INGENIEUR
INGENIEUR
Average costs of electricity from biomass for power span a lower range than fossil fuel-fired electricity generation costs
system at any point in time. The forecasting techniques are more accurate if a larger number of power plants are included and they are not concentrated in one location. This means that the system will need relatively fewer reserves to guarantee the same level of reliability. However, these benefits will only materialise if the system is operated in the appropriate way. Whatever the source of electricity, whatever resources exist to balance supply and demand, the sub-area of the power market over which balance is maintained in real time( the balancing area) is central to the challenge.
Balancing areas are defined to a large extent by the historical development of the grid( often originally unconnected parts), and by the distinct utilities and institutions that drove that development and have subsequently endured. Protocols will need to be created to govern the flow of electricity across these boundaries, and long-term collaboration may have to exist, but not necessarily ones that allow for interchanges of electricity inside the balancing timeframe. Coupled with congestion in( weaker) border areas, this will hinder shared balancing activities.
Co-operation between balancing areas can significantly reduce the operational costs of power systems. The benefits of larger balancing areas tend to be more pronounced when VRE is part of the generation portfolio( IRENA, 2015).
Lowering barriers to VRE integration
When analysing current trends and future outlook, the continued expansion of VRE globally and in the Asia-Pacific region remains highly likely. This continued expansion of VRE integration within an evolving power sector will require grids to advance into smarter and more flexible energy systems that can efficiently accommodate new VRE generation capacity.
VRE electricity generation is considered expensive. However, with the continuing trend of falling technology prices, investment costs are rapidly decreasing for solar PV and wind power. When considering the LCOE of building and operating a power-generating plant over an assumed financial life and duty cycle, utility-scale solar and wind are already competing with fossil fuels. Prices are expected to continue to fall in the coming decades( IEA, 2014b), and therefore investment cost considerations can be expected to be eliminated as a significant obstacle.
Grid instability is another commonly cited barrier to VRE integration. However, recent experience in Germany and Denmark suggest that high levels of grid stability with increased share of VRE are possible. In 2010 and 2011, these countries, behind only Luxembourg, boasted the lowest rates of system disruption 19 – 15.91 and 14.75 minutes per year, respectively – while integrating some of the highest shares of VRE electricity generation in the EU at 12 % and 20 %( CEER, 2014). Enabling this are a number of other factors, including advanced weather( wind and sun) forecasting, generation spread over a large geographical area, large system balancing areas achieved through the use of international power markets and the use of advanced transmission system operators.
As more advanced grid technologies are adopted through the Asia-Pacific region, and as power grids become more integrated, the ability to maintain stable grids while upping the share of VRE will increase. Still, cost-effective integration of VRE will require long-term planning and a system-wide transformation. Typically, four specific flexibility considerations are needed when integrating VRE, including flexible power plants, electricity storage, grid infrastructure and demand-side management. Each country may possess diverse challenges when integrating an increased share of VRE, and there is no‘ one-sizefits-all’ approach, but rather a slate of options to achieve meaningful energy transformation. Simply adding VRE generation into an inflexible
46 VOL 67 JULY-SEPTEMBER 2016