Despite the slower expansion, production per capita is projected to rise 0.7% annually. For instance, producing a tonne of beef can require almost 20 times more water than is needed to produce a tonne of maize (Zimmer and Renault, 2003). But hacking may increase risks of water shortage at the local level, and risks of water contamination by methane and hacking fluids. Natural gas power plants use less water than coal plants.