Forest Biofibre in Ontario's climate change plans
| In May, 2010, the ECO released its second Annual Report on the progress of activities in Ontario to reduce or make more efficient use of electricity, natural gas, propane, oil and transportation fuels. Click here for more information on this report, including videos and communications materials. | ||
The government’s commitment to stop burning coal at the province’s remaining coal-fired power plants
by 2014 represents a significant and laudable step towards reducing GHG emissions in the province.
According to the government, this single initiative will be responsible for 26.4 Mt, or 77 per cent of the
government’s forecasted emissions reductions for 2014.
Operated by Ontario Power Generation (OPG), the four coal-fired power plants have a combined capacity of 6,077 MW. These plants operate as needed and, in 2008, CO2 emissions from these facilities were 23 Mt, a significant decrease from 27.8 Mt in 2007. Emissions from these stations will continue to decline as OPG takes measures to comply with directives from the Ontario government. In particular, these directives require OPG to reduce its CO2 emissions from its coal-fired power plants to 19.6 Mt for 2009 and 15.6 Mt for 2010. By 2011, OPG forecasts that emissions will be lowered to 11 Mt. Pursuant to Ontario Regulation 496/07 – Cessation of Coal Use, made under the Environmental Protection Act, none of these stations will be permitted to burn coal after December 31, 2014.
The ECO notes that these power stations will not be mothballed and it is expected that they will continue to emit CO2 whether as a result of conversion to biomass or to natural gas. Even with the expected increase in renewable generation, these stations are likely to continue in operation. A factor in support of this observation is the government’s recent retreat from making a decision on new nuclear.
As part of its efforts to phase-out coal, OPG is now assessing the use of biomass as a renewable energy source for up to 11 of the 15 units at its four coal-fired stations. Biomass is the biological material derived from living, or recently living organisms, such as trees and grasses. OPG’s focus is on both forest products (wood pellets) and agricultural biomass and 2012 is targeted as the year OPG will begin using biomass as a replacement fuel.
Engineering work is currently underway to completely convert the Atikokan facility to use wood pellets, and it is anticipated that the facility’s capacity when operating with pellets will be close to that reached when operating with coal. At the Thunder Bay facility, OPG is exploring the conversion of one of two units and is assessing whether full electrical output capability can be reached. At the Nanticoke and Lambton facilities several of the 12 units will be converted, however OPG projects that when compared with existing coal-fired operations, the use of biomass at these units will result in much lower annual electricity production. Due to several technical issues, Nanticoke’s capacity on wood pellets is estimated to be 50 per cent of its coal-fired capacity.
Once OPG’s conversion program is complete, it anticipates that annual biomass fuel requirements will be in the range of two to three million tonnes of wood pellets, an amount that represents about 20 per cent of the total annual allowable forest harvest in Ontario. At Atikokan alone, approximately 90,000 tonnes of wood pellet fuel will be required, or approximately two per cent of the 2005/2006 harvest in northwest Ontario.
According to OPG, there are several benefits associated with a conversion to biomass. As is the case with coal, electricity production using biomass is dispatchable, which means that it can easily be shut down or brought back online. Given the intermittent nature of other renewable energy generators (such as wind and solar), this provides the power grid with increased flexibility. As well, because existing plants can be converted to biomass, capital costs will be low. Finally, replacing coal with biomass will help to reduce OPG’s coal-related GHG emissions. A life-cycle analysis conducted for OPG in 2009 compared the GHG emissions associated with the use of wood pellets (made from harvested wood) versus coal. For the Nanticoke and Atikokan facilities, the analysis concluded that reductions in GHG emissions of 91 and 92 per cent, respectively, would result if coal is completely replaced by wood pellets, whereas an 18 per cent reduction would result if wood pellets and coal are co-fired in a 20/80 ratio.
Given the constraints, however, on the volume of pellets that would be available (based on the goal of maintaining a sustainable forest harvest), the overall GHG reductions that could be achieved by pellet- generated electricity is 2.1 Mt. When measured against the approximately 23 Mt that were emitted in 2008, this represents a 9 per cent reduction in emissions. As a portion of Ontario’s overall electricity supply, pellet-generated electricity would provide only 1.6 per cent of Ontario’s total electricity supply at current demand levels. In order to increase the possible GHG reductions from biomass, OPG is also exploring the use of agricultural materials, both by-products and purpose-grown, and has contracted to have a similar life-cycle analysis conducted for these feedstocks.
Forests and plants serve a key function in the carbon cycle. As they grow, they sequester CO2 from the atmosphere during photosynthesis and store it both above ground in stems, branches and leaves, as well as below ground in roots. The process, however, may take many years and forests in particular are slow to regenerate. When the above-ground biomass is burned to produce electricity, however, the carbon dioxide within is released immediately to the atmosphere. Over the long term, and where the cycle of growth and harvest are sustained, the amount of carbon dioxide absorbed and released during this process is the same. This has lead to the widespread conclusion that the use of biomass as a fuel source is ‘carbon neutral’. Indeed, in the aforementioned life-cycle analysis conducted for OPG, a key assumption was made that “emissions of CO2 resulting from the combustion of biomass are entirely balanced by the carbon incorporated during re-growth of the forest during the time period considered” as long as the forest is sustainably managed. In other words, the study made an assumption of ‘carbon neutrality’. While the claims of carbon neutrality may be valid over a longer time-frame, over a shorter time frame the claim requires some nuancing.
A study on the net effect of forest harvest on CO2 emissions to the atmosphere has found that the time lag involved in a forest’s regeneration and consequent uptake of the CO2 released from burning wood biomass is such that a substantial, short-to medium-term “surge” of CO2 is incurred. In other words, the released CO2 will be taken up by new growth, but only gradually, so that the full amount is not sequestered for a considerable period of time. Depending upon several variables, including the rate at which trees grow and the rate of harvest, this short- to medium-term “surge” will be problematic in a 390 ppm world.
The ECO raised a similar issue (along with other concerns relating to forest biodiversity) in our 2008/2009 Annual Report, as part of our review of MNR’s Forest Biofibre Policy. The ECO pointed out that these shorter-term carbon increases will arise over the next few decades in the context of critical climate change ‘tipping points’. In response to some of the concerns raised around biodiversity and forest productivity, the government has agreed that “assessing new policies and program initiatives on a lifecycle basis is an important advance that will inform CCAP measures.” It has not as yet provided a direct response to the concern about the carbon surge issue and its possible impact on tipping points or its implication for achieving the government’s 2014 and 2020 GHG targets.
In summary, the ECO applauds OPG’s initiative in conducting a life-cycle analysis on the use of wood pellets versus coal. The ECO believes that further work needs to be done, however, and sees a pressing need for further time-sensitive modelling of overall forest carbon levels, in order to assess the assumption of ‘carbon neutrality’ in the context of OPG’s plans to use wood pellets as a fuel source.
| Recommendation :
The ECO recommends that Ontario Power Generation complete a comprehensive assessment of the assumption of carbon neutrality with respect to plans to use biomass as a feedstock in its coal-fired generating stations. |
| Previous section: Revisiting Ontario’s Greenhouse Gas Reduction Targets |
| Next section: Monitoring, Reporting and Verification Priorities |
Citing This Article:
Environmental Commissioner of Ontario. 2010. Annual Greenhouse Gas Progress Report 2009/2010: Broadening Ontario's Climate Change Policy Agenda. Toronto, ON : Environmental Commissioner of Ontario. pp. 12-14
