Utilities traditionally have met renewable portfolio standards with power purchases from IPPs. But new approaches are allowing utilities to build their rate bases with investments in solar...
Solar Tech Outlook
Manufacturers scale up for utility applications.
the transmission grid, this shouldn’t be a significant challenge for most utilities, as the production of solar energy matches peak customer demand. Weather patterns are predictable, and with modern information technology, variations in solar energy caused by clouds can be predicted with great accuracy and dealt with by schedule coordinators. Even in Germany, which isn’t known for a constant, sunny climate, the integration of large amounts of intermittent solar energy hasn’t been a problem because Germany has made the right investments in its transmission grid.
From a policy perspective, which is as important and perhaps even more important to solve than the technology challenges, we need to create viable long-term markets for solar electricity, and the best way to do that is through government policy initiatives, such as feed-in-tariffs or guaranteed rate structures for a specified period of time. These types of relatively short-term investments have been used successfully in other countries—most notably Germany—to develop viable long-term markets. In the United States, California’s renewable portfolio standard is providing a similar public policy stimulus to grow the solar market from a subsidized phase to a sustainable scale.
Woolard, BrightSource Energy: The challenges of utility-scale solar production vary by technology. For PV, the challenge is reaching higher capacity levels because these technologies inefficiently convert the sun’s rays into energy. This low capacity factor means that projects must be sized larger to achieve the same level of output of power as more efficient technologies, like solar thermal. Of course, this means that the cost of these types of PV plants will also increase as more inputs are added. It also means more land will be needed to produce the energy. PV must also find ways of making the energy produced at utility scale more firm and dispatchable. As intermittent renewables become a greater part of the mix, the issue of reliability will increasingly become a greater focus for utilities and grid planners. Those technologies that can offer low-carbon, cost-effective and reliable resources will ultimately serve as a primary power resource.
Along the same vein, solar-thermal providers must also continue to drive efficiency improvements in order to lower the overall cost of solar. The Holy Grail in solar thermal power production is creating high temperature and high pressure steam. By reaching these high temperature and pressure levels, the solar thermal power plants experience tremendous efficiency gains because they can follow the requirements of the latest turbine technologies. An often used analogy can be found in the computing industry. The most efficient solar power plants must be like today’s leading personal computers in that they must use the latest turbines, the equivalent of the most efficient microprocessors in computing. Otherwise, these plants would be functioning like a modern computer with a 486-MHz microprocessor, where all of the efficiency and power advantages are lost.
MacDonald, Skyline Solar: The non-dispatchable nature of utility-scale solar is a significant hurdle. By combining large-scale CPV with short-term energy storage solutions, solar will be better able to deliver the reliable performance that utility customers depend upon. Another challenge is reducing the complexity and