Richard's Comments

One other marketing tool you can use for your company (and web site) is sponsorship of renewable energy projects. Projects like "The Sunpark Challenge" ask companies to sponsor the solar cells that make up the solar park in return for marketing and promotional opportunities. The underlying premise is that every visitor to the the project web site will have actively been searching for information on solar power, and will see the logos and information from all the companies that have contributed. Links to each company's web site increase their Internet page ranking and drive traffic to their web site.
With the right sponsorship, you could potentially receive positive PR that normal advertising could not hope to achieve, often at a much lower cost.