Top 5 Emerging Renewable Energies By wakewan  [6 more lists]

Anaerobic digestion produces biogas, which is mostly methane. Common production sources are anaerobic digesters and landfills. The UK government is currently offering financial incentives for people to invest in anaerobic digesters. A typical installation would be at a farm. Building an anaerobic digester helps reduce animal waste and offset energy consumption for the farm by producing biogas. Plus, the digestate (the stuff left over after the process) can be used as fertilizer. Here's an example of a company in the UK design of anaerobic digesters .

Micro hydro is typically defined as a hydropower installation that produces up to 100kW. A typical installation does not use a dam but instead relies on the year-round flow of a small stream. Micro hydro is most often used to produce power for small communities or even isolated homes. The power from micro hydro is also sometimes simply added to the electrical grid and can be a money-maker for the owner.

While geothermal energy is not exactly new, it is gaining greater acceptance as a viable renewable energy type. Recent innovations allow for the production of electricity and/or electricity and hot water for heating from what were traditionally non-viable geothermal fields. These innovations include, Kalina cycle geothermal , Organic Rankine Cycle (ORC) cycle, and others. These innovations allow power plants to produce power from low to medium temperature fields. Also, there is work being done with Enhanced Geothermal Systems (EGS). The simplest way to think of EGS is drilling into hot, dry rock (HDR) - much more common than wet geothermal fields - and artificially stimulating the well with water to replicate a wet geothermal field.

This refers to tidal energy, wave energy and ocean thermal energy conversion (OTEC), which uses the temperature difference between deep and shallow waters to run a heat engine. Ocean energy may seem kind of "fringe" but don't underestimate it's potential. In the UK, the government estimates that ocean energy could produce ~14% of current national demand.

There are two main types of biofuels: bioethanol and biodiesel. We all know of large-scale bioethanol production in America, Brazil and elsewhere. Ethanol production in the US is not without controversy (for more reasons than I can feasibly list here). However, new technologies are being developed to produce ethanol from what is called cellulosic biomass feedstocks, like trees and grasses. These feedstocks are more abundant and diverse are are not feedcrops.