Global investment in clean energy fell for the second year in a row to $254bn last year, with green investment in Europe crashing by 41%, new figures showed on Wednesday.

The drop casts a pall over a high-profile investor summit at the United Nations on Wednesday.

The summit, organised by the Ceres investor network, was supposed to build momentum for the shift to a clean energy economy – a transformation requiring global investment of some $1 trillion a year by 2030.

But investment in clean energy headed downwards last year, according to the figures released at the summit by Bloomberg New Energy Finance (BNEF). It was the second year of declining investment in clean energy from a record $318bn in 2011, the research showed.

BNEF's founder, Michael Liebreich, said there were some bright spots in the decline. "The top‐line figures don't tell the whole story," he said in a statement.

He said the sharp fall in investment in Europe was partly the result of declining costs for solar panels, bringing down the costs of rooftop solar. Even with the lower figures for clean energy investment, global solar installations grew by 20% last year.

Meanwhile, Liebreich said there was new investor interest in electric vehicles and renewable power projects.

But with big economies such as Germany, Italy and France scaling back government support for new projects, clean energy investment fell from $98bn to $58bn in Europe, a drop of 41%.

Germany saw the biggest decline, from $26.2bn in 2012 to $14.1bn last year – the lowest since 2006.

Britain, in contrast, saw a relatively modest decline from $14.3bn to $13.1bn.

Clean energy investment was even down in China – for the first time in decade – with a 3.8% drop. In America, investment in clean energy and technologies fell by 8.4% to $48.4bn, Bloomberg said.

The biggest exception to the downward trend was Japan, where clean energy investment rose 55% to $35.4bn last year, as the country tried to replace its nuclear power plants.

The new BNEF figures look set to add even more urgency to appeals for financial institutions to drastically step up investment in clean energy.

The UN's climate chief, Christiana Figueres, this week urged global financial institutions to triple their investments in clean energy to reach the $1 trillion figure needed to avoid a climate catastrophe.

Figueres planned to take her case directly to the financial institutions at the investor summit on Wednesday.

She will try to persuade investors that it is in their financial interest to move now to limit their exposure to coal and oil.

"There is study after study coming out saying: 'beware we are invested in assets that are already and will soon be losing value'," she said.

But with the latest figures from Bloomberg, Figueres's task became even more difficult.

It appears that clean energy investment will have to grow four-fold – an even more ambitious target than Figueres had originally estimated.