Wolf D. Grossmann

Indicators To Determine Winning Renewable Energy Technologies with an Application to Photovoltaics

Several forms of renewable energy compete for supremacy or for an appropriate role in global energy supply. A form of renewable energy can only play an important role in global energy supply if it fulfills several basic requirements. Its capacity must allow supplying a considerable fraction of present and future energy demand, all materials for its production must be readily available, land demand must not be prohibitive, and prices must reach grid parity in the nearer future. Moreover, a renewable energy technology can only be acceptable if it is politically safe. We supply a collection of indicators which allow assessing competing forms of renewable energy and elucidate why surprise is still a major factor in this field, calling for adaptive management. Photovoltaics (PV) are used as an example of a renewable energy source that looks highly promising, possibly supplemented by solar thermal electricity production (ST). We also show why energy use will contribute to land use problems and discuss ways in which the right choice of renewables may be indispensible in solving these problems.

Solar electricity supply isolines of generation capacity and storage

Significance The recent sharp drop in the cost of photovoltaic (PV) electricity generation accompanied by globally rapidly increasing investment in PV plants calls for new planning and management tools for large-scale distributed solar networks. We found that pairs of electricity generation capacity G and storage S, such that S is minimal to provide a given dispatchable electricity capacity for a given G, exhibit a smooth relationship of mutual substitutability between G and S. These G−S isolines support the solution of several tasks. This includes optimizing the size of G and S for dispatchable electricity, optimizing connections between solar parks across time zones for minimizing intermittency, and management of storage in situations of far below average insolation. The recent sharp drop in the cost of photovoltaic (PV) electricity generation accompanied by globally rapidly increasing investment in PV plants calls for new planning and management tools for large-scale distributed solar networks. Of major importance are methods to overcome intermittency of solar electricity, i.e., to provide dispatchable electricity at minimal costs. We find that pairs of electricity generation capacity G and storage S that give dispatchable electricity and are minimal with respect to S for a given G exhibit a smooth relationship of mutual substitutability between G and S. These isolines between G and S support the solving of several tasks, including the optimal sizing of generation capacity and storage, optimal siting of solar parks, optimal connections of solar parks across time zones for minimizing intermittency, and management of storage in situations of far below average insolation to provide dispatchable electricity. G−S isolines allow determining the cost-optimal pair (G,S) as a function of the cost ratio of G and S. G−S isolines provide a method for evaluating the effect of geographic spread and time zone coverage on costs of solar electricity.

Oceans and new renewable energy systems

Major relationships between energy systems and oceans are due to marine transportation of energy resources, emissions from use of these resources, and mining and exploration, in particular of natural gas and crude oil. These relationships are poised to change. A multitude of problems have emerged in the fossil fuel energy sector, e.g., “peak oil” and even “peak coal”, wildly fluctuating prices of energy from fossil fuels, and massive emissions causing environmental problems such as ocean acidification. Hence, globally, significant efforts are directed at the creation of new energy systems based on renewable energy. Such systems, if constructed on a large scale, would change many parameters of ocean affairs. Large-scale construction is expected given significant investments in renewable energy systems in different parts of the globe and the prospect that such systems may become competitive in many regions in 2014. We discuss parameters of such renewable energy systems and elaborate effects on transportation of resources and on the wider environment including oceans, and draw conclusions on possible changes for oceans.