An online clean technology database

The Center for Learning on Decentralised Generation

Combined Heat and power (CHP): small-scale

small cogeneration system

Co-generation is the combined production of useful thermal energy and electricity (Combined Heat and Power, CHP) from the same primary fuel. CHP can take on many forms and encompasses a range of technologies, but will always be based upon an efficient, integrated system that combines electricity production and heat recovery. By using the heat output from the electricity production for heating or industrial applications, CHP plants generally convert 75-80% of the fuel source into useful energy, while the most modern CHP plants reach efficiencies of 90% or more (IPCC, 2007).

Clean Development Mechanism market status: 

Concentrating Solar Power

A solar collector assembly

Concentrating solar power (CSP) systems concentrate the energy from the sun for electricity production. This is done by heating a fluid which is then used to raise steam for a conventional turbine for on and off-grid electricity provision. These systems can also provide heat, either at high temperatures directly for chemical reactions, e.g., chemical processing, or as a by-product for desalination plants or cooling systems, depending on requirements.

Energy tower downdraft

image energy tower downdraft

Energy towers are vertical, hollow towers constructed in dry desert regions with heights of 400 metres or more. Water from nearby sources (such as a sea) is pumped to the top of the tower and sprayed into it so that it cools the air. This creates a downwards draft through the tower which is transferred into energy through wind turbines. The technology is still in a research and development stage with involvement of research institutes from Israel and India.

Geothermal Electricity Production

geothermal flash steam

Inside the Earth's crust there are several reservoirs with hot water which can be used for heating buildings and/or production of electricity. The process causes relatively little CO2 emissions (from the steam), which could potentially be reinjected in the earth's crust through carbon capture and storage. Contrary to conventional geothermal power plants, present generation plants re-inject the condensated steam or hot water into the underground acquifer so that the reservoir capacity could remain intact.

Clean Development Mechanism market status: 

[this information is kindly provided by the UNEP Risoe Centre Carbon Markets Group]

Project developers of geothermal projects in the CDM pipeline mainly apply the following methdologies:

ACM2 “Consolidated baseline methodology for grid-connected electricity generation from renewable sources”
AMS-I.D. “Grid connected renewable electricity generation”
AMS I.C. “Thermal energy production with or without electricity”
Further information on these metholodogies can be found here.

There are 14 geothermal projects in the CDM pipeline. Projects based on geothermal energy, therefore, represent a very small part of all CDM projects in the pipeline. It is worth noting that more than 1/3 of all geothermal CDM projects are located in Indonesia. [media:image:6]

Example CDM project:Amatitlan Geothermal Project by Ortitlan Limitada (CDM Ref. No. 2022)
The Amatitlan Geothermal Project is a geothermal power plant in the Department of Escuintla, in Guatemala. Total installed capacity of the project will be 25.2 MW, with an actual net capacity of 20.5 MW. The plant will utilise three turbines (two with installed capacities of 12 MW each, and one at 1.2 MW) and has a predicted power generation of 162,000 MWh per annum. The purpose of the project is to utilise the geological resources of the Amatitlan Geothermal Field in a state-of-the-art geothermal power plant to generate renewable energy that will be dispatched to the grid.
Project investment: N.A.
Project CO2 reduction over a crediting period of 7 years: 580,849 tCO2e
Expected CER revenue (USD 10/CER): 5,808,490

Small hydropower

Small Hydro in Indonesia

Small hydropower here refers to hydroelectric power plants below 10MW installed capacity. Hydroelectric power plants are power plants that produce electrical energy by driving turbines and generators thanks to the gravitational force of falling or flowing water. Through the natural water cycle mainly evaporation, wind and rain, the water is then brought back to its original height. It is thus a renewable form of energy.

Clean Development Mechanism market status: 

[This information is kindly provided by the UNEP Risoe Centre Carbon Markets Group]

Project developers of hydro projects (excluding run of river projects) in the CDM pipeline mainly apply the following CDM methdologies: ACM2 “Consolidated baseline methodology for grid-connected electricity generation from renewable sources” for large-scale projects and AMS-I.D. “Grid connected renewable electricity generation” for small-scale projects

CDM projects based on hydro represent 27.4% of all CDM projects in the pipeline and, as such, are the most common project type in the pipeline. The geographical distribution of hydro projects is concentrated around Asia and in particular China [media:image:6] Excluding run of the river projects, the CDM pipeline contains 522 hydropower projects as of March 2011. Out of these 261 projects are registered and for a 101 projects CERs have been issued. 

Example CDM project:

Title: “Santa Cruz I Hydro Power Plant” (CDM Ref. No. 2405)
The CDM project is a run-of-the-river hydropower plant, located north east of Peru’s capital city of Lima at 1,985 metres above sea level, in the basin of the Blanco River (Santa Cruz) in the district of Colcas. The plant will have an installed capacity of 5.9 megawatts and a projected yearly average generation of 35,827 megawatt hours. The objective of the Santa Cruz I Hydroelectric Power Plant is renewable electricity generation to be supplied to the Peruvian National Inter-connected Electric Grid.
Project investment: USD 7,500,000
Project CO2 reduction over a crediting period of 7 years: 118,490 tCO2e
Expected CER revenue (CER/USD 10): USD 1,184,900
Hydropower plants represent 27% of all CDM projects requesting validation (UNEP Risoe). In absolute numbers this would mean 1351 projects and an installed capacity of 44995MW (UNEP Risoe). Currently 553 projects are registered.

Wind energy: small-scale

Small wind turbines on the isle of Eigg, Scotland

Smaller-scale wind turbines can be found in a wide range of applications including off-grid power; either directly by charging a storage battery or in combination with another form of generation to cover intermittent periods when there is little to no wind. In such instances small wind may be cost effective depending on the costs of alternate off-grid technologies and fuel prices; however the overall contribution of small wind to climate change mitigation will probably be limited due to the long payback periods required to offset the carbon used in their manufacture.

Clean Development Mechanism market status: 

[this information is kindly provided by the UNEP Risoe Centre Carbon Markets Group]

Project developers of small-scale wind projects under the CDM mainly apply the following CDM methdologies:

AMS-I.D.: Grid connected renewable electricity generation

AMS-I.A.: Electricity generation by the user

CDM projects based on wind represent 17.3% of all CDM projects in the pipeline. Recent years have shown a tendency towards a more widening geographical dispersal of CDM wind projects, indicating that countries other than India and China observe the CDM as a tool to support wind projects. [media:image:3] 

To build capacity of utilities and government to scale-up decentralised generation and renewable energy use.


15° 46' 46.92" S, 47° 55' 46.92" W
Main activity and output: 
  • Organise a training and capacity building course;
  • Develop a methodology that helps decision makers to select the best option: decentralised generation or grid extension;
  • Improve and fine-tune the management and business model developed;
  • Organise training in the sustainable maintenance of decentralised generation in isolated or remote areas;
  • Develop a demonstrative center for decentralised generation solutions and productive use of renewable energy;
  • Install a demonstrative project were the utilities' teams can practice under field conditions.
Expected impact: 
  • Increase local renewable energy knowledge and capability amongst the utilities, government and local organisations, facilitating the promotion of energy access and the productive use of renewable energy, mainly in the Brazilian Amazonian region and the Southeast Brazilian region, under the rural electrification public policy called "Luz para Todos" Programme.