Monday, July 27, 2009

Algae as source of bio-fuel

It has been believed that algae can help replace petroleum or fuels made from crops like corn and soybeans. Algae as the source of bio-fuel has gathered new interest and investment amid a search for energy sources that will limit carbon dioxide emissions blamed for climate change.

Its advantage is that it absorbs carbon dioxide, and thus can be used to 'scrub' emissions from coal-burning power plants and produce ethanol fuel. In a sign of the new enthusiasm, ExxonMobil announced in mid-July it would invest up to 600 million dollars in an alliance with biotech firm Synthetic Genomics to make a new bio-fuel from photosynthetic algae.

Friday, July 24, 2009

Ozone Pollution

Elevated ozone levels cause health problems, premature deaths, reduces agricultural crop yields, damage plants in semi-natural ecosystems and corrosion of physical infrastructure and cultural heritage.

The key findings of the European Environment Agency (EEA) on ground level ozone formation in Europe are:

•The longest time series in Airbase (14–16 years) are available for four countries. These indicate that ground-level ozone has declined significantly in the Netherlands and the United Kingdom, falling during the 1990s and leveling off thereafter. No significant trends were identified in Austria and Switzerland.
•Inter-annual variations in weather conditions have a significant impact on yearly ozone levels. Discerning the effect of reduced ozone precursor emissions therefore requires long time series of data from stable monitoring networks. Unfortunately, extended time series are generally unavailable, particularly in southern Europe where ozone pollution is a major problem.
•Several unknown complicate attempts to model ozone levels. Significant uncertainties exist regarding the magnitude and distribution of inter-continental inflows of ozone and its precursors, and the size and distribution of isoprene emissions from plants.
•The importance of meteorological conditions in ozone formation suggests that predicted changes in climate could also lead to increased ground-level ozone in many regions of Europe.
•Computer modeling was used to estimate the ozone levels that would arise if precursor emissions declined (as countries reported) or if they held constant at 1995 levels. The ozone levels recorded in 18 countries across Europe correspond more closely to the model output based on the assumption of declining emissions.
•Ground-level ozone has become a hemispheric or even global air pollution and climate change problem. Ozone abatement should be integrated into local, regional and global strategies and measures that simultaneously address emissions of air pollutants and greenhouse gases.

Ozone Pollution

Elevated ozone levels cause health problems, premature deaths, reduces agricultural crop yields, damage plants in semi-natural ecosystems and corrosion of physical infrastructure and cultural heritage.

The key findings of the European Environment Agency (EEA) on ground level ozone formation in Europe are:

•The longest time series in Airbase (14–16 years) are available for four countries. These indicate that ground-level ozone has declined significantly in the Netherlands and the United Kingdom, falling during the 1990s and leveling off thereafter. No significant trends were identified in Austria and Switzerland.
•Inter-annual variations in weather conditions have a significant impact on yearly ozone levels. Discerning the effect of reduced ozone precursor emissions therefore requires long time series of data from stable monitoring networks. Unfortunately, extended time series are generally unavailable, particularly in southern Europe where ozone pollution is a major problem.
•Several unknown complicate attempts to model ozone levels. Significant uncertainties exist regarding the magnitude and distribution of inter-continental inflows of ozone and its precursors, and the size and distribution of isoprene emissions from plants.
•The importance of meteorological conditions in ozone formation suggests that predicted changes in climate could also lead to increased ground-level ozone in many regions of Europe.
•Computer modeling was used to estimate the ozone levels that would arise if precursor emissions declined (as countries reported) or if they held constant at 1995 levels. The ozone levels recorded in 18 countries across Europe correspond more closely to the model output based on the assumption of declining emissions.
•Ground-level ozone has become a hemispheric or even global air pollution and climate change problem. Ozone abatement should be integrated into local, regional and global strategies and measures that simultaneously address emissions of air pollutants and greenhouse gases.

Eco-Innovation

Eco – innovation is an innovation where its use is less environmentally harmful than the use of relevant alternatives. This plays a critical role in sustainable development and addressing climate change. The major activities for supporting eco-innovation are by improving environmental impact, identifying supply chain opportunities and considering global issues.

Tuesday, July 7, 2009

Building as a System

Proper operational control of energy use is often a starting point for making cost-effective improvements and reducing carbon emissions. On the other hand it is also helpful to recognise a building as a dynamic system - with energy consumption influenced by its site and orientation, building envelop micro-climate, occupant behaviour, and landscaping and the surrounding vegetation. For example, ground soil and groundwater are both warmer in the winter and cooler in the summer than the ambient air temperature. Ground source pumps use these temperature differentials to pre-cool incoming air and reduce the energy requirement of air conditioners in summer, and do the reverse in winter.
Construction materials can play an important role, such as; masonry has a higher thermal mass than glass and steel, and therefore maintains a more even temperature. The lag time between heating and cooling can be used to maintain interior temperatures and reduce air conditioning loads.
Building occupants can be motivated to reduce internal heat gains in the summer by ensuring lights, computers, printers and other electrical equipment is turned off when not in use. Meanwhile staff can be encouraged not to overcool buildings simply because air conditioning is available. In fact it is better to encourage casual wear on hotter days to reduce cooling requirements.

Landscaping can provide a shade canopy in the summer, lock up carbon through photosynthesis, and reduce ambient temperatures through evapo-transpiration. Broad-leaf deciduous trees in particular have canopies which reduce passive solar gain in the summer while allowing it when needed in the winter.

This type of holistic view is easier for new-builds, where such considerations can be factored in at the planning stage. Options for cost-effective improvements are more limited with existing buildings. However, renovation does present real opportunities to improve the building envelope to manage heat flow. Natural ventilation can be improved by considering the placement of internal partition walls that do not impede cross ventilation, and windows can be retrofitted to make better use of night time cooling to lower cooling requirements during the day.