Feature articles
COâ‚‚energy assessment: making optimal use of carbon emissions
01/04/2008
International oil and gas engineer: Alternative energy Africa
Energy fuels economic activity and growth. At present, hydrocarbons supply more than 80% of global energy needs, and they are expected to provide the foundation of the world’s energy for the remainder of this century.
Consequently, management of carbon dioxide (CO₂) emissions is a priority. Shell believes that the CO₂challenge cannot be met by one company alone. Instead, the Shell Group is striving for public-private partnerships and a strong policy framework. In addition, Shell has been one of the first energy companies to acknowledge the threat of climate change and believes that most businesses can take steps to reduce their energy consumption and carbon emissions. The company set aggressive, voluntary CO₂emissions targets, aiming to reduce emissions from Shell’s operations in 2010 to a level at least 5% lower than in 1990. In 2005, emissions fell to 107 million tonnes of CO₂equivalent – 15% below the 1990 level. This reduction was achieved through reduced flaring and increased efficiency in company operations.
Pursuing research and development into leading-edge technologies to further improve energy efficiency generate energy cleanly and mitigate CO₂emissions are other options taken by Shell. Developing cost-effective technologies to capture carbon emissions from power plants and refineries and sequestering them underground is another option. Several storage possibilities exist that are being explored through a range of projects. For example, in Queensland, Australia, Shell and others are exploring sites to store CO₂captured from a power plant. Shell is the preferred provider of gasification technology and is providing drilling and CO₂storage expertise. Currently, it is thought that up to 420,000 tonnes of CO₂the majority of the demonstration plant’s CO₂emissions could be annually captured and stored. Commercial versions would have carbon emissions nearly 40% lower than those from a comparably sized conventional natural gas-fired power plant.
The company is already one of the world’s largest distributors of biofuels. Since 2000, it has invested more than $1 billion in alternative energy sources including wind, solar and hydrogen. Public campaigns such as Fuel-Stretch, the Shell Springboard Awards and the Shell Eco-Marathon have raised awareness and prompted innovation. The current Eco-Marathon world record stands at 3,620 Km/l. That is the same as driving from Britain to Australia on one gallon of petrol.
The Carbon Energy Management Consultancy (CEM), from Shell Global Solutions, brings together technology and expertise from across Shell’s operations, gained from reducing its own CO₂footprint, to benefit other companies facing the same challenges by saving energy, reducing costs and lowering CO₂. The CEM programme examines current emission positions of clients and benchmarks them against optimal industry operating practices.
Strategic options are proposed to improve the client’s emission position, such as energy efficiency programmes, carbon optimisation, CO₂sales and carbon-allowance trading. Using Shell’s extensive technical and operating experience from its plants, the CEM is designed to be modular and builds upon Energise—the company’s proven energy efficiency programme. Energise has helped large industrial sites save energy and cut emissions with minimum capital expenditure. This proven programme achieves reductions in energy usage by between 2% and 10% with minimal capital investment. Strategies for energy efficiency could include best available technology assessments, hydrocarbon management reviews, asset reliability improvements and catalyst optimisation.
The company’s own energy efficiency improvements are already delivering CO₂savings of about 1 million tonnes per year. A company’s options for carbon optimisation can be explored through carbon abatement curves. These help to inform strategy through analysing different technologies that are available for mitigating greenhouse gas emissions and their costs. Switching to less carbon-intensive fuels, introducing renewable fuels sources, make-or-buy decisions for power supply, CO₂mineralisation and storage can all be considered.
CEM also looks at the options for carbon allowance trading and offsetting, within the European Union Emission Trading Scheme (EUETS) and using the Kyoto instruments, such as the Clean Development Mechanism and Joint Implementation. The CEM programme considers options against the parameters of feasibility and impact. Once a preferred implementation approach is identified, CEM can support its delivery and provide ongoing support to ensure that energy or carbon savings are sustained. Changes in management practices, operator training, monitoring tools and leadership focus play a role in preventing value erosion once consultants leave a client’s site. Positive results from the CEM programme have already been seen. By focusing on better operational performance, the Fredericia refinery in Denmark achieved sustainable energy savings of 9%. The refinery was Shell’s second most energy-efficient refinery; yet, the CEM programme still managed to generate more savings. For example, the Fredericia refinery’s crude distiller changed the way skimming oil in the hydrodesulphurisation unit was managed. The refinery achieved more energy savings. The energy-efficiency stream of the programme has also helped Malaysia LNG decrease the amount of feed gas used as fuel to run the plant and reduce venting of hydrocarbons through flaring or incineration.
The saved fuel is available as additional feed gas for conversion into LNG product. Shell’s Energy Management System, a key tool to help ensure that value is sustained, is a combination of structured management processes and monitoring tools linked to real-time plant data systems. If implemented and sustained correctly, it can help develop a self-sustaining energy culture that forms an infinite loop of energy improvements. In exploring the potential for one Russian refinery, estimates suggested that operational excellence based on the energy management monitoring system could generate annual savings approaching US$250,000 on its most efficient crude unit, based on the preliminary assessment.
Another innovative approach to carbon management is also bringing results. For example, Shell’s Pernis refinery in The Netherlands has reduced emissions by using a pipeline to redirect CO₂from the plant to horticultural growers in the south of The Netherlands. The additional benefit is that pure CO₂accelerates crop growth (up to a 25% increase in production) and the growers now no longer need to run greenhouse-heating systems during the summer just to maintain CO₂flow.
Shell Global Solutions has also facilitated the sale of CO₂for other industrial applications including the paper industry in which it is converted to precipitated calcium carbonate and used as a paper whitener. Shell actively supports carbon trading and it completed the first-ever trade of CO₂emission allowances in 2003. This was within the EUETS, on behalf of Nuon Energy Trade and Wholesale, to effectively open the European emissions trading market. Shell Global Solutions Carbon and Energy Management Consultancy won the Petroleum Economist Cleaner Energy Initiative Award 2007.
Jeroen van der Veer, Shell Chief Executive, has said, “Meeting the world’s growing energy needs in an environmentally responsible manner is a tremendous challenge. Technology is essential to answering that challenge.” Already, the technologies that are being developed are enabling major steps to reduce and to manage CO₂and to meet the mandates, which are being laid before the oil and gas sectors.
Success of Shell Global Solutions, Carbon and Energy Management Consultancy includes:
- A US specialty chemicals plant reduced its energy bill by approximately 9% and realised savings of $1.17 million/yr.
- One of Shell’s UK refineries identified energy savings worth 5%–6% of the site’s energy bill through Energise.
These examples were achieved with commensurate savings in CO2.
- Energy management software developed by Shell Global Solutions was awarded “Highly Commended” in the IChemE AspenTech award for information technology.