Low-lying and densely populated, Bangladesh is among the countries most at risk from climate change and rising sea levels. Yet this vulnerable south Asian nation has ambitious plans to increase its use of coal — a big contributor to global warming — with the help of international donors.

The aim is to increase coal's share of electricity output from 2 per cent to 50 per cent by 2030. Like neighbouring India, which will also be severely affected by climate change, Bangladesh says it has little choice but to expand coal-fired power generation to develop its fast-growing economy, even at the expense of its own environment.

This south Asian paradox is most visible at the Rampal project, a 1,320 megawatt coal plant under construction 15km from the Sunderbans swamplands, a Unesco world heritage site on the Ganges delta that is the world's largest contiguous mangrove forest.

The location for the plant, a joint venture between Bangladesh and India's state-owned National Thermal Power Corp, was chosen near the coast to access shipments of 5m tonnes of imported coal each year.

Ships will enter the forest — which is rich in wildlife and home to the royal Bengal tiger — and transfer their cargoes to smaller vessels at a dolphin sanctuary inside the park.

Potential western financiers, including French bank BNP Paribas and the Norwegian state pension fund, said they would not lend to the Rampal project because it could contribute to what one called "severe environmental damage".

Albrecht Conze, then German ambassador to Dhaka, also criticised the project, but Fichtner, a German engineering company, won the bid to become its chief consultant.

While working at home to remove coal from its domestic energy mix, Berlin continues to finance the export of coal technology. The Overseas Development Institute, a British think-tank, notes in a joint study that in 2013-14 German international coal-fired power subsidies amounted to almost $1.5bn worldwide, largely through credit insurance group Euler Hermes, a subsidiary of Allianz.

Bangladesh, like many developing nations, suffers severe energy shortages. An energy "master plan" published in 2011 with the assistance of Japanese donors and Tokyo Electric Power Co (Tepco), recommended the building of a dozen coal plants around the country, which would help increase the country's generating capacity from 8 gigawatts in 2015 to 33GW by 2030.

Industry, including the crucial garment sector, suffers severe power shortages that it mitigates with the use of costly and polluting diesel generators. Such heavy generators on upper floors are thought to have contributed to the collapse of the Rana Plaza building in 2013, a disaster that killed 1,100 garment workers.

Domestically produced natural gas provides 80 per cent of Bangladesh's electricity, but the gasfields are fast being depleted and government regulations, including a ban on exports and subsidised prices for consumers, leading some of the lowest prices globally, have discouraged further exploration. The remaining electricity supply is generated by expensive diesel and furnace oil plants.

In spite of protests against new coal plants such as the Rampal project, Professor Ijaz Hossain of the Bangladesh University of Engineering Technology asks: "What choice do we have? It's either coal or nuclear. LNG [liquid natural gas] is too expensive." Rampal, furthermore, will use the most efficient "ultra supercritical" technology, exports of which are excluded from a recent OECD ban on coal technology trade.

Japan, which helped to write the energy master plan, is also involved in funding coal plants in Bangladesh.

The $4bn Matarbari "energy hub" project, near the southern town of Cox's Bazar, will be mostly financed by Jica, the Japanese development agency. This will see an initial two 600MW coal plants operational at the site by 2026, and possibly two more by 2030. JICA's $3.7bn outlay compares with Japanese public financing of coal projects globally of $5.4bn in 2013-14, and with Rampal's $1.5bn — although one reason for the high cost of the Japanese project is the need to build a deepwater port.

In spite of the promise of relatively efficient coal plants, some Bangladeshis and foreign analysts suspect foreign donors or suppliers will try to sell power station technology that will lock Bangladesh into a high-carbon economy for decades to come. Professor Saleemul Huq, director of the International Centre for Climate Change and Development, says "donors are trying to keep companies afloat by paying them" to provide Bangladesh with "the energy of the past".

Prof Huq says it would be better to save energy by improving the efficiency of transmission, with losses through theft and technical problems now often as high as 50 per cent. Bangladesh, he insists, can "leapfrog" the centralised, fossil fuel reliant model of electricity supply and