The Brighton Energy Co-operative is to set up the first community-owned solar power scheme in the area.
The pioneering project is looking for local supporters to help it raise £200,000 through a share offer.
The port and the two churches will receive free electricity for 25 years in exchange for hosting arrays of solar panels equivalent to the size of a football pitch.
The panels are expected to generate enough electricity over their 25-year life to power 40 homes and save 1,085 tonnes of carbon dioxide.
Brighton Energy Co-operative said that it would receive income from the electricity that they generated from the feed-in-tariff, a government-backed subsidy that is guaranteed for 25 years.
It said that this would be used to pay annual interest to investors and fund community projects such as insulating homes to make them more energy efficient.
The team behind the energy co-op will hold an event for potential investors at the Friends Meeting House in Ship Street, Brighton, at 7.45pm next Wednesday (16 May).
The share offer will run from Wednesday 16 May to Thursday 14 June.
Interested parties can make a pledge to buy shares before the launch on the Brighton Energy Co-operative website www.brightonenergy.org.uk.
Brighton Energy Co-operative chairman Will Cottrell said: “We are delighted to be able to bring this offer to Brighton and Hove residents.
“It’s a great opportunity for local people to get involved in and own a renewable energy scheme in the city.
“By supporting the generation of clean energy, they are helping Brighton and Hove reduce its reliance on polluting fossil fuels, lower its carbon dioxide emissions and become one of the country’s greenest cities.”