Energy

The article explores energy policy tradeoffs faced by states that expand renewable electricity production and are part of cross-border electricity systems. We develop the concept of an impossible energy trinity (IET), which posits that many states cannot simultaneously achieve energy security, sustainability, and sovereignty. We argue that these states have three options to cope with the challenge of intermittent electricity production from domestic renewables. The dirty option resorts to base or reserve electric generating capacity from non-sustainable sources. The insecure option accepts system stability risks and/or higher electricity prices. The non-autonomous option cedes control over domestic energy rules to pursue integration with neighboring electricity grids and markets. We empirically illustrate our novel concept using the case of Switzerland, which finds itself at the crossroads of the three options. The country has to choose whether to add conventional generation capacities, accept grid instabilities and higher electricity prices, or integrate with the EU electricity market and rules. We discuss generalizations to other countries and ways to manage the IET. We conclude that public pressure for decarbonization and economic pressure to maintain secure energy supply render the non-autonomous option most likely in many states. The operation and governance of transboundary grid structure thereby influence energy transitions on national and subnational scales.

Horizontal bar rack bypass systems (HBR-BS) are characterized by a horizontal bar rack (HBR) with narrow clear bar spacing of 10–20 mm and an adjacent bypass (BS) to efficiently protect and guide downstream moving fish at water intakes. The small bar spacing may lead to operational challenges, such as clogging and high head losses. This study investigated whether combining an HBR with a low-voltage electric field (e-HBR) allows one to increase the clear bar spacing while maintaining a high standard of fish protection and guidance efficiency. To this end, an HBR-BS with 20 mm bar spacing and an e-HBR-BS with 20 and 51 mm bar spacing were tested with spirlin (Alburnoides bipunctatus) and European eel (Anguilla anguilla) in a laboratory flume. The racks were electrified with 38 V pulsed direct current. The protection efficiency of the e-HBR with 51 mm was 96% for spirlin and 86% for eels, which are similar results to those of the HBR with 20 mm. Some eels passed through the e-HBR, but only when they were parallel to the rack. Fish injuries of variable severeness due to the electrification were observed. The results highlight the potential of hybrid barriers for the protection of downstream moving fish. However, fish injuries due to electricity may occur; and reporting applied voltage, electrode geometry, resulting electric field strength and the pulse pattern of the electrified rack setup is necessary to ensure comparability among studies and to avoid injuries.

In the effort to de-carbonize the building stock, heat pumps are increasingly utilized in Switzerland, with 70% of the fast-growing heat pump market using ambient air as heat source. Inexpensive and easy to implement, these heat pumps are, however, less efficient than their ground- or water-source counterparts. In this modeling study, we aim at increasing the efficiency of air-source heat pumps using domestic greywater-contained heat. We assess the performance improvement relative to standard heat pump configurations across various climates, seasons, building envelopes, and domestic hot water consumption patterns. The results show that the annually-averaged coefficient of performance improves by 4.1% on average - ranging from 0.6% to 7.5%. This efficiency gain translates on average to 1.8 kWh/week of compressor electricity savings. Although attractive due to its simplicity, the proposed open-loop configuration - preheating of an external heat source - only leads to moderate performance improvement of air-source heat pumps. Based on these results, we extensively discuss and compare alternative system configurations and identify several fundamental differences in the heat recovery dynamics of each configuration. We show that closed-loop systems - using greywater as direct heat source - show the largest performance improvement potential, although being more expensive and complex to implement.

Renewable energy sectors are becoming increasingly globalized with lead firms appropriating value on a global scale: This creates challenges for nations seeking to anchor some of the value locally through indigenous industrial development. Since lead firms select their suppliers for a given deployment project, national governments can set incentives for these firms to opt for local suppliers. We use the case of offshore wind in Europe to quantitatively measure the origin of suppliers across three global value chain governance modes: market, modular and relational. Suppliers can originate from the windfarm country, the lead firm's country or the global market. We test supplier selection across the modes of governance, domestic market size and local content push using a database of over 12,000 supplier contracts. The results indicate that lead firms mostly draw from the global market for market-coordinated segments, while favoring local suppliers under local content regulations. Local lead firms have a higher tendency to source locally for both market and relationally coordinated suppliers. However, local content push reduces the tendency of local lead firms to select local relational suppliers. Therefore, local content requirements seem to be broadly successful to stimulate locally sourced suppliers of the market-coordinated type; on the other hand, our results show that national governments should have local lead firms commission projects without imposing local content regulations to increase the odds that local relational suppliers are selected.