A nation's energy strategies can be hidden in texts full of jargon and acronyms that put on the table in Lima. But it's clear that a clean energy race has started here.

Thousands of environmentalists, students and indigenous groups marched in Lima on Wednesday, site of the United Nations' Climate Change Conference attended by 194 nations. They called on leaders to ensure a global shift to 100 percent clean energy by 2050.

2050 is only 35 years from now, which seems to be an ambitious timetable. Nonetheless, it's nice to have a lofty goal.

Energy companies appear prominently on the Fortune 500 list. Is it possible for oil, natural gas and coal companies to make the transition in three decades?

Do they share the same awareness of climate change risks as negotiators and observers at the climate change conference?

Countries will submit their intended nationally determined contributions by the first quarter of 2015, according to the conference's agenda.

The three biggest players?- China, the European Union and the United States?- already have announced their targets. As part of that, China pledged to increase the non-fossil fuel share of all energy to around 20 percent by 2030. The EU set a target of 27 percent by 2030.

The 2030 targets announced by the two economies are ambitious, but still indicate that it will be nearly impossible for the two to switch to zero emissions by 2050. China is the world's largest renewable energy investor.

But many inspiring pioneers emerged. Denmark is an unparalleled leader in clean energy. It plans to reach 100 percent renewable energy in electricity and heating by 2035 and run its economy entirely on renewable power by 2050. Finland plans to increase its renewable energy output to 38 percent by 2020, from 35 percent in 2012.

There are good examples in Latin America. Costa Rica has decided to go for a target of 100 percent renewable energy by 2021. Uruguay is going to reach a 50 percent share of renewables in the primary energy supply by 2015. Brazil's electricity generation from renewables has almost doubled in 10 years.

These targets for cutting greenhouse gas emissions may be opposed by some of those countries' citizens. But surely renewable energy will be the key to keeping a global temperature rise within 2 C or 1.5 C. Scientists believe exceeding that threshold could trigger dangerous levels of global warming.

Jim Yong Kim, the president of the World Bank, suggested a more realistic emissions target: The global community should aim for zero net emissions by 2100. He called on countries to eliminate fossil fuel subsidies and create conditions that favor renewable energy.

But will the current five-year low in oil prices affect the future of renewable energies and lower investors' enthusiasm if the trend lingers?

The price drop is indirect, as oil affects mainly transportation, and most electricity is based on other sources of energy in the US, said Leonardo Martinez-Diaz, US deputy assistant secretary for energy and environment.

"If it lasts too long, it could be an issue," he said, "If it lasts for a long time, it will slow the development and consumption of electric cars and efficient cars."

But those in the clean energy industry believe such a trend would actually favor the expansion of renewable energy.

"I think it's good for us because it's hurting the oil industry more than it's hurting us," said Jeremy Leggett, a British green-energy entrepreneur and founder of Solarcentry. Historical low prices exacerbate the volatility of the oil industry and encourage them to think about alternatives, he said.

Zhou Dadi, a Chinese energy expert and a member of the national expert team of China for Climate Change, said that the positive actions of pioneering countries indicate the world is swiftly switching to the next generation of technologies.

Nations need to generate internal demand as opposed to facing outside pressure to cut greenhouse gas emissions, Zhou said.

China should set challenging goals for capping its energy and coal consumption. Otherwise, the goals cannot work as an efficient forcing mechanism for low-carbon transition, he added.

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