Carbon Emissions

 

Reducing Emissions

Even though the contribution of aggregates operations to UK carbon emissions is small, energy use and rising prices are a major cost to the operator so it makes good commercial sense to reduce consumption and, therefore, the bill, as well as levels of carbon emissions. Overall use of energy can be reduced through increased efficiency throughout operations. This needs careful consideration of the ways in which energy is used at all stages, identification of improvements that can be made, implementation of these and monitoring and review of progress. There is a need to consider estimate and compare alternative options for supply of aggregates within wider sustainability issues and other aims of Government. There are a number of steps that can be considered:

1. locating quarries close to the market thus reducing transport off materials - transporting minerals from source to users is clearly carbon-intensive with haulage accounting for just over 32% of the embodied carbon in the extraction and initial movement to first point of UK land-won minerals L0561. Minimising haulage distances and associated costs is generally desirable but not if cutting the initial transport distance adds distance to the movement of products to market.


2. improving the energy efficiency of plant and equipment through design improvements, improvements of the ways in which equipment is used, and better location of plant within the site relative to haulage provisions.


3. using "greener" energy – the main contribution to this will be an increase in the energy from renewable sources (wind, water and solar power) coming through national supplies but there is some scope for locating renewable energy facilities at some quarry sites. Vehicles may use more biofuels although there are some negative environmental impacts from these that are not associated with carbon. Some sites located close to traditional landfills have made use of methane emissions from these to generate power but this source will become less available as the amount of landfill decreases and less biodegradable materials go into remaining landfills.


4. off-setting energy use - atmospheric carbon dioxide is captured and stored in living vegetation and other "reservoirs" (soils, certain geological formations, oceans, wood products etc). Land that absorbs and stores carbon over long periods ("carbon sinks") may help to offset carbon dioxide emissions at least in the short to medium term. The process of quarrying also, necessarily, removes vegetation and soils from the worked areas with a temporary reduction of carbon storage at the site but quarrying can more than redress that imbalance later through site restoration. Soils are stored and then spread on completed workings and these can be returned to uses such as agriculture, forestry and wildlife conservation with enhanced prospects for carbon storage. For instance, the minerals industry, dominated by aggregates producers, planted just under 130,000 trees in 2009 L0562

In addition to direct measures, other factors can affect energy use. For instance, planning requirements may affect the location, design and conditions of operation of sites as well as the distances of these from the market. It makes sense to take energy into account from the start of site planning. Recent planning guidance has emphasised the need for energy efficiency L0567.

Taking action

It is sensible to take action to reduce carbon emissions for environmental reasons but also because it saves money. Also, good performance in cutting carbon emissions is likely to be required increasingly by customers and clients. But action requires an understanding of energy use throughout the "life cycle" of any product; in this case from planning a site, through extraction and restoration, and taking account of processing of the mineral, manufacture of value-added products and delivery to the market. In the complete sense life cycle analysis would also look at the use of materials in construction, operational use of facilities and, ultimately decommissioning and recycling. This is, of course, extremely complicated and requires detailed data that are not generally available. In practice, it is a case of working on the basis of best available estimates and gradually improving these through monitoring of operations. It also makes the process more feasible to consider only those parts of the cycle that are within control of the operator i.e. from site inception to material being delivered to the customer. Resulting actions can be identified and implemented either voluntarily or through regulation. In the aggregates sector the emphasis is currently on voluntary steps.

Some available "tools" for assessing sources and reductions of emissions are;

• a Publicly Available Specification for carbon "footprinting" methodologies, although not specifically for the minerals sector L0563.


• a guide for managers in the extractive industries on fuel, power and water L0564;


• a Carbon Management Good Practice Guide L0565;


• a set of aggregates life cycle assessment resources L0375;


• an "Aggregates Carbon Reduction Portal" that can be accessed through www.aggregatescarbonreduction.com or link through www.mineralsproducts.org . This explains how business can maximise its carbon reduction and also save money. It provides a "journey navigator" consisting of five steps for the company as a whole. These are: energy awareness, finding and evaluating opportunities, implementing opportunities, tracking and measuring progress, and energy management. A "tool box" consisting of talks, guides to enable staff to identify opportunities, posters, case studies and videos, an energy saving assessment tool, opportunities database and a spreadsheet to log and track cutting opportunities from identification to implementation is provided;
• there is also a report written by The Boston Consulting Group "Aggregates Sector Strategy Review"L0007 commissioned be the Carbon Trust.

 

Aggregates Levy Sustainability Fund Projects

A number of ALSF projects touched on carbon emissions issues in:

• considering overall sustainability of aggregates extraction L0009, L0155;


• optimising the environmental performance of quarries L0076, L0078;


• reduction of transport impacts L0074;


• the role of restoration of workings in securing low carbon energy production L0118; and


• comparing the relative sustainability of extraction of marine and land won sand and gravel M0017, M0021.

 

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