Amber Rudd has refuted suggestions that HM Treasury is running energy policy during what turned out to be a difficult session before the select committee for the energy secretary.

Rudd was before the committee to discuss last weekend’s COP21 agreement but was quickly grilled on the perceived uncertainty caused within the renewables market by her department’s policy decisions, Labour’s Rushanara Ali proving to be particularly critical of government policy to date.

The committee referenced the evidence it has heard to date as part of its inquiry into investor confidence – particularly comments made by NextEnergy Capital’s Abid Kazim yesterday – to suggest that solar in particular had been “unsettled” by decisions purportedly taken by DECC.

Rudd prompted a fiery response from SNP MP Alastair Carmichael by dismissing the uncertainty caused by recent policy moves. He questioned where Rudd believed industry experts that have provided evidence to the inquiry so far were incorrect. “I know the solar industry wants certainty but it is not a one-way street,” Rudd replied.

Rudd also dismissed suggestions that the timing of policy announcements had been surprising for the solar industry. She pointed to the fact that reviews of the feed-in tariff are bound by European law and that it was first confirmed in March that a review would occur this year.

But the most heated exchanges related to MPs including Ali, her Labour colleague Matthew Pennycook and select committee chairman Angus MacNeil pouring scorn over the true driving force behind cuts to clean energy.

Pennycook said that there was a “sense that the Treasury drives energy policy”, to which Ali said that decisions passed down from HMT threatened to “undermine” Rudd and DECC’s achievements and “made life difficult” for her and her department.

The secretary of state angrily dismissed the suggestions, insisting that it was not the case and that she had the support of the entire government in tackling climate change. Despite this, Rudd would not shed more light on a purported cross-department climate change committee that includes other secretaries of state. While Rudd said she “valued transparency”, she claimed she was not at liberty to divulge their identities, nor details of meetings.

Rudd did however suggest that she would be prepared to revisit prospective changes to the feed-in tariff should they result in a significant downturn in deployment, seemingly mindful of the more ambitious commitments made in Paris last weekend.

The solar sector is still awaiting the results of the FiT consultation. It is now widely expected to be confirmed tomorrow and could be revealed as early as 7am. MacNeil – who has already lambasted the secretary for her department making policy announcements in the days following committee hearings – pressed Rudd on announcements to be made before Christmas.

She refused to provide a firm date but did confirm the feed-in tariff consultation – as well as others, most likely the Renewables Obligation consultation outcome – would be released before the end of the year. MacNeil continued his criticism of the move, stating that there needed to be “proper scrutiny” of major policy announcements and that select committee hearings were integral for that to occur.