Future energy: 5 new disruptive energy technologies
Future energy is one of today's most important challenges, not only because of climate change but also because of the recent crisis in Europe following the war in Ukraine. Wind, photovoltaic, hydroelectric, biomass... Everyone has heard of these technologies at some point. In this article, we talk about 5 less known but no less important breakthrough energy technologies.
If you are interested in this topic, visit our open innovation page and discover a few innovative projects for the production and storage of renewable energy.
Reverse photovoltaic panels
The first prototypes of the "reverse photovoltaic panel" were created last January. This new type of technology allows to generate electricity even on cloudy days or at night, solving one of the big problems of photovoltaic solar energy.
The operation of these panels is based on so-called thermal radiation cells. These are devices that receive infrared radiation from the heat of other bodies and transform it into electrical energy. This radiation has a wavelength and energy content that depends on the temperature of the body, and always goes from the hottest to the coldest bodies.
In the case of conventional panels, the hot body is the sun and the cold body is the panels, which absorb the sun's radiation. For the inverter panels, the hot body is the surface of the earth while the cold body is space. The most fascinating thing is that these inverse panels are able to absorb the radiation emitted by the Earth at night and convert it into electrical energy, being able to generate at night 50% of what a conventional panel produces during the day.
Conventional vs Reverse photovoltaic panels
These devices were already known and some applications had been developed to improve the efficiency of thermal engines, recapturing part of their waste heat and transforming it into electrical energy. Thanks to this progress, the constant generation of renewable energy by photovoltaic panels is getting closer.
Ocean thermal energy (OTEC)
Highly exothermic chemical reactions (such as coal combustion or nuclear fission) are used in thermal plants to heat fluids that spin a turbine. These fluids must be subsequently condensed when in contact with a coolant, usually water. Therefore, the fluid passes from a hot bulb to a cold bulb leaving a temperature gradient. In certain areas of the planet there are large differences or temperature gradients between surface and deep water.
Map detailing sea water temperature gradients in the world
This temperature gradient can be used for electrical power generation. This type of future energy power generation is known as ocean thermal energy conversion (OTEC). There are different types of OTEC power plants: open-cycle (where the seawater itself circulates through the turbine, with a capacity of up to 40 MW generation) and closed-cycle (where the temperature gradient is used to circulate another fluid, such as ammonia, with a capacity of up to 150 MW).
These plants are already in operation in some parts of the world, mainly in Japan, Hawaii and Southeast Asia. Due to their dependence on the water temperature gradient they cannot be installed anywhere.
Generation IV nuclear power plants
The fourth generation is the term used to refer to new nuclear power plants that dramatically improve safety, sustainability, efficiency and cost compared to current technology. The vast majority of those plants are still under investigation, but the first, known as HTR-PM, was commissioned in China.
There are 6 technologies that are considered suitable for the 4th generation:
- The Very High Temperature Reactor (VHTR)
- Molten Salt Reactor (MSR)
- Supercritical Cooled Reactor (SCWR)
- Rapid Gas Reactor (GFR)
- Fast Sodium Reactor (SFR) and
- Fast Lead Reactor (LFR).
All of these technologies, with the exception of VHTR, would allow a closed fuel cycle, which means the reuse of nuclear waste from other plants to extract their energy.
Generation IV plants are capable of extracting up to 300 times more energy from the same amount of uranium. Thanks to such improved performance, remarkable in the field of safety and efficiency, makes these plants an excellent complement to renewable energies, to achieve a continuous supply, and an intermediate step until nuclear fusion is mastered.
Synthesis of hydrogen using CO2
Carbon capture and storage (CCS) include a series of techniques designed to reduce CO2 emissions from heavy industries and thermal plants, as well as to clean the atmosphere of CO2. CCS allows a reduction in emissions from these polluting activities of between 10 and 55%. Once captured, the CO2 is stored in underground reservoirs for later reuse.
Although these techniques are already valuable because of their positive environmental impact, their value does not end with the elimination of atmospheric CO2. This gas can then be re-used for the synthesis of less polluting thermal fuels, the improvement of the petroleum extraction process and the synthesis of hydrogen.
Among all these possible uses, hydrogen synthesis is the most promising. New technologies are currently being investigated to enable hydrogen synthesis using CO2 as a reagent and generating electricity at the same time. This process would be extremely valuable for the future energy essentially for two reasons:
- First, because today's hydrogen synthesis processes do not use CO2, thus achieving a much "cleaner" hydrogen.
- Second, by transforming CO2 into hydrogen, the need to store it underground, as has been the case until now, is eliminated.
Considering that hydrogen is positioning itself as the new main energy vector, this technology has many prospects for the future. In this article you can find different uses of hydrogen as an energy source.
Diagram explaining the process of generating hydrogen from CO2
One of the major problems faced by renewable energies, except hydroelectric energy, is the low electrical inertia they bring to the system. A power system with low inertia is very vulnerable to generation-demand imbalances, which causes its frequency to vary greatly. This means that the electrical appliances we have plugged in may not work properly.
In small countries with small electricity systems, the inertia is lower and the possibility of decompensations is higher, so they could not be supplied exclusively by renewable energy. However, this is not the case in larger countries. The key to mitigating this problem may lie in a power electronics system known as the static compensator.
Static Synchronous Series Compensator (SSSC) scheme
The static compensator is a device that essentially provides inertia to those electrical systems that do not have it, manipulating reactive power injections. Coupled with renewable energy generators such as wind or photovoltaic energy, it would increase the inertia they contribute to the power grid, thus allowing us to keep using conventional thermal power plants for grid stability reasons. These devices already exist and are used primarily in microgrids, but have not yet been adapted to large-scale applications, such as for use in a national power grid, so research and development of these devices still has much potential.