Martin Junginger

Global experience curves for wind farms

In order to forecast the technological development and cost of wind turbines and the production costs of wind electricity, frequent use is made of the so-called experience curve concept. Experience curves of wind turbines are generally based on data describing the development of national markets, which cause a number of problems when applied for global assessments. To analyze global wind energy price development more adequately, we compose a global experience curve. First, underlying factors for past and potential future price reductions of wind turbines are analyzed. Also possible implications and pitfalls when applying the experience curve methodology are assessed. Second, we present and discuss a new approach of establishing a global experience curve and thus a global progress ratio for the investment cost of wind farms. Results show that global progress ratios for wind farms may lie between 77% and 85% (with an average of 81%), which is significantly more optimistic than progress ratios applied in most current scenario studies and integrated assessment models. While the findings are based on a limited amount of data, they may indicate faster price reduction opportunities than so far assumed. With this global experience curve we aim to improve the reliability of describing the speed with which global costs of wind power may decline.

Cost Reduction Prospects for Offshore Wind Farms

The economics of offshore wind farms are presently less favorable than for onshore wind energy. Consequently there is a strong need for significant cost reductions in order to become competitive. About 70% of the electricity cost of offshore wind farms is determined by the initial investment costs, which mainly consist of the wind turbines, foundations, internal and external grid-connections and installation. Possible cost reductions until 2020 are explored for each of these components. Technological developments and cost reduction trends in both the offshore and onshore wind sector are analyzed. Information is also taken from offshore oil and gas sector and from the experience with high-voltage submarine transmission of electricity. Where possible, cost reduction trends are quantified using the experience curve concept, or otherwise based on expert judgments. Main drivers for cost reduction appear to be (a) design improvements and upscaling of wind turbines, (b) the continuing growth of onshore wind capacity, and (c) the development and high utilization rates of purpose-built installation vessels. Other factors are: reduction of steel prices, technological development of HVDC converter stations and cables, standardization of turbine and foundation design, and economies of scale for the wind turbine production. It is concluded that under different growth scenarios, investment costs of offshore wind farms may decline about 25–39% by 2020. Assuming an identical decline of annual O&M costs, the levelized electricity production costs are reduced from 6.8–7.2 to 4.2–5.4 €ct/kWh.

Technological Learning in the Energy Sector

Technological learning is a key driver behind the improvement of energy technologies and subsequent reduction of production costs. Understanding how and why production costs for energy technologies decline, and whether they will continue to do so in the future, is of crucial importance for policy makers, industrial stakeholders and scientists alike. This timely and informative book therefore provides a comprehensive review of technological development and cost reductions for renewable energy, clean fossil fuel and energy-efficient demand-side technologies.

Carbon payback period and carbon offset parity point of wood pellet production in the South-eastern United States

This study examines the effect of methodological choices to determine the carbon payback time and the offset parity point for wood pellet production from softwood plantations in the South‐eastern United States. Using the carbon accounting model GORCAM we model low‐, medium‐ and high‐intensity plantation management scenarios for a single stand level, an increasing stand level and a landscape level. Other variables are the fossil‐fuel reference system and the electrical conversion efficiency. Due to the large amount of possible methodological choices and reference systems, there is a wide range of payback times (≤1 year at landscape to 27 years at stand level) and offset parity points (2–106 years). Important aspects impacting on the carbon balances are yield, carbon replacement factor, system boundaries and the choice of reference scenario used to determine the parity point. We consider the landscape‐level carbon debt approach more appropriate for the situation in the South‐eastern United States, where softwood plantation is already in existence, and under this precondition, we conclude that the issue of carbon payback is basically nonexistent. If comparison against a protection scenario is deemed realistic and policy relevant, and assuming that wood pellets directly replace coal in an average coal power plant, the carbon offset parity point is in the range 12–46 years; i.e. one or two rotations. Switching to intensively managed plantations yields most drastic reduction in the time to parity points (≤17 years in 9 of 12 cases).

Global solid biomass trade for energy by 2020: an assessment of potential import streams and supply costs to North‐West Europe under different sustainability constraints

The expected use of solid biomass for large‐scale heat and power production across North–West Europe (NW EU) has led to discussions about its sustainability, especially due to the increasing import dependence of the sector. While individual Member States and companies have put forward sustainability criteria, it remains unclear how different requirements will influence the availability and cost of solid biomass and thus how specific regions will satisfy their demand in a competitive global market. We combined a geospatially explicit least‐cost biomass supply model with a linear optimization solver to assess global solid biomass trade streams by 2020 with a particular focus on NW EU. We apply different demand and supply scenarios representing varying policy developments and sustainability requirements. We find that the projected EU solid biomass demand by 2020 can be met across all scenarios, almost exclusively via domestic biomass. The exploitation of domestic agricultural residue and energy crop potentials, however, will need to increase sharply. Given sustainability requirements for solid biomass as for liquid biofuels, extra‐EU imports may reach 236 PJ by 2020, i.e., 400% of their 2010 levels. Intra‐EU trade is expected to grow with stricter sustainability requirements up to 548 PJ, i.e., 280% of its 2010 levels by 2020. Increasing sustainability requirements can have different effects on trade portfolios across NW EU. Excluding pulpwood pellets may drive the supply costs of import dependent countries, foremost the Netherlands and the UK, whereas excluding additional forest biomass may entail higher costs for Germany and Denmark which rely on regional biomass. Excluding solid biomass fractions may create short‐term price hikes. Our modeling results are strongly influenced by parameterization choices, foremost assumed EU biomass supply volumes and costs and assumed relations between criteria and supply. The model framework is suited for the inclusion of dynamic supply–demand interactions and other world regions.

Damaged forests provide an opportunity to mitigate climate change

British Columbia (BC) forests are estimated to have become a net carbon source in recent years due to tree death and decay caused primarily by mountain pine beetle (MPB) and related post‐harvest slash burning practices. BC forest biomass has also become a major source of wood pellets, exported primarily for bioenergy to Europe, although the sustainability and net carbon emissions of forest bioenergy in general are the subject of current debate. We simulated the temporal carbon balance of BC wood pellets against different reference scenarios for forests affected by MPB in the interior BC timber harvesting area using the Carbon Budget Model of the Canadian Forest Sector (CBM‐CFS3). We evaluated the carbon dynamics for different insect‐mortality levels, at the stand‐ and landscape level, taking into account carbon storage in the ecosystem, wood products and fossil fuel displacement. Our results indicate that current harvesting practices, in which slash is burnt and only sawdust used for pellet production, require between 20–25 years for beetle‐impacted pine and 37–39 years for spruce‐dominated systems to reach pre‐harvest carbon levels (i.e. break‐even) at the stand‐level. Using pellets made from logging slash to replace coal creates immediate net carbon benefits to the atmosphere of 17–21 tonnes C ha−1, shortening these break‐even times by 9–20 years and resulting in an instant carbon break‐even level on stands most severely impacted by the beetle. Harvesting pine dominated sites for timber while using slash for bioenergy was also found to be more carbon beneficial than a protection reference scenario on both stand‐ and landscape level. However, harvesting stands exclusively for bioenergy resulted in a net carbon source unless the system contained a high proportion of dead trees (>85%). Systems with higher proportions of living trees provide a greater climate change mitigation if used for long lived wood products.

Life-cycle analysis of greenhouse gas emissions from renewable jet fuel production

BackgroundThe introduction of renewable jet fuel (RJF) is considered an important emission mitigation measure for the aviation industry. This study compares the well-to-wake (WtWa) greenhouse gas (GHG) emission performance of multiple RJF conversion pathways and explores the impact of different co-product allocation methods. The insights obtained in this study are of particular importance if RJF is included as an emission mitigation instrument in the global Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA).ResultsFischer–Tropsch pathways yield the highest GHG emission reduction compared to fossil jet fuel (86–104%) of the pathways in scope, followed by Hydrothermal Liquefaction (77–80%) and sugarcane- (71–75%) and corn stover-based Alcohol-to-Jet (60–75%). Feedstock cultivation, hydrogen and conversion inputs were shown to be major contributors to the overall WtWa GHG emission performance. The choice of allocation method mainly affects pathways yielding high shares of co-products or producing co-products which effectively displace carbon intensive products (e.g., electricity).ConclusionsRenewable jet fuel can contribute to significant reduction of aviation-related GHG emissions, provided the right feedstock and conversion technology are used. The GHG emission performance of RJF may be further improved by using sustainable hydrogen sources or applying carbon capture and storage. Based on the character and impact of different co-product allocation methods, we recommend using energy and economic allocation (for non-energy co-products) at a global level, as it leverages the universal character of energy allocation while adequately valuing non-energy co-products.

Wood pellets, what else? Greenhouse gas parity times of European electricity from wood pellets produced in the south-eastern United States using different softwood feedstocks

Several EU countries import wood pellets from the south‐eastern United States. The imported wood pellets are (co‐)fired in power plants with the aim of reducing overall greenhouse gas (GHG) emissions from electricity and meeting EU renewable energy targets. To assess whether GHG emissions are reduced and on what timescale, we construct the GHG balance of wood‐pellet electricity. This GHG balance consists of supply chain and combustion GHG emissions, carbon sequestration during biomass growth and avoided GHG emissions through replacing fossil electricity. We investigate wood pellets from four softwood feedstock types: small roundwood, commercial thinnings, harvest residues and mill residues. Per feedstock, the GHG balance of wood‐pellet electricity is compared against those of alternative scenarios. Alternative scenarios are combinations of alternative fates of the feedstock materials, such as in‐forest decomposition, or the production of paper or wood panels like oriented strand board (OSB). Alternative scenario composition depends on feedstock type and local demand for this feedstock. Results indicate that the GHG balance of wood‐pellet electricity equals that of alternative scenarios within 0–21 years (the GHG parity time), after which wood‐pellet electricity has sustained climate benefits. Parity times increase by a maximum of 12 years when varying key variables (emissions associated with paper and panels, soil carbon increase via feedstock decomposition, wood‐pellet electricity supply chain emissions) within maximum plausible ranges. Using commercial thinnings, harvest residues or mill residues as feedstock leads to the shortest GHG parity times (0–6 years) and fastest GHG benefits from wood‐pellet electricity. We find shorter GHG parity times than previous studies, for we use a novel approach that differentiates feedstocks and considers alternative scenarios based on (combinations of) alternative feedstock fates, rather than on alternative land uses. This novel approach is relevant for bioenergy derived from low‐value feedstocks.

Medium and Long-Term Perspectives of International Bioenergy Trade

In the coming decades, huge challenges in the global energy system are expected. Scenarios indicate that bioenergy will play a substantial role in this process. However, up to now there is very limited insight regarding the implication this may have on bioenergy trade in the long term. The objectives of this chapter are: (1) to assess how bioenergy trade is included in different energy sector models and (2) to discuss the implications and perspectives of bioenergy trade in different energy scenarios. We grouped scenarios from the models IMAGE/TIMER, POLES and GFPM according to their policy targets and increase of bioenergy use in “ambitious” and “moderate” bioenergy scenarios and compared results regarding bioenergy trade for solid and liquid biomass. Trade balances for various world regions vary significantly in the different models and scenarios. Nevertheless, a few robust trends and results can be derived up to the year 2050: Russia and former USSR countries could turn into strong biomass exporting countries. Moreover, Canada, South-America, Central and Rest-Africa as well as Oceania could cover another substantial part of the bioenergy supply. As importing countries, India, Western Europe and China might play a key role. The results show (1) the high relevance of the topic, (2) the high uncertainties, (3) the need to better integrate social, ecological, economic and logistical barriers and restrictions into the models and (4) the need to better understand the potential role of bioenergy trade for a sustainable, low-carbon future energy system.

A General Introduction to International Bioenergy Trade

The development of functional international markets for bioenergy has become an essential driver to develop bioenergy potentials, which are currently under-utilised in many regions of the world. Technical potential of bioenergy may be as large as 500 EJ/yr by 2050. However, large uncertainty exists about important factors such as market and policy conditions that affect this potential. Potential deployment levels by 2050 could lay in the range of 100–300 EJ/yr. Realizing this potential represents a major challenge but would substantially contribute to the world’s primary energy demand in 2050. The possibilities to export biomass-derived commodities for the world’s energy market can create important socioeconomic development incentives for rural communities. But bioenergy markets are still immature, relying on policy objectives and incentives, that prove to be erratic in many cases. Further improvement is needed to develop both supply and demand in a balanced way and avoid distortions and instability that can threaten investments. Furthermore, it is necessary to develop and exploit biomass resources in a sustainable way and to understand what this means in different settings. In some markets, prices of biomass resources are volatile, including indirect effects on price of raw material prices for e.g. the forest industry as well as on food. Sustainability demands serve as a starting point for policies supporting bioenergy in many countries. The proliferation of initiatives registered worldwide to develop and implement sustainability frameworks and certification systems for bioenergy, can lead to a fragmentation of efforts. This asks for harmonization and for international collaboration.