Termodinamica

4. Scenario variants

Our scenario is a modified version of the Strong Europe scenario, as defined in the WLO (Janssen et al., 2008, Farla et al., 2008 and van Beek et al., 2008). Our “No limits” scenario variant uses the WLO narrative, but has no targets for CO2 emissions reductions. Building on our No limits variant, we prepare an additional eight scenario variants with various degrees of reduction commitments and options, as shown in table 9.

Our scenario variants focus on the transport sector, but we also examine the effect on production of electricity and heat. Table 10 shows some of the bounds used in our scenario variants. A cap is set on the CO2 emissions to reduce these by 27% in 2020 and then annually by 5–6% compared to the year before, which results in total reductions of 87% in 2050 compared to 1990 level. This cap is in line with targets of 20% and 80%, because we assume that relatively more CO2 emission reduction is realised in the CO2 intensive industry than in other sectors (of the 25 Mt of industrial emissions, around 11–22 MtCO2 may be captured and stored per year). The equivalent CO2 emissions reduction targets are 50% in 2030 and 68% in 2040.

Our reduction scenario variants are compatible with the EU 20/20/20 strategy for 2020 (European Commission, 2008). The Forced electric car and fuel cell variants are meant to illustrate the effect of forcing a transition to these cars and fuels.

5. Results

MARKAL models generate solutions with the least net present value of total system cost within the scenario bounds. Our model runs up to 2050 for purposes of optimisation, but in this chapter, we show results up to 2040. Due to high investment costs of low- or zero emission cars, a shift in fuels is the cheapest option to realise direct CO2 emissions reductions in transportation. However, the potential for this shift is limited by energy resource constraints.

5.1. Energy sources

Fig. 2 shows the combined primary energy consumption for road transport, electricity and heat generation in the Netherlands in 2020 and 2040. These sectors consume around half of the total Dutch primary energy.

The No limits variant shows almost a quintupling of coal consumption. This is caused by PC electricity generation, which more than doubles, and by crude oil-based diesel and petrol being replaced by coal-based FT fuels.

In the reduction scenario variants there is a preference for co-firing biomass in electricity plants combined with coal-based FT fuel production with CCS if sufficient CO2 storage capacity is available (Utsira variant). If CO2 storage capacity is limited, a combination of wind electricity and biomass-based FT fuel production with CCS turns out to be the cheapest option. Generation of wind electricity is complemented by NGCC, as wind electricity is an intermittent source. The overall shift can be explained by the very low additional costs for CCS with FT fuel production.

The use of biomass is consistent across reduction scenario variants. While the shares of biomass converted to ethanol, FT fuel and electricity shifts with the exact scenario variant, all available biomass is used in our optimisations. Further analysis shows that if a nuclear option is introduced, wind and natural gas are partially replaced by nuclear power. Adoption of electric cars does not lead to an increase in electricity generation capacity, because most of the charging in our model takes place in off-peak times of the day.

In all reduction scenario variants, no PC plants are built with CCS, but 30–45% of PC plants are later retrofitted with CCS. IGCC is used only in the Utsira variant, where ample CO2 storage capacity is available.

The share of renewables in total energy resources is larger than 20% in 2020 in all of the reduction scenario variants, except the Utsira variant. In the reduction scenario variants, FT fuel plants co-produce 11–21 PJ of base load electricity, or 2–4% of total electricity.

5.2. Fuels and vehicles

Fig. 3 shows the transportation fuels consumed in our scenario variants in 2020 and 2040. In all scenario variants except the Cheap oil variant, we observe a shift to imported ethanol and FT diesel from regular diesel and petrol derived from oil. By 2020, the cheapest overall transportation system uses less than 50% crude oil derived fuel, and after 2030, oil is not used at all for transportation. This shift is entirely due to the projected oil price of 10 €/GJ (90 $/bbl), because oil refining costs have a very limited share of the total cost of diesel and petrol. The partial shift in 2020 is due to limited availability of biomass, except in the No limits variant, where FT fuel is produced entirely from coal.

In the Cheap oil variant, oil retains a significant market share combined with FT fuel made from biomass with CCS to reduce CO2 emissions. In this variant, biomass is used for electricity generation instead of producing fuels.

Diesel, biodiesel, and FT diesel are used in buses, trucks, and vans, which together account for almost half of the total fuel consumed. Bio-ethanol is the preferred fuel for cars. Substituted bio-ethanol in 2020 is between 50 and 170 PJ/year, which would require between 2400 and 8000 km2 (at an average yield of 212 GJethanol/ha/year for cellulosic ethanol).8 Cellulosic ethanol is used exclusively in the 2020–2030 timeframe, as it has higher yield per available amount of biomass. However, we also observe a switch back to sugar cane ethanol in later years as the availability of biomass increases. This is because of competition in the model between sugar cane and cellulosic ethanol, with lower cost for sugar cane and more efficient production for cellulosic ethanol. In reality, these ethanol production technologies not interchangeable, as feedstocks for cellulosic ethanol can be grown on a wider range of soil types and climates.

Substituted FT production capacity in 2020 ranges up to 288 PJ/year, replacing up to 160,000 bbl of crude oil per day. In the No limits variant, FT fuel is entirely produced from coal without CCS. In all reduction scenario variants, FT fuel is produced from a varying mix of coal and biomass, with full use of CCS. Methanol and DME did not appear in any of our least-cost configurations.

Total secondary energy used in cars in the Forced electric car variant declines, because the energy efficiency of electric vehicles is higher than of regular cars. However, conversion efficiency of producing electricity in a power plant is lower than the efficiency of oil refining or FT production. The resulting total primary energy consumption is still lower in the Forced electric car variant (compare Fig. 2 with Fig. 3 or 4). The same applies mutatis mutandis to the Forced fuel cell

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