SOLUTIONS
The Future Is Renewable
The deployment of Renewables on a scale to replace fossil fuels will require industry to be re-tooled. The extraordinary 1940s domestic U.S. war effort was accomplished without modern computing, automation or robotics. A worldwide programme like that would abolish the root causes of climate breakdown and energy insecurity through a single policy shift. Its scientific and socio-political foundations have been described in pioneering works by Lester Brown [1] and Herman Scheer [2]. Below we describe some existing renewable energy technologies that are ready for large scale roll-out.
Concentrating Solar Power (CSP)
Solar Troughs, Kramer Junction CSP plant, Mojave Desert
CSP technologies concentrate the sun’s heat to generate steam, which drives a turbine or engine, yielding 15% conversion efficiency to electricity. CSP overcomes the intermittency of sunlight by heating (molten) salts like sodium and potassium nitrate up to 600C. So a plant can run into the night, providing base load electricity to the grid without sunlight. It can be scaled up to thousands of megawatts capacity. It is ideal for very sunny arid or desert lands in the southern U.S.A., Mediterranean countries, India, etc.
In the Dish-Stirling CSP system seen above, a series of mirrors is arranged in a concave plate, focussing sunlight onto a Stirling external combustion engine. The heat drives pistons by continually expanding and condensing hydrogen gas. The conversion efficiency is 24%. Units are deployed in arrays. An 1800MW CSP project under construction in California uses this technology.
Utility-scale CSP and Solar-Hybrid power plants have been developed by U.S. company Ausra, whose solar steam generators can be combined with a gas fired backup boiler. Such scalable hybrid systems (see below) are likely to have multiple applications. Ausra was purchased (2010) by a major French nuclear power company, who estimate that CSP deployment is likely to increase 30-fold by 2020.
1. Lester Brown [2010] Plan B 4.0
2. Herman Scheer [2007] Energy Autonomy