You are right to highlight the uncertainty that Scotland's inadequate planning system is bringing to our renewable energy potential (Renewable energy targets ridiculed, February 23).

That same planning system is also holding up the development of small-scale renewable energy technologies, known as microrenewables, that have the potential to take the strain off the grid by allowing households and businesses to generate their own renewable electricity and heat locally.

The previous Scottish Executive issued national planning policy guidelines requiring most new housing and commercial developments to reduce carbon dioxide emissions by 15% over and above building regulation requirements. A year on, research by Friends of the Earth Scotland shows the majority of local authorities have not translated that into local plans and have received no support from the Scottish Government to ensure they do.

Scotland is also dragging its heels on planning rules governing the installation of microrenewables on existing buildings. Regulations in England are set to change to allow people to install solar panels and other microrenewables without the expense and bureaucracy of getting planning permission. Here in Scotland, despite independent advice more than a year ago to take the same path, the Scottish Government has yet to issue its consultation paper to get the ball rolling. Scotland has the most ambitious climate change targets in the world and a fledgling microrenewables industry. Both may be under threat if the Scottish Government does not show greater urgency in tackling the planning obstacles facing small-scale renewables.

Liz Murray, Campaigns and research officer, Friends of the Earth Scotland, Edinburgh.

Yesterday we heard about a trial Virgin flight to Amsterdam partly powered by biodiesel from palm oil and coconut oil. Will tomorrow's headlines be: "Total loss of rainforests likely within a decade. Rice and wheat cultivation under threat from biofuels. Increasing malnutrition. Many species face extinction"?

The misplaced idea that biofuels represent any benefit has taken grip of the public imagination, fuelled by entrepreneurs such as Sir Richard Branson. The increasing use of biodiesel will result not in benefit to the planet, but rather a global disaster.

The tracts of land that might now be taken into intense production for biofuels will cause an upsurge of CO2 to be released into the atmosphere.

Growing biofuels will be more profitable to landowners than staples such as rice or wheat, resulting in increased exposure to starvation for the world's poor. And we will say goodbye to many species of plant and animals inhabiting the forests and jungles which will be sacrificed on the altar of greed and consumerism.

Biofuels will not save the planet; quite the reverse, they will likely kill it.

Ottilia Stevenson, Auchterarder.