It should be made clear that there are considerable differences between biofuels in terms of greenhouse gas emissions (Biofuels: a solution that became part of the problem, March 25). Sugarcane is by far the most productive, cost-efficient and carbon-saving feedstock for biofuel production. Sugarcane ethanol allows for a 90% reduction in emissions, compared with petrol, and its energy balance is 8.3 to one, ie for every unit of energy used in production eight units of energy are created. Gains in agricultural productivity in Brazil have led to a simultaneous increase in ethanol and food production. Brazil now produces enough ethanol to power 45% of its passenger vehicles using only 3.4m hectares, or 1%, of its arable land. This production is located mainly in the centre-south of Brazil, 2,500km distant from the Amazon. Brazil's ethanol production is expected to triple by 2020, but the increase will require only 6m additional hectares, only a fraction of the 30m hectares of degraded pasture currently available. Thanks to hydroelectric power and to biofuels, approximately 45% of Brazil's total energy mix is comprised of renewable sources, compared with the EU's average of 6.7% and the UK's 2%.

Felipe Costa

Embassy of Brazil

The government wishes to offset UK-funded overseas wind farms against the UK's renewables commitment (Report, March 29). A 12MW proposal in the greenbelt near our village would be financed from Germany, and use Danish turbines. Has the government thought through the implications of counter-offsetting foreign-funded UK-based windfarms?

Steve Pardoe

Acton Bridge, Cheshire