
Energy Secretary Chris Huhne will say he is determined to "get tough" with the six biggest energy companies, in his speech to the Lib Dem conference.
Mr Huhne will outline plans to help keep fuel bills down by making it easier for people to spot cheaper deals and switch providers.
He will also say Ofgem should be given power to force companies to give money back to customers for "bad behaviour".
The conference is due to debate adult social care and green economic growth.
Additionally, Pensions Minister Steve Webb will address party members at the International Convention Centre in Birmingham, on the fourth day of the conference.
He will take to the conference stage on Tuesday to pledge to help people get better deals from the "big six" energy companies - British Gas, Scottish Power, Scottish and Southern, Npower, E.On and EDF.
The energy secretary will say companies should tell customers if they have a cheaper tariff on offer and that he plans to make it easier and quicker to switch companies.
"We are determined to get tough with the big six energy companies to ensure that the consumer gets the best possible deal. We want simpler tariffs, requiring energy companies to tell you whether you could buy more cheaply on another tariff."
He said the regulator Ofgem should get new powers to make firms pay up to customers when there has been "bad behaviour" - such as breaching licence conditions.
Ofgem already has powers to fine companies up to 10% of their annual turnover.
Other plans include stopping delays to Ofgem rulings by giving firms a right of appeal - rather than allowing them to refer rulings to the Competition Commission, which can hold up the process.
And he will criticise those who keep prices high for millions of customers, while offering cut price deals online - something he says is anti-competitive.
"That looks to me like predatory pricing. It must and will stop."
He will also say it "makes sense" to reduce reliance on expensive oil and gas and promote instead low-carbon energy businesses.
And he will pledge to make people in "fuel poverty" - defined as households which spend more than 10% of their income on fuel costs - a priority for the government's Green Deal - which aims to allow people to make their homes more energy efficient and pay for it out of the resulting savings to their gas and electricity bills in the long term.
Other items on the agenda on Tuesday include a question and answer session on the NHS shake-up and a debate on adult social care.