Introduction Of Renewable Energy Research Articles

Absorption of PV Power Prediction Errors with Headroom Control by Statistical, Machine Learning and Combined Models

Owing to the mass penetration of renewable energy (RE) in Japan, the replacement reserve for feed‐in tariff (RR‐FIT) was introduced in 2021. To promote the further introduction of RE, we attempted to provide reserve power value to the balancing market by controlling the headroom of photovoltaic (PV) power with a PV power plant as a research subject. At the planning stage, the information available is the predicted value, and PV prediction error always occur on the day. Therefore, in this research, we proposed an algorithm to determine the absorption of prediction errors headroom in PV output, thereby maximally reducing negative imbalance. In addition, we developed a statistical model, SVR model, and combined models to calculate and compare the number of imbalance spots and amount of imbalance. Accordingly, the proposed methods can significantly reduce imbalance compared to planning with predicted values, without setting the headroom of prediction errors. © 2023 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Scenario Analysis of Renewable Energy–Biodiversity Nexuses Using a Forest Landscape Model

The introduction of renewable energy (RE) in harmony with nature is essential for building a sustainable society. However, the poorly designed introduction of RE can cause conflicts between energy production and biodiversity conservation. This study conducted a scenario analysis to evaluate potential conflicts in the nexuses between energy and biodiversity for a case study area, the Bekambeushi River watershed located in northeastern Japan. The increasing rate of pastureland abandonment resulting from a decreasing farmer population is a source of great uncertainty in this area. Two alternative sources of RE were selected to utilize these abandoned pasturelands, each taking a contrasting approach to meet targets stipulated by regional energy plans, thereby implying different ecological consequences at the landscape level. Thirty-one RE introduction cases were simulated, comprising a range of pastureland abandonment expansion speeds and ratios of solar photovoltaic (PV) plant installation to biomass energy use. These were superimposed using two IPCC representative concentration pathway (RCP) scenarios, 2.6 and 8.5, resulting in 62 cases that were summarized as three scenarios based on the RE supply–demand balance and the ecological impacts. The LANDIS-II model was used to simulate these scenarios from 2016 to 2100. The results indicate that both the rate of pastureland abandonment and the ratio of the two RE sources had a large impact on changes in tree species diversity and the habitat suitability of raptorial birds. Abandoned pastureland converted to tree biomass energy production shifted to pioneer species-dominated forest. The plant species composition of transitional forests varied between the climate scenarios. The higher temperature of the RCP 8.5 scenario toward 2100 prevented the establishment of Betula platyphylla and altered tree species diversity and the habitat suitability of Ketupa blakistoni blakistoni. Biomass energy utilization produced less energy than the demand but increased the three ecological indicators. Solar PV systems provided more energy than the regional demand, but the three ecological indicators decreased. However, an appropriate mixture of the two RE sources satisfied the regional energy demand and maintained ecological conditions. Our results suggest that land–energy planning should consider energy–biodiversity nexuses to a strike balance between decarbonization and biodiversity conservation.

Optimal Scheduling Method of Controllable Loads in Smart Home Considering Re-Forecast and Re-Plan for Uncertainties

Renewable energies (REs) such as photovoltaic generation (PV) have been gaining attention in distribution systems. Recently, houses with PV and battery systems, as well as electric vehicles (EV) are expected to contribute to not only the suppression of global warming but also reducing electricity bill on the consumer side. However, there are numerous challenges with the introduction of REs at the demand side such as the actual output of REs often deviating from the forecasted output, which causes fluctuation of the power flow and this is challenging for the distribution or transmission system operator. For this challenge, it is expected that smart grid technology using controllable loads such as a fixed battery or EV battery, can suppress fluctuation of power flow. This paper presents a decision method of optimal scheduling of controllable loads to suppress the fluctuation of power flow by PV output in the smart home. An optimization method to cope with uncertainties such as variability of PV power and effective forecasting methods are considered in the proposed scheme. In order to decrease the expected operational cost and to validate the robustness for the uncertainty’s optimization approach, statistical analysis is executed for the optimal scheduling scheme. From the optimization results, the proposed methodology suppressed the fluctuation of power flow in the smart home and also minimized the consumer operational cost.

Recent trends and future opportunities in UK bioenergy: Maximising biomass penetration in a centralised energy system

Abstract In the past decade or so, the British government policy support for renewable energy (RE) has been at the core of the rapid growth of bioenergy in the UK rather than genuine market forces. Policy support has been through various instruments which are discussed in this paper, with particular attention given to co-firing and transport fuels. The UK energy sector remains dominated by large fossil fuels power plants and this does not facilitate the introduction of RE. One exception is co-firing which in 2005 generated 2.5 TWh. Another area of considerable potential and interest is the use of biofuels (biodiesel and bioethanol) for transport, although current contribution remains still very small (0.18% of total fuel sales in 2005). In 2005, the UK used 1.4 million tonnes of biomass in co-firing, mostly imported, while considerable potential exists for further expansion should policy incentives continue. It is also generally accepted that the UK will have to rely largely on imports if it is to fulfil its 5% minimum biofuel blends agreed for 2010 and 10% in 2015. Both sectors present excellent opportunities for international bioenergy trade, despite the domestic production potential, as demonstrated in this paper. In addition, the forthcoming introduction of carbon and sustainability reporting should incentivise greater reporting along the supply chain, encouraging trade in the most sustainable biofuels.