Portugal has shown that in terms of electricity at least, the answer is yes. For 107 hours in May 2016 the sun, wind and rain powered a nation.

It's not just big energy companies who are boosting the green energy infrastructure. Portugal's first renewable energy cooperative has also been busy.

Starting in December 2013 with just 16 members, Coopérnico has just installed its seventh photovoltaic facility on the roof of the Irene Rolo foundation, in Tavira on the south coast of Portugal.

Now with almost 500 members on its books, Coopérnico raised the 55,750 euros needed for this project in just one week. It was so quick, people missed out.

"There were members who wanted to invest and they didn't get there in time, so the investment was already closed," says Coopérnico board member Susana Fonseca.

Members invest a sum of money over 12 years. In Tavira the individual amounts ranged from 250 to 12,000 euros. Each year stakeholders receive a portion of their initial outlay back, and also the interest generated.

Investment potential

With a competitive interest rate of 4 per cent, there are undoubtedly those attracted by the investment potential.

But the main driver for membership, says Fonseca, is the fact it's one of the few opportunities in Portugal to invest in sustainability.

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"This is not only about producing renewable energy. People are investing in something they consider sustainable. It's the opposite to putting your money in the bank and never knowing what they are doing with it. So here, people know where their money is going."

Coopérnico works with non-profit entities like schools and municipalities. The Irene Rolo foundation in Tavira works with disabled people. Coopérnico rents the roof space, installs the solar panels, and sells the energy to the national grid. After 15 years the equipment is donated to the host institution.

"In Denmark 80% of wind power that is produced is owned by citizens through co-operatives. So it is a very viable model and we do believe that it is a substantial part of the future", says Fonseca. "We see renewable energy as the future."

107 hours

And in Portugal the future has arrived. In May 2016 the country managed to run for four and a half days on renewable electricity alone. Thanks to favorable weather, and the use of 83 hydroelectric dams to store green energy. There has been considerable investment in wind and hydro over the last few decades.

Now the plan is to beef up solar supplies to help meet electricity demand in the summer months, while leaning on wind and hydro through the winter.

Solar energy in particular makes sense in Portugal.

"We are the European country that has the highest number of sunshine hours," says Francisco Ferreira of Portuguese sustainability NGO Zero. "So, solar is really a source that we have to grow. At the moment solar only represents around one tenth of the power compared with hydro or wind."

The Amareleja plant in the Alentejo region was the biggest in the world when it was installed in 2008. Today there are 12 large-scale solar facilities across the country.

The solar cooperative Coopérnico is also hoping to grow. Plans for the future include expanding into electricity supply and being able to sell exclusively clean energy to its members. "That's the dream!" says Fonseca.

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