The San Diego Unified School District is going solar - and by adopting solar power, it will save a substantial amount of money.

The district announced last week a plan to buy 5.2 megawatts of solar energy from AMSOLAR, a company based in Solana Beach, California. AMSOLAR will install and maintain 23,000 solar panels on rooftops throughout the school district.

By buying energy from the solar company and not San Diego Gas & Electric, the SDUSD will save $300,000 in the first year it goes solar and as much as $20 million over the next 22 years.

And because the SDUSD is relying on a power-purchase agreement to buy energy from AMSOLAR, it won't need to assume the upfront cost of solar installations.

For cash-strapped public school systems, buying clean energy is a far more palatable way to cut costs than teacher layoffs or four-day school weeks (which Hawaii imposed during the past school year). Solar power systems can also serve an educational purpose: Having solar panels on the roof of a school building can provide opportunities for teachers to show their students the benefits of clean power.