The S&P/ASX 200 (ASX: XJO) benchmark index has fallen consecutively this past month and has slipped 1.7% in the red, in early morning trade on Friday.

It's been a similarly difficult month for the ASX renewables sector in September as well, as a wave of crises plagues the European energy markets.

The VanEck Global Clean ETF (ASX: CLNE), which serves as a good proxy to track the performance of ASX renewables shares, had its share price clipped almost 6% this month.

Amid this sea of red, let's take a closer look at which ASX renewables shares outperformed their peers in September.

Infratil Ltd (ASX: IFT)

New Zealand based Infratil's share price has climbed over 6% in the last month, despite there being no market sensitive information for the green energy company.

Infratil shares finished yesterday's close at $7.5 apiece, giving the company a market capitalisation of $5.5 billion.

Infratil shares have been lifting since the company announced it had completed the 65.15% stake in Tilt Renewables (ASX: TLT) in August.

The company finalised the sale for gross proceeds of $1.98 billion, to which it has paid a portion of some towards its existing bank facilities.

Infratil estimated the accounting gain from the Tilt divestment is $965 million, thereby generating a return on the company's investment of approximately 35.2% per annum.

The moves follow Infratil's $590 million of capital expenditures and investment into renewable energy in its FY21 earnings report for the year ended 31 March 2021.

Infratil shares have climbed 10% this year to date, and are up around 64% in the last 12 months.

Timah Resources Ltd (ASX: TML)

Timah Resources primarily engages in the production of renewable energy via its subsidiary, Mistral Engineering.

In September, Timah's share price gained an additional 12.5% to a 5-year high of 9 cents each, extending its gain over the last 12 months to 70%.

On 25 August, Timah announced that Mistral had suspended its memorandum of understanding with palm oil milling company Toupos Palm Oil Mill.

Just prior to this, the Department of Environment of Malaysia issued a letter to stop Toupos Palm Oil Mill from delivering palm oil to Mistral.

As the letter was received, Timah took no chances and immediately terminated all contracts with Toupos.

Aside from this, the company also released its half yearly accounts on the same day, where it recognised a 144% increase in net profit over the year prior.

In the days following these announcements, investors piled into Timah Resources shares and pushed it from 7.8 cents to the 5-year highs of today.

Foolish takeaway

The ASX renewables sector has had a difficult month in September, with the broad sector posting a loss in most instances.

Yet, these two names stand out as clear outperformers this past month.

Both of these ASX renewables shares have also climbed over 60% in the last 12 months, perhaps indicating a wider trend when factoring in a longer-term view.

The post These were the best performing ASX renewables shares in September appeared first on The Motley Fool Australia.