Duck Chart Threatens Renewable Energy Expansion

Greetings from the Australian National University in Canberra, where Arnold McKinley, is speaking on "PV-Grid Integration Issues in the United States, Recent Developments, 2013". He showed what a graph of non-renewable energy demand over a day, showing a large dip during daylight hours (when solar panels provide power) and then a steep climb at sunset. The graph resembles a duck, thus the term a "duck chart". This represents a danger to the network as it is difficult to supply the sudden rise in power need during the evening, when the sun goes down (so solar power is not available), just as people get home to cook dinner and demand more power.

There are also problems caused by the rapid changes caused by solar panels as clouds cross the panels. This can cause voltage fluctuations on supply lines. Arnie discusses some low-teach solutions, such as heavier gauge wire to overcome some problems. A higher tech solution is to use smart inverters on the solar panels which help adjust the voltage.

One interesting option presented was power-pole mounted solar panels. This makes use of space the utility company already owns and the panels each have a smart inverter to help regulate the voltage as well as supplement power use.

It occurred to me that not-very-smart appliances in homes might help stabilize the grid. As an example, could smart phones and tablet computers be programmed to stop charging their batteries when the grid is stressed. In addition large power appliances such as air-conditioners could switch to low power.

ABSTRACT: The first global energy crises of 1973 and 1979 initiated a large number of energy studies within the United States that outlined future energy scenarios. Many experts expected a growth in solar and other renewables during the last few decades of the 20th century. That expectation did not occur, primarily because the crises disappeared and the price of oil in the US remained low. Recently, climate change scenarios, a more receptive political climate, and a successful growth in renewables in Europe has set the stage for another possible rise in these technologies in the US. Several global indicators suggest that this time the rise in renewables may be successful. But there are problems. The principle hindrance to PV penetration on the electrical grid comes from the inherited cost of already built power generation facilities, which become less and less needed as PV comes on line. The utilities are worried about paying for them. They are also worried that renewables cannot provide the same level of grid security and stability that traditional fuels have provided. This talk is about the current perspective of several US utilities and Independent System Operators (ISOs) as they speak about these problems in their own words. We will examine the projects that operators in several states have put in place to gather data on the effects that PV actually has on the grid system. We will also discuss projects underway by the Department of Energy and the NREL. Lastly we will talk about an interesting project now underway in Belgium to study the efficacy of micro-grids.

BIO: Arnold McKinley worked as an intern in the Electrical Planning Department at San Diego Gas and Electric company in the early 1970's. In 1977 he led a multi-disciplinary team of faculty, graduate students and industry experts at Stanford University in a study of the US Energy System to the year 2025 for the US Department of Energy. He co-taught a course at San Diego State University on Energy issues in the Physics Department in the early 1980's. From 2005-2009, he worked as Senior Scientist at Apparent, Inc a startup in California on a micro-inverter for PV solar modules. He wrote the internet applications used to browse data from the device and wrote several papers on how micro-inverters can help manage voltage levels and reactive power flow on the electrical grid. His name appears on two of the patents. Since coming to the ANU in 2010 to work on a PhD, he has lectured on renewables and grid integration in several courses.