British Gas will donate and install solar panels worth between £20,000 and £40,000 ($29,997 and $59,994) per school in up to 750 schools, amounting to £15m ($22m).
With the solar panels, each school will be able to generate its own power, saving about 20% on its annual electricity bill, according to the energy company.
The panel-produced energy is expected to create around £1.3m ($1.9m) per year for the next 25 years.
Selected schools will be able to meet their carbon reduction targets with the installations, reducing CO2 emissions by up to 1,400t per year.
The schools will also receive smart meters along with the solar panels to measure the electricity generated in real time.