of a hopeless romantic but rather the idea of a the German architect André Brößel who was watching her daughter play with glass marbles one day and was inspired to create a system that takes advantage of moonlight to produce electricity. The maximum efficiency of a commercial PV system is about 20%. In contrast the “crystal ball collector” invented by the architect achieves 50% efficiency. Prototypes of the system have proven to be four times more efficient than traditional solar cells given that the crystal ball, which is just less than two meters in diameter and filled with distilled water, can concentrate dim moonlight up to 20000 times.

Energía lunarPhoto: Rawlemon

Even though this technology is still in its development phase, there are already some car companies that are interested in the possibilities for this new energy generation system that seems very promising. We could have solar energy by day and lunar energy by night–energy that is not only clean, but also romantic.

Juan Roberto Paredes is Senior Renewable Energy Specialist at the Energy Division of the Inter-American Development Bank. Juan is responsible for the technical due diligence of renewable energy projects in the bank, including wind and marine energy. Previously he worked for wind consultancies from Germany and the UK, gaining extensive experience by assessing more than 1000MW of planned and existing wind farms.  Ju has a B.S. in Mechanical Engineering and Physics from the University of Los Andes in Bogotá, Colombia, and a M.Sc. in Renewable Energies from Oldenburg University in Germany. He has also executive degrees on Innovation in Infrastructure at the Kennedy School of Government at Harvard University and Energy and Climate Change at the Massachusetts Institute of Technology (MIT).  He is also the author of a book titled “Energy without End”  designed especially for children eager to know more about the relation between climate change and sustainable energy coming from natural sources as the sun or wind.