Other renewable energy technologies are still under development and include cellulosic ethanol, dry and hot geothermal energy, and marine energy.  These technologies are not yet widely proven or have limited commercialization. Many are on the horizon and may have potential comparable to other renewable energy technologies, but they still depend on attracting sufficient attention and funding for research, development and demonstration (RD & D) . 
There are many organizations in the academic, federal and commercial sectors conducting large scale advanced research in the field of renewable energy. This research covers several areas of interest in the spectrum of renewable energies. Most research aims to improve efficiency and increase overall energy yields.  Many research organizations supported by the federal government have focused on renewable energy in recent years. Two of the largest laboratories are Sandia National Laboratories and the National Renewable Energy Laboratory (NREL), both funded by the US Department of Energy and supported by various corporate partners. Sandia has a total budget of $ 2.4 billion , while NREL’s budget is $ 375 million. 
- Enhanced Geothermal Systems (EGS) are a new type of geothermal energy technologies that do not require natural convective hydrothermal resources. The vast majority of geothermal energy at drilling range is in dry, non-porous rocks.  EGS technologies “improve” and / or create geothermal resources in this “hot dry rock (HDR)” through hydraulic stimulation. EGS and HDR technologies, such as hydrothermal geothermal energy, should be basic resources that produce energy 24 hours a day as a fossil plant. Distinct from hydrothermal, HDR and EGS can be feasible anywhere in the world, depending on the economic limitations of the drilling depth. Good locations are on deep granite covered by a thick layer (3-5 kilometers) of insulating sediments that slow down the heat loss.  HDR and EGS systems are currently being developed and tested in France, Australia, Japan, Germany, the United States and Switzerland. The largest EGS project in the world is a 25 megawatt demonstration plant being developed in the Cooper Basin, Australia. The Cooper Basin has the potential to generate 5,000 to 10,000 MW.
- Cellulosic ethanol
- Several refineries able to process biomass and convert it into ethanol are built by companies like Iogen, POET and Abengoa, while other companies like Verenium Corporation, Novozymes and Dyadic International  produce enzymes that could allow commercialization. future. The transition from raw materials from food crops to waste residues and native grasses provides significant opportunities for a range of actors, from farmers to biotech companies, and project developers to investors. 
- Marine energy
- Marine energy (sometimes also referred to as ocean energy) refers to the energy carried by ocean waves, tides, salinity, and ocean temperature differences. The movement of water in the world’s oceans creates a vast store of kinetic energy, or energy in motion. This energy can be exploited to produce electricity to power homes, transportation and industries. The term marine energy encompasses both the power of waves – energy from surface waves, and tidal energy – obtained from the kinetic energy of large bodies of moving water. Reverse Electrodialysis (RED) is a technology that produces electricity by mixing fresh river water and saltwater in large power cells designed for this purpose. from 2016, it is tested on a small scale (50 kW). Offshore wind energy is not a form of marine energy because wind energy comes from the wind, even if the wind turbines are placed on the water. The oceans have a lot of energy and are close to many populations, if not the most concentrated ones. Ocean energy has the potential to provide a substantial amount of new renewable energy around the world. even if the wind turbines are placed on the water. The oceans have a lot of energy and are close to many populations, if not the most concentrated ones. Ocean energy has the potential to provide a substantial amount of new renewable energy around the world. even if the wind turbines are placed on the water. The oceans have a lot of energy and are close to many populations, if not the most concentrated ones. Ocean energy has the potential to provide a substantial amount of new renewable energy around the world. 
|1.||Sihwa Lake Tidal Power Station||South Korea||254 MW|||
|2.||Tidal energy station of Rance||la France||240 MW|||
|3.||Annapolis Royal Power Station||Canada||20 MW|||
- Experimental solar energy
- Concentrated photovoltaic (PV) systems use concentrated sunlight on photovoltaic surfaces for the purpose of generating electricity. Thermoelectric or “thermo-photovoltaic” devices convert a difference in temperature between dissimilar materials into an electric current.
- Solar floating sets
- Floating solar panels are PV systems that float on the surface of drinking water tanks, quarry lakes, irrigation canals, and sanitation and tailings ponds. A few of these systems exist in France, India, Japan, South Korea, the United Kingdom, Singapore and the United States.     The systems would have advantages over terrestrial photovoltaics. The cost of the land is higher and there are fewer rules and regulations for structures built on bodies of water that are not used for recreation. Unlike most terrestrial solar power plants, floating networks can be unobtrusive because they are hidden from view by the public. They achieve higher yields than PV panels on the ground because the water cools the panels. The panels have a special coating to prevent rust or corrosion.  In May 2008, the Far Niente Winery of Oakville, California, inaugurated the first floating system in the world by installing 994 solar modules with a total power of 477 kW on 130 pontoons and floating them in the irrigation pond. .  Industrial scale floating photovoltaic farms are beginning to be built. Kyocera will develop the world’s largest 13.4 MW farm above Yamakura Dam in Chiba Prefecture  using 50,000 solar panels.   Saltwater resistant floating farms are also constructed for use in the ocean.  The largest floating project so far announced is a 350 MW power plant in the Amazon region of Brazil. 
- Solar heat pump
- A heat pump is a device that provides thermal energy from a heat source to a destination called a “heat sink”. Heat pumps are designed to move thermal energy away from the direction of spontaneous heat flow by absorbing heat from a cold space and releasing it to a higher temperature. A solar heat pump represents the integration of a heat pump and solar thermal panels into a single integrated system. Typically, these two technologies are used separately (or only by placing them in parallel) to produce hot water.  In this system, the solar thermal panel fulfills the function of the heat source at low temperature and the heat produced is used to supply the evaporator of the heat pump.  The purpose of this system is to achieve high COP and to produce energy more efficiently and cheaply.
- It is possible to use any type of solar thermal panel (foil and tubes, roll-bond, heat pipe, thermal plates) or hybrid (mono / polycrystalline, thin film) in combination with the heat pump. The use of a hybrid panel is preferable because it allows to cover a part of the demand of electricity of the heat pump and to reduce the consumption of energy and consequently the variable costs of the system.
- Artificial photosynthesis
- Artificial photosynthesis uses techniques including nanotechnology to store solar electromagnetic energy in chemical bonds by separating water to produce hydrogen, and then using carbon dioxide to produce methanol.  The researchers in this field strive to design molecular imitations of photosynthesis that use a wider region of the solar spectrum, use catalytic systems made from abundant and inexpensive materials that are robust, easily repaired, non-toxic and stable. environmental conditions and function more efficiently, allowing a greater proportion of photon energy to end up in storage compounds, ie, carbohydrates (rather than building and maintaining living cells) .  However, Sun Catalytix, a spin-off of MIT, stopped expanding its fuel cell prototype in 2012, as it offers little savings on other ways to produce hydrogen from the sunlight. 
- Combustible algae
- The production of liquid fuels from oil-rich algae varieties is an ongoing research topic. Various microalgae grown in open or closed systems are being tested, including a system that can be set up in brownfields and desert lands.
- Solar plane
- An electric airplane is an airplane that runs on electric motors rather than internal combustion engines, with electricity coming from fuel cells, solar cells, supercapacitors, radiating power,  or batteries.
- At present, piloted electric aircraft are essentially experimental demonstrators, although many small unmanned aerial vehicles are powered by batteries. Model aircraft with electric propulsion have been flown since the 1970s, with a report in 1957.   The first electric powered flights were made in 1973.  Between 2015-2016, an inhabited aircraft, Solar powered aircraft, Solar Impulse 2, has completed a circumnavigation of the Earth. 
- Solar ascend tower
- The solar tower is a renewable energy plant that produces electricity from low-temperature solar heat. The sun heats the air under a very large structure of collectors covered with greenhouses surrounding the central base of a very tall chimney tower. The resulting convection causes a hot air flow in the tower through the chimney effect. This airflow drives wind turbines into the chimney’s updraft or around the base of the chimney to generate electricity. Plans for enlarged versions of demonstration models will provide significant energy production, and could allow the development of other applications, such as water extraction or distillation, and agriculture or horticulture.
- Space-based solar energy
- For photovoltaic or thermal systems, one option is to loft them in space, in particular the geosynchronous orbit. To be competitive with Earth-based solar energy systems, the specific mass (kg / kW) multiplied by the cost of loft mass plus the cost of parts must be $ 2,400 or less. That is, for a cost of parts plus $ 1,100 / kWe, the product of $ / kg and kg / kW must be $ 1,300 / kW or less.  Thus, for 6.5 kg / kW, the transport cost can not exceed $ 200 / kg. While this requires a 100% reduction, SpaceX is aiming for a reduction of ten to one; the reaction engines can make a reduction of 100 to one possible.
Renewable electricity production from sources such as wind and solar is sometimes criticized for being variable or intermittent, but not for concentrated solar, geothermal and biofuel plants that have continuity. In any case, the International Energy Agency has stated that the deployment of renewable technologies generally increases the diversity of electricity sources and, through local production, contributes to the flexibility of the system and its resistance to central shocks. 
There have been “no in my backyard” (NIMBY) concerns about the visual and other impacts of some wind farms, with local residents sometimes fighting or blocking construction.  In the United States, the Massachusetts Cape Wind Project has been delayed for years due in part to aesthetic concerns. However, residents from other regions have been more positive. According to a city councilor, the vast majority of residents believe that the Ardrossan wind farm in Scotland has improved the area. 
A recent British government paper states that “projects are generally more likely to succeed if they enjoy broad public support and the consent of local communities, which means giving communities both the right to speak and stake”.  In countries such as Germany and Denmark, many renewable energy projects belong to communities, particularly through cooperative structures, and contribute significantly to overall levels of renewable energy deployment.  
The market for renewable energy technologies has continued to grow. Climate change concerns and more and more green jobs, associated with high oil prices, peak oil, oil wars, oil spills, promotion of electric vehicles and renewable electricity, nuclear disasters and increase government support, are to increase renewable energy legislation, incentives and marketing.  New government spending, regulations and policies have helped the industry weather the 2009 economic crisis better than many other sectors.  
While renewable energy has been very successful in their growing contribution to electric power, there is no country dominated by fossil fuels that has a plan to stop and get that energy from renewable. Only Scotland and Ontario have stopped burning coal, thanks largely to good natural gas reserves. In transportation, fossil fuels are even more entrenched and solutions are more difficult to find.  It is not known if there are any failures with politics or renewable energy, but twenty years after the Kyoto Protocol, fossil fuels are still our main source of energy and consumption continues to grow.