We shall be in "Renewable Energy" conference in Kayseri on 16-17 October 2009. On behalf of Chamber of Turkish Mechanical Engineers, your writer will make a presentation on "Biomass Cofiring" which is basically description of firing municipality refuse with local lignite in the nearby thermal power plants.
On 16th July 2009 together with a number of leading local businessmen, your writer had the opportunity to have a business lunch in Bursa Botanical Park with new elected Mayor of Bursa Greater Municipality.
Bursa Greater Municipality evaluates takeover possibility of Bursa Keles lignite mine reserves from Turkish Coal Board, and open a tender to construct a new thermal power plant based on CFB steam boiler technology, and make necessary cofiring to dispose the municipality refuse in that plant
That is widely used operation in Northern America and Western Europe
There is available local technology to construct a thermal power plant based on CFB technology in biomass cofiring of municipality waste with local low quality lignite
Municipality disposes the refuse and also generates electricity and creates income for the municipality to use in other public projects.
Cofiring is the combustion of two different types of materials at the same time. One of the advantages of cofiring is that an existing plant can be used to burn a new fuel, which may be cheaper or more environmentally friendly. Biomass is sometimes cofired in existing coal plants instead of new biomass plants. Cofiring can also be used to improve the combustion of fuels with low energy content.
First you make necessary recycling operation on incoming municipality refuse. That means you screen out metals, paper/ cardboard, and plastics for reutilization. The remaining is your mass refuse. If you can dehydrate, take the water out by pressing or via centrifugals, you get relatively high heating value fuel to burn and get electricity to generate income.
Rule of thump cost figure is that for each 2 million inhabitants of a selected greater municipality, you can have an economic capacity of maximum 60 Mwe electricity generation where you can co-fire municipality refuse together with local poor LHV quality lignite. Fuel is cheap, so is the generated electricity.
As long as the electricity or heat produced with the biomass and landfill gas was otherwise going to be produced with non-renewable fuels, the benefits are essentially equivalent whether they are cofired or combusted alone. Cofiring can be used to lower the emission of some pollutants. Cofiring biomass with coal results in less sulfur emissions than burning coal by itself.
Cofiring (also referred usually as co-firing or co-combustion) is the combustion of two different fuels in the same combustion system. Fuels can be solid fuels, Liquid fuels or gaseous, and its nature either fossil or renewable.
Therefore use of heavy fuels assisting coal power stations may be considered technically co-firing. However the term cofiring is used in the present technological framework to designate combined combustion of two (or more) fuels sustained in the time, as a normal daily practice.
The interest for cofiring and the use of this term sprung in the 80's in the U.S. and Europe, and referred specifically to the use of waste solid residues (paper, plastic, solvents, tars, etc.) or biomass in coal power stations that were initially designed for combustion of sole coal, and attempted, because of existence of those new opportunity fuels, to carry out a combined combustion in order to increase benefit margins.
This interest on cofiring has grown in the last decade mainly due to the increasing social concerns on global warming and greenhouse gas (GHG) emissions.
Consequences of this concern are the new policies on energy and environment aiming at reducing emissions. Cofiring is regarded as a great opportunity for replacing coal (solid fossil fuel) used for power generation easily with renewable fuels (biomass) with low costs and a direct repercussion in the decrease of greenhouse gas emissions.
During the last decades research has provided very diverse solutions for cofiring biomass in coal power stations with a limited impact in efficiency, operation and lifespan.
Power generation with better efficiency: generally biomass power plants produce electricity with relative low efficiency (18 to 22%) respect the huge coal units (32 to 38%) with optimised cycles given the economy of scale
Flexible operation: original plant can operate still at 100% load with fossil fuel. Co-firing facility is less sensitive to seasonality in biomass production and to biomass availability and price
Incentives for development of biomass markets: diverse European countries have proven the promotion of co-firing is a key for the development of biomass markets as well as for the creation of expertise on biomass handling and combustion
Biomass co-firing represents, compared to other renewable sources, a technically feasible option with the potential of contributing to the EU energy supply meanwhile ensuring sustainable development.
Co-firing of biomass with coal offers several advantages, such as the utilisation of large quantities at low combustion rates in the current combustion systems, lower investments and higher conversion efficiencies compared to systems fired exclusively with biomass.
The EC has recognised the need of promoting the use of biomass co-firing in order to comply with the Kyoto Protocol, which implies a reduction of 8% of the greenhouse emissions between 2006 and 2012.
In spite of numerous successful experiences achieved in Europe, this technology still deserves attention in order to find solutions for technical problems as well as to improve efficiency, reduce costs and emission levels.
Today, the accession of the 10 new members to the EU 25 brings a new opportunity for the development of biomass co-firing, due to the coal combustion infrastructure already installed, the land availability for energy crops and the current dependency on imported fossil fuels.
According to the Council resolution on renewable energies of May 1998, the share of biomass has to be increased from 3.1% in 1995 up to 8.5% in 2010, a target which will not be met unless an unified approach of biomass co-firing in the European level comes into play.
We conclude that this is a win-win solution. Greater municipalities exploit the nearby lignite resources and dispose their municipality refuse, and generate cheap electricity. There is EU project funding for BioMass cofiring. All you have to do is proper application to the EU funds.
“The difficult I’ll do right now, the impossible will take a little while”, Billie Holiday, my favorite Jazz Singer
We shall be too pleased to receive your evaluations and contributions. Your comments are always welcome
Haluk Direskeneli, Ankara based Energy Analyst