DE can lower climate destabalizing carbon dioxide emissions.
According to the IEA World Energy Outlook 2006 electricity generation is responsible for around 40% of global carbon dioxide emissions and the power sector is also the sector where emissions are expected to grow the fastest. The heating sector is another significant source of climate pollution. DE is a very strong position to cost-effectively reduce these emissions. Emission reductions via DE can be analysed by looking from either a geographic or sectoral angle.
Any industry or economic sector that uses large amounts of energy can potentially benefit from DE. For every sector WADE has so far looked at research has shown significant scope for economic savings and reduced emissions as a result of increased DE investment.
CO2 Emission Reduction through DE - Buildings
About one third of global carbon emissions (1.8 billion tons) resulted from heating, cooling and powering commercial and residential buildings in 2005. Integrating DE in buildings has a huge potential to significantly reduce emissions in the building sector. According to a WADE study DE applications in buildings could cut CO2 emissions in the US by over 200 Mt per year by 2020, displacing 20% of the country's total emissions growth. The same study found that potential for DE in buildings in China could reduce projected emissions from all sectors from between 1.3% and 11% depending on rate of uptake. This study did not look at the potential efficiency gains of using DE in applicaitons where buildings are grouped together in district energy systems. District energy has the potential to reduce emissions even further.
CO2 Emission Reduction through DE - Cement
About 5% of total global primary energy goes into the manufacture of cement and the sector is responsible for between 3 an 5% of total global CO2 emissions. In a recent WADE report it has been estimated that, based on 2005 clinker production statisitcs, over 68.9TWh of electricity could be generated annually if the potential for DE in the cement was realized. The study looked at bottom cycle cogeneration, top cycle cogeneration and power only applications although the 68.9TWh considers only bottom cycle. This translates into about 68.9Mt CO2 annual emissions reductions or about 0.23% of total annual emissions.
CO2 Emission Reduction through DE - Sugar
WADE has issued a study highlighting that massive unrealised potential exists worldwide for generating useful heat and power from sugar cane waste known as bagasse. The technology offers particular promise in developing countries where most of the sugar cane is grown. If sugar processing facilities around the world were to install combined heat and power (CHP) capability based on state of the art technology the sector represents a power generating potential equivalent to about 10% of the EU’s annual electricity consumption. Displacing this amount of grid power would result in considerable carbon emission reductions. WADE has estimated that 3.7GW of bagasse CHP capacity is already installed worldwide, and more is being commissioned every day.
CO2 Emissions Reductions through DE – National Level
Considered on a broader scale, CO2 emissions reductions can be even more significant. The reduced pollution benefits from increased DE are largely due to reduced fossil fuel use and higher efficiency rates in the use of fossil fuels. WADE’s global survey for 2006 and a UK economic model application both found that the projected CO2 emissions reductions for the UK could be reduced by 2.83 Mt in 2023 when generating energy from DE. This would be a saving of 8% relative to centralised generation. The figure below demonstrates the CO2 savings found in previous applications of the WADE economic model.
CO2 Emissions Reduction through DE – The Clean Development Mechanism
DE’s ability to reduce CO2 emissions cost-effectively makes DE projects attractive for climate change mitigation, particularly in developing countries. Combined Heat and Power (CHP) projects play therefore an important role in the Clean Development Mechanism (CDM) of the Kyoto Protocol. A WADE study found that in September 2006 CHP projects represented 20% of all registered projects, with reductions totalling over 3.5 Mt/yr. The CDM creates therefore a perfect incentive for governments and project developers to increase the deployment of DE technologies.
The above figure illustrates the growth in CHP projects registered under the CDM between September 2005 and September 2006.