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This paper aims to provide insights in the cost developments of offshore wind energy in Europe. This is done by analysing 46 operational offshore wind farms commissioned after 2000. An increase of the Capital Expenditures (CAPEX) is found that is linked to the distance to shore and depth of more recent wind farms and commodity prices. Analysis results indicate that these two factors are only responsible for about half of the observed CAPEX increase, suggesting other factors such as turbine market with limited competition also led to an increasing CAPEX. Using CAPEX, Annual Energy Production, Financings costs and Operational Expenditures, the development of average Levelized Cost of Electricity (LCoE) is shown to increase from 120 €/MWh in 2000 towards 190 €/MWh in 2014, which is a direct result of the CAPEX increase. The results indicate very different LCoE values among European countries, from currently about 100 Euro/MWh in Denmark and Sweden to 150-220 Euro/MWh in all other countries investigated suggesting an effect of national policy frameworks on the LCoE of offshore wind energy.

PV Economics, Markets and Policies, PV-Related Policies, Strategies and Societal Issues, Development of BIPV Courseware for Higher Education and Professionals 1 1

Demand response, defined as the shifting of electricity demand, is generally believed to have value both for the grid and for the market: by matching demand more closely to supply, consumers could profit from lower prices, while in a smart grid environment, more renewable electricity can be used and less grid capacity may be needed. However, the introduction of residential demand response programmes to support the development of smart grids that includes renewable generation is hampered by a number of barriers. This paper reviews these barriers and categorises them for different demand programmes and market players. The case study for the Netherlands shows that barriers can be country specific. Two types of demand response programmes have been identified as being the most promising options for households in smart grids: price-based demand response and direct load control, while they may not be beneficial for market players or distribution system operators.

The potential of demand side management (DSM) of wet appliances (washing machine, dishwasher and tumble dryer) in households with photovoltaic (PV) systems is studied experimentally focusing on evening peak demand reduction and increase in PV self-consumption. In a sample of 100 Dutch households the electricity demand is monitored for one year at high time resolution. It is found that the dishwasher has the best DSM potential, with a median average peak reduction potential up to 35 W per household on average for all appliances, while PV self-consumption for the median household can be increased with 68 kWh/year per appliance. The tumble dryer and washing machine’s potentials are 30 W and 25 W per household, respectively, for the mean average peak reduction, and 38 kWh and 28 kWh, respectively, per household per year for increase in PV self-consumption per appliance. Further, the median peak reduction potential of a single group of wet appliances ranges from 1% to 5% of the power demand in peak hours, while combined they could add up to 10% of the total peak. The median increase in PV self-consumption is in the range between 1.5% and 4% for separate appliances, while the median total could provide an increase up to 129 kWh per household per year if a household possesses and utilizes the potential of all appliances, which is about 6% of the annual household demand. In conclusion, DSM potential for wet appliances is limited.

In order to perform predictions of a photovoltaic (PV) system power production, a neural network architecture system using the Nonlinear Autoregressive with eXogenous inputs (NARX) model is implemented using not only local meteorological data but also measurements of neighbouring PV systems as inputs. Input configurations are compared to assess the effects of the different inputs. The added value of the information of the neighbouring PV systems has demonstrated to further improve the accuracy of predictions for both winter and summer seasons. Additionally, forecasts up to 1 month are tested and compared with a persistence model. Normalized root mean square errors (nRMSE) ranged between 9% and 25%, with the NARX model clearly outperforming the persistence model for forecast horizons greater than 15min.

Silicon heterojunction (SHJ) cells offer high efficiencies and several advantages in the production process compared to conventional crystalline silicon solar cells. We performed a life-cycle assessment to identify the greenhouse gas (GHG) footprint, energy payback time (EPBT) and cumulative energy demand of four different SHJ solar cell designs. We analyse these environmental impacts for cell processing and complete systems for both current and prospective designs. On the basis of in-plane irradiation of 1700kWh/m2, results for current designs show that life-cycle GHG emissions could be 32 gCO2-eq/kWh for complete SHJ photovoltaic (PV) systems (module efficiencies of 18.4%), compared with 38 gCO2-eq/kWh for conventional monocrystalline silicon systems (module efficiency of 16.1%). The EPBT of all SHJ designs was found to be 1.5years, compared with 1.8years for the monocrystalline PV system. Cell processing contributes little (≤6%) to the overall environmental footprint of SHJ PV systems. Among cell processing steps, vacuum based deposition contributes substantially to the overall results, with 55-80%. Atomic layer deposition of thin films was found to have a significantly lower environmental footprint compared to plasma enhanced chemical vapour deposition and sputtering. Copper-based compared with silver-based metallization was shown to reduce the impact of this processing step by 74-84%. Increases in cell efficiency, use of thin silicon wafers and replacement of silver-based with copper-based metallization could result in life-cycle GHG emissions for systems to be reduced to 20 gCO2-eq/kWh for SHJ systems and 25 gCO2-eq/kWh for monocrystalline system, while EPBT could drop to 0.9 and 1.2years, respectively.

We compared surface passivation of c-Si by a-Si:H with and without atomic hydrogen treatment prior to a-Si:H deposition. The atomic hydrogen is produced by hot-wire chemical vapor deposition (HWCVD). For this purpose, we deposited a-Si:H layers onto both sides of n-type FZ c-Si wafers and measured the minority carrier effective lifetime and implied VOC for different H treatment times ranging from 5 s to 30 s prior to a-Si:H deposition. We found that increasing hydrogen treatment times led to lower effective lifetimes and implied VOC values for the used conditions. The treatments have been performed in a new virgin chamber to exclude Si deposition from the chamber walls. Our results show that a short atomic hydrogen pretreatment is already detrimental for the passivation quality which might be due to the creation of defects in the c-Si. AFM measurements do not show any change in the surface roughness of the different samples.

The influence of thermal annealing on the crystalline silicon surface passivating properties of selected amorphous silicon containing layer stacks (including intrinsic and doped films), as well as the correlation with silicon heterojunction solar cell performance has been investigated. All samples have been isochronally annealed for 1 h in an N 2 ambient at temperatures between 150 °C and 300 °C in incremental steps of 15 °C. For intrinsic films and intrinsic/n-type stacks, an improvement in passivation quality is observed up to 255 °C and 270 °C, respectively, and a deterioration at higher temperatures. For intrinsic/n-type a-Si:H layer stacks, a maximum minority carrier lifetime of 13.3 ms at an injection level of 10 15 cm - 3 has been measured. In contrast, for intrinsic/p-type a-Si:H layer stacks, a deterioration in passivation is observed upon annealing over the whole temperature range. Comparing the lifetime values and trends for the different layer stacks to the performance of the corresponding cells, it is inferred that the intrinsic/p-layer stack is limiting device performance. Furthermore, thermal annealing of p-type layers should be avoided entirely. We therefore propose an adapted processing sequence, leading to a substantial improvement in efficiency to 16.7%, well above the efficiency of 15.8% obtained with the 'standard' processing sequence.

The effect on solar cell performance of planar converters containing quantum dots (QDs) as wavelength-shifting entities on top of multicrystalline silicon cells was investigated by means of model studies with varying incident spectra. These included global, direct, and diffuse spectra with Air Mass (AM) values ranging from 1 to 10. In case of AM1.5, a planar converter with QDs emitting at 603nm yields a short-circuit current increase of 6.3%, 9.6%, and 28.6% for direct, global, and diffuse irradiation, respectively, as a result of the larger blue/green content of diffuse spectra with respect to direct and global ones. For other AM values, similar results are calculated, with a lower increase toward high AM values.