Energy harvesting that are able to operate in higher temperature gradients, and that can conduct electricity well without also conducting heat (something that was until recently thought impossible ), will result in increased efficiency. Future work in thermoelectrics could be to convert wasted heat, such as in automobile engine combustion, into electricity. This type of harvesting is based on the changing capacitance of vibration-dependent capacitors. Vibrations separate the plates of a charged variable capacitor, and mechanical energy is converted into electrical energy. Electrostatic energy harvesters need a polarization source to work and to convert mechanical energy from vibrations into electricity. The polarization
Energy policy of China provide renewable electricity to 3.5 million households in 10,000 villages by 2010. This is to be followed by full rural electrification using renewable energy by 2015. Although a majority of the renewable energy in China is from hydropower, other renewable energy sources are in rapid development. In 2006, a total of 10 billion US dollars had been invested in renewable energy, second only to Germany. In 2006, 16 million tons of corn have been used to produce ethanol. However, because food prices in China rose sharply during 2007, China has decided to ban the further expansion of the corn ethanol