Grey Green recently completed a comprehensive energy audit at one of the largest tyre manufacturers in Africa. Our team investigated all energy and material flows. Excellent savings opportunities were found on:
- Air compressors, plus compressed air distribution and use
- Boiler, steam distribution and use
- Materials handling
- Solid waste
- Water heating
The sixteen best savings opportunities gave payback periods between immediate (no Capex required, just improved control or maintenance) to ~3.9 years, with the average at less than 2 years. These were also quantified in terms of reduced carbon dioxide emissions and decreased carbon tax liability.
Annual financial savings were several millions of Rands.
The tyre company management shall also be able to use our Scenario Planning Tool to:
- Graphically compare the savings produced by each savings opportunity
- Decide when each opportunity should be implemented
Grey Green also conducted pre-feasibility studies on various sources of renewable energy:
- Earth – Biogas, from anaerobic digestion of locally sourced organic matter and biomass as a boiler fuel
- Wind – Wind turbines opportunities in the region
- Fire – Solar PV (i.e. photovoltaic) and solar water heating
- Water – Hydro-electric options available.
As expected, the renewable energy opportunities have longer payback periods than energy efficiency opportunities, but once factory efficiency has been maximised, the only way of reducing energy costs further is by producing one’s own energy from renewable sources.
SARS’s 12 i scheme allows companies to claim tax rebates for capital expenditure which produces energy savings. Several requirements apply. One is a baseline report which shows the energy intensity before installation of the energy savings equipment.
Grey Green compiled a baseline report for a large dairy in the Eastern Cape.
The baseline report met all the requirements and the diary is proceeding with installation of energy savings equipment.
Baseline reports have to conform to the procedures of the IPMVP [International Performance Measurement and Verification Protocol) and SANS 50010 – South Africa’s standard for Measurement and Verification.
Producing the baseline included correlating energy usage with production. The following graphic is an example.
Effect of Production on Steam Usage
Seasonal variations in production and therefore energy are common with agro-processing. For our dairy client these were investigated by first considering how output varies from month to month. The following graphic shows that there is considerable seasonal variation.
Seasonal Variation in Production
Next month to month electricity usage was investigated. The following graphic indicates that it does not change much.
Seasonal Variation in Electricity Usage
In addition to using a baseline report for tax rebate applications, the data will often reveal opportunities for energy savings. For example, comparison of the previous two graphics seems to show a mismatch between production variations and monthly changes in energy consumed.
Grey Green’s assessment dealt with each of the client’s 10 buildings at different sites around the country as follows:
Perform detailed electricity consumption assessments, determined each building’s electrical reticulation boundaries, performed structural assessment of the roof structure of each of the buildings with respect to its ability to accommodate the anticipated wind loads imposed by the fitment of a PV system; performed a site assessment of each building roof with regard to the likely impact of shading, space available and ease of access on the production and maintenance of the system.
Arising from those assessments, we proposed with detailed specifications and budget estimates, the largest yielding PV installation possible, stating R/kWh given a 25 year lifetime for the plant. We also prepared a yield assessment for the proposed PV Plant in terms of solar irradiation and electricity production. Our financial analysis presented the simple cost effectiveness based on the capital cost, operating cost and value of the offset electricity savings over the system life span assuming instantaneous embedded consumption and using the tariff applicable to the building as well as payback period.
This study was conducted as part of a due diligence exercise for a client who was interested in investing in 3 separate projects spread across SA, and developed for the Small Scale IPP bid round. Grey Green completed a high-level concept design and costing exercise as part of this feasibility study in order to enable our client to determine whether the project was feasible, both in terms of the total EPCM costs as well as the long term returns from the PV plant’s generation over its 25 year lifespan. This project was completed with the assistance of our Spanish partner DISEPROSA.
The Peace Parks Foundation contracted Grey Green to provide on-going consulting services to oversee the supply of three off-grid Solar PV systems to provide power to two schools and a clinic in a rural community in Zambia. The consulting services comprised reviewing a number of local supplier quotes and designs as well as making recommendations to improve the efficiency of the design and ensure more reliability and safety.
Read an interesting paper about PV Facts and Figures by an independent electrical consulting engineer.
Feasibility study for Bio-gas turbine and waste water management system for the Mhlonto Municipality in Eastern Cape