Unilever, the consumer goods giant, has pledged to eliminate coal from its energy usage within five years, and derive all of its energy worldwide solely from renewable sources by 2030.

The company will become “carbon positive” by 2030, through its own use of renewables, and by investing in generating more renewable energy than it needs, selling the surplus on the markets and making it available to local communities in areas where it operates. About 40% of the company’s energy use currently comes from green sources.

Unilever made the commitment ahead of the crunch UN climate change conference in Paris, which begins this weekend.

Paul Polman, chairman of the company, told the Guardian the target was “do-able, really do-able”. He cited a new factory in China which is powered by wind and solar energy, and an office in Paris which is “carbon positive”, contributing green electricity to the power grid.

He hoped other businesses would come forward with carbon-cutting plans at the conference, known as COP21. “We obviously want Paris to be ambitious and successful,” he told the Guardian in an interview. “[It will be] if the agreement has the right things in there, like a zero goal, a decarbonisation goal. I’m for 2050. Perhaps if we’re lucky they will say by the end of this century, but that’s a starting point.”

He said progress had been made towards an agreement by countries coming forward with targets on cutting or curbing their emissions, and he also called for a Paris deal to include a process of five-yearly reviews of emissions goals, with a provision for “no backsliding” – that countries can strengthen their targets in future but not row back on them.

He said he would also like to see a price put on carbon dioxide emissions, to encourage companies to cut them, but conceded that this was unlikely to be an outcome from the two weeks of talks.

Polman will attend the Paris conference along with business leaders from the World Business Council on Sustainable Development and other business groupings such as “the B team”, spearheaded by Sir Richard Branson, which call for stronger action on global warming.

The heavy presence of businesses at the conference has been criticised by some climate activists, but Polman said their presence, and commitments they make there, would encourage world leaders to be able to take a stronger stance. “We’re trying to keep the pressure up to get all these things from Paris.” Much of the financing for climate change projects comes from companies, he noted – “they really do more of the financing than the governments” in some areas, he said.

He also called for a strong focus on forestry at the talks, including pledges from rich nations to help the poor to protect their existing forests. “We want a moratorium on deforestation,” he said.

One of the leading causes of deforestation is to make way for palm oil plantations. Unilever was criticised recently by the Rainforest Action Network.

Polman defended the company’s stance, which includes membership of the Round Table on Sustainable Palm Oil, a body that attempts to increase the supply of the oil grown in environmentally friendly conditions. “The reality of palm oil, it’s in many of the products we use today, from candles to food. And it’s actually a high-yield, very effective product. So if you look at alternatives, which are available, and we use them also in our products, then you need to actually use much more land surface to cultivate them. And the effects, some people would argue, would be worse. The issue with any crop that you grow, the beef from Argentina or Brazil, is that you grow it sustainably without deforestation.”

He said the main problem with unsustainable palm oil was now coming from smallholder farms “which are not in our supply chain as far as we can see”. He called for “an international effort by the whole community to ‘produce and protect’ schemes because the smallholder farmers need training, they need access to financing, they need land rights”. This would require providing financial assistance to the farmers, and would encourage small farmers to sign up to sustainable practices, because they would get higher yields.

Polman’s pledge to make Unilever “carbon positive” and remove coal from its operations has been accompanied by personal action, in that he has ensured that his own investments are not in fossil fuels. “My wife has made sure of that,” he said. Unilever’s pension funds are also committed to “responsible investing”, though it is not clear whether this means a full disinvestment from all fossil fuels and carbon-intensive businesses. Polman said the funds are operated at arms’ length from the company.

Subsidies for fossil fuels are still far outstripping those for renewable energy, he noted, even though the plummeting price of solar and wind are “exciting” for companies. “We barely subsidise green energy – one tenth of what we spend on fossil fuel subsidies goes to green energy,” he said.

More people would move to the “sharing economy”, he predicted, which would help to change the current model of capitalism. The growth of sharing, including web sites such as Airbnb and Gumtree, has been one of the recent surprises of the internet. Polman predicted that the changes that have happened in the music industry because of online sales – whereby the vinyl records of his youth gave way to CDs, which gave way to downloading – would be replicated in other areas.

He gave the example of a power drill, of which many people in the affluent world may own several. “The average time in our lifetime that we use a drill is less than two minutes, because you go jup and the hole is there. Then after six months you need to hang another picture, jup, another second. So there is an abundance of drills. So that becomes sharing economy.”

This would change the way economies grow, he said. “A hundred things that were made with stuff are now provided for in non-stuff, but it has the same service, and you are willing to pay for it.”

Critics might point out that most of Unilever’s products – from ice-cream to shower gel – are consumed once and cannot be shared after consumption.