Environmental credit

Fischer and co-workers undertook a LCA of the 26 organic solvents which they had already assessed in terms of EHS criteria (see above).They used the Eco-solvent software tool (http //www.sust-chem.ethz.ch/tools/ecosolvent/), which on the basis of industrial data considers the birth of the solvent (its petrochemical production) and its death by either a distillation process or treatment in a hazardous waste incineration plant. For both types of end-of-life treatment, environmental credits were granted where appropriate, e.g. solvent recovery and reuse upon distillation. The results of this assessment are shown in Figure 1.2. From an LCA perspective, tetrahydrofuran (THF), butyl acetate, cyclohexanone and 1-propanol are not good solvents. This is primarily due to the environmental... 

Figure 4 continues the theme and includes the environmental credit for the electricity generated. It is the analysis of this Figure that gives the real process insight. If the desire were to cut the impact of the process, then beyond the issues of Figure 2 the most fruitful route would be to increase the energy efficiency. This is constrained by the low steam temperature and a use for around 80 MW of warm water. 

As mentioned previously, biodegradable polymers can be derived from both petroleum and renewable sources. Both types of biodegradable polymers have attracted attention in the industry. Petroleum-based biodegradable polymers may help to overcome the accumulation of non-degradable plastic waste. However, renewable biodegradable polymers not only possess biodegradability, but the polymers are also derived from sustainable sources with environmental credit. 

In the environmental credit analysis of PLA, there are two major aspects that need to be considered — the PLA manufacturing process and the post-consumer PLA product disposal. Several research projects on lifecycle analysis of PLA mass production have been conducted in recent years. Two of the life cycle analyses of PLA production have been undertaken by NatureWorks and Purac. The objective here is to summarize these studies rather than directly perform life cycle analysis of PLA. More detailed information can be found in the relevant publications (Vink et al., 2003 Vink et al., 2007 Vink et ak, 2010 Groot and Boren, 2010). 

Alcohol Production. Studies to assess the costs of alcohol fuels and to compare the costs to those of conventional fuels contain significant uncertainties. In general, the low cost estimates iadicate that methanol produced on a large scale from low cost natural gas could compete with gasoline when oil prices are around 140/L ( 27/bbl). This comparison does not give methanol any credits for environmental or energy diversification benefits. Ethanol does not become competitive until petroleum prices are much higher. 

These cost comparisons do not assign any credit to methanol for environmental improvements or energy security. Energy security benefits could be large if methanol were produced from domestic coal. 

Ethanol. Accurate projections of ethanol costs are much more difficult to make than are those for methanol. Large scale ethanol production would impact upon food costs and have important environmental consequences that are rarely cost-analyzed because of the complexity. Furthermore, for corn, the most likely large-scale feedstock, ethanol costs are strongly influenced by the credit assigned to the protein by-product remaining after the starch has been removed and converted to ethanol. 

The need to meet environmental regulations can affect processing costs. Undesirable air emissions may have to be eliminated and Hquid effluents and soHd residues treated and disposed of by incineration or/and landfilling. It is possible for biomass conversion processes that utilize waste feedstocks to combine waste disposal and treatment with energy and/or biofuel production so that credits can be taken for negative feedstock costs and tipping or receiving fees. 

Another factor is the potential economic benefit that may be realized due to possible future environmental regulations from utilizing both waste and virgin biomass as energy resources. Carbon taxes imposed on the use of fossil fuels in the United States to help reduce undesirable automobile and power plant emissions to the atmosphere would provide additional economic incentives to stimulate development of new biomass energy systems. Certain tax credits and subsidies are already available for commercial use of specific types of biomass energy systems (93). 

Cofiring biomass has environmental benefits in addition to lowering greenhouse gases. Since biomass has little or no sulfur, sulfur dioxide (SOj) emissions are less when biomass fuels are used. In the United States, power plants have allowable sulfur dioxide levels for each gigawatt of power produced. If they produce less than the allowable amount of sulfur dioxide, they receive credits with which they can trade on the open market. The price for these sulfur dioxide credits is about 70 to 200 per ton. 

If a hue monetary value were established for carbon emissions, nuclear power could be the major beneficiary of an emissions credit trading market. Nuclear power advocates - and environmental advocates - need to play an active role in setting the regulatory framework that will advance our environmental interests. 

Finally, it is worthy note that regulatory disincentives to voluntary reductions of emissions from petrolenm refineries also exist. Many environmental statutes define a baseline period and measnre progress in pollution reductions from that baseline. Any reduction in emissions before it is required could lower a facility s baseline emissions. Conseqnently, fnture regulations requiring a specified reduction from the baseline conld be more difficult (and consequently, more costly) to achieve because the most easily applied and hence the most cost-effective reductions would already have been made. With no credit given for voluntary reductions, those facilities that do the minimum may be in fact be rewarded when emissions reductions are reqnired. 

New York State Department of Environmental Conservation (2000) New York State green building tax credit legislation overview. Available at http //www.dec.ny.gov/energy/1540. html. Accessed 30 May 2011... 

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