It is well known that a major part of China's pollution comes from burning coal for power generation. But it doesn't have to be that way.

Recently, the European Union (EU) released a remarkable report, which says investing in renewable energy is as cost-effective in the long run as using conventional fuel resources such as coal and gas. This is an important report for China to consider, because if the most important issue for governments is to ensure a cost-effective, reliable and stable energy supply, there is little reason to continue relying on conventional energy sources that pollute heavily and contribute to global warming.

Thanks to this rather comprehensive analysis by the EU, greenhouse gas (GHG) emissions could now be reduced dramatically and we could enjoy clear blue skies far more often. Besides, this plan could be adopted by countries across the world.

Imagine a China that gets most of its energy from wind and solar power plants, and operating world-leading smart energy infrastructure that increases energy efficiency dramatically.

Not only China, but also many other parts of the world can attain such a future, says the new road map of the European Commission (EC), the executive arm of the EU. To reach that point, however, power sectors will need proper investment and political attention now, not a few decades later.

The "Energy Road Map 2050" explores different scenarios intended to lower GHG emissions to about 90 percent below 1990 levels by 2050. All of these scenarios lead toward an increased demand for renewable energy, saving more energy, and decreased availability and use of fossil fuels.

In all these "decarbonizing" scenarios, renewable energy use increases markedly and the use of fossil fuels shrinks correspondingly. According to the road map scenarios, the substantial increase in renewable energy would account for at least 55 percent of gross energy consumption by 2050 - up 45 percentage points from today's level of about 10 percent. The share of renewables in electricity consumption would reach 64.8 percent in the "high energy efficiency scenario" and even 97 percent in a "high renewables scenario".

But let's not forget energy efficiency. For this expanded and green energy system to work, the EC says, smart technology will need to increase energy efficiency to the point where consumption shrinks at least 32 percent by 2050.

With renewable energy quadrupled and energy efficiency reaching historic levels, GHG emission is bound to fall drastically. But the key is for the right investments to be made now rather than later. The EC's report says timing is critical. Europe will need to realize a major infrastructure overhaul by 2030, or else the boat bound for a green future will have left the harbor.

Citing figures from the International Energy Agency, the EU road map says that for every US dollar that isn't invested in the power sector before 2020, an additional $4.30 would have to be spent after 2020 to compensate for increased GHG emissions.

If the investments are postponed, "they will cost more and create greater disruption in the longer term", the report says. In other words, if the infrastructure overhaul is not realized by 2030, then emission reduction won't be realized by 2050 - which would be a sad case of missed investment opportunities.

In China, solar and wind power expansion has hit record levels. The country is the biggest green energy investor in the world. The government's ambition for clean energy development by 2020 is 15 percent of the total energy pie. But China still does not have a longer-term goal.

For instance, China is simultaneously expanding the number of coal-fired and nuclear plants on an unprecedented level. Coal seems cheap now, but air and water pollution across the country, as well as serious health impacts, have already revealed its true costs. The noxious chemicals that coal-fired power and heating plants release also cause the soupy haze we see in many northeastern and the acid rain in southeastern Chinese cities.

So when all human and environmental harm is factored into the cost of coal, it doesn't seem so cheap after all.

China may want to take serious note of the EU Energy Road Map 2050, which makes it clear that renewable energy can be more cost effective in the long run. China needs radical renewable energy ambition to power its sustainable growth as well. The road map provides clearer and more compelling evidence that renewable energy, coupled with smart energy infrastructure, can satisfy power needs while sustaining economic development and creating new jobs.

Simply put: Thinking about burning fossil fuels such as coal for China's energy needs for the next four decades does not have to be the only way forward to ensure energy security and reliability. Renewable energy sources are the way of the future - if we want to have a clean and healthy future, that is.

The author is Greenpeace East Asia head of climate and energy campaign.