A new kind of hybrid is being launched in Florida across 500 acres near West Palm Beach, later this year. The utility, Florida Light and Power (FPL Group) is assembling 190,000 shimmering mirrors and thousands of steel pylons that stretch as far as the eye can see. When it is completed by the end of the year, this vast project will be the world’s second-largest solar plant according to a NY Times article.
Yes this is a power station hybrid, not a car, and yet the intent is largely the same, to reduce fuel consumption and carbon dioxide emissions by marrying a conventional power source to a “green supply source. In this case, the solar panels will concentrate the sun’s rays onto a vacuum-sealed tube that contains a synthetic oil. The oil then heats up to 748 degrees F and is used to produce steam that is fed into an existing turbine to produce electricity. Using small sensors, the mirrors will be able to rotate during the day to track the sun’s movement. The difference here is that the turbines, electrical generating equipment and transmission system are already in place for the 3800 MW gas fired power station alongside which the solar farm is being built. By piggy-backing on the existing plant, FPL expects to be able to run the solar plant when the sun shines with the gas plant on reduced output and crank up the gas plant to full power during low light or during the night. Such a combination saves some 20% of the costs for a conventional standalone solar farm says the company and is the future for achieving a proportion of all power being produced from renewable sources such as Congress intended with its now stalled legislation to mandate a 25% target by 2025. Although 75MW for the solar contribution will allow the utility to achieve only 19% of total output from solar when the sun shines, it will on average of course achieve much less. The question is will the reduction in capital costs make solar power economical without subsidy or will tax payers and consumers be expected to pay higher charges for the pleasure of knowing they are creating less greenhouse gasses? FPL estimates the $475m project will allow the company to cut its natural gas consumption by 1.3 billion cu ft a year and cut carbon emissions by 2.75m tons over the 30 year life, on the European carbon trading market that would be worth some $50m at current prices and could feasibly be sold forward to help meet the capital cost, if a similar system existed in the US.
The reality is neither solar nor wind appear likely to be economically viable under current conditions (i.e. no carbon penalty) and without subsidies or increased consumer tariffs, but that won’t stop utilities developing projects like this to try and position themselves for the future. A hybrid system has a lot of logic especially in reducing capital costs and in synchronizing the balance of contributions from the conventional power source with the more variable renewable source. We say anything that reduces the subsidy burden to the consumer has got to be a good idea.