The LCA life cycle analysis deals with the environmental aspects and potential environmental impacts (for example, the use of resources and the environmental consequences of emissions and discharges) throughout the life cycle of a product since the acquisition of the raw material, going through the production, use, final treatment, recycling until its final disposal, that is, from the cradle to the grave.

There are four phases in an LCA study: the definition phase of the object and the scope, the inventory analysis phase, the environmental impact assessment phase and the interpretation phase.

The LCA systematically evaluates the environmental aspects and impacts of the product systems, from the acquisition of the raw material to the final disposal, in accordance with the established objective and scope. The relative nature of an LCA is due to the characteristics of the functional unit within the methodology, the level of detail and duration can vary considerably, depending on the object and scope. The methodology is open to the inclusion of new scientific findings and improvements in the state of the art.
NTC ISO 14044. Environmental Management. Analysis of the Life Cycle. Requirements and Guidelines. Life Cycle Requirements

This standard describes the requirements and guidelines for the analysis of the life cycle (LCA) of a product, including: the definition of the objective and scope of the LCA, the analysis phase of the life cycle inventory (LCI), the phase of the Life Cycle Impact Assessment (EICV), the life cycle interpretation phase, the report and the critical life cycle review, the limitations of the LCA, the relationship between the LCA phase and the conditions of use of value and optional elements.

This standard includes the LCA life cycle analysis studies and the LCI life cycle inventory analysis studies.

One of the main purposes of a functional unit is to provide a reference from which the input and output data are normalized (in a mathematical sense). Therefore, the functional unit must be clearly defined and must be measurable.

The limits of the system determine which unit processes must be included within the LCA, be consistent with the object of study, and must identify and explain the criteria used to establish the limits of the system.

The energy inputs and outputs must be treated like any other input and output of an ACV. In LCA practice, several cut-off criteria are used to decide which inputs are included in the evaluation, such as: mass, energy, and environmental importance.

Entries may include, but not be limited to, the use of mineral resources. As part of the air emissions, the emissions of CO, CO2, SO2, NO2, etc. can be separately identified.

Air emissions and discharges to water and soil, often come from point or diffuse sources after having passed through pollution control devices, this data should include fugitive emissions, parameters may include: BOD, COD, AOX, content of halogens and VOCs.
Life Cycle Analysis of Distributed Energy System Projects’ Energy Consumption and GHG Emission – A Case of Beer Brewery Auxiliary Power Supply in China

Recent researches are tailored to projects set in China. Projects in China are unique and interesting because policy-makers are trying hard to promote Distributed Energy System projects, making the policy environment of projects dynamic and fast-changing, and enabling researchers to compare different scenarios with ample evidence. Gas based projects are researched in a full spectrum of aspects including economic value, environmental value and other value. Ding Xiaochuan analyzes the economic feasibility of natural gas based distributed energy system projects, simulating the prices of oil and gas as well as the operating scenarios. The research makes several interesting assumptions to derive the break- even point: the selling prices of heat and cooling are at their fuel costs; the prices of gas and electricity are independent; the efficiency of Absorption type lithium bromide refrigerator and boilers is on average. Wang Yanling research the comprehensive value of Gas-based Distributed Energy System projects, with detailed calculation methods of economic value, user value, system value and environmental value. Researchers use machine configuration to simulate and compare the environmental performance. To examine the environmental performance of real projects, Wang Weilin makes a case study, comparing the emission of the project and that in an alternative case where heat, cooling and electricity are provided individually. Renewable energy base projects are analyzed in a different way. Since fuel costs and emissions are considerably small in renewable technology, energy consumption and emission during life-cycle processes like machine production should not be neglected. Thus, Life-Cycle Analysis (LCA) method is frequently used to analyze renewable energy-based projects, and the results provide solid foundation for further research in this field.

-       Compile an inventory of the most important inputs and outputs of a product's system

-       Evaluate the potential environmental impact associated with these inputs and outputs

-       Interpret the results of the inventory analysis and the stages evaluated in accordance with the objectives of the study.

These are some examples of Categories of Environmental Impacts associated with the Life Cycle of products and services:

-        Impacts on renewable resources

-       Impacts on non-renewable resources

-       Global warming potential (carbon footprint)

-       Potential for deterioration of the ozone layer

-       Acidification potential

-       Potential for photochemical creation of ozone

-       Use of energy

-       Use of water

-       Toxicity (human, terrestrial, aquatic)

OBJECTIVES OF LIFE CYCLE ANALYSIS

-       Obtaining key and specific information associated with the production of goods.

-       Identification of the critical points in the productive processes.

-       Optimization of the system in the short term and reduction of the environmental impact.

-        Long-term strategic planning.

-       Enter differential market niches.

-       Offer consumers clear, relevant and usable information.

-       Development and improvement of products.

-       Strategic planning: optimization of processes and reduction of risks associated with competitiveness with similar products.

-       Marketing and advertising: improves the image of the brand.

-       Access to international markets and compliance with current environmental regulations (Ley Grenelle 2) and future ones.

-       Positioning before the Retail Sector (TESCO, Metro Group, M & S, Wal-Mart, Pepsico, etc.).

-       Admission to differential market niches: possibility of expanding the market.

-       Selection of specific environmental performance indicators for each producT

 

Step 1: Convert the output to energy input.

Step 2: Use energy input to calculate life cycle energy consumption and GHG emission based on former literature.

Step 3: Calculate the energy saving and emission reduction rate.

It was designed 6 cases to better capture the potential development of Distributed Energy System projects:  All NG, Coal+Grid Electricity, All Coal,  Local Solar Maximum Utilization, Local Biomass Maximum Utilization, Outside Wind Electricity.

In conclusion:  When compared with traditional project, gas based Distributed Energy System project seems to use 7% more energy as input, but in a Life-Cycle view, it reduces energy consumption and GHG  emission significantly (8% and 38% respectively).
When boiler efficiency is set to be 60%, a more modest number, the performance of natural gas based projects like the base case is even more outstanding.

It shows renewable energy technology, especially the integrated use of biomass and wind power, has great potential in the development of Distributed Energy System projects.