The unwavering predictability and scale of the tides in some parts of the world make them an attractive renewable energy source. Some estimates put the energy in the world's tides at as much as 1 million GWh per year, or about 5 per cent of the electricity generated worldwide, though only a fraction of this is likely to be exploited due to practical constraints.

One of the key problems with renewables is their intermittent availability. You can only generate energy from the wind when it is blowing, or from the sun when it's shining. Critics argue this is why we will never be able to rely on renewables for the majority of our electricity generation. But that criticism may soon be silenced.

At first glance, geothermal energy seems almost too good to be true. It's clean, inexhaustible, provides predictable 24-hour power and you can get it just about anywhere. There is a snag, however. Outside of geologically blessed places like Iceland, Japan and New Zealand, where volcanically active rocks are close to the surface, the Earth's heat is locked away under several kilometres of rock.

Wave power generation cum shore protection project envisages tapping the energy of ocean waves and wind for the generation of electricity and integrating it with the national power grid. A number of impellors are arranged parallel to the shore for a span of 500 m at a distance of about 100 m from the seashore. Impellers are designed to tap the trienergies of ocean waves.

With the average price of a gallon of gasoline hovering somewhere around $4 in the U.S. and oil prices continuing to rise the whole world is refocusing their attention on the viability of alternative energy sources. A window seems to be opening for genuine progress in lessening our dependence on fossil fuels.

Thermoelectric materials are solid-state energy converters whose combination of thermal, electrical, and semiconducting properties allows them to be used to convert waste heat into electricity or electrical power directly into cooling and heating.