mandag 23. september 2013

Climate policies in Norway and the EU

By a group of PhD students who have attended the NorRen Summer School 2013.

Emissions of greenhouse gases (GHG) have become a huge problem worldwide. The global temperature is expected to increase over the next century with potentially devastating consequences. As a part of the Climate and Energy Package the EU decided on the 20-20-20 goal by 2020 with the intention of limiting the global warming to two degrees Celsius by 2050. 20-20-20 refers to a 20 % reduction in GHG emissions, 20 % improvement in energy efficiency, and 20 % use of renewable energy in the EU. In order for this goal to be achieved, Norway set a national target of 67.5 % renewable energy [1]. Figure 1 shows how the GHG emissions are distributed within different sectors in EU and Norway. It is obvious that Norway is in a different situation than the rest of Europe, which will be reflected in the way the country plans to reduce its GHG emissions compared to in the EU.
Figure 1.  Emissions by sector in the EU and Norway in 2009. Adapted from [2,3].

mandag 9. september 2013

The new combination of solar cells and super caps

Av Øyvind Sunde Sortland, Thomas Holm, Guillherme Gaspar, Denny Ehrler, Sandro Hommel and Peng Liu, NorRen Summer School 2013


The share of electricity generation from solar cells is increasing rapidly and already has a high share in countries like Germany and Italy. A high share of photovoltaic (PV) electricity generation poses challenges for grid operators to provide stable electricity supply due to the highly intermittent solar radiation, varying over time scales of minutes as shown in Figure 1. The output power of PV systems can drop from maximum to a very low value and increase just as suddenly due to passages of clouds.

Intermittency of power production measured for a 2 kWp PV system during a day.

The minute scale fluctuations in PV power supply are particularly detrimental to grid stability because they are not predicted by weather forecasts. Grid operators would thus benefit from a smooth power supply profile, which provide an opportunity for integrating short-term storage in the PV systems. This post provides a preliminary assessment of the potential for supercapacitors (Electrochemical Double Layer Capacitors, EDLC) to complement batteries for short-term load leveling before feeding the grid. Integrated household and neighborhood systems of renewable energy production and storage also have potential to provide local load-leveling.

fredag 6. september 2013

Contributions from Smart Grids to a Sustainable Energy System

By Livingstone Senyonga NorRen Summer School 2013 

“In the coming decades, electricity’s share of total energy is expected to continue growing, and more intelligent processes will be introduced into this network […]. It is envisioned that the electric power grid will move from an electromechanically controlled system to an electronically controlled network in the next two decades.” Amin et al. (2005).