Industrial engineer, Santiago Galbete Goyena’s PhD thesis, aimed at finding viable technical and economic solutions to achieve a 100% renewable electricity supply system for Spain, concluded that, “the development of a system of renewable generation is not by any means an unviable challenge for current industry and 20 years should be sufficient to achieve it”. The PhD thesis was entitled, “The technical-economic viability for 100% renewable electricity supply in Spain”.

In his research, Mr. Galbete reminds us that the proportion of renewable electricity production in peninsular Spain is only about 35%, compared to the overall demand. “We have a country very poor in non-renewable resources, especially natural gas, petroleum oil and uranium – practically non-existent –, but we nevertheless have an enormous potential for solar, wind and hydraulic energy, not forgetting the potential of other possibilities – still at development phase –, such as tidal, wave and geothermic energy. So, it would seem clear that aiming for a local, renewable resources-based energy system is recommendable”. In this context, the industrial, social and financial advantages of such as decision “would overcome by far the evident difficulties that this change would undoubtedly entail”.

In concrete, this researcher has put forward a series of solutions to show that an electric energy supply system such as that of Spain can work in a guaranteed manner, based solely on renewable sources, efficiently and with the same cost ranges as the current system.

In drawing up this PhD and through Acciona Energy, with the goal of seeking opinions about this project from current renewable energy circles worldwide, articles were presented at a number of international congresses (Valencia, Amsterdam, London and Beijing).

Combination of resources

For his research, Mr. Galbete prepared a mathematical environment enabling using energy models and incorporating the maximum amount of real information, such as production time slots for different renewable technologies over a period of ten years. He explained that, “one of the main difficulties was drawing up a strategy to compensate for the rapid variations in energy production from solar and wind resources. In order to solve this problem efficiently, the ideal is to be able to store excess energy at any given moment in order to use it subsequently when required”. To this end, the PhD thesis also provides novel techniques and analyses the various options of energy storage.

The solution he believes to be the most ideal, from a technical perspective, involves a combination of various renewable technologies. Thus, terrestrial wind energy should be increased from the current 22 GW (gigawatts) to 48 GW. “Taking into account the potential of current wind turbine generators, this increase would involve installing on average 200 wind turbine generators in each Spanish province and would be sufficient in a period of 20 years”. As regards solar energy, it would have to go from 6 GW to 27.5 GW with “existing resources and available surface area. Taking into account that, just in 2008, 2.3 GW was connected to the grid, the time necessary to achieve the required estimated production would not be a problem”.
With respect to energy from biomass, it will be necessary to have about 12 GW of power, something also viable within twenty years. Hydraulic energy only requires a repowering of the existing power plants from the current 14.8 GW to 17 GW for the 100% renewable energy proposal. With pumping power stations, adding to the current 2.7 GW, those already projected will be sufficient to reach the required 6.1 GW.

“Twenty years should be sufficient to install the power necessary to achieve an electric supply system which is 100% from renewable energy”, explained the engineer. “Nevertheless, given the strong legislative obstacles being faced by renewable energy production in Spain, in the PhD I have put forward a more conservative option and I have considered that, taking a fairly straightforward path, the 100% supply of renewable energy could be achieved by 2050”.

Lower costs

Once demonstrated the technical viability for the 100% supply of renewable energy, the aim of this study was not to seek the financing of investment opportunities, but the economic viability of a national, 100% renewable energy system. To this end, new production costs, based on technological innovations, have been updated. With these calculations, conclusions can be drawn regarding both renewable and conventional energy sources.

The LCOE (levelised cost of energy) is the most representative figure internationally for the study of energy costs. In this sense, the author indicated that the actual energy mix has lower production costs than a hypothetical 100% renewable system. Nevertheless, “a tendency to converge between both has been observed, consequence of the technological evolution of renewable energy sources and taking into account other external factors of non-renewable energy. Significantly, it has also been observed that, for projections for 2050, renewable energy costs will be lower than those of conventional energy sources”.

A second method used in the thesis, that validates the previous results, is the study of the Relative Rate of Return on investment. The estimates for 2050 anticipate rates of return for renewable energy sources greater (4.1%) than those for current, mixed ones (3.7%).

With the goal of achieving a 100% renewable and stable system, in this PhD a period of transition is proposed to enable achieving a 100% renewable energy system by 2050.

* Elhuyar translation, published in www.basqueresearch.com