The Index is made up of companies active in the following seven Sectors^*:

1. Renewable – Wind

Wind is a major and growing renewable technology that’s had relatively large impacts on (clean) energy usage over the past few decades. Coming decade/s will see continued activity whether in developed, or developing countries, in sites both onshore – and now offshore with latter starting from nearly-scratch. This Wind sector includes components, parts and subassemblies for wind turbines, as well as manufacturers of turbines themselves. Also new fields relating to wind are starting up. And a big portion too of this sector increasingly consists of related developers, generators, utilities and engineering firms that have sprung up to exploit opportunities to build wind farms around the world.

2. Renewable – Solar

The Solar sector covers all technologies that capture energy directly from the sun, either using a photovoltaic (PV) material, or via solar thermal technologies such as concentrators, stirling engines etc. The solar energy sector is already substantial – and growing quickly. Cost reductions through new technologies or through increased manufacturing scale should see it breaking into new areas of energy demand over the coming decades.

3. Renewables – Biofuels & Biomass

Liquid transportation fuels including biodiesel and bioethanol can be derived from a range of biomass sources, including sugar cane, rapeseed/canola, soybeans, and importantly ahead as being greener, cellulosic biomass. The Index may include suppliers of biofuels, of the processing technologies and equipment, logistics and distribution players, manufacturers of energy systems specially adapted for the use of biofuels and products. The Index may also include companies involved in production and consumption of solid or gaseous fuels derived from biomass. Solid biomass can also consist of crop residues such as straw. Other waste matter for energy generation may be included, but is not a priority.

4. Renewables – Other

One of the characteristics of the clean energy industry is it is based on making sustainable use of a diverse range of renewable energy sources. This sector allows coverage of companies active in renewable categories other than main ones of solar, wind. For example geothermal power has long played a part in the energy mix of countries with natural geothermal resources, such as Iceland and Japan. Geothermal energy might also play an increasing role worldwide. New drilling techniques allow users to tap into resources formerly too deep, and new ways of extracting useful power from lower-temperature geothermal fields allow use of resources that were not economical in the past. Low-temperature geothermal heat could be used to reduce the cost of heating residential and commercial buildings. Hydroelectric too is seeing some new use as the world shifts to new energy solutions, but with understandable controversies about its ecological impacts and so sustainability of large-scale hydroelectric power projects; that said there’s interesting advances in smaller-scale, low-head hydro and even micro-scale, the latter technologies generally preferred for this Index.

5. Energy Conversion

The Energy Conversion sector covers conversion technologies and fuels. Hydrogen & fuel cell technology for example is included, from production and storage of hydrogen, to distribution as well as related technologies. Hydrogen is not a renewable fuel source per se — but an energy carrier, in the way electricity is not a source but a carrier of power. Produced renewably, ‘clean’ hydrogen just might perhaps be promising in helping replace fossil fuels very long term – not only in transport, but perhaps other applications too. Some observers imagine hydrogen and fuel cells may eventually be part of a post-fossil-fuels architecture: but many breakthroughs would be required first, as their high manufacturing costs, low reliability, inefficiencies, and difficulty storing and using hydrogen means they’ve yet to capture mass markets – and it is far from certain they will ever do so. A number of companies and research initiatives are hoping to change that over decades. Advanced turbines, and lower-carbon fuel systems may also be covered in this sector, as well as potentially whole systems such as alternative fuel vehicles allowing renewables to power new greener transportation.

6. Energy Storage

Renewable solar, wind, and other green technologies typically harness natural resources that are either intermittent, or have response curves that are unable to follow the dynamic demands that are put on them when deployed. Batteries and other energy storage technologies may therefore become key enablers for large-scale shift to these greener technologies. We include here too newly emerging storage technologies, and also extant mechanical technologies like flywheels and components like ultra-capacitors, which are potentially complimentary with batteries. Systems built around large-scale storage such as EVs (Electric Vehicles) like electric cars, electric buses and trucks, electric ships, trains and planes etc etc might potentially be included here as well.

7. Energy Efficiency

Companies in this sector are working to deliver step-change improvements in efficiency of existing generation and distribution systems. Important technologies include software to improve electricity demand management or reduce grid losses, as well as breakthroughs in motor or generator design. This sector could also include technologies for combined heat and power (i.e. those which enable the capture and use of waste heat from power generation). Demand-side energy conservation technologies and practices are highly relevant to renewable and low-carbon energy. Shifts towards renewable energy sources in coming decades moreover must be accompanied by wholesale improvements in energy efficiency. We may include in this sector technologies that reduce use of energy in homes, retail and commercial buildings. These may include building components that reduce energy use, intelligent systems for managing power consumption and technologies that more efficiently use power. Note: Nuclear power is not considered clean energy for purpose of this Index, and it is thus Excluded (very minor tangental involvement will not disqualify a company).

^* Effective at the rebalance for Q1 2008, the previous Services and Suppliers Sector (SS) is discontinued, and the Demand Side Energy Savings (DS) and the Generation Efficiency & Smart Distribution (GE-SD) Sectors are consolidated into Energy Efficiency.

^* Effective at the rebalance for Q1 2009, The Hydrogen and Fuel Cells (HFC) Sector is changed to Energy Conversion (ECV).

^* For consistency in use of “energy”, the Power Storage Sector is changed to the Energy Storage Sector (ENS)..

^** After early 2019 Market Consultation, NEX constituents have become straight-equal-weighted starting Q3 2019; additionally all NEX Sector Weights are assigned from Q3 2019 according to # of Constituents in each NEX Sector (rather than by external Surveys).