The solar installers can submit their bids for solar power projects as per their choice. They can quote item and scope wise. Panel or per Watt installation rates. They can place bids on complete project or by parts (mechanical works, electrical commissioning, electronic programming).
There is a wide scope to optional provide Service-Level-Agreements and consolidate roles with regards to after-sales when it comes to providing troubleshooting and maintenance services in your respective areas.