Query: How many liters of water per minute did Shuman's engine pump in litres?
Context: Shuman built the world’s first solar thermal power station in Maadi, Egypt, between 1912 and 1913. Shuman’s plant used parabolic troughs to power a 45–52 kilowatts (60–70 hp) engine that pumped more than 22,000 litres (4,800 imp gal; 5,800 US gal) of water per minute from the Nile River to adjacent cotton fields. Although the outbreak of World War I and the discovery of cheap oil in the 1930s discouraged the advancement of solar energy, Shuman’s vision and basic design were resurrected in the 1970s with a new wave of interest in solar thermal energy.