PLANTING nut trees and salvaging old frying fat to make biodiesel are among ideas devised by communities across Britain competing for government money to fight climate change. Twenty-two struck lucky. Over the past two months the Department of Energy and Climate Change (DECC) has given these winners of the Low Carbon Community Challenge (LCCC) grants of up to £500,000 ($780,000). Most of the projects involve small communities of 1,000 to 3,000 people planning a mix of measures such as new hydro-, wind, solar and biomass power; home insulation; electric transport and growing their own food.

This may seem small beer given Britain's target of an 80% cut in greenhouse- gas emissions by 2050. But by letting a thousand flowers bloom, DECC wants to understand “what is and isn't working…on the ground,” said Joan Ruddock, minister for energy and climate change, on February 8th. Many local councils have appointed climate-change officials. A plethora of foundations offer advice and support. But there is nothing like a bit of competition to stiffen sinews.

DECC is seizing a moment which may be brief. It announced the challenge in July, awarded the first ten grants in December and another 12 on February 4th. Why the hurry? DECC was stitched together from the Department for Business and the Department for the Environment, Food and Rural Affairs late in 2008 and needs to make its mark soon. Moreover, an election looms, which may see Ms Ruddock and her boss, Ed Miliband, thrown out of office.

Most important, perhaps, the programme will coincide with the birth of electricity feed-in tariffs on April 1st. Small electricity providers with up to 5MW capacity will be able to sell their excess power to the grid at a subsidised premium. Many of the LCCC projects depend on getting repaid through such sales. Ministers hope the new tariffs will create up to 750,000 micro-power installations by 2020. (That may be overly optimistic: in Germany, where feed-in tariffs began in 2000, there were just 290,000 micro-power installations by the end of 2006.)

The question is whether these measures will make much difference. A study by the Royal Academy of Engineering suggests that small wind turbines are not cost-effective and that insulating homes is a better use of money. One LCCC project includes building 30 German-inspired Passiv houses, which require less than 15kWh per square metre per year to heat (a standard house uses 55kWh).

Fortunately for those that missed out on the latest handouts, there are other sources of cash. The South West has grand ambitions to make itself a renewable-energy powerhouse. Its Regional Development Agency (with some assistance from Europe) has financed the Wave Hub project in Cornwall, which will feed power from numerous offshore wave-power machines into the grid. Russell Geake at Community Energy Plus, a charity, thinks the county could save £260m a year on its energy bills.