The biggest scheme at a cost of £2.9m will be at Sheffield Teaching Hospitals NHS Foundation Trust which will save £810,000 a year on hot water.
In a separate project worth £150,000, the Sheffield Health & Social Care NHS Foundation Trust will install a combined heat and power centre at the Michael Carlisle centre in Nether Edge. The trust will also save more cash in a £16,000 project to install a system to automatically shut down computers.
Together the schemes are expected to make nearly £1m in savings.
Health Minister Dan Poulter said the schemes were among 69 across the country worth £50m which have been approved and will cut the NHS energy bill by £13.7m a year.
“The NHS is one of the largest users of energy in the country, making it increasingly more important to work efficiently to help save the environment, cut energy waste and save money,” he said.
“These schemes show a range of innovative ways the NHS can make improvements to help reduce energy inefficiencies, as well as cutting the energy bill – money that will be reinvested directly in to patient care.”
The NHS spends about £600m a year on energy. Hospitals run a 365-day-a-year service and it takes a huge amount of energy to power life-saving equipment such as intensive care beds.